Submit to Materials Review for Materials Propose a Special Issue

Journal Menu

Journal Browser

Advances in Micromechanical Behavior of Materials

Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 25311

Share This Special Issue

Special Issue Editor

Dr. Elena Ferretti

E-Mail Website
Guest Editor

Department of Civil, Chemical, Environmental, and Materials Engineering (DICAM), Università di Bologna, 40126 Bologna, BO, Italy
Interests: material characterization; non-destructive testing; fracture mechanics; algebraic formulation; multi-scale numerical modelling; composite materials; reinforced concrete; masonry structures; earthen buildings; additive 3D printing in construction.
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The purpose of this Special Issue is to provide essential readings to researchers interested in the current developments in materials mechanics, with particular attention to the mechanics of heterogeneous materials. The published papers will share the common goal of building continuum models based on the micro-behavior of materials.

Micro-mechanics describes the mechanical behavior starting from the grain scale level, which relates the microscopic parameters to macroscopic behavior. The first studies in this field were developed starting from experimental results, while, more recently, many numerical methods helped researchers to model the overall mechanical behavior derived from the changes in the internal structures, from component properties, and from interactions between aggregates and matrix.

I am pleased to invite you to submit new studies on experimental techniques, constitutive theories, and modeling methods related to micro-mechanics. The main topics to be covered include, but are not limited to, size-effect, strain-softening, dilatancy, creep, material anisotropy, and heterogeneity resulting from the shape and distribution of aggregates within the matrix, and by the way in which the relative positions of the aggregates change during deformation. Advantages, limitations, perspectives, and needs for future research of the proposed micro-mechanical approaches must also be discussed. Full papers, communications, and reviews are all welcomed.

Dr. Elena Ferretti
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. Materials is an international peer-reviewed open access semimonthly 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 2600 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

Material characterization
Constitutive relations of heterogeneous materials
Numerical modeling
Multi-scale modeling
Size-effect
Strain-softening
Creep and viscosity
Deformation-induced anisotropy
Deformation-induced heterogeneity

Published Papers (10 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

11 pages, 4101 KiB

Open AccessArticle

Mechanical Properties of GaN Single Crystals upon C Ion Irradiation: Nanoindentation Analysis

by Zhaohui Dong, Xiuyu Zhang, Shengyuan Peng, Fan Jin, Qiang Wan, Jianming Xue and Xin Yi

Materials 2022, 15(3), 1210; https://doi.org/10.3390/ma15031210 - 05 Feb 2022

Cited by 3 | Viewed by 1511

Abstract

Mechanical properties of gallium nitride (GaN) single crystals upon carbon ion irradiation are examined using nanoindentation analysis at room temperature. Pop-in events in the load-depth curves are observed for unirradiated and irradiated GaN samples. A statistical linear relationship between the critical indentation load for the occurrence of the pop-in event and the associated displacement jump is exhibited. Both the slope of linear regression and the measured hardness increase monotonically to the ion fluence, which can be described by logistic equations. Moreover, a linear relationship between the regression slope as a micromechanical characterization and the hardness as a macroscopic mechanical property is constructed. It is also found that the maximum resolved shear stress of the irradiated samples is larger than that of the unirradiated samples, as the dislocation loops are pinned by the irradiation-induced defects. Our results indicate that the nanoindentation pop-in phenomenon combined with a statistical analysis can serve as a characterization method for the mechanical properties of ion-irradiated materials. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Figure 1

31 pages, 6393 KiB

Open AccessArticle

Rice-Husk Shredding as a Means of Increasing the Long-Term Mechanical Properties of Earthen Mixtures for 3D Printing

by Elena Ferretti, Massimo Moretti, Alberto Chiusoli, Lapo Naldoni, Francesco de Fabritiis and Massimo Visonà

Materials 2022, 15(3), 743; https://doi.org/10.3390/ma15030743 - 19 Jan 2022

Cited by 15 | Viewed by 3757

Abstract

This paper is part of a study on earthen mixtures for the 3D printing of buildings. To meet the ever increasing environmental needs, the focus of the paper is on a particular type of biocomposite for the stabilization of earthen mixtures—the rice-husk–lime biocomposite—and on how to enhance its effect on the long-term mechanical properties of the hardened product. Assuming that the shredding of the vegetable fiber is precisely one of the possible ways to improve the mechanical properties, we compared the results of uniaxial compression tests performed on cubic specimens, made with both shredded and unaltered vegetable fiber, for three curing periods. The results show that the hardened earthen mixture is not a brittle material, in the strict sense, because it exhibits some peculiar behaviors that are anomalous for a brittle material. However, being a “designable” material, its properties can be varied with a certain flexibility in order to become as close as possible to the desired ones. One of the peculiar properties of the hardened earthen mixture deserves further investigation, rather than corrections. This is the vulcanization that occurs (in a completely natural way) over the long term, thanks to the mineralization of the vegetable fiber by the carbonation of the lime. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Figure 1

31 pages, 12678 KiB

Open AccessArticle

Mechanical Properties of a 3D-Printed Wall Segment Made with an Earthen Mixture

by Elena Ferretti, Massimo Moretti, Alberto Chiusoli, Lapo Naldoni, Francesco De Fabritiis and Massimo Visonà

Materials 2022, 15(2), 438; https://doi.org/10.3390/ma15020438 - 07 Jan 2022

Cited by 10 | Viewed by 3235

Abstract

This study provides a contribution to the research field of 3D-printed earthen buildings, focusing, for the first time, on the load-bearing capacity of these structures. The study involves the entire production and testing process of the earthen elements, from the design, to the preparation of the mixture and the 3D printing, up to the uniaxial compression test on a wall segment. The results indicate that 3D-printed earthen elements have a compressive strength of 2.32 MPa, comparable to that of rammed earth structures. The experimental data also made it possible to draw conclusions on the action of the infill, which seems to have the function of stopping the propagation of cracks. This has a positive effect on the overall behavior of 3D-printed earthen elements, since it avoids the onset of dilative behavior in the final stages of the load test and maintains ultimate load values higher than 50% of the maximum load. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Figure 1

55 pages, 1725 KiB

Open AccessFeature PaperArticle

General Consistency of Strong Discontinuity Kinematics in Embedded Finite Element Method (E-FEM) Formulations

by Alejandro Ortega Laborin, Emmanuel Roubin, Yann Malecot and Laurent Daudeville

Materials 2021, 14(19), 5640; https://doi.org/10.3390/ma14195640 - 28 Sep 2021

Cited by 3 | Viewed by 1516

Abstract

This paper performs an in-depth study of the theoretical basis behind the strong discontinuity methods to improve local fracture simulations using the Embedded Finite Element Method (E-FEM). The process starts from a review of the elemental enhancement functions found in current E-FEM literature, providing the reader a solid context of E-FEM fundamentals. A set of theoretical pathologies is then discussed, which prevent current frameworks from attaining full kinematic consistency and introduce unintended mesh dependencies. Based on this analysis, a new proposal of strong discontinuity enhancement functions is presented considering generalised fracture kinematics in a full tridimensional setting and a more robust definition of internal auxiliary functions. Element-level simulations are performed to compare the outputs within a group of selected E-FEM approaches, including the novel proposal. Simulations show that the new element formulation grants a wider level of basic kinematic coherence between the local fracture outputs and element kinematics, demonstrating an increase in robustness that might drive the usefulness of E-FEM techniques for fracture simulations to a higher level. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Graphical abstract

18 pages, 4842 KiB

Open AccessArticle

On Phase Identification of Hardened Cement Pastes by Combined Nanoindentation and Mercury Intrusion Method

by Jingwei Ying, Xiangxin Zhang, Zhijun Jiang and Yijie Huang

Materials 2021, 14(12), 3349; https://doi.org/10.3390/ma14123349 - 17 Jun 2021

Cited by 6 | Viewed by 1969

Abstract

The micro-mechanical properties of hardened cement paste can be obtained by nanoindentation. Phases at different locations can generally be determined by using the Gaussian mixture model (GMM) method and the K-means clustering (KM) method. However, there are differences between analysis methods. In this study, pore structure and porosity of hardened cement paste aged three, seven, and 28 days were obtained by mercury intrusion porosimetry (MIP), and their micro-mechanical properties were obtained by the nanoindentation method. A new method, GMM-MIP and KM-MIP, was proposed to determine the phase of hardened cement paste based on the pore structure and nanoindentation results. The results show that GMM-MIP and KM-MIP methods are more reasonable than GMM and KM methods in determining the phase of hardened cement paste. GMM-MIP can be used to obtain reasonable phase distribution. If the micro-mechanical properties of each phase in hardened cement paste do not satisfy the normal distribution, the GMM method has significant defects. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Figure 1

19 pages, 6172 KiB

Open AccessArticle

Microparticle Size and Quantities Effect on the Mechanical Features of End of Life Tires in Thermoplastic Composites

by Marc Marín-Genescà, Jordi García-Amorós, Ramon Mujal-Rosas, Lluís Massagués Vidal and Xavier Colom Fajula

Materials 2020, 13(23), 5561; https://doi.org/10.3390/ma13235561 - 06 Dec 2020

Cited by 1 | Viewed by 1852

Abstract

Currently, the huge use of tires generates large quantities of waste material which represents a severe environmental problem. The common technique used for processing waste tires is crushing using mechanical methods and separating tire components like fibers, metals, and rubber from the used tire. The aim of this research is the recycling of this rubber from crushed tires, called ground tire rubber (GTR). With this aim, the manuscript analyses key mechanical properties of the thermoplastic composites produced by blending of crushed and micronized small particles of waste rubber tires with several industrial thermoplastic polymers. These types of composites are defined based on the total amount GTR in percent by weight, in the composite, and also, the particle sizes used in each case, so these aforementioned two variables (microparticle size and amounts) along with seven common industrial polymers define a series of composites for which the mechanical properties were tested, studied, analyzed and finally presented. Finally, the results obtained show that this proposed recycling method could be a way to enhance some specific polymer properties and could contribute to reducing the total of end of life used tire stocks environmental problem. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Figure 1

22 pages, 2994 KiB

Open AccessArticle

Topology Optimization for Maximizing the Fracture Resistance of Periodic Quasi-Brittle Composites Structures

by Daicong Da and Julien Yvonnet

Materials 2020, 13(15), 3279; https://doi.org/10.3390/ma13153279 - 23 Jul 2020

Cited by 23 | Viewed by 2815

Abstract

Topology optimization for maximizing the fracture resistance of particle-matrix composites is investigated. The methodology developed in our previous works, combining evolutionary topology optimization and phase field method to fracture embedding interfacial damage, is applied and extended to periodic composites and multiple objectives. On one hand, we constrain the periodicity of unit cells geometry and conduct their topology optimization for one given load prescribed over the whole structure. On the other hand, we consider a single unit cell whose topology is optimized with respect to the fracture energy criterion when subjected to multiple loads. Size effects are investigated. We show that significant enhancement of the fracture resistance can be achieved for the studied composite structures by the present method. In addition, a first attempt to fracture resistance enhancement of a unit cell associated with a material is investigated for multiple loads, exhibiting a complex optimized microstructure. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Graphical abstract

15 pages, 3089 KiB

Open AccessArticle

A Two-Stage Reconstruction of Microstructures with Arbitrarily Shaped Inclusions

by Ryszard Piasecki, Wiesław Olchawa, Daniel Frączek and Agnieszka Bartecka

Materials 2020, 13(12), 2748; https://doi.org/10.3390/ma13122748 - 17 Jun 2020

Cited by 5 | Viewed by 1651

Abstract

The main goal of our research is to develop an effective method with a wide range of applications for the statistical reconstruction of heterogeneous microstructures with compact inclusions of any shape, such as highly irregular grains. The devised approach uses multi-scale extended entropic descriptors (ED) that quantify the degree of spatial non-uniformity of configurations of finite-sized objects. This technique is an innovative development of previously elaborated entropy methods for statistical reconstruction. Here, we discuss the two-dimensional case, but this method can be generalized into three dimensions. At the first stage, the developed procedure creates a set of black synthetic clusters that serve as surrogate inclusions. The clusters have the same individual areas and interfaces as their target counterparts, but random shapes. Then, from a given number of easy-to-generate synthetic cluster configurations, we choose the one with the lowest value of the cost function defined by us using extended ED. At the second stage, we make a significant change in the standard technique of simulated annealing (SA). Instead of swapping pixels of different phases, we randomly move each of the selected synthetic clusters. To demonstrate the accuracy of the method, we reconstruct and analyze two-phase microstructures with irregular inclusions of silica in rubber matrix as well as stones in cement paste. The results show that the two-stage reconstruction (TSR) method provides convincing realizations for these complex microstructures. The advantages of TSR include the ease of obtaining synthetic microstructures, very low computational costs, and satisfactory mapping in the statistical context of inclusion shapes. Finally, its simplicity should greatly facilitate independent applications. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Graphical abstract

17 pages, 9108 KiB

Open AccessArticle

Experimental and Numerical Investigation on the Effect of Scratch Direction on Material Removal and Friction Characteristic in BK7 Scratching

by Wei Wang, Zhenping Wan, Shu Yang, Junyuan Feng, Liujie Dong and Longsheng Lu

Materials 2020, 13(8), 1842; https://doi.org/10.3390/ma13081842 - 14 Apr 2020

Cited by 9 | Viewed by 2793

Abstract

In order to study the influence of scratch direction on the deformation characteristics and material removal mechanism of optical glass BK7, nanoscratching experiments were conducted on a Nano indenter using Vickers indenter. Results indicate that the face-forward scratch is more likely to induce the initiation and propagation of lateral cracks, which is found to be more beneficial to material removal processes; in contrast, small chips and debris are released from the machined grooves without introducing lateral cracks in the edge-forward condition, leading to poor material removal efficiency. In addition, the choice of scratch direction can make differences to the elastic recovery rate of optical glass BK7. The results revealed that both the elastic recovery rate and the residual stresses of the material under the face-forward scratching are greater than those of the edge-forward scratching. A theoretical model for coefficient of friction (COF) under different scratch directions was established. It is found that the COF between indenter and workpiece in the edge-forward scratching is larger than the face-forward scratching under otherwise identical conditions, this finding is consistent with experimental results. A stress field analysis using finite element method (FEM) was conducted to understand the different crack initiation and propagation behaviors from different scratch directions. The current study discusses the significance of scratch direction on material removal behavior of optical glass BK7, and the results would encourage further research on investigating the connections between tool geometry and material removal mechanism. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Figure 1

21 pages, 5761 KiB

Open AccessArticle

Robust Optimization Scheme for Inverse Method for Crystal Plasticity Model Parametrization

by Mahdieh Shahmardani, Napat Vajragupta and Alexander Hartmaier

Materials 2020, 13(3), 735; https://doi.org/10.3390/ma13030735 - 06 Feb 2020

Cited by 13 | Viewed by 2149

Abstract

A bottom-up material modeling based on a nonlocal crystal plasticity model requires information of a large set of physical and phenomenological parameters. Because of the many material parameters, it is inherently difficult to determine the nonlocal crystal plasticity parameters. Therefore, a robust method is proposed to parameterize the nonlocal crystal plasticity model of a body-centered cubic (BCC) material by combining a nanoindentation test and inverse analysis. Nanoindentation tests returned the load–displacement curve and surface imprint of the considered sample. The inverse analysis is developed based on trust-region-reflective algorithm, which is the most robust optimization algorithm for the considered non-convex problem. The discrepancy function is defined to minimize both the load–displacement curves and the surface topologies of the considered material under applying varied indentation forces obtained from numerical models and experimental output. The numerical model results based on the identified material properties show good agreement with the experimental output. Finally, a sensitivity analysis performed changing the nonlocal crystal plasticity parameters in a predefined range emphasized that the geometrical factor has the most significant influence on the load–displacement curve and surface imprint parameters. Full article

(This article belongs to the Special Issue Advances in Micromechanical Behavior of Materials)

► Show Figures

Journal Menu

Journal Browser

Advances in Micromechanical Behavior of Materials

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (10 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI