Analytical, Numerical and Experimental Methodologies for the Analysis of Multilayered Structures

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

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 26279

Special Issue Editors


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Guest Editor
Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
Interests: smart structures; composite and FGM materials; multifield problems; thermal and hygroscopic stress analysis; carbon nanotubes; inflatable structures; plate and shell finite elements; 3D and 2D exact and numerical solutions for plate and shell structures; additive manufacturing and UAVs
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Guest Editor
Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
Interests: additive manufacturing; UAVs; composite structures and 3D shell models

Special Issue Information

Dear Colleagues,

The proposed Special Issue is aimed at papers concerning analytical, numerical and experimental analyses of multilayer structures with simple or complex geometry (plates, shells, arcs, beams, specific specimens and so on) and produced by means of classical technologies or advanced technologies such as those relating to additive manufacturing. In details, static, dynamic, free vibration, buckling and non-linear analyses of multilayered composite, sandwich, functionally graded, piezoelectric, piezomagnetic, polymeric, nanoreinforced and anisotropic structures can be proposed. Experimental tensile, compressive and bending tests can be developed to validate numerical and analytical models or to opportunely characterize the material properties. Analytical and numerical models can be based on closed-form solutions, finite element models, boundary element models, generalized differential quadrature method, Galerkin and Ritz methods and so on. The analyzed structures can be subjected to several loading types such as mechanical, thermal, hygroscopic, electrical and magnetic ones, and the response can be evaluated in terms of displacements, elastic, thermal and hygroscopic stresses, strains, frequencies, vibration modes, critical loads and so on.

Prof. Dr. Salvatore Brischetto
Mr. Roberto Torre
Guest Editors

Manuscript Submission Information

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Keywords

  • Composite structures
  • Sandwich structures
  • Smart structures embedding piezoelectric and piezomagnetic layers
  • Multilayered structures
  • Plates, shells and beams
  • 1D, 2D and 3D numerical and analytical structural models
  • Finite element method
  • Boundary element method
  • Closed-form solutions
  • Generalized differential quadrature method
  • Galerkin and Ritz methods
  • Static, dynamic, free vibration, buckling and non-linear analyses
  • Functionally graded structures
  • Nanoreinforced structures
  • Carbon nanotubes
  • Thermal stress analysis
  • Hygroscopic stress analysis
  • Experimental tensile, compression and bending tests on composite, multilayered or 3D printed structures
  • Additive manufacturing

Published Papers (7 papers)

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Research

17 pages, 4548 KiB  
Article
Composite Overwrapped Pressure Vessel Design Optimization Using Numerical Method
by Yohannes Regassa, Jema Gari and Hirpa G. Lemu
J. Compos. Sci. 2022, 6(8), 229; https://doi.org/10.3390/jcs6080229 - 05 Aug 2022
Cited by 9 | Viewed by 6756
Abstract
Composite Overwrapped Pressure Vessels (COPVs) are widely used in fields including aeronautics and by companies such as SpaceX to hold high pressure fluids. They are favored for these applications because they are far lighter than all-metal vessels, although they demand special design, manufacturing, [...] Read more.
Composite Overwrapped Pressure Vessels (COPVs) are widely used in fields including aeronautics and by companies such as SpaceX to hold high pressure fluids. They are favored for these applications because they are far lighter than all-metal vessels, although they demand special design, manufacturing, and testing requirements. In this study, finite element modeling was used to conducted stress and damage assessments on a composite overwrapped pressure vessel that has a 4 mm thick aluminum core cylinder. To develop the optimum COPV, the lamina sequences, thickness, and fiber winding angle were considered. The relationship between these variables and the composite-overwrapped structure’s maximum burst pressure bearing capacity was assessed. The ABAQUS composite modeler was used to design and generate 14 models of COPVs from carbon fiber/epoxy plies with a consistent thickness of 6.5 mm and various fiber angle orientations. The effects of the ply stacking order were analyzed by the finite element analysis approach for all designed models, which had 13 layers of uniform thickness but a varying fiber orientation. A ply stacking sequence of [55°, −55°] PP winding pattern had an optimum COPV design profile, with a burst pressure bearing capacity of 24 MPa. The stress–strain distribution along the geometry of the COPV was also obtained using the finite element method, and it was found that the distribution is uniform over the surface of the COPV and that its peak values are found towards the polar boss section of the COPV. Extreme stress gradients were noticed when the boss nears its geometrical transition to the dome phase. This factor is evident from the change in the ply thickness caused by the overlapped fiber orientation. The results obtained from this study are useful for the design and application of composite overwrapped pressure vessels. Full article
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19 pages, 5302 KiB  
Article
Experimental Analysis of Plastic-Based Composites Made by Composite Plastic Manufacturing
by Raghunath Bhaskar, Javaid Butt and Hassan Shirvani
J. Compos. Sci. 2022, 6(5), 127; https://doi.org/10.3390/jcs6050127 - 26 Apr 2022
Cited by 2 | Viewed by 3292
Abstract
The significance of composites cannot be overstated in the manufacturing sector due to their unique properties and high strength-to-weight ratio. The use of thermoplastics for composites manufacturing is also gaining attention due to their availability, ease of operation, and affordability. However, the current [...] Read more.
The significance of composites cannot be overstated in the manufacturing sector due to their unique properties and high strength-to-weight ratio. The use of thermoplastics for composites manufacturing is also gaining attention due to their availability, ease of operation, and affordability. However, the current methods for plastic-based composites are limited due to the requirements of long curing times and pre- and post-treatment, thereby resulting in longer lead times for the desired product. These methods also limit the freedom to operate with different forms of materials. Therefore, a new manufacturing process for plastic-based composites is required to overcome such limitations. This research presents a new manufacturing process to produce high-quality plastic-based composites with bespoke properties for engineering applications. The process is referred to as Composite Plastic Manufacturing (CPM) and is based on the principle of fused filament fabrication (FFF) equipped with a heat chamber. The process integrates two material extrusion additive manufacturing technologies, i.e., filament and syringe extrusion. The paper presents the principle of the process, both in theory and in practice, along with the methodology and materials used to manufacture plastic composites. Various composites have been manufactured using the CPM process with thermally activated materials and tested according to British and International standards. Polylactic Acid (PLA) has been interlaced with different thermally activated materials such as graphene-carbon hybrid paste, heat cure epoxy paste, and graphene epoxy paste. The process is validated through a comparative experimental analysis involving tests such as ultrasonic, tensile, microstructural, and hardness to demonstrate its capabilities. The results have been compared with commercially available materials (PLA and Graphene-enhanced PLA) as well as literature to establish the superiority of the CPM process. The CPM composites showed an increase of up to 10.4% in their tensile strength (54 MPa) and 8% in their hardness values (81 HD) when compared to commercially available PLA material. The composites manufactured by CPM have also shown strong bonding between the layers of PLA and thermally activated materials; thus, highlighting the effectiveness of the process. Furthermore, the composites showed a significant increase of up to 29.8% in their tensile strength and 24.6% in their hardness values when compared to commercially available Graphene-enhanced PLA material. The results show that the CPM process is capable of manufacturing superior quality plastic composites and can be used to produce products with bespoke properties. Full article
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13 pages, 2234 KiB  
Article
A Ternary Model for Particle Packing Optimization
by Taher M. Abu-Lebdeh, Ransford Damptey, Liviu Marian Ungureanu and Florian Ion Tiberiu Petrescu
J. Compos. Sci. 2022, 6(4), 113; https://doi.org/10.3390/jcs6040113 - 10 Apr 2022
Cited by 8 | Viewed by 4441
Abstract
Powder packing in metal powders is an important aspect of additive manufacturing (otherwise known as 3-D printing), as it directly impacts the physical and mechanical properties of materials. Improving the packing density of powder directly impacts the microstructure of the finished 3D-printed part [...] Read more.
Powder packing in metal powders is an important aspect of additive manufacturing (otherwise known as 3-D printing), as it directly impacts the physical and mechanical properties of materials. Improving the packing density of powder directly impacts the microstructure of the finished 3D-printed part and ultimately enhances the surface finish. To obtain the most efficient packing of a given powder, different powder blends of that material must be mixed to minimize the number of voids, irrespective of the irregularities in the particle morphology and flowability, thereby increasing the density of the powder. To achieve this, a methodology for mixing powder must be developed, for each powder type, to obtain the maximum packing density. This paper presents a model that adequately predicts the volumetric fraction of the powder grades necessary for obtaining the maximum packing density for a given powder sample. The model factors in the disparity between theoretical assumptions and the experimental outcome by introducing a volume reduction factor. We outline the model development steps in this paper, testing it with a real-world powder system. Full article
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28 pages, 3492 KiB  
Article
Preliminary Finite Element Analysis and Flight Simulations of a Modular Drone Built through Fused Filament Fabrication
by Salvatore Brischetto and Roberto Torre
J. Compos. Sci. 2021, 5(11), 293; https://doi.org/10.3390/jcs5110293 - 06 Nov 2021
Cited by 4 | Viewed by 3472
Abstract
This paper discusses the architecture and preliminary design of an Unmanned Aerial Vehicle (UAV), whose actual operative scenario and required performances drive its flying configuration. The UAV is a multirotor and can be adapted to be used as a tricopter, a quadcopter, a [...] Read more.
This paper discusses the architecture and preliminary design of an Unmanned Aerial Vehicle (UAV), whose actual operative scenario and required performances drive its flying configuration. The UAV is a multirotor and can be adapted to be used as a tricopter, a quadcopter, a hexacopter, and an octocopter: the number (and consequent arrangement) of the arms modify its performance. Customization is combined with the concept of additive manufacturing, as all components are designed to be produced in Fused Filament Fabrication (FFF). This approach does not limit the application scenarios of the drone; it is instead a further push in the direction of customization, as it permits continuous upgrades over time. The paper simulates four scenarios and discusses how to optimize performances such as payload, thrust-to-weight ratio, efficiency, flight time, and maximum speed through suitable configurations. Avionic components already available on the market integrate into a customizable and adaptable frame. This analysis reveals the most severe conditions for the structure, and conducts a structural validation of its performance. Validating the functional use of FFF-produced parts is challenging due to the anisotropic behavior of the parts. However, some structural elements are thin-walled and enjoy being printed with a 100% linear infill. A simplified approach to those elements has already been proposed and validated through a parallel with UniDirectional Composites, whose 2D testing procedures and methodologies have been derived and adapted. An FEA of some elements of the frame is conducted, using shell elements to discretize the geometry. A proper definition of their mechanical response is possible because the constitutive model is not isotropic a priori but reflects the behavior of the finished parts. The tensile strength variability in the material reference system is high: a component-by-component comparison proves the design to be adequate and measured to the surrounding conditions; however, it highlights the absence of a defined failure criterion. Full article
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22 pages, 9233 KiB  
Article
Numerical Modelling of Bond Strength in Overmoulded Thermoplastic Composites
by Bernd-Arno Behrens, Klaus Dröder, Kai Brunotte, Hendrik Wester, André Hürkamp, Tim Ossowski and Ralf Lorenz
J. Compos. Sci. 2021, 5(7), 164; https://doi.org/10.3390/jcs5070164 - 23 Jun 2021
Cited by 7 | Viewed by 2558
Abstract
Overmoulding of thermoplastic composites combines the steps of thermoforming and injection moulding in an integrated manufacturing process. The combination of continuous fibre-reinforced thermoplastics with overmoulded polymer enables the manufacturing of highly functionally integrated structures with excellent mechanical properties. When performed as a one-shot [...] Read more.
Overmoulding of thermoplastic composites combines the steps of thermoforming and injection moulding in an integrated manufacturing process. The combination of continuous fibre-reinforced thermoplastics with overmoulded polymer enables the manufacturing of highly functionally integrated structures with excellent mechanical properties. When performed as a one-shot process, an economically efficient manufacturing of geometrical complex lightweight parts within short cycle times is possible. However, a major challenge in the part and process design of overmoulded thermoplastic composites (OTC) is the assurance of sufficient bond strength between the composite and the overmoulded polymers. Within the framework of a simulation-based approach, this study aims to develop a methodology for predicting the bond strength in OTC using simulation data and a numerical model formulation of the bonding mechanisms. Therefore, a modelling approach for the determination of the bond strength depending on different process parameters is presented. In order to validate the bond strength model, specimens are manufactured with different process settings and mechanical tests are carried out. Overall, the results of the numerical computation are in good agreement with the experimentally determined bond strength. The proposed modelling approach enables the prediction of the local bond strength in OTC, considering the interface conditions and the processing history. Full article
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14 pages, 7334 KiB  
Article
Numerical Simulation of the Forming Process of Veneer Laminates
by David Zerbst, Christian Liebold, Thomas Gereke, Sebastian Clauß and Chokri Cherif
J. Compos. Sci. 2021, 5(6), 150; https://doi.org/10.3390/jcs5060150 - 03 Jun 2021
Viewed by 2714
Abstract
In automotive manufacturing, laminated veneer sheets are formed to have 3D geometries for the production of trim parts with wood surfaces. Nowadays, investigation of the formability requires extensive tests with prototype tools, due to the brittle, anisotropic and inhomogeneous material behaviors. The present [...] Read more.
In automotive manufacturing, laminated veneer sheets are formed to have 3D geometries for the production of trim parts with wood surfaces. Nowadays, investigation of the formability requires extensive tests with prototype tools, due to the brittle, anisotropic and inhomogeneous material behaviors. The present paper provides numerical methods for the simulation of the forming process of veneers with non-woven backings. Therefore, a conventional forming process of an interior trim part surface is carried out experimentally and numerically, using veneer samples with different individual textures originating from the characteristic growth ring structure. Gray scale images of these samples are mapped to finite element models to account for the wood-specific structure. The forming simulation process comprises two steps, where a gravity simulation depicts the initial position of the blank sheets and the closing of the tool induces the material deformation. The virtual forming of the digital twins accurately reproduces the wrinkling behavior observed in experimental studies. Based on the proposed methods, the design process of manufacturing wood trim parts based on tedious prototype tooling can be replaced by a fully virtual forming process taking into account the individual growth-related properties of the veneer structure. Full article
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14 pages, 9924 KiB  
Article
Numerical Buckling Analysis of Hybrid Honeycomb Cores for Advanced Helmholtz Resonator Liners
by Moritz Neubauer, Martin Dannemann, Michael Kucher, Niklas Bleil, Tino Wollmann and Niels Modler
J. Compos. Sci. 2021, 5(5), 116; https://doi.org/10.3390/jcs5050116 - 23 Apr 2021
Cited by 1 | Viewed by 1957
Abstract
In order to realize novel acoustic liners, honeycomb core structures specially adapted to these applications are required. For this purpose, various design concepts were developed to create a hybrid cell core by combining flexible wall areas based on thermoplastic elastomer films and rigid [...] Read more.
In order to realize novel acoustic liners, honeycomb core structures specially adapted to these applications are required. For this purpose, various design concepts were developed to create a hybrid cell core by combining flexible wall areas based on thermoplastic elastomer films and rigid honeycomb areas made of fiber-reinforced thermoplastics. Within the scope of the presented study, a numerical approach was introduced to analyze the global compressive failure of the hybrid composite core structure, considering local buckling and composite failure according to Puck and Cuntze. Therefore, different geometrical configurations of fiber-reinforced tapes were compared with respect to their deformation as well as their resulting failure behavior by means of a finite element analysis. The resulting compression strength obtained by a linear buckling analysis agrees largely with calculated strengths of the more elaborate application of the failure criteria according to Puck and Cuntze, which were implemented in the framework of a nonlinear buckling analysis. The findings of this study serve as a starting point for the realization of the manufacturing concept, for the design of experimental tests of hybrid composite honeycomb core structures, and for further numerical investigations considering manufacturing as well as material specific aspects. Full article
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