Pub Date : 2025-10-26DOI: 10.1016/j.mechmat.2025.105533
Yasin Mohammadi, Sharif Shahbeyk
The mechanical performance of EPS concrete is strongly influenced by bead content and size, with smaller beads generally enhancing strength. This study develops a continuum mechanics framework that explicitly incorporates mortar, aggregates, and EPS beads. The mortar is modeled using a plastic-damage law, enhanced with a new compressive damage–strain relation and a strain-shifting procedure to reduce mesh sensitivity, while EPS beads are represented by an isotropic crushable foam model calibrated from experiments. A comprehensive set of meso-scale finite element analyses was conducted under both uniaxial compression and three-point bending, enabling prediction of compressive strength and modulus of rupture. The framework reproduces experimental strength–size dependencies, elucidates porosity-driven damage initiation and evolution, and introduces a new mathematical relation linking compressive strength with EPS volume ratio.
{"title":"Mesoscale finite element modeling of EPS bead size effect on the strength and failure of lightweight concrete","authors":"Yasin Mohammadi, Sharif Shahbeyk","doi":"10.1016/j.mechmat.2025.105533","DOIUrl":"10.1016/j.mechmat.2025.105533","url":null,"abstract":"<div><div>The mechanical performance of EPS concrete is strongly influenced by bead content and size, with smaller beads generally enhancing strength. This study develops a continuum mechanics framework that explicitly incorporates mortar, aggregates, and EPS beads. The mortar is modeled using a plastic-damage law, enhanced with a new compressive damage–strain relation and a strain-shifting procedure to reduce mesh sensitivity, while EPS beads are represented by an isotropic crushable foam model calibrated from experiments. A comprehensive set of meso-scale finite element analyses was conducted under both uniaxial compression and three-point bending, enabling prediction of compressive strength and modulus of rupture. The framework reproduces experimental strength–size dependencies, elucidates porosity-driven damage initiation and evolution, and introduces a new mathematical relation linking compressive strength with EPS volume ratio.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105533"},"PeriodicalIF":4.1,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-25DOI: 10.1016/j.mechmat.2025.105532
Abdalla Elbana, Amar Khennane
This study presents a multiscale framework to model the nonlinear constitutive behavior of particulate composites containing hollow ceramic inclusions. The composite consists of an elasto-plastic epoxy matrix, plastic in compression and linear elastic in tension, reinforced with brittle, linearly elastic fly ash microbubbles Representative volume elements (RVEs) with varying particle volume fractions (15–45 %) are used to capture the micromechanical response under multiaxial loading. A structured modeling strategy is employed, including the idealization of fly ash microbubbles as hollow spheres and calibration of cohesive zone models using experimental data and SEM fracture imaging. A three-dimensional yield surface is constructed from RVE simulations, incorporating pressure sensitivity and Lode angle dependence. A custom VUMAT subroutine was developed to implement the proposed yield function which incorporates compressive hardening, tensile softening via a fracture strain limit and a viscosity-based regularization scheme enhances stability in explicit dynamic simulations, especially under small strain increments with low hardening modulus or perfect plasticity. This unified micromechanics-driven approach enables simulation of progressive failure in syntactic foams and related composites.
{"title":"Development of generalized yield surface of fly ash microbubble composites using nonlinear multiscale analysis","authors":"Abdalla Elbana, Amar Khennane","doi":"10.1016/j.mechmat.2025.105532","DOIUrl":"10.1016/j.mechmat.2025.105532","url":null,"abstract":"<div><div>This study presents a multiscale framework to model the nonlinear constitutive behavior of particulate composites containing hollow ceramic inclusions. The composite consists of an elasto-plastic epoxy matrix, plastic in compression and linear elastic in tension, reinforced with brittle, linearly elastic fly ash microbubbles <span><math><mrow><mrow><mo>(</mo><mrow><mn>40</mn><msub><mrow><mi>A</mi><mi>l</mi></mrow><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub><mo>−</mo><mn>60</mn><mi>S</mi><mi>i</mi><msub><mi>O</mi><mn>2</mn></msub></mrow><mo>)</mo></mrow><mtext>.</mtext></mrow></math></span> Representative volume elements (RVEs) with varying particle volume fractions (15–45 %) are used to capture the micromechanical response under multiaxial loading. A structured modeling strategy is employed, including the idealization of fly ash microbubbles as hollow spheres and calibration of cohesive zone models using experimental data and SEM fracture imaging. A three-dimensional yield surface is constructed from RVE simulations, incorporating pressure sensitivity and Lode angle dependence. A custom VUMAT subroutine was developed to implement the proposed yield function which incorporates compressive hardening, tensile softening via a fracture strain limit and a viscosity-based regularization scheme enhances stability in explicit dynamic simulations, especially under small strain increments with low hardening modulus or perfect plasticity. This unified micromechanics-driven approach enables simulation of progressive failure in syntactic foams and related composites.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105532"},"PeriodicalIF":4.1,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-18DOI: 10.1016/j.mechmat.2025.105516
Adam Najem, Guillaume Altmeyer, Louis Esnault, Arnaud Duchosal
This work focuses on the characterization of the X100CrMoV5 steel alloy and the identification of its constitutive parameters for machining simulations using shear tests. Experimental tests were conducted on a thermo-mechanical Gleeble machine under dynamic conditions, at ambient and elevated temperatures. A numerical model was developed to simulate the shear test, enabling a comprehensive comparison with the experimental data. Both experimental and numerical data were de-noised using the Singular Value Decomposition (SVD) method, effectively removing experimental noise and numerical instabilities. The Levenberg–Marquardt identification algorithm based on gradient descent was then employed to minimize the error between numerical and experimental results, facilitating the simultaneous identification of all parameters of the material behavior model. This behavior model included an elastic phase, described by Hooke’s Law, followed by a thermo-visco-plastic phase, modeled using the Johnson–Cook law. The Johnson–Cook damage criterion was applied to determine the material’s rupture point, while the Hillerborg energy criterion was used to model energy dissipation during the damage process. Additionally, the Taylor–Quinney coefficient was incorporated to model thermo-mechanical dissipation. All parameters were identified through a global identification approach, wherein they were determined simultaneously to account for their inter-dependencies using all available experimental data. The experimental data sets where used either individually or collectively influencing the identification procedure. The results of the characterization and identification of the behavior of X100CrMoV5 are presented here, highlighting the material’s response under varying conditions and the role of the identification approach used.
{"title":"Influence of experimental data set choice for constitutive parameters identification for machining simulations","authors":"Adam Najem, Guillaume Altmeyer, Louis Esnault, Arnaud Duchosal","doi":"10.1016/j.mechmat.2025.105516","DOIUrl":"10.1016/j.mechmat.2025.105516","url":null,"abstract":"<div><div>This work focuses on the characterization of the X100CrMoV5 steel alloy and the identification of its constitutive parameters for machining simulations using shear tests. Experimental tests were conducted on a thermo-mechanical Gleeble machine under dynamic conditions, at ambient and elevated temperatures. A numerical model was developed to simulate the shear test, enabling a comprehensive comparison with the experimental data. Both experimental and numerical data were de-noised using the Singular Value Decomposition (SVD) method, effectively removing experimental noise and numerical instabilities. The Levenberg–Marquardt identification algorithm based on gradient descent was then employed to minimize the error between numerical and experimental results, facilitating the simultaneous identification of all parameters of the material behavior model. This behavior model included an elastic phase, described by Hooke’s Law, followed by a thermo-visco-plastic phase, modeled using the Johnson–Cook law. The Johnson–Cook damage criterion was applied to determine the material’s rupture point, while the Hillerborg energy criterion was used to model energy dissipation during the damage process. Additionally, the Taylor–Quinney coefficient was incorporated to model thermo-mechanical dissipation. All parameters were identified through a global identification approach, wherein they were determined simultaneously to account for their inter-dependencies using all available experimental data. The experimental data sets where used either individually or collectively influencing the identification procedure. The results of the characterization and identification of the behavior of X100CrMoV5 are presented here, highlighting the material’s response under varying conditions and the role of the identification approach used.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105516"},"PeriodicalIF":4.1,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145418205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-16DOI: 10.1016/j.mechmat.2025.105525
Federico Califano , Jacopo Ciambella
An established method for incorporating inelastic constitutive equations into finite element software is the use of rheological elements, assembled in series or in parallel, to describe the constitutive response at each material point. This approach can be extended to finite strains by exploiting the multiplicative decomposition of the deformation gradient. In this study, we propose an hybrid approach that integrates traditional elements with elements, with constitutive equations defined through deep neural networks (DNNs), into an assemblage of standard rheological elements. We formulate DNNs to guarantee thermodynamic consistency, enabling us to model the time-dependent, large strain response of elastomers and predict the Payne effect in filled rubber. This effect, characterized by deformation-enhanced shear thinning, poses unique modeling challenges. Additionally, we discuss data augmentation procedures to address the data-intensive nature of training neural networks, showcasing the effectiveness of utilizing ordinary dynamic mechanical analysis (DMA) tests for this purpose.
{"title":"Enhancing nonlinear viscoelastic modeling of elastomers through neural networks: A deep rheological element","authors":"Federico Califano , Jacopo Ciambella","doi":"10.1016/j.mechmat.2025.105525","DOIUrl":"10.1016/j.mechmat.2025.105525","url":null,"abstract":"<div><div>An established method for incorporating inelastic constitutive equations into finite element software is the use of rheological elements, assembled in series or in parallel, to describe the constitutive response at each material point. This approach can be extended to finite strains by exploiting the multiplicative decomposition of the deformation gradient. In this study, we propose an hybrid approach that integrates traditional elements with elements, with constitutive equations defined through deep neural networks (DNNs), into an assemblage of standard rheological elements. We formulate DNNs to guarantee thermodynamic consistency, enabling us to model the time-dependent, large strain response of elastomers and predict the Payne effect in filled rubber. This effect, characterized by deformation-enhanced shear thinning, poses unique modeling challenges. Additionally, we discuss data augmentation procedures to address the data-intensive nature of training neural networks, showcasing the effectiveness of utilizing ordinary dynamic mechanical analysis (DMA) tests for this purpose.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105525"},"PeriodicalIF":4.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.mechmat.2025.105515
Mohsen Farsiani , Hossein M. Shodja
A precise analytical treatment for predicting the behavior of nano-sized magneto-electro-elastic (MEE) antennas and resonators under incident acoustic waves requires careful consideration of multiphysics surface/interface effects, including magnetization, polarization, and elasticity. To date, no analytical solutions have incorporated all three phenomena simultaneously. By addressing these surface effects, this work presents a rigorous mathematical analysis of a nano-sized spherically isotropic embedded MEE spherical shell subjected to incident acoustic waves. The set of coupled spectral constitutive relations relevant to the bulk of the MEE spherical shell is distinguished from those pertinent to its free inner surface and matrix-shell interface. The surrounding matrix may consist of an isotropic dielectric or metallic material. Conventional electrodynamics theories are insufficient to address this problem, as they do not adequately account for MEE effects at the surface or interface. To overcome this limitation, the study employs the equivalent impedance matrix (EIM) method combined with surface/interface elasticity to model the surface/interface MEE behaviors rigorously. For metallic matrices, a plasmonics-based mathematical framework is utilized, with the optical properties described by the plasma model to accurately capture metallic behavior. The spectral EIM method, combined with vector and tensor spherical harmonics forming a Schauder basis for square-integrable vector fields and second-rank symmetric tensor fields on the unit sphere, is shown to be a pivotal tool for solving the fully coupled elastodynamics and Maxwell’s equations. This approach is particularly effective in capturing significant MEE surface/interface effects. This methodology enables a detailed exploration of surface/interface characteristic lengths, facilitating the examination of size-dependent effects on electromagnetic radiated power and fundamental resonance frequency. The findings provide valuable insights into the behavior of acoustically actuated nanospherical antennas, nanosensors, and nanoresonators based on MEE nanospheres. Moreover, these results have significant implications for the design and optimization of nanoscale devices in advanced technological applications.
{"title":"An augmented surface impedance theory for acoustically actuated magneto-electro-elastic nanospheres with terahertz nanoantenna applications","authors":"Mohsen Farsiani , Hossein M. Shodja","doi":"10.1016/j.mechmat.2025.105515","DOIUrl":"10.1016/j.mechmat.2025.105515","url":null,"abstract":"<div><div>A precise analytical treatment for predicting the behavior of nano-sized magneto-electro-elastic (MEE) antennas and resonators under incident acoustic waves requires careful consideration of multiphysics surface/interface effects, including magnetization, polarization, and elasticity. To date, no analytical solutions have incorporated all three phenomena simultaneously. By addressing these surface effects, this work presents a rigorous mathematical analysis of a nano-sized spherically isotropic embedded MEE spherical shell subjected to incident acoustic waves. The set of coupled spectral constitutive relations relevant to the bulk of the MEE spherical shell is distinguished from those pertinent to its free inner surface and matrix-shell interface. The surrounding matrix may consist of an isotropic dielectric or metallic material. Conventional electrodynamics theories are insufficient to address this problem, as they do not adequately account for MEE effects at the surface or interface. To overcome this limitation, the study employs the equivalent impedance matrix (EIM) method combined with surface/interface elasticity to model the surface/interface MEE behaviors rigorously. For metallic matrices, a plasmonics-based mathematical framework is utilized, with the optical properties described by the plasma model to accurately capture metallic behavior. The spectral EIM method, combined with vector and tensor spherical harmonics forming a Schauder basis for square-integrable vector fields and second-rank symmetric tensor fields on the unit sphere, is shown to be a pivotal tool for solving the fully coupled elastodynamics and Maxwell’s equations. This approach is particularly effective in capturing significant MEE surface/interface effects. This methodology enables a detailed exploration of surface/interface characteristic lengths, facilitating the examination of size-dependent effects on electromagnetic radiated power and fundamental resonance frequency. The findings provide valuable insights into the behavior of acoustically actuated nanospherical antennas, nanosensors, and nanoresonators based on MEE nanospheres. Moreover, these results have significant implications for the design and optimization of nanoscale devices in advanced technological applications.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105515"},"PeriodicalIF":4.1,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-15DOI: 10.1016/j.mechmat.2025.105529
Zhigang Liu , Guian Man , Xuhui Fan , Boyuan Huang , Jiangyu Li
Dielectric polymers such as biaxially oriented polypropylene (BOPP) are widely used in capacitors for electric energy storage and pulse power. Under working conditions, they are subjected to high voltage as well as cyclic charging and discharging, resulting in significant Maxwell strain that evolves due to viscoelasticity. Such creep behavior has important implications to the reliability, aging, and breakdown failure of dielectric polymers, and we seek to understand it with the goal to predict the long term strain evolution using short term experimental data. We established a digital image correlation based experimental setup to monitor field induced deformation in-situ, observing significant strain concentration as well as creep. We carried out systematical analysis using Burgers model and find that it is incapable of predicting long term local creep of BOPP at strain concentration, despite its success in capturing mechanical creep as well as the evolution of average strain under an electric field. We thus developed a modified Burgers model that accounts for the evolution of concentrated electric field and accurately predicted long term local creep under either constant or cyclic voltage. In particular, we successfully predicted the evolution of concentrated local strain up to 106 s using the experimental data in the first 103 s, demonstrating the power of our modified Burgers model. We expect that the modified Burgers model will play an important role in analyzing aging and failure behaviors of dielectric polymers and capacitive devices.
{"title":"Electrically induced local creep in dielectric polymers: Experiments and modeling","authors":"Zhigang Liu , Guian Man , Xuhui Fan , Boyuan Huang , Jiangyu Li","doi":"10.1016/j.mechmat.2025.105529","DOIUrl":"10.1016/j.mechmat.2025.105529","url":null,"abstract":"<div><div>Dielectric polymers such as biaxially oriented polypropylene (BOPP) are widely used in capacitors for electric energy storage and pulse power. Under working conditions, they are subjected to high voltage as well as cyclic charging and discharging, resulting in significant Maxwell strain that evolves due to viscoelasticity. Such creep behavior has important implications to the reliability, aging, and breakdown failure of dielectric polymers, and we seek to understand it with the goal to predict the long term strain evolution using short term experimental data. We established a digital image correlation based experimental setup to monitor field induced deformation <em>in-situ</em>, observing significant strain concentration as well as creep. We carried out systematical analysis using Burgers model and find that it is incapable of predicting long term local creep of BOPP at strain concentration, despite its success in capturing mechanical creep as well as the evolution of average strain under an electric field. We thus developed a modified Burgers model that accounts for the evolution of concentrated electric field and accurately predicted long term local creep under either constant or cyclic voltage. In particular, we successfully predicted the evolution of concentrated local strain up to 10<sup>6</sup> s using the experimental data in the first 10<sup>3</sup> s, demonstrating the power of our modified Burgers model. We expect that the modified Burgers model will play an important role in analyzing aging and failure behaviors of dielectric polymers and capacitive devices.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105529"},"PeriodicalIF":4.1,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.mechmat.2025.105528
Jiaxuan Wang , Rou Du , Liu Chen , Hansong Ma , Xiaoming Liu , Yueguang Wei
Nickel-based single crystal (NBSC) superalloys are extensively used in the fabrication of turbine blades for aero engines, where their deformation behaviours play a critical role in ensuring flight safety. The deformation behaviours are governed by complex micro-scale mechanisms, such as matrix slip, precipitate shearing, interface dislocation pile-up, dislocation climb, coarsening, and rafting. However, many existing models either inadequately account for the underlying deformation mechanisms or rely heavily on temperature-sensitive material parameters, both of which undermine their predictive accuracy and generalizability under diverse loading and thermal conditions. To address these limitations, this study develops a robust and versatile crystal plasticity model that incorporates the above mechanisms. The model decouples temperature effects from constitutive parameters to mitigate parameter sensitivity to temperature variations. Additionally, a parameter decoupling strategy is employed to reduce the number of adjustable parameters and facilitate their identification. The model is validated against experimental data for the DD6 superalloy under uniaxial tension, creep, and low-cycle fatigue tests conducted across a wide temperature range (20–980 °C). The predicted mechanical responses demonstrate good agreement with the experimental results. Finally, the model is applied to simulate the mechanical behaviour of a specimen with inclined cooling holes. The model gives a nearly linear response of creep displacement, which matches well with the experiments.
{"title":"A physics-based crystal plasticity model of nickel-based single crystal superalloy for different loading conditions under a wide temperature range","authors":"Jiaxuan Wang , Rou Du , Liu Chen , Hansong Ma , Xiaoming Liu , Yueguang Wei","doi":"10.1016/j.mechmat.2025.105528","DOIUrl":"10.1016/j.mechmat.2025.105528","url":null,"abstract":"<div><div>Nickel-based single crystal (NBSC) superalloys are extensively used in the fabrication of turbine blades for aero engines, where their deformation behaviours play a critical role in ensuring flight safety. The deformation behaviours are governed by complex micro-scale mechanisms, such as matrix slip, precipitate shearing, interface dislocation pile-up, dislocation climb, coarsening, and rafting. However, many existing models either inadequately account for the underlying deformation mechanisms or rely heavily on temperature-sensitive material parameters, both of which undermine their predictive accuracy and generalizability under diverse loading and thermal conditions. To address these limitations, this study develops a robust and versatile crystal plasticity model that incorporates the above mechanisms. The model decouples temperature effects from constitutive parameters to mitigate parameter sensitivity to temperature variations. Additionally, a parameter decoupling strategy is employed to reduce the number of adjustable parameters and facilitate their identification. The model is validated against experimental data for the DD6 superalloy under uniaxial tension, creep, and low-cycle fatigue tests conducted across a wide temperature range (20–980 °C). The predicted mechanical responses demonstrate good agreement with the experimental results. Finally, the model is applied to simulate the mechanical behaviour of a specimen with inclined cooling holes. The model gives a nearly linear response of creep displacement, which matches well with the experiments.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105528"},"PeriodicalIF":4.1,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-14DOI: 10.1016/j.mechmat.2025.105527
Yubo Hou , Adel Noori , Kairan Zhang , Yuhan Zheng , Hao Wang , Yubin Lu
Bamboo has gained significant attention in sustainable buildings for its rapid growth rate and impressive mechanical properties comparable to wood. The volume fraction and gradient arrangement of vascular bundles directly influence the mechanical properties of bamboo. This paper proposes a novel gradient random distribution method, which can accurately restore the gradient distribution of bamboo vascular bundles along the radial direction of the culm wall. The aim is to uncover the relationship between the gradient distribution pattern of vascular bundles and the mechanical properties. The gradient random distribution method helps to transform the uniform random Representative Volume Element model into a gradient random distribution numerical model using the concept of coordinate transformation. The comparative analysis was conducted between the uniform random distribution method and the gradient random distribution method to predict the effective elastic properties of bamboo vascular bundles. The results indicated that elastic modulus and shear modulus of bamboo exhibit an exponential increase from the inner to the outer layers along the radial direction of the culm wall. Larger fiber spacing can slightly decrease the corresponding shear modulus. Moreover, the gradient random distribution method is capable of predicting accurately the elastic stiffness properties of full-sized bamboo culm compared to the uniform random distribution method.
{"title":"Micromechanical modeling and property prediction of bamboo with gradient random vascular bundles","authors":"Yubo Hou , Adel Noori , Kairan Zhang , Yuhan Zheng , Hao Wang , Yubin Lu","doi":"10.1016/j.mechmat.2025.105527","DOIUrl":"10.1016/j.mechmat.2025.105527","url":null,"abstract":"<div><div>Bamboo has gained significant attention in sustainable buildings for its rapid growth rate and impressive mechanical properties comparable to wood. The volume fraction and gradient arrangement of vascular bundles directly influence the mechanical properties of bamboo. This paper proposes a novel gradient random distribution method, which can accurately restore the gradient distribution of bamboo vascular bundles along the radial direction of the culm wall. The aim is to uncover the relationship between the gradient distribution pattern of vascular bundles and the mechanical properties. The gradient random distribution method helps to transform the uniform random Representative Volume Element model into a gradient random distribution numerical model using the concept of coordinate transformation. The comparative analysis was conducted between the uniform random distribution method and the gradient random distribution method to predict the effective elastic properties of bamboo vascular bundles. The results indicated that elastic modulus and shear modulus of bamboo exhibit an exponential increase from the inner to the outer layers along the radial direction of the culm wall. Larger fiber spacing can slightly decrease the corresponding shear modulus. Moreover, the gradient random distribution method is capable of predicting accurately the elastic stiffness properties of full-sized bamboo culm compared to the uniform random distribution method.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105527"},"PeriodicalIF":4.1,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-11DOI: 10.1016/j.mechmat.2025.105523
Zahra Ghasemi , Tiago dos Santos , Debjoy D. Mallick , José A. Rodríguez-Martínez , Ankit Srivastava
We examine the interplay between strain-rate hardening and structural inertia in dynamic indentation, with the objective of identifying when dynamic hardness reflects intrinsic material response versus when it is influenced by inertia. Finite element simulations and theoretical calculations – based on a dynamic cavity expansion model – are performed for materials described by a strain- and strain-rate-dependent constitutive model with thermal softening. The analysis spans a broad range of indentation velocities, depths, material densities, and strain-rate sensitivity exponents. Our results show that at relatively low to moderate indentation velocities, dynamic hardness can be interpreted as an intrinsic material property. However, at sufficiently high velocities, the indentation response is significantly influenced by inertia-induced resistance, manifested by a rapid increase in hydrostatic stress and, consequently, in dynamic hardness. The extent of this resistance scales with indentation strain rate, indentation depth, and material density. We introduce a normalization approach that, for a given material, accounts for inertia by scaling dynamic hardness and indentation strain rate with reference functions that depend on indentation velocity. This procedure enables the identification of the loading rate at which inertia begins to dominate the indentation response and allows data across a wide range of indentation strain rates and depths to be interpreted in terms of the material’s intrinsic strain-rate-dependent constitutive behavior. The excellent agreement between finite element simulations and theoretical predictions underscores the robustness of the proposed approach and establishes a foundation for extracting strain-rate-sensitive material properties from dynamic indentation experiments.
{"title":"Delineating strain-rate hardening and inertial effects on dynamic hardness of materials","authors":"Zahra Ghasemi , Tiago dos Santos , Debjoy D. Mallick , José A. Rodríguez-Martínez , Ankit Srivastava","doi":"10.1016/j.mechmat.2025.105523","DOIUrl":"10.1016/j.mechmat.2025.105523","url":null,"abstract":"<div><div>We examine the interplay between strain-rate hardening and structural inertia in dynamic indentation, with the objective of identifying when dynamic hardness reflects intrinsic material response versus when it is influenced by inertia. Finite element simulations and theoretical calculations – based on a dynamic cavity expansion model – are performed for materials described by a strain- and strain-rate-dependent constitutive model with thermal softening. The analysis spans a broad range of indentation velocities, depths, material densities, and strain-rate sensitivity exponents. Our results show that at relatively low to moderate indentation velocities, dynamic hardness can be interpreted as an intrinsic material property. However, at sufficiently high velocities, the indentation response is significantly influenced by inertia-induced resistance, manifested by a rapid increase in hydrostatic stress and, consequently, in dynamic hardness. The extent of this resistance scales with indentation strain rate, indentation depth, and material density. We introduce a normalization approach that, for a given material, accounts for inertia by scaling dynamic hardness and indentation strain rate with reference functions that depend on indentation velocity. This procedure enables the identification of the loading rate at which inertia begins to dominate the indentation response and allows data across a wide range of indentation strain rates and depths to be interpreted in terms of the material’s intrinsic strain-rate-dependent constitutive behavior. The excellent agreement between finite element simulations and theoretical predictions underscores the robustness of the proposed approach and establishes a foundation for extracting strain-rate-sensitive material properties from dynamic indentation experiments.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105523"},"PeriodicalIF":4.1,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-10DOI: 10.1016/j.mechmat.2025.105524
Özgün Şener , Altan Kayran
The effect of microdamaging on the failure of unidirectional Interglas 92145/CR80 GFRP laminates is studied through experiments and a numerical approach combining Enhanced Schapery Theory (EST) and Crack Band Theory (CBT). Open-hole tension tests with various layer configurations, along with flat tensile tests were conducted to examine failure modes and their progression. The initiation and development of failure mechanisms were tracked experimentally using DIC imaging. In the numerical model, the matrix microdamage is represented through dissipated energy-dependent functions derived from standardized mechanical tests. Without discretely modeling splitting cracks, the numerical approach captured narrow zones of fiber and matrix failure coincident with experimentally observed crack paths. Axial, transverse, and shear strain fields from the physical and virtual tests were compared at the critical stages of the testing regimen. Comparison of the strain fields, as well as stress-strain curves from the numerical and experimental studies showed good agreement, suggesting that incorporation of microdamage modeling—rarely implemented in progressive failure analyses—offers potential for improving failure predictions in GFRP laminates.
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