Characterization and Modelling of Composites, Volume III

A special issue of Journal of Composites Science (ISSN 2504-477X). This special issue belongs to the section "Composites Modelling and Characterization".

Deadline for manuscript submissions: closed (31 July 2023) | Viewed by 53331

Special Issue Editor


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Guest Editor
General Department, Evripus Campus, National and Kapodistrian University of Athens, Psachna, Evoia, Greece
Interests: nanostructures; nanocomposites; composite structures; finite element method; design; modeling; computational analysis; nanotechnology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Composites have been increasingly used in various structural components in the aerospace, marine, automotive, and wind energy sectors. Composites’ material characterization is a vital part of the product development and production process. Physical, mechanical, and chemical characterization helps developers to further their understanding of products and materials, thus ensuring quality control. Achieving an in-depth understanding and consequent improvement of the general performance of these materials, however, still requires complex material modeling and simulation tools, which are often multiscale and encompass multiphysics.

This Special Issue is aimed at soliciting promising, recent developments in composite modeling, simulation, and characterization, in both design and manufacturing areas, including experimental as well as industrial-scale case studies. All submitted manuscripts will undergo a rigorous review and will only be considered for publication if they meet journal standards. 

Dr. Stelios K. Georgantzinos
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Composites Science is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • fiber-reinforced composites
  • unidirectional and woven reinforcements
  • noncrimp fabrics (NCFs)
  • three-dimensional composites
  • nanocomposites
  • natural fiber and biocomposites
  • hybrid composites
  • composite structures
  • modeling and characterization
  • numerical simulation
  • experimental studies
  • industrial case studies

Published Papers (43 papers)

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Editorial

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10 pages, 256 KiB  
Editorial
Characterization and Modelling of Composites, Volume III
by Stelios K. Georgantzinos
J. Compos. Sci. 2023, 7(11), 446; https://doi.org/10.3390/jcs7110446 - 27 Oct 2023
Cited by 1 | Viewed by 1182
Abstract
The realm of composite materials continues to evolve, with researchers pushing the boundaries of understanding and application. This Special Issue published in the Journal of Composites Science encapsulates the essence of these advancements, presenting a curated collection of research articles that highlight the [...] Read more.
The realm of composite materials continues to evolve, with researchers pushing the boundaries of understanding and application. This Special Issue published in the Journal of Composites Science encapsulates the essence of these advancements, presenting a curated collection of research articles that highlight the latest developments in the characterization and modelling of composites. The diversity of the covered topics ranges from a foundational understanding of composite behaviours to the application of cutting-edge modelling techniques. Each contribution offers a fresh perspective, expanding our knowledge of composites and setting the stage for future explorations in this dynamic domain. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)

Research

Jump to: Editorial, Review

11 pages, 2944 KiB  
Article
The Morphological and Thermal Characteristics of Hollow-Glass-Microsphere-Coated Phase Change Material–Cow Pie Embedded Recycled Plastic Tiles for Cool Roofs
by S. Krishna Satya and P. S. Rama Sreekanth
J. Compos. Sci. 2024, 8(4), 148; https://doi.org/10.3390/jcs8040148 - 13 Apr 2024
Viewed by 390
Abstract
This study addresses the global plastic waste crisis and the urban heat island effect by developing an innovative solution: recycled plastic roof tiles embedded with phase change material (PCM) and coated with hollow-glass-microsphere-based white paint. The samples were fabricated with cow pie fibers, [...] Read more.
This study addresses the global plastic waste crisis and the urban heat island effect by developing an innovative solution: recycled plastic roof tiles embedded with phase change material (PCM) and coated with hollow-glass-microsphere-based white paint. The samples were fabricated with cow pie fibers, OM37 and OM42 PCM materials with different wt./vol. values, i.e., 15/50, 20/50, 25/50, 30/50 ratios. The fabricated tiles were coated with hollow glass microspheres to provide a reflective layer. The tiles’ effectiveness was evaluated through morphological examination and thermal analysis. The SEM analysis revealed an excellent bonding ability for the PCM blend, i.e., OM37 and OM42 at a 20/50 ratio (wt./vol.) with cow pie fibers. Adding cow pie fibers to the PCM shifted the melting points of OM37 and OM42, indicating an increased heat storage capacity in both blends. The thermal conductivity results revealed decreased thermal conductivity with an increased cow pie fiber percentage. The recycled plastic roof tile of the PCM composite at a 20/50 (wt./vol.) ratio showed good thermal properties. Upon testing in real-time conditions in a physical setup, the roof tiles showed a temperature reduction of 8 °C from outdoors to indoors during the peak of summer. In winter, cozy temperatures were maintained indoors due to the heat regulation from the roof. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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17 pages, 8050 KiB  
Article
A Numerical Assessment of the Influence of Local Stress Ratio in the Fatigue Analysis of Post-Buckled Composite Single-Stringer Specimen
by Antonio Raimondo and Chiara Bisagni
J. Compos. Sci. 2024, 8(4), 143; https://doi.org/10.3390/jcs8040143 - 11 Apr 2024
Viewed by 274
Abstract
This paper presents a numerical approach for investigating fatigue delamination propagation in composite stiffened panels loaded in compression in the post-buckling field. These components are widely utilized in aerospace structures due to their lightweight and high-strength properties. However, fatigue-induced damage, particularly delamination at [...] Read more.
This paper presents a numerical approach for investigating fatigue delamination propagation in composite stiffened panels loaded in compression in the post-buckling field. These components are widely utilized in aerospace structures due to their lightweight and high-strength properties. However, fatigue-induced damage, particularly delamination at the skin–stringer interface, poses a significant challenge. The proposed numerical approach, called the “Min–Max Load Approach”, allows for the calculation of the local stress ratio in a single finite element analysis. It represents the ratio between the minimum and maximum values of the stress along the delamination front, enabling accurate evaluation of the crack growth rate. The methodology is applied here in conjunction with the cohesive zone model technique to evaluate the post-buckling fatigue behavior of a composite single-stringer specimen with an initial delamination. Comparisons with experimental data validate the predictive capabilities of the proposed approach. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 3571 KiB  
Article
Numerical Investigation on the Capability of Modeling Approaches for Composite Cylinders under Low-Velocity Impact Loading
by Shiva Rezaei Akbarieh, Dayou Ma, Claudio Sbarufatti and Andrea Manes
J. Compos. Sci. 2024, 8(4), 141; https://doi.org/10.3390/jcs8040141 - 10 Apr 2024
Viewed by 328
Abstract
Composite pressure vessels can be exposed to extreme loadings, for instance, impact loading, during manufacturing, maintenance, or their service lifetime. These kinds of loadings may provoke both visible and invisible levels of damage, e.g., fiber breakage matrix cracks and delamination and eventually may [...] Read more.
Composite pressure vessels can be exposed to extreme loadings, for instance, impact loading, during manufacturing, maintenance, or their service lifetime. These kinds of loadings may provoke both visible and invisible levels of damage, e.g., fiber breakage matrix cracks and delamination and eventually may lead to catastrophic failures. Thus, the quantification and evaluation of such damages are of great importance. Considering the cost of relevant full-scale experiments, a numerical model can be a powerful tool for such a kind of study. This paper aims to provide a numerical study to investigate the capability of different modeling methods to predict delamination in composite vessels. In this study, various numerical modeling aspects, such as element types (solid and shell elements) and material parameters (such as interface properties), were considered to investigate delamination in a composite pressure vessel under low-velocity impact loading. Specifically, solid elements were used to model each layer of the composite pressure vessel, while, in another model, shell elements with composite layup were considered. Compared with the available experimental data from low-velocity impact tests described in the literature, the capability of these two models to predict both mechanical responses and failure phenomena is shown. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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22 pages, 11714 KiB  
Article
Dynamic Behavior and Permanent Indentation in S2-Glass Woven Fabric Reinforced Polymer Composites under Impact: Experimentation and High-Fidelity Modeling
by Mohammad Rezasefat, Yogesh Kumar, Amanda Albertin Xavier da Silva, Sandro Campos Amico, James David Hogan and Andrea Manes
J. Compos. Sci. 2024, 8(4), 138; https://doi.org/10.3390/jcs8040138 - 09 Apr 2024
Viewed by 296
Abstract
This paper studies the behavior of S2-glass woven fabric reinforced polymer composite under low-velocity impact at 18–110 J energy. A macro-homogeneous finite element model for the prediction of their response is implemented, considering the non-linear material behavior and intralaminar and interlaminar failure modes [...] Read more.
This paper studies the behavior of S2-glass woven fabric reinforced polymer composite under low-velocity impact at 18–110 J energy. A macro-homogeneous finite element model for the prediction of their response is implemented, considering the non-linear material behavior and intralaminar and interlaminar failure modes for the prediction of impact damage. The model accurately predicted the permanent indentation caused by impact. By applying the Ramberg-Osgood formulation, different initial stiffness values are examined to assess the post-impact unloading response. This approach reveals the significant role of initial stiffness in inelastic strain accumulation and its consequent effect on permanent indentation depth. A higher initial stiffness correlates with increased inelastic strain, influencing the impactor rebound and resulting in greater permanent indentation. By accurately predicting permanent indentation, and damage accumulation for different impact energies, this study contributes to a better understanding of the impact behavior of composite materials, thereby promoting their wider application. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 2189 KiB  
Article
Mechanical and Thermal Properties of the Hf–Si System: First-Principles Calculations
by Panxin Huang, Guifang Han, Huan Liu, Weibin Zhang, Kexue Peng, Jianzhang Li, Weili Wang and Jingde Zhang
J. Compos. Sci. 2024, 8(4), 129; https://doi.org/10.3390/jcs8040129 - 02 Apr 2024
Viewed by 485
Abstract
The relatively low melting point of a traditional Si bonding layer limits the upper servicing temperature of environmental barrier coatings (EBC). To explore suitable high temperature bonding layers and expedite the development of EBC, first-principles calculation was used to evaluate the mechanical properties [...] Read more.
The relatively low melting point of a traditional Si bonding layer limits the upper servicing temperature of environmental barrier coatings (EBC). To explore suitable high temperature bonding layers and expedite the development of EBC, first-principles calculation was used to evaluate the mechanical properties and thermal conductivity of HfSi2, HfSi, Hf5Si4, Hf3Si2, and Hf2Si with much higher melting points than that of Si. Among them, HfSi2 has the lowest modulus capable of good modulus matching with SiC substrate. In addition, these Hf-Si compounds have much lower high temperature thermal conductivity with Hf2Si being the lowest of 0.63 W m−1 K−1, which is only half of Si, capable of improved heat insulation. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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20 pages, 17545 KiB  
Article
Impact Characteristics and Repair Approaches of Distinct Bio-Based Matrix Composites: A Comparative Analysis
by Bharath Ravindran, Timotheos Agathocleous, Beate Oswald-Tranta, Ewald Fauster and Michael Feuchter
J. Compos. Sci. 2024, 8(4), 126; https://doi.org/10.3390/jcs8040126 - 29 Mar 2024
Viewed by 426
Abstract
Increasing global concerns regarding environmental issues have driven significant advancements in the development of bio-based fiber reinforced polymer composites. Despite extensive research on bio-composites, there remains a noticeable gap in studies specifically addressing the challenges of repairing bio-composites for circular economy adoption. Traditional [...] Read more.
Increasing global concerns regarding environmental issues have driven significant advancements in the development of bio-based fiber reinforced polymer composites. Despite extensive research on bio-composites, there remains a noticeable gap in studies specifically addressing the challenges of repairing bio-composites for circular economy adoption. Traditional repair techniques for impacted composites, such as patching or scarf methods, are not only time-consuming but also require highly skilled personnel. This paper aims to highlight cost-effective repair strategies for the restoration of damaged composites, featuring flax fiber as the primary reinforcement material and distinct matrix systems, namely bio-based epoxy and bio-based vitrimer matrix. Glass fiber was used as a secondary material to validate the bio-based vitrimer matrix. The damage caused specifically by low impact is detrimental to the structural integrity of the composites. Therefore, the impact resistance of the two composite materials is evaluated using instrumented drop tower tests at various energy levels, while thermography observations are employed to assess damage evolution. Two distinct repair approaches were studied: the resin infiltration repair method, employing bio-based epoxy, and the reconsolidation (self-healing) repair method, utilizing the bio-based vitrimer matrix. The efficiency of these repair methods was assessed through active thermography and compression after impact tests. The repair outcomes demonstrate successful restoration and the maintenance of ultimate strength at an efficiency of 90% for the re-infiltration repair method and 92% for the reconsolidation repair method. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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28 pages, 26981 KiB  
Article
Micro- and Macro-Scale Topology Optimization of Multi-Material Functionally Graded Lattice Structures
by Jerónimo Santos, Abdolrasoul Sohouli and Afzal Suleman
J. Compos. Sci. 2024, 8(4), 124; https://doi.org/10.3390/jcs8040124 - 28 Mar 2024
Viewed by 471
Abstract
Lattice structures are becoming an increasingly attractive design approach for the most diverse engineering applications. This increase in popularity is mainly due to their high specific strength and stiffness, considerable heat dissipation, and relatively light weight, among many other advantages. Additive manufacturing techniques [...] Read more.
Lattice structures are becoming an increasingly attractive design approach for the most diverse engineering applications. This increase in popularity is mainly due to their high specific strength and stiffness, considerable heat dissipation, and relatively light weight, among many other advantages. Additive manufacturing techniques have made it possible to achieve greater flexibility and resolution, enabling more complex and better-performing lattice structures. Unrestricted material unit cell designs are often associated with high computational power and connectivity problems, and highly restricted lattice unit cell designs may not reach the optimal desired properties despite their lower computational cost. This work focuses on increasing the flexibility of a restricted unit cell design while achieving a lower computational cost. It is based on a two-scale concurrent optimization of the lattice structure, which involves simultaneously optimizing the topology at both the macro- and micro-scales to achieve an optimal topology. To ensure a continuous optimization approach, surrogate models are used to define material and geometrical properties. The elasticity tensors for a lattice unit cell are obtained using an energy-based homogenization method combined with voxelization. A multi-variable parameterization of the material unit cell is defined to allow for the synthesis of functionally graded lattice structures. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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17 pages, 12134 KiB  
Article
Mitigating Crack Propagation in Hybrid Composites: An Experimental and Computational Study
by Suma Ayyagari and Marwan Al-Haik
J. Compos. Sci. 2024, 8(4), 122; https://doi.org/10.3390/jcs8040122 - 27 Mar 2024
Viewed by 482
Abstract
The exceptional properties of carbon nanotubes (CNTs) make them ideal nanofillers for various composite materials. In carbon fiber-reinforced polymer (CFRP) composites. CNTs can be grown on the carbon fiber surface to act as a third interface between the fiber and the matrix. However, [...] Read more.
The exceptional properties of carbon nanotubes (CNTs) make them ideal nanofillers for various composite materials. In carbon fiber-reinforced polymer (CFRP) composites. CNTs can be grown on the carbon fiber surface to act as a third interface between the fiber and the matrix. However, it was established that the uncontrolled random growth of CNTs could exacerbate delamination in composite structures. Thick nanofiller films could hinder the epoxy from seeping into the carbon fiber, resulting in insufficient interlaminar strength. Hence, the density and distribution of nanofillers play a crucial role in determining the hybrid composite fracture mechanisms. In this investigation, CNTs were grown using the low-temperature technique into specific patterns over carbon fibers to discern their derived composites’ fracture properties. The composite fracture energy release was probed using a double cantilever beam (DCB) test setup and digital image correlation (DIC) to monitor interlaminar crack propagation. A standard finite element simulation model based on the cohesive zone method (CZM) was also utilized to delineate fracture behaviors of the various composite configurations. Results conclude that a coarser pattern of CNT growth enhances resistance to crack propagation, thus improving the interlaminar fracture toughness of a composite structure. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 4060 KiB  
Article
Optimization of a Tapered Specimen Geometry for Short-Term Dynamic Tensile Testing of Continuous Fiber Reinforced Thermoplastics
by Florian Mischo and Sebastian Schmeer
J. Compos. Sci. 2024, 8(3), 93; https://doi.org/10.3390/jcs8030093 - 03 Mar 2024
Viewed by 754
Abstract
Continuous fiber reinforced thermoplastics (cFRTP) are one of the most promising lightweight materials. For their use in structural components, reproducible and comparable material values have to be evaluated, especially at high strain rates. Due to their high stiffness and outstanding strength properties, the [...] Read more.
Continuous fiber reinforced thermoplastics (cFRTP) are one of the most promising lightweight materials. For their use in structural components, reproducible and comparable material values have to be evaluated, especially at high strain rates. Due to their high stiffness and outstanding strength properties, the evaluation of the material behavior at high strain rates is complex. In the presented work, a new tensile specimen geometry for strain rate testing is virtually optimized using a metamodel approach with an artificial neural network. The final specimen design is experimentally validated and compared with rectangular specimen results for a carbon fiber reinforced polycarbonate (CF-PC). The optimized specimen geometry leads to 100% valid test results in experimental validation of cross-ply laminates and reaches 9% higher tensile strength values than the rectangle geometry with applied end tabs at a strain rate of 40 s−1. Through the optimization, comparable material parameters can be efficiently generated for a successful cFRTP strain rate characterization. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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17 pages, 3297 KiB  
Article
Experimental Comparative Analysis of the Through-Thickness and In-Plane Compression Moduli of Unidirectional CFRP Laminates
by Raffael Bogenfeld
J. Compos. Sci. 2024, 8(2), 76; https://doi.org/10.3390/jcs8020076 - 13 Feb 2024
Viewed by 959
Abstract
This study explores the experimental characterization of the through-thickness compression properties in unidirectional laminates using cube compression tests. Cubical specimens, each with an edge length of 10 mm, were symmetrically outfitted with biaxial strain gauges and subjected to a compression test. While similar [...] Read more.
This study explores the experimental characterization of the through-thickness compression properties in unidirectional laminates using cube compression tests. Cubical specimens, each with an edge length of 10 mm, were symmetrically outfitted with biaxial strain gauges and subjected to a compression test. While similar methodologies exist in the literature, this work primarily addresses the potential biases inherent in the testing procedure and their mitigation. The influence of friction-induced non-uniform deformation behavior is compensated through a scaling of the stiffness measurements using finite element (FE) analysis results. This scaling significantly enhances the accuracy of the resulting parameters of the experiments. The ultimate failure of the specimens, originating from stress concentrations at the edges, resulted in fracture angles ranging between 60° and 67°. Such fracture patterns, consistent with findings from other researchers, are attributed to shear stress induced by friction at the load introduction faces. The key findings of this research are the comparisons between the through-thickness modulus (E33c) and strength (X33c) and their in-plane counterparts (E22c and X22c). The results indicate deteriorations of E33c and X33c from E22c and X22c by margins of 5% and 7%, respectively. Furthermore, the results for E22c and X22c were compared with the results obtained through a standard test, revealing a 12% enhancement in strength X22c and 4% underestimated stiffness E22c in the cube compression test. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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14 pages, 9975 KiB  
Article
Development of a Novel Lightweight Utility Pole Using a New Hybrid Reinforced Composite—Part 2: Numerical Simulation and Design Procedure
by Qianjiang Wu and Farid Taheri
J. Compos. Sci. 2024, 8(2), 50; https://doi.org/10.3390/jcs8020050 - 30 Jan 2024
Viewed by 991
Abstract
The first paper of this two-part series discussed the development of a novel lightweight 3D wood dowel-reinforced glass epoxy hybrid composite material (3DdrFRP) and its manufacturing procedures. It also experimentally compared the performance of scaled utility poles made from conventional 2D E-glass epoxy [...] Read more.
The first paper of this two-part series discussed the development of a novel lightweight 3D wood dowel-reinforced glass epoxy hybrid composite material (3DdrFRP) and its manufacturing procedures. It also experimentally compared the performance of scaled utility poles made from conventional 2D E-glass epoxy and 3DdrFRP materials. In the second part, the development of robust, efficient, and fairly accurate nonlinear finite element (FE) models is outlined. The models are calibrated based on experimental results and used to simulate the performance of equivalent 2D and 3D poles, proving the integrity of the numerical models. Additionally, a simplified analytical calculation method is developed for practicing engineers to evaluate the stiffness of 3D-DrFRP poles fairly accurately and quickly. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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12 pages, 5834 KiB  
Article
Characterization of Interlaminar Friction during the Forming Processes of High-Performance Thermoplastic Composites
by Daniel Campos, Pere Maimí and Alberto Martín
J. Compos. Sci. 2024, 8(2), 38; https://doi.org/10.3390/jcs8020038 - 23 Jan 2024
Viewed by 1167
Abstract
Friction is a pivotal factor influencing wrinkle formation in composite material shaping processes, particularly in novel thermoplastic composites like polyetheretherketone (PEEK) and low-melting polyaryletherketone (LM-PAEK) matrices reinforced with unidirectional carbon fibers. The aerospace sector lacks comprehensive data on the behavior of these materials [...] Read more.
Friction is a pivotal factor influencing wrinkle formation in composite material shaping processes, particularly in novel thermoplastic composites like polyetheretherketone (PEEK) and low-melting polyaryletherketone (LM-PAEK) matrices reinforced with unidirectional carbon fibers. The aerospace sector lacks comprehensive data on the behavior of these materials under forming conditions, motivating this study’s objective to characterize the interlaminar friction of such high-performance thermoplastic composites across diverse temperatures and forming parameters. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were employed to analyze the thermomechanical behaviors of PEEK and LM-PAEK. These data guided friction tests covering room-to-forming temperatures. Horizontal pull-out fixed-plies tests were conducted to determine the friction coefficient and shear stress dependency concerning temperature, pressure, and pulling rate. Below the melting point, both materials adhered to Coulomb’s law for friction behavior. However, above the melting temperature, PEEK’s friction decreased while LM-PAEK’s friction increased with rising temperatures. These findings highlight the distinct responses of these materials to temperature variations, pulling rates, and pressures, emphasizing the need for further research on friction characterization around glass transition and melting temperatures to enhance our understanding of this phenomenon. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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20 pages, 10998 KiB  
Article
The Behavior of Banyan (B)/Banana (Ba) Fibers Reinforced Hybrid Composites Influenced by Chemical Treatment on Tensile, Bending and Water Absorption Behavior: An Experimental and FEA Investigation
by Prabhakar C. G, M Sreenivas Reddy, Shashanka Rajendrachari, Rayappa Shrinivas Mahale, V. Mahesh and Anup Pandith
J. Compos. Sci. 2024, 8(1), 31; https://doi.org/10.3390/jcs8010031 - 13 Jan 2024
Viewed by 1188
Abstract
Natural fiber-based composites are highly prioritized in present industries due to their properties and benefits over synthetic fibers. Due to their biodegradable nature, banyan and banana fibers were used for the present work. This paper deals with an experimental and FEA investigation of [...] Read more.
Natural fiber-based composites are highly prioritized in present industries due to their properties and benefits over synthetic fibers. Due to their biodegradable nature, banyan and banana fibers were used for the present work. This paper deals with an experimental and FEA investigation of the tensile and bending behavior of banyan (B) and banana (Ba)-reinforced composites with different volume fractions, such as 25B/25Ba, 30B/20Ba, and 35B/15Ba, with a 50% weight fraction of epoxy resin and different fiber orientations. The hybrid composites treated with a 5% NaOH solution have better results as compared to untreated hybrid composites, with a volume fraction of 30% banyan fibers and 20% banana fiber (30B/20Ba), giving greater tensile and flexural properties for both treated and untreated fiber composites when compared to other volume fraction composites at 0/0/0/0 orientation. The maximum tensile and bending strength was found in the 30B/20Ba volume fractions to be 63.37 MPa and 67.07 MPa, respectively. For treated fiber composites, water absorption increases with an increase in the duration of immersion in composites up to 144 h. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 2795 KiB  
Article
Prediction of the Bond Strength of Externally Bonded FRP Sheets Applied to Concrete via Grooves Technique Using Artificial Neural Networks
by Abdelatif Salmi
J. Compos. Sci. 2024, 8(1), 30; https://doi.org/10.3390/jcs8010030 - 12 Jan 2024
Cited by 1 | Viewed by 1297
Abstract
The present study aims to fill a gap in the literature on the estimation of the bond strength of fiber reinforced polymer sheets bonded to concrete, via the externally bonded reinforcement on grooves (EBROG) technique, employing the curve-fitting on existing datasets in the [...] Read more.
The present study aims to fill a gap in the literature on the estimation of the bond strength of fiber reinforced polymer sheets bonded to concrete, via the externally bonded reinforcement on grooves (EBROG) technique, employing the curve-fitting on existing datasets in the literature and the methodology of Artificial Neural Networks (ANNs). Therefore, a dataset of 39 experimental results derived from EBROG technique is collected from the literature. A mathematical equation for the bond strength of FRP sheets applied on concrete via the EBROG technique was suggested using curve-fitting and general regression. The proposed mathematical equation is compared and validated with experimental results. The developed ANN model was constructed after testing diverse hidden layers and neurons to find the optimal predictions. The validation of the model is carried out using the experimental results and a statistical analysis is applied to assess the proposed mathematical equation and the proposed ANN model. Furthermore, a parametric study using the ANN model was also performed to investigate the influence of various factors on the bond strength of FRP sheets bonded to concrete. The parametric study proves that the bond strength increases with increasing the tensile stiffness per width, the FRP sheet width, and the concrete compressive strength; however, the effect of the Groove’s width and depth is found to be not monotonous. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 10066 KiB  
Article
Development and Characterization of Flax–Gypsum Composites
by Vamsi Chakarala, Jens Schuster and Yousuf Pasha Shaik
J. Compos. Sci. 2024, 8(1), 27; https://doi.org/10.3390/jcs8010027 - 11 Jan 2024
Viewed by 1220
Abstract
Flax–gypsum composites are an emerging class of environmentally friendly materials that combine the mechanical properties of gypsum with the advantageous characteristics of flax fibers. The production of flax–gypsum composites involve the incorporation of flax fibers, derived from the flax plant, into gypsum matrix [...] Read more.
Flax–gypsum composites are an emerging class of environmentally friendly materials that combine the mechanical properties of gypsum with the advantageous characteristics of flax fibers. The production of flax–gypsum composites involve the incorporation of flax fibers, derived from the flax plant, into gypsum matrix systems. In order to create a uniform distribution of fibers within the gypsum matrix, the hand lay-up approach has been used to produce the specimens. The fiber content and orientation significantly influence the resulting mechanical and physical properties of the composites. Various tests were conducted on the samples, such as a flexural test, a compression test, a density test, a water absorption test, and a microscopy test. The addition of flax fibers imparts several desirable properties to the gypsum matrix. When combined with gypsum, these fibers enhanced the composite’s mechanical properties, such as flexural strength and compressive strength. The results indicated improved compression and flexural strengths due to effective load transfer within the matrix, for up to 10% of fiber loading. A decrease in composite density upon flax fiber addition results in a lighter material, enabling insights for various applications. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 14588 KiB  
Article
Quasi-Static Fracture Toughness and Damage Monitoring in Liquid Metal Reinforced Hybrid Composites
by Zachary Safford, Mohammed Shonar and Vijaya Chalivendra
J. Compos. Sci. 2024, 8(1), 25; https://doi.org/10.3390/jcs8010025 - 11 Jan 2024
Viewed by 1169
Abstract
An experimental study is performed to investigate the quasi-static fracture toughness and damage monitoring capabilities of liquid metal (75.5% Gallium/24.5% Indium) reinforced intraply glass/carbon hybrid composites. Two different layups (G-0, where glass fibers are along the crack propagation direction; C-0, where carbon fibers [...] Read more.
An experimental study is performed to investigate the quasi-static fracture toughness and damage monitoring capabilities of liquid metal (75.5% Gallium/24.5% Indium) reinforced intraply glass/carbon hybrid composites. Two different layups (G-0, where glass fibers are along the crack propagation direction; C-0, where carbon fibers are along the crack propagation direction) and two different weight percentages of liquid metal (1% and 2%) are considered in the fabrication of the composites. A novel four-probe technique is employed to determine the piezo-resistive damage response under mode-I fracture loading conditions. The effect of layups and liquid metal concentrations on fracture toughness and changes in piezo-resistance response is discussed. The C-composite without liquid metal demonstrated higher fracture toughness compared to that of the G-composite due to carbon fiber breakage. The addition of liquid metal decreases the fracture initiation toughness of both G- and C-composites. Scanning electron microscopy images show that liquid metal takes the form of large liquid metal pockets and small spherical droplets on the fracture surfaces. In both C- and G-composites, the peak resistance change of composites with 2% liquid metal is substantially lower than that of both no-liquid metal and 1% liquid metal composites. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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14 pages, 3920 KiB  
Article
Finite Element Modelling of the Effect of Adhesive Z-Connections on the Swelling of a Laminated Wood Composite
by Mohammad Sadegh Mazloomi, Wenchang He and Philip David Evans
J. Compos. Sci. 2023, 7(10), 442; https://doi.org/10.3390/jcs7100442 - 18 Oct 2023
Cited by 1 | Viewed by 1230
Abstract
This study used finite element analysis (FEA) to model the effects of adhesive Z-connections on the thickness swelling of laminated wood composites exposed to water. We hypothesized that the area density, diameter, and spatial distribution of adhesive Z-connections will influence the ability of [...] Read more.
This study used finite element analysis (FEA) to model the effects of adhesive Z-connections on the thickness swelling of laminated wood composites exposed to water. We hypothesized that the area density, diameter, and spatial distribution of adhesive Z-connections will influence the ability of Z-connections to restrain thickness swelling of the composites. We tested this hypothesis by modelling a wood composite in ANSYS FEA software v. 17.0 to explore the effect of moisture on the thickness swelling of the wood composite. The results were compared with those obtained experimentally. We then examined the effect of the area density, size (diam.), and spatial distribution of the adhesive Z-connections on the thickness swelling of wood composites. Our results showed a positive correlation between the number of adhesive Z-connections in the composites and restriction of thickness swelling following 72 h of simulated moisture diffusion. Similarly, increasing the size of adhesive Z-connections also restricted thickness swelling. In contrast, different spatial distributions of Z-connections had little effect on restraining thickness swelling. Our modelling approach opens up opportunities for more complex designs of adhesive Z-connections, and also to examine the effect of wood properties, such as permeability, density, and hygroscopic swelling ratios on the thickness swelling of laminated wood composites. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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21 pages, 18024 KiB  
Article
The Intra-Ply Shear Behaviour of Non-Isothermal Thermoplastic Composite Laminates
by George E. Street and Michael S. Johnson
J. Compos. Sci. 2023, 7(10), 432; https://doi.org/10.3390/jcs7100432 - 13 Oct 2023
Cited by 1 | Viewed by 1354
Abstract
During the thermoforming of fibre-reinforced thermoplastic (FRTP) organosheets, the desire to minimise tool temperatures leads to non-isothermal temperature profiles through the laminate thickness. The aim of this study was to understand the influence of these non-isothermal conditions on FRTP intra-ply shearing. Novel non-isothermal [...] Read more.
During the thermoforming of fibre-reinforced thermoplastic (FRTP) organosheets, the desire to minimise tool temperatures leads to non-isothermal temperature profiles through the laminate thickness. The aim of this study was to understand the influence of these non-isothermal conditions on FRTP intra-ply shearing. Novel non-isothermal bias extension tests were conducted, revealing that an average between the isothermal shear curves of both laminate faces approximately represented the respective non-isothermal condition. However, these findings were irrespective of FRTP thickness, and only applied to laminates that wholly remained above the crystallisation onset temperature. Upon the onset of crystallisation in a single ply, the non-isothermal shear resistance skewed heavily towards that (within 5%) of the crystallised ply and inhomogeneous shear angles were observed. Non-isothermal thermoforming validated these findings with the presence of wrinkles on non-isothermal hemispheres in which a single ply had reached crystallisation. This reaffirms the importance of accurate thermal monitoring during FRTP processing. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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24 pages, 12336 KiB  
Article
A Comparison of Three Simulation Techniques for Modeling the Fan Blade–Composite Abradable Rub Strip Interaction in Turbofan Engines
by Aleksandr Cherniaev
J. Compos. Sci. 2023, 7(9), 389; https://doi.org/10.3390/jcs7090389 - 14 Sep 2023
Cited by 1 | Viewed by 1332
Abstract
Turbofan engine models for foreign object impact simulations must include a representation of fan blade interactions with surrounding components of the engine, including rubbing against the abradable lining. In this study, three numerical techniques, namely, the finite element method (FEM), smoothed particles hydrodynamics [...] Read more.
Turbofan engine models for foreign object impact simulations must include a representation of fan blade interactions with surrounding components of the engine, including rubbing against the abradable lining. In this study, three numerical techniques, namely, the finite element method (FEM), smoothed particles hydrodynamics (SPH), and the adaptive (hybrid) FEM/SPH approach (ADT), were evaluated for their applicability to modeling of the blade–abradable rub strip (ARS) interaction. Models developed using these methods in the commercial code LS-DYNA were compared in terms of their computational cost, robustness, sensitivity to mesh density, and certain physical and non-physical parameters. As a result, the applicability of the models to represent the blade-ARS interaction was ranked as follows (1—most applicable, 3—least applicable): 1—SPH, 2—FEM, and 3—ADT. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 5431 KiB  
Article
Mechanical Properties of Uncured Thermoset Tow Prepreg: Experiment and Finite Element Analysis
by Mina Derakhshani Dastjerdi, Massimo Carboni and Mehdi Hojjati
J. Compos. Sci. 2023, 7(8), 312; https://doi.org/10.3390/jcs7080312 - 29 Jul 2023
Viewed by 1029
Abstract
This paper presents an experimental analysis of the tensile behavior of unidirectional carbon/epoxy prepreg, focusing on the nonlinearity observed at the beginning of the stress–strain curve. Due to the material’s high viscosity, securely holding specimens during testing was challenging, prompting modifications in the [...] Read more.
This paper presents an experimental analysis of the tensile behavior of unidirectional carbon/epoxy prepreg, focusing on the nonlinearity observed at the beginning of the stress–strain curve. Due to the material’s high viscosity, securely holding specimens during testing was challenging, prompting modifications in the gripping method to ensure reliable data. By using a longer gauge length, the slippage impact on elastic modulus measurement was minimized, resulting in good repeatability among the test samples. Experimental findings highlighted the significant interaction between fiber waviness and the viscous matrix, leading to stiffness reduction. The linear stiffness of the samples closely matched that of the fibers and remained unaffected by temperature variations. However, at higher temperatures, the epoxy matrix’s decreased viscosity caused an upward shift in the stiffness plot within the non-linear region. To support the experimental findings, a micromechanical model of prepreg tow with fiber waviness was proposed. An RVE model of periodically distributed unidirectional waved cylindrical fibers embedded within the matrix was developed to predict effective material stiffness parameters. The simulation outcomes aligned well with the uniaxial tensile test of the prepreg tow, demonstrating the proposed RVE model’s capability to accurately predict elastic properties, considering factors like fiber arrangement, waviness, and temperature. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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15 pages, 4638 KiB  
Article
An Efficient Method for Simulating the Temperature Distribution in Regions Containing YAG:Ce3+ Luminescence Composites of White LED
by Quang-Khoi Nguyen and Thi-Hanh-Thu Vu
J. Compos. Sci. 2023, 7(7), 301; https://doi.org/10.3390/jcs7070301 - 22 Jul 2023
Cited by 1 | Viewed by 987
Abstract
A thermal model was built to estimate the temperature distribution in the hemispherical packaging volume of a white LED at a steady state. Inherent heat sources appeared in the white LED when its power was measured. A simplified 3D to 2D space process [...] Read more.
A thermal model was built to estimate the temperature distribution in the hemispherical packaging volume of a white LED at a steady state. Inherent heat sources appeared in the white LED when its power was measured. A simplified 3D to 2D space process that improves the model and solves the heat diffusion equation in a simpler and faster manner is presented. The finite element method was employed using MATLAB software (version R2017b) to identify the temperature distribution. The model was applied for different values of injection current, including 50 mA, 200 mA, 350 mA, and 500 mA. The influence of the injection current and thermal conductivity difference on the temperature distribution of the encapsulant, blue LED die, and substrate region was clearly observed. The results indicate that white light packaging technology should locate phosphor far from the LED die, that the thermal conductivity of the silicone–phosphor region should be improved, that heat should be dissipated for pc-WLEDs when using a high operating power, and that the injection current should be kept as moderate as possible. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 3999 KiB  
Article
Statistical Analysis and Optimization of the Experimental Results on Performance of Green Aluminum-7075 Hybrid Composites
by Olanrewaju Seun Adesina, Abayomi Adewale Akinwande, Oluwatosin Abiodun Balogun, Adeolu Adesoji Adediran, Olufemi Oluseun Sanyaolu and Valentin Romanovski
J. Compos. Sci. 2023, 7(3), 115; https://doi.org/10.3390/jcs7030115 - 13 Mar 2023
Cited by 9 | Viewed by 1330
Abstract
The present study assessed the potential of engaging response surface analysis in the experimental design, modeling, and optimization of the strength performance of aluminum-7075 green composite. The design of the experiment was carried out via the Box–Behnken method and the independent variables are [...] Read more.
The present study assessed the potential of engaging response surface analysis in the experimental design, modeling, and optimization of the strength performance of aluminum-7075 green composite. The design of the experiment was carried out via the Box–Behnken method and the independent variables are rice husk ash (RHA) at 3–12 wt.%, glass powder (GP) at 2–10 wt.%, and stirring temperature (ST) at 600–800 °C. Responses examined are yield, ultimate tensile, flexural, and impact strengths, as well as microhardness and compressive strength. ANOVA analysis revealed that the input factors had consequential contributions to each response, eventually presenting regression models statistically fit to represent the experimental data, further affirmed by the diagnostic plots. The result of the optimization envisaged an optimal combination at 7.2% RHA, 6.2 GP, and 695 °C with a desirability of 0.910. A comparison between the predicted values for the responses and the values of the validation experiment revealed an error of <5% for each response. Consequently, the models are certified adequate for response predictions at 95% confidence, and the optimum combination is adequate for the design of the composite. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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12 pages, 2505 KiB  
Article
A Mathematical Approach for Sound Insulation Characteristics and Cost Optimization of Double-Layer Composite Structures
by Liang Zhang, Huawei Zhang, Qiyu Chen and Danfeng Long
J. Compos. Sci. 2023, 7(3), 110; https://doi.org/10.3390/jcs7030110 - 09 Mar 2023
Cited by 1 | Viewed by 1608
Abstract
The compressor is the primary source of noise in a refrigeration system. Most compressors are wrapped with multi-layer sound insulation cotton for noise reduction and sound insulation. We explore the sound insulation law of different polyvinyl chloride thicknesses and non-woven fibers. Polyvinyl chloride [...] Read more.
The compressor is the primary source of noise in a refrigeration system. Most compressors are wrapped with multi-layer sound insulation cotton for noise reduction and sound insulation. We explore the sound insulation law of different polyvinyl chloride thicknesses and non-woven fibers. Polyvinyl chloride with varying thicknesses and non-woven fibers are then combined by bonding to study the sound insulation characteristics of a two-layer composite structure. A sound insulation prediction model is established using the multi-parameter nonlinear regression method. An optimal cost mathematical model is established based on experimental and mathematical methods that can quickly determine the optimal cost scheme for different designs with the same effect. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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23 pages, 4426 KiB  
Article
Characterization of UV Light Curable Piezoelectric 0-0-3 Composites Filled with Lead-Free Ceramics and Conductive Nanoparticles
by Rytis Mitkus, Lena Piechowiak and Michael Sinapius
J. Compos. Sci. 2023, 7(2), 89; https://doi.org/10.3390/jcs7020089 - 20 Feb 2023
Cited by 3 | Viewed by 1715
Abstract
Lead-free piezoelectric materials are essential for our healthy future but offer lower performance than lead-based materials. Different material combinations are explored to improve the performance of lead-free materials. By filling the UV light curable photopolymer resin with 30 vol.% lead-free piezoelectric ceramics and [...] Read more.
Lead-free piezoelectric materials are essential for our healthy future but offer lower performance than lead-based materials. Different material combinations are explored to improve the performance of lead-free materials. By filling the UV light curable photopolymer resin with 30 vol.% lead-free piezoelectric ceramics and with up to 0.4 wt.% conductive nanofillers, thin and flexible piezoelectric 0-0-3 composites are formed. Two particle sizes of Potassium Sodium Niobate (KNN) and Barium Titanate (BTO) ceramics were used with four conductive nanofillers: Graphene Nanoplatelets (GNPs), Multi-Walled Carbon Nanotubes (MWCNTs), and two types of Graphene Oxide (GO). Resulting high viscosity suspensions are tape-cast in a mold as thin layers and subsequently exposing them to UV light, piezoelectric composite sensors are formed in 80 s. Even low nanofiller concentrations increase relative permittivities, however, they strongly reduce curing depth and increase undesirable dielectric losses. Non-homogeneous dispersion of nanofillers is observed. In total, 36 different compositions were mixed and characterized. Only six selected material compositions were investigated further by measuring mechanical, dielectric, and piezoelectric properties. Results show KNN composite performance as piezoelectric sensors is almost six times higher than BTO composite performance. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 19409 KiB  
Article
Micro-Scale Model of rCF/PA6 Spun Yarn Composite
by Tobias Georg Lang, Mir Mohammad Badrul Hasan, Anwar Abdkader, Chokri Cherif and Thomas Gereke
J. Compos. Sci. 2023, 7(2), 66; https://doi.org/10.3390/jcs7020066 - 06 Feb 2023
Cited by 2 | Viewed by 1294
Abstract
Recycling carbon fibers (rCF) for reuse is one approach to improve the sustainability of CFRP. However, until now, recycled carbon fiber plastics (rCFRP) had limited composite properties due to the microgeometry of the fibers, which made it difficult to use in load-bearing components. [...] Read more.
Recycling carbon fibers (rCF) for reuse is one approach to improve the sustainability of CFRP. However, until now, recycled carbon fiber plastics (rCFRP) had limited composite properties due to the microgeometry of the fibers, which made it difficult to use in load-bearing components. The production of hybrid yarns from rCF and PA6 fibers allows the fibers to be aligned. The geometric properties of the yarn and the individual fibers influence the mechanical properties of the composite. An approach for the modeling and simulation of hybrid yarns consisting of recycled carbon fibers and thermoplastic fibers is presented. The yarn unit cell geometry is modeled in the form of a stochastic fiber network. The fiber trajectory is modeled in form of helical curves using the idealized yarn model of Hearle et al. The variability in the fiber geometry (e.g., length) is included in form of statistical distributions. An additional compaction step ensures a realistic composite geometry. The created model is validated geometrically and by comparison with tensile tests of manufactured composites. With the validated model, multiple parameter studies investigating the influence of fiber and yarn geometry are carried out. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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20 pages, 3351 KiB  
Article
Comparative Analysis of ANN-MLP, ANFIS-ACOR and MLR Modeling Approaches for Estimation of Bending Strength of Glulam
by Morteza Nazerian, Masood Akbarzadeh and Antonios N. Papadopoulos
J. Compos. Sci. 2023, 7(2), 57; https://doi.org/10.3390/jcs7020057 - 04 Feb 2023
Cited by 3 | Viewed by 1232
Abstract
Multiple linear regression (MLR), adaptive network-based fuzzy inference system–ant colony optimization algorithm hybrid (ANFIS-ACOR) and artificial neural network–multilayer perceptron (ANN-MLP) were tested to model the bending strength of Glulam (glue-laminated timber) manufactured with a plane tree (Platanus orientalis L.) wood [...] Read more.
Multiple linear regression (MLR), adaptive network-based fuzzy inference system–ant colony optimization algorithm hybrid (ANFIS-ACOR) and artificial neural network–multilayer perceptron (ANN-MLP) were tested to model the bending strength of Glulam (glue-laminated timber) manufactured with a plane tree (Platanus orientalis L.) wood layer adhered with different weight ratios (WR) of modified starch/urea formaldehyde (UF) adhesive containing different levels of nano-ZnO (NC) used at different levels of the press temperature (Tem) and time (Tim). According to X-ray diffraction (XRD) and stress–strain curves, some changes in the behavior of the product were seen. After selecting the best model through determining statistics such as the determination coefficient (R2) and root mean square error (RMSE), mean absolute error (MAE) and sum of squares error (SSE), the production process was optimized to obtain the highest modulus of rupture (MOR) using the Genetic Algorithm (GA) combined with MLP. It was determined that the MLP had the best accuracy in estimating the response. According to the MLP-GA hybrid, the optimum input values for obtaining the best response include: WR—49.1%, NC—3.385%, Tem—199.4 °C and Tim—19.974 min. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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12 pages, 2923 KiB  
Article
On the Influence of Fatigue Damage in Short-Fibre Reinforced Thermoplastic PBT GF30 on Its Residual Strength under High Strain Rates: An Approach towards Simulative Prediction
by Christian Witzgall, Patrick Steck and Sandro Wartzack
J. Compos. Sci. 2023, 7(1), 23; https://doi.org/10.3390/jcs7010023 - 10 Jan 2023
Cited by 3 | Viewed by 1571
Abstract
Only by using accurate material data can precise simulation results be achieved. This principle also and especially applies in the field of crash simulation. However, in the simulation of short-fibre reinforced thermoplastics, material parameters are usually used that originate from the material testing [...] Read more.
Only by using accurate material data can precise simulation results be achieved. This principle also and especially applies in the field of crash simulation. However, in the simulation of short-fibre reinforced thermoplastics, material parameters are usually used that originate from the material testing of as-new samples. In order to get closer to the condition on the roads, where not only new vehicles are driving, the influence of service loads on the crashworthiness has to be investigated. This paper reports on studies of PBT GF30, a polybutylene terephthalate reinforced with 30% glass fibres, in which fatigue damage was induced in the material by cyclic loading. The residual strength was then determined in a high-speed experiment and compared with the strength of virgin samples. In order to enable the usability of the findings in the simulation, a modified failure criterion was implemented that takes the previous fatigue damage into account. The prediction quality of the simulation model was compared with the experimental findings and it can be concluded that there is good agreement. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 1664 KiB  
Article
Development of Prediction Models for the Torsion Capacity of Reinforced Concrete Beams Using M5P and Nonlinear Regression Models
by Sadiq N. Henedy, Ali H. Naser, Hamza Imran, Luís F. A. Bernardo, Mafalda M. Teixeira and Zainab Al-Khafaji
J. Compos. Sci. 2022, 6(12), 366; https://doi.org/10.3390/jcs6120366 - 02 Dec 2022
Cited by 7 | Viewed by 1215
Abstract
Torsional strength is related with one of the most critical failure types for the design and assessment of reinforced concrete (RC) members due to the complexity of the associated stress state and low ductility. Previous studies have shown that reliable methods to predict [...] Read more.
Torsional strength is related with one of the most critical failure types for the design and assessment of reinforced concrete (RC) members due to the complexity of the associated stress state and low ductility. Previous studies have shown that reliable methods to predict the torsional strength of RC beams are still needed, namely for over-reinforced and high-strength RC beams. This research aims to offer a novel set of models to predict the torsional strength of RC beams with a wide range of design attributes and geometries by using advanced M5P tree and nonlinear regression models. For this, a broad database with 202 experimental tests is used to generate highly reliable and resilient models. To build the models, three independent variables related with the properties of the RC beams are considered: concrete cross-section area (area enclosed within the outer perimeter of the cross-section), concrete compressive strength, and torsional reinforcement factor (which accounts for the type—longitudinal or transverse—amount, and yielding strength of the torsional reinforcement). In contrast to multiple nonlinear regression approaches, the findings show that the M5P tree approach has the best estimation in terms of both accuracy and safety. Furthermore, M5P model predictions are far more accurate and safer than the most prevalent design equations. Finally, sensitivity and parametric studies are used to confirm the robustness of the presented models. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 6994 KiB  
Article
Micromechanical Approach to Predict Mechanical Properties of Particulate-Dispersed Composites with Dissimilar Interfacial Phases
by Tomoyuki Fujii, Keiichiro Tohgo, Takahiro Omi and Yoshinobu Shimamura
J. Compos. Sci. 2022, 6(12), 356; https://doi.org/10.3390/jcs6120356 - 22 Nov 2022
Cited by 1 | Viewed by 1088
Abstract
The mechanical properties of composites are affected by their constituents. For the development of high-performance composites, it is expected that a technique will be developed which can predict the mechanical properties of composites based on the mechanical properties of their constituents. This study [...] Read more.
The mechanical properties of composites are affected by their constituents. For the development of high-performance composites, it is expected that a technique will be developed which can predict the mechanical properties of composites based on the mechanical properties of their constituents. This study developed a technique based on a micromechanical approach to predict the mechanical properties of composites with interfacial phases between reinforcements and matrix. A double-inclusion model (Hori and Nemat-Nasser, 1993) is effective for the solution of such problems, of which the validity remains unclear. Problems with a particle surrounded by an interfacial phase embedded in an infinite body were calculated via the model and finite element analysis to verify the model. It was found that the macroscopic average stress of the double inclusion could be accurately solved by the model, although the microscopic stress of each phase could not be calculated with high accuracy. Therefore, a micromechanical approach based on the model was formulated and applied to particulate-dispersed composites consisting of zirconia and titanium, and fabricated by spark plasma sintering, in which Ti oxides were created along the interface between zirconia and titanium. As a result, the elastic-plastic stress–strain curves of the composites could be predicted. The approach can investigate the mechanical properties of composites with various shapes of reinforcement surrounded by dissimilar materials in a matrix. It can be concluded that the approach is promising for the development of composites with an excellent mechanical performance. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 3352 KiB  
Article
Investigation of Mechanical Properties of Coffee Husk-HDPE-ABS Polymer Composite Using Injection-Molding Method
by Berhanu Tolessa Amena, Holm Altenbach, Getechew Shunki Tibba and Nazia Hossain
J. Compos. Sci. 2022, 6(12), 354; https://doi.org/10.3390/jcs6120354 - 22 Nov 2022
Cited by 4 | Viewed by 1907
Abstract
Waste biomass-based natural fibers are being extensively researched nowadays as a composite material with various waste-based high-density polyethylene (HDPE) to utilize the waste biomass and recycle the plastic waste in an effective approach. In this study, chemically modified spent coffee husk (CH) has [...] Read more.
Waste biomass-based natural fibers are being extensively researched nowadays as a composite material with various waste-based high-density polyethylene (HDPE) to utilize the waste biomass and recycle the plastic waste in an effective approach. In this study, chemically modified spent coffee husk (CH) has been applied with different ratios of HDPE to produce composite material and characterized comprehensively to determine the mechanical stability of the products. The injection molding method was used for composite development containing HDPE with untreated and 10 wt% NaOH-treated CH weight ratios of 0%, 15%, 20%, and 25% together with 10 wt% coupling agent and filler materials of acrylonitrile butadiene styrene (ABS) and kaolin clay, respectively. Physicochemical characteristics of untreated CH, 10 wt% NaOH treated CH, pristine HDPE and HDPE-CH composites have been analyzed comprehensively in this study. Adding 25 wt% fiber with 65 wt% HDPE and 10 wt% of ABS (7 wt%)-kaolin clay (3 wt%) increased the tensile and bending properties significantly. This composite presented the maximum tensile, flexural, and impact strengths, which were 36 MPa, 7.5 MPa, and 2.8 KJ/m2, respectively. The tensile strength and bending strength of NaOH-treated coffee husk fibers (CHF) were enhanced by 32% and 29%, respectively. The microstructural characteristics of HDPE with treated and untreated CHF composites analyzed by scanning electron microscopy (SEM) demonstrated the fibers’ and matrix’s excellent adhesion and compatibility. Thus, HDPE polymer-treated CH composite presented excellent stability, which can be expected as a new addition for construction, food packaging, and other industrial applications. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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22 pages, 4663 KiB  
Article
Influence of Spatially Distributed Out-of-Plane CFRP Fiber Waviness on the Estimation of Knock-Down Factors Based on Stochastic Numerical Analysis
by Andreas Schuster, Richard Degenhardt, Christian Willberg and Tobias Wille
J. Compos. Sci. 2022, 6(12), 353; https://doi.org/10.3390/jcs6120353 - 22 Nov 2022
Cited by 1 | Viewed by 1122
Abstract
The presence of waviness defects in CFRP materials due to fiber undulation affects the structural performance of composite structures. Hence, without a reliable assessment of the resulting material properties, the full weight-saving potential cannot be exploited. Within the paper, a probabilistic numerical approach [...] Read more.
The presence of waviness defects in CFRP materials due to fiber undulation affects the structural performance of composite structures. Hence, without a reliable assessment of the resulting material properties, the full weight-saving potential cannot be exploited. Within the paper, a probabilistic numerical approach for improved estimation of material properties based on spatially distributed fiber waviness is presented. It makes use of a homogenization approach to derive viable knock-down factors for the different plies on the laminate level for reference material and is demonstrated for a representative tension loadcase. For the stochastic analysis, a random field is selected which describes the complex inner geometry of the plies in the laminate model and is numerically discretized by the Karhunen–Loeve expansion methods to fit into an FE model for the strength analysis. Conducted analysis studies reveal a substantial influence of randomly distributed waviness defects on the derived knock-down factors. Based on a topological analysis of the waviness fields, the reduction of the material properties was found to be weakly negatively correlated related to simple geometrical properties such as maximum amplitudes of the waviness field, which justifies the need for further subsequent sensitivity studies. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 5475 KiB  
Article
Utilizing of Magnetized Water in Enhancing of Volcanic Concrete Characteristics
by Mostafa M. Keshta, Mohamed M. Yousry Elshikh, Mohamed Abd Elrahman and Osama Youssf
J. Compos. Sci. 2022, 6(10), 320; https://doi.org/10.3390/jcs6100320 - 19 Oct 2022
Cited by 12 | Viewed by 1990
Abstract
Volcanic concrete is an eco-friendly concrete type in that it contains coarse and fine aggregates that all extracted from the igneous volcanic rock. However, utilizing of volcanic ash (VA) as partial/full replacement of concrete cement significantly affects the concrete workability, especially at high [...] Read more.
Volcanic concrete is an eco-friendly concrete type in that it contains coarse and fine aggregates that all extracted from the igneous volcanic rock. However, utilizing of volcanic ash (VA) as partial/full replacement of concrete cement significantly affects the concrete workability, especially at high cement replacement ratios. This has also some adverse effects on concrete strength. Utilizing magnetized water (MW) in concrete as a partial/full replacement of ordinary tap water (TW) has a notable effect on enhancing the fresh and hardened concrete properties. This research aims to study the effect of using MW prepared in a magnetic field of 1.4 Tesla on the workability and hardened properties (compressive, tensile, and flexural strengths) of volcanic concrete. In this study, VA partially replaced volcanic concrete cement with ratios of 5%, 10%, 15%, and 20%. Ten volcanic concrete mixes were prepared in two groups. The first one was prepared with VA (0–20%) and mixed with TW. The other group was prepared with the same VA contents like group one, but mixed with MW. Microstructure imaging for volcanic concrete was also conducted in this study. Results of water tests showed 17% and 15% increase in total dissolved solids (TDS) and pH, respectively, of MW compared with those of TW. In addition, the water magnetization decreased the water surface tension by 7% compared with that of TW. Results of hardened concrete tests showed that the best ratio of VA in volcanic concrete was 5% with and without using magnetized water. The volcanic concrete slump decreased when using TW; however, using MW enhanced the volcanic concrete slump by up to 8%. The compressive strength was improved by 35%, 23%, and 20% at 7 days, 28 days, and 120 days, respectively, with no VA and with the presence of MW. The compressive strength was improved by 11%, 12%, and 11% after 7 days, 28 days, and 120 days, respectively, with using 5% VA and with the presence of MW. Both splitting tensile strength and flexural strength of volcanic concrete with and without VA or MW behaved similar to that of the corresponding compressive strength. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 3517 KiB  
Article
Mixed-Mode I/II Testing of Composite Materials—A Refined Data Reduction Scheme for the Wedge-Loaded Asymmetric Double Cantilever Beam Test
by Michael May, Philipp Hahn, Borhan Uddin Manam and Mathieu Imbert
J. Compos. Sci. 2022, 6(10), 319; https://doi.org/10.3390/jcs6100319 - 18 Oct 2022
Cited by 3 | Viewed by 1766
Abstract
The wedge-loaded asymmetric double cantilever beam (WADCB) test is an experimental method to determine the mixed-mode I/II fracture toughness of composite materials by inserting a wedge into the specimen along a potential delamination path. Whilst the current closed-form solution for the ADCB test [...] Read more.
The wedge-loaded asymmetric double cantilever beam (WADCB) test is an experimental method to determine the mixed-mode I/II fracture toughness of composite materials by inserting a wedge into the specimen along a potential delamination path. Whilst the current closed-form solution for the ADCB test assumes identical forces acting in both specimen arms, this manuscript proposes a refined closed-form solution allowing for different forces acting on both specimen arms, which is thought to be more general and more rigorous. WADCB tests were carried out on composites made from Torayca T700SC/2592 unidirectional prepreg. Both the current and the refined closed-form solution were used to analyze the data, and some differences were found in the predictions, indicating that the forces in the two specimen arms are indeed not identical. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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10 pages, 1935 KiB  
Article
Threshold Identification and Damage Characterization of Woven GF/CF Composites under Low-Velocity Impact
by Marzio Grasso and Yigeng Xu
J. Compos. Sci. 2022, 6(10), 305; https://doi.org/10.3390/jcs6100305 - 11 Oct 2022
Cited by 2 | Viewed by 1218
Abstract
The Delamination Threshold Load (DTL) is a key parameter representing damage resistance of a laminate and is normally identified by locating a sudden drop in the impact force-time history for the laminate made of unidirectional layers. For the woven composite, however, their failure [...] Read more.
The Delamination Threshold Load (DTL) is a key parameter representing damage resistance of a laminate and is normally identified by locating a sudden drop in the impact force-time history for the laminate made of unidirectional layers. For the woven composite, however, their failure mechanisms appear different and the current literature is not providing any clear procedure regarding the identification of the delamination initiation, as well as the evolution of the failure mechanisms associated with it. In this paper, experimental data have been collected using woven glass and carbon fiber composites. The results are analyzed in terms of force-time and force-displacement curves. While delamination and other damages were clearly observed using ultrasonic scans, the analysis of the results does not reveal any trend changes of the curves that can be associated with the incipient nucleation of delamination. A preliminary discussion regarding the nature of the mechanisms through which the delamination propagates in woven composite and a justification for the absence of a sudden change of the stiffness have been presented. It raises a question on the existence of DTL for woven composites under low velocity impact. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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16 pages, 6694 KiB  
Article
Mitigation of Heat Propagation in a Battery Pack by Interstitial Graphite Nanoplatelet Layer: Coupled Electrochemical-Heat Transfer Model
by Barbara Palmieri, Fabrizia Cilento, Ciro Siviello, Francesco Bertocchi, Michele Giordano and Alfonso Martone
J. Compos. Sci. 2022, 6(10), 296; https://doi.org/10.3390/jcs6100296 - 09 Oct 2022
Cited by 8 | Viewed by 1792
Abstract
The use of high thermal conductive materials for heat transfer is gaining attention as a suitable treatment for improving battery performance. Thermal runaway is a relevant issue for maintaining safety and for proficient employment of accumulators; therefore, new solutions for thermal management are [...] Read more.
The use of high thermal conductive materials for heat transfer is gaining attention as a suitable treatment for improving battery performance. Thermal runaway is a relevant issue for maintaining safety and for proficient employment of accumulators; therefore, new solutions for thermal management are mandatory. For this purpose, a hierarchical nanomaterial made of graphite nanoplatelet has been considered as an interface material. High-content graphite nanoplatelet films have very high thermal conductivity and might improve heat dissipation. This study investigates the effect of a thermally conductive material as a method for safety enhancement for a battery module. A numerical model based on the finite element method has been developed to predict the heat generation during a battery pack’s charge and discharge cycle, using the Multiphysics software Comsol. The lumped battery interface generates appropriate heat sources coupled to the Heat Transfer Interface in 3D geometry. Simulation results show that the protection of neighbouring cells from the interleaved layer is fundamental for avoiding heat propagation and an uncontrollable heating rise of the entire battery pack. The use of graphite nanocomposite sheets could effectively help to uniform the temperature and delay the TR propagation. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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10 pages, 3231 KiB  
Article
A Study on the Structural Features of Amorphous Nanoparticles of Ni by Molecular Dynamics Simulation
by Tuan Tran Quoc, Dung Nguyen Trong, Van Cao Long, Umut Saraç and Ştefan Ţălu
J. Compos. Sci. 2022, 6(9), 278; https://doi.org/10.3390/jcs6090278 - 19 Sep 2022
Cited by 3 | Viewed by 1379
Abstract
This study deals with the impact of the heating rate (HR), temperature (T), and the number of atoms (N) on the structural features of amorphous nanoparticles (ANPs) of Ni by molecular dynamics simulation (MDS) with the Pak–Doyama pair interaction potential field (PD). The [...] Read more.
This study deals with the impact of the heating rate (HR), temperature (T), and the number of atoms (N) on the structural features of amorphous nanoparticles (ANPs) of Ni by molecular dynamics simulation (MDS) with the Pak–Doyama pair interaction potential field (PD). The obtained results showed that the structural features of ANPs of Ni are significantly affected by the studied factors. The correlation between the size (D) and the N was determined to be D~N−1/3. The energy (E) was proportional to N−1, and the Ni-Ni link length was 2.55 Å. The glass transition temperature (Tg) derived from the E-T graph was estimated to be 630 K. An increase in the HR induced a change in the shape of the ANPs of Ni. Furthermore, raising the HR caused an enhancement in the D and a decrement in the density of atoms. The obtained results are expected to contribute to future empirical studies. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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13 pages, 3726 KiB  
Article
Finite Element Simulation of FRP-Strengthened Thin RC Slabs
by Maha Assad, Rami Hawileh and Jamal Abdalla
J. Compos. Sci. 2022, 6(9), 263; https://doi.org/10.3390/jcs6090263 - 08 Sep 2022
Cited by 7 | Viewed by 1509
Abstract
This study aims to investigate the flexural behavior of high-strength thin slabs externally strengthened with fiber-reinforced polymer (FRP) laminates through a numerical simulation. A three-dimensional (3D) finite element (FE) model is created to simulate the response of strengthened reinforced concrete (RC) slabs under [...] Read more.
This study aims to investigate the flexural behavior of high-strength thin slabs externally strengthened with fiber-reinforced polymer (FRP) laminates through a numerical simulation. A three-dimensional (3D) finite element (FE) model is created to simulate the response of strengthened reinforced concrete (RC) slabs under a four-point bending test. The numerical model results in terms of load-deflection behavior, and ultimate loads are verified using previously published experimental data in the literature. The numerical results show a good agreement with the experimental results. The FE model is then employed in a parametric study to inspect the effect of concrete compressive strength on the performance of RC thin slabs strengthened with different FRP types, namely carbon fiber-reinforced polymers (CFRP), polyethylene terephthalate fiber-reinforced polymers (PET-FRP), basalt fiber-reinforced polymers (BFRP) and glass fiber-reinforced polymers (GFRP). The results showed that the highest strength enhancement was obtained by the slab that was strengthened by CFRP sheets. Slabs that were strengthened with other types of FRP sheets showed an almost similar flexural capacity. The effect of concrete compressive strength on the flexural behavior of the strengthened slabs was moderate, with the highest effect being a 15% increase in the ultimate load between two consecutive values of compressive strength, occurring in the CFRP-strengthened slabs. It can thus be concluded that the developed FE model could be used as a platform to predict the behavior of reinforced concrete slabs when strengthened with different types of FRP composites. It can also be concluded that the modulus of elasticity of the composite plays a major role in determining the flexural capacity of the strengthened slabs. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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15 pages, 6263 KiB  
Article
Experimental and Finite Element Study of a Novel Two-Way Corrugated Steel Deck System for Composite Slabs
by Keerthana John, Mahmud Ashraf, Matthias Weiss and Riyadh Al-Ameri
J. Compos. Sci. 2022, 6(9), 261; https://doi.org/10.3390/jcs6090261 - 08 Sep 2022
Cited by 2 | Viewed by 1597
Abstract
This paper investigates the structural performance of a new two-way profiled steel decking system for steel-concrete composite slabs. Several studies have investigated steel decking for steel-concrete composite slabs and focused on utilising the conventional deck as a one-way floor system. The newly developed [...] Read more.
This paper investigates the structural performance of a new two-way profiled steel decking system for steel-concrete composite slabs. Several studies have investigated steel decking for steel-concrete composite slabs and focused on utilising the conventional deck as a one-way floor system. The newly developed deck consists of top-hat sections formed by bending corrugated sheets at 90°, which are attached to a corrugated base sheet. The deck is designed for improved composite and two-way action contributed by its unique geometry due to corrugations in the transverse and longitudinal directions. This paper experimentally tested a novel steel decking geometry under construction stage loading. It was in the absence of concrete to establish the deck’s suitability for construction and contribution towards loading capacity and performance for future use as a two-way composite slab. Ultimate load, two-way action, and failure modes were identified. A finite element model was also developed, and parameters assessed that could influence the performance when the deck is potentially used in the composite stage. It was concluded that, while increasing the thickness of the corrugated base sheet significantly affects the load-carrying capacity, the thickness of the top hats has no significant impact. Improved load transfer with two-way behaviour is observed when the bottom flanges of the top hats are continuously connected to the bottom flanges of the adjacent top hats to form a deck. This contrasts with the concept deck, where individual top hats are attached to a corrugated base sheet. In this case, decks with a corrugated base sheet perform 54% better in ultimate load capacity than decks without a corrugated base sheet. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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22 pages, 4853 KiB  
Article
Development and Characterization of PHB-PLA/Corncob Composite for Fused Filament Fabrication
by Okezie Ohaeri and Duncan Cree
J. Compos. Sci. 2022, 6(9), 249; https://doi.org/10.3390/jcs6090249 - 26 Aug 2022
Cited by 5 | Viewed by 1830
Abstract
The development of environmentally friendly polymeric composites holds great potential for agricultural leftovers. This study explores the effects of lignocellulosic corncob powder as a filler in a polyhydroxybutyrate (PHB)/polylactic acid (PLA) biopolymer matrix. The PHB-PLA matrix consists of a 55% to 45% blend, [...] Read more.
The development of environmentally friendly polymeric composites holds great potential for agricultural leftovers. This study explores the effects of lignocellulosic corncob powder as a filler in a polyhydroxybutyrate (PHB)/polylactic acid (PLA) biopolymer matrix. The PHB-PLA matrix consists of a 55% to 45% blend, respectively, while the filler loadings range from 0 wt.% to 8 wt.%. The components are combined and directly extruded into fused filaments for three-dimensional (3D) printing. The tensile strength of both the filament and dog-bone samples, flexural strength, and Charpy impact toughness of the composites, all decreased as filler loading increased. The tensile and flexural modulus of all samples examined improved noticeably with increasing filler loading. The filler particles had dense, mildly elongated sheet-like shapes, whereas the fractured surfaces of the composite samples had flat features for the pure polymer blend, but became rougher and jagged as filler loading increased. The fractured surface of Charpy impact test samples had smoother morphology when tested at cryogenic temperatures, compared to room temperature testing. All attributes showed a fourth-degree polynomial relationship to filler loading and all improved as filler loading increased, with the best results obtained at 6 wt.% loading. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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17 pages, 56661 KiB  
Article
Prediction of Damage in Non-Crimp Fabric Composites Subjected to Transverse Crushing: A Comparison of Two Constitutive Models
by Milad Kazemian and Aleksandr Cherniaev
J. Compos. Sci. 2022, 6(8), 224; https://doi.org/10.3390/jcs6080224 - 04 Aug 2022
Cited by 1 | Viewed by 1971
Abstract
Non-crimp fabrics (NCFs) are increasingly used in industry for manufacturing of composite structures due to a combination of high mechanical properties and excellent manufacturability. As with other composites, in-service damage can be a cause for severe reduction in load-carrying capacity of NCF-reinforced plastics. [...] Read more.
Non-crimp fabrics (NCFs) are increasingly used in industry for manufacturing of composite structures due to a combination of high mechanical properties and excellent manufacturability. As with other composites, in-service damage can be a cause for severe reduction in load-carrying capacity of NCF-reinforced plastics. In this experimental and numerical study, two constitutive material models previously used only for damage prediction in unidirectional (UD) tape and woven fabric-reinforced materials (LS-DYNA’s *MAT_ENHANCED_COMPOSITE_DAMAGE—MAT54 and *MAT_LAMINATED_COMPOSITE_FABRIC—MAT58) were evaluated for simulating transverse crushing of composite parts processed from a non-crimp carbon fabric. For this purpose, UD NCF components of tubular shape were subjected to transverse crushing through a controlled indentation of a metallic cylinder, and results of the experiment were compared with numerical modeling. Considered verification metrics included the observed and the predicted patterns of interlaminar damage, the extent of delamination, as well as the ability of the models to replicate force-displacement response exhibited by the tested specimens. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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Review

Jump to: Editorial, Research

26 pages, 2124 KiB  
Review
Material Characterization Required for Designing Satellites from Fiber-Reinforced Polymers
by Esha and Joachim Hausmann
J. Compos. Sci. 2023, 7(12), 515; https://doi.org/10.3390/jcs7120515 - 11 Dec 2023
Viewed by 1614
Abstract
This review paper discusses the effect of polymers, especially thermoplastics, in environments with low earth orbits. Space weather in terms of low earth orbits has been characterized into seven main elements, namely microgravity, residual atmosphere, high vacuum, atomic oxygen, ultraviolet and ionization radiation, [...] Read more.
This review paper discusses the effect of polymers, especially thermoplastics, in environments with low earth orbits. Space weather in terms of low earth orbits has been characterized into seven main elements, namely microgravity, residual atmosphere, high vacuum, atomic oxygen, ultraviolet and ionization radiation, solar radiation, and space debris. Each element is discussed extensively. Its effect on polymers and composite materials has also been studied. Quantification of these effects can be evaluated by understanding the mechanisms of material degradation caused by each environmental factor along with its synergetic effect. Hence, the design elements to mitigate the material degradation can be identified. Finally, a cause-and-effect diagram (Ishikawa diagram) is designed to characterize the important design elements required to investigate while choosing a material for a satellite’s structure. This will help the designers to develop experimental methodologies to test the composite material for its suitability against the space environment. Some available testing facilities will be discussed. Some potential polymers will also be suggested for further evaluation. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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21 pages, 1640 KiB  
Review
Review on Characterization of Biochar Derived from Biomass Pyrolysis via Reactive Molecular Dynamics Simulations
by Zhong Hu and Lin Wei
J. Compos. Sci. 2023, 7(9), 354; https://doi.org/10.3390/jcs7090354 - 25 Aug 2023
Cited by 2 | Viewed by 1755
Abstract
Biochar is a carbon-rich solid produced during the thermochemical processes of various biomass feedstocks. As a low-cost and environmentally friendly material, biochar has multiple significant advantages and potentials, and it can replace more expensive synthetic carbon materials for many applications in nanocomposites, energy [...] Read more.
Biochar is a carbon-rich solid produced during the thermochemical processes of various biomass feedstocks. As a low-cost and environmentally friendly material, biochar has multiple significant advantages and potentials, and it can replace more expensive synthetic carbon materials for many applications in nanocomposites, energy storage, sensors, and biosensors. Due to biomass feedstock species, reactor types, operating conditions, and the interaction between different factors, the compositions, structure and function, and physicochemical properties of the biochar may vary greatly, traditional trial-and-error experimental approaches are time consuming, expensive, and sometimes impossible. Computer simulations, such as molecular dynamics (MD) simulations, are an alternative and powerful method for characterizing materials. Biomass pyrolysis is one of the most common processes to produce biochar. Since pyrolysis of decomposing biomass into biochar is based on the bond-order chemical reactions (the breakage and formation of bonds during carbonization reactions), an advanced reactive force field (ReaxFF)-based MD method is especially effective in simulating and/or analyzing the biomass pyrolysis process. This paper reviewed the fundamentals of the ReaxFF method and previous research on the characterization of biochar physicochemical properties and the biomass pyrolysis process via MD simulations based on ReaxFF. ReaxFF implicitly describes chemical bonds without requiring quantum mechanics calculations to disclose the complex reaction mechanisms at the nano/micro scale, thereby gaining insight into the carbonization reactions during the biomass pyrolysis process. The biomass pyrolysis and its carbonization reactions, including the reactivity of the major components of biomass, such as cellulose, lignin, and hemicellulose, were discussed. Potential applications of ReaxFF MD were also briefly discussed. MD simulations based on ReaxFF can be an effective method to understand the mechanisms of chemical reactions and to predict and/or improve the structure, functionality, and physicochemical properties of the products. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume III)
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