Mechanics of Materials最新文献_第7页

Fractional order strain and viscosity in the Moore–Gibson–Thompson thermoelastic diffusion model: A study of transient responses in one-dimensional half-space Moore-Gibson-Thompson热弹性扩散模型中的分数阶应变和黏度：一维半空间瞬态响应的研究

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-11-07 DOI: 10.1016/j.mechmat.2025.105542

Geetanjali Geetanjali , Pawan Kumar Sharma

In the mathematical modeling of viscoelastic materials such as biological tissues, polycrystalline metals, and high polymers, fractional order strain is widely adopted to highlight their rheological properties. Moreover, models incorporating fractional calculus provide more rational results. In this light, we consider fractional Moore–Gibson–Thompson model of generalized visco-thermoelastic-diffusion to study the transient responses of a one dimensional half space. The novelty of the present work lies in considering fractional order strain and fractional viscosity in the considered framework. Initially, the medium is kept at rest and at the boundary, thermal shock is applied in a stress free state. The basic equations and relations governing the problem are non-dimensionalized and solved in a Laplace transformed domain using the boundary restrictions. The solution of the problem is obtained in the original domain via a numerical inversion technique. This work aims to underline the impact of different models, fractional order strain, and viscosity parameters on physical quantities. Graphical representation of the results elucidates that fractional viscosity softens the stiffness in the distribution of field variables and fractional order strain eliminates the sudden increment in their peak points. Also, different models have varying degree of influence on all the field variables.

在生物组织、多晶金属和高聚物等粘弹性材料的数学建模中，广泛采用分数阶应变来突出其流变性能。此外，结合分数阶微积分的模型提供了更合理的结果。在这种情况下，我们考虑广义粘热弹扩散的分数阶Moore-Gibson-Thompson模型来研究一维半空间的瞬态响应。本工作的新颖之处在于在考虑的框架中考虑分数阶应变和分数阶粘度。最初，介质保持静止，在边界处，热冲击以无应力状态施加。控制问题的基本方程和关系是无量纲化的，并在拉普拉斯变换域中利用边界限制进行求解。通过数值反演技术在原域得到了问题的解。这项工作的目的是强调不同的模型，分数阶应变和粘度参数对物理量的影响。结果的图形表示表明，分数阶粘度软化了场变量分布中的刚度，分数阶应变消除了其峰值点的突然增量。不同的模型对各场变量的影响程度也不同。

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引用次数: 0

Disordered origins, deterministic outcomes: How the architecture of elastic networks imprints relaxed structure and mechanics 无序的起源，确定性的结果：弹性网络的结构如何影响松弛结构和力学

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-11-03 DOI: 10.1016/j.mechmat.2025.105538

Stefanie Heyden , Mohit Pundir , Eric R. Dufresne , David S. Kammer

This work targets the influence of disorder on the relaxed structure and macroscopic mechanical properties of elastic networks. We construct network classes of different types of disorder (length, topology and stiffness), which are subsequently equilibrated in a finite kinematics setting. Relaxed network structures are distinct among network classes, which opens the path towards exploiting easily accessible experimental measures as a way of inferring further microstructural details.

本工作的目标是无序对弹性网络的松弛结构和宏观力学性能的影响。我们构建了不同类型的无序（长度，拓扑和刚度）的网络类，这些网络类随后在有限的运动学设置中进行平衡。松弛的网络结构在网络类别中是不同的，这为利用容易获得的实验措施作为推断进一步微观结构细节的方法开辟了道路。

引用次数: 0

Mechanical behaviour and damage assessment of AlSi10Mg lattice structures fabricated by laser powder bed fusion under static and fatigue loading 静态和疲劳载荷下激光粉末床熔合制备AlSi10Mg晶格结构的力学行为及损伤评估

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-31 DOI: 10.1016/j.mechmat.2025.105530

Hugo Soul , Vladimir Brailovski , Alejandro Yawny

The monotonic and fatigue mechanical behaviour of diamond cell lattice structures fabricated by Laser Powder Bed Fusion (L-PFB) from Al10SiMg powder with two relative densities (∼40 and 50 %) was investigated. Pseudostatic tensile, compression and cyclic uniaxial loading tests were carried out with stress ratios R of 0.1 (pull-pull), 10 (push-push) and −1 (symmetric pull-push). The lattice specimens' design incorporated fully dense end regions to facilitate clamping and enable the application of both tensile and compressive loads. Furthermore, smooth graded transitions between the central region of constant relative density and the fully dense extremities were implemented to mitigate stress concentration effects during cyclic loading. The study included measurements of the Young's modulus, the yielding behaviour, the strength, the ductility and the fracture characteristics, and involved a comparison between the tensile and compression monotonic test results, including the collapse and crush patterns associated with the tests. The fatigue test results were then used to analyze damage accumulation over the specimens' lifetimes as indicated by the measured strain response, which exhibited a three-stage pattern. Subsequently, S-N diagrams were built as a function of the global stress amplitude and global maximum stress applied. A novel local stress parameter, encompassing the maximum normal and shear stresses, was proposed as an alternative method for rationalizing fatigue data for lattice structures. This comprehensive investigation provides insight into the mechanical performance and fatigue characteristics of diamond cell lattice structures under various loading conditions.

研究了相对密度（~ 40%和50%）的Al10SiMg粉末激光粉末床熔合（L-PFB）制备的金刚石细胞晶格结构的单调力学行为和疲劳力学行为。拟静力拉伸、压缩和循环单轴加载试验，应力比R分别为0.1（拉-拉）、10（推-推）和−1（对称拉-推）。晶格试样的设计结合了完全密集的端区，以方便夹紧，并使拉伸和压缩载荷的应用。此外，在恒定相对密度的中心区域和完全密集的末端之间实现平滑的渐变过渡，以减轻循环加载时的应力集中效应。该研究包括杨氏模量、屈服行为、强度、延性和断裂特征的测量，并涉及拉伸和压缩单调试验结果之间的比较，包括与试验相关的崩溃和挤压模式。然后使用疲劳试验结果来分析试样寿命期间的损伤积累，这表明测量的应变响应呈现出三个阶段的模式。随后，建立了S-N图，作为全局应力幅值和全局最大应力的函数。提出了一种新的局部应力参数，包括最大法向应力和最大剪应力，作为优化晶格结构疲劳数据的替代方法。这项全面的研究提供了对不同载荷条件下金刚石细胞晶格结构的力学性能和疲劳特性的深入了解。

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引用次数: 0

An accelerated shock fatigue life model for complex shock loads with load dispersion 考虑载荷分散的复杂冲击载荷的加速冲击疲劳寿命模型

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-30 DOI: 10.1016/j.mechmat.2025.105535

Yi Sun, Shuai Ma, Yongbin Dang, Zhiqiang Yang

This paper presents an accelerated shock fatigue life model based on load dispersion, which utilizes the experimental life data under high-magnitude loads to assess whether the structure meets the fatigue life design requirements under its original load conditions, thereby improving the experimental efficiency. Firstly, a shock fatigue life database is established by combining experiments with finite element analysis. Then, the shock load dispersion effect is quantified by data fitting, and the relationship between the shock response spectrum parameters and the Weibull parameters is obtained. Finally, a new accelerated shock fatigue life model is established by introducing a relative dispersion factor based on the inverse power law model. Taking BGA solder joints as an example, the shock fatigue damage equivalent boundary of BGA solder joints is calculated. The results show that the error between the predicted boundary and the actual boundary is in the range of −5 %–7 %, verifying the effectiveness of the model.

本文提出了一种基于载荷分散的加速冲击疲劳寿命模型，利用高量级载荷下的实验寿命数据来评估结构在其原始载荷条件下是否满足疲劳寿命设计要求，从而提高了实验效率。首先，将实验与有限元分析相结合，建立了冲击疲劳寿命数据库；然后，通过数据拟合量化冲击载荷弥散效应，得到冲击响应谱参数与威布尔参数之间的关系。最后，在逆幂律模型的基础上引入相对弥散因子，建立了新的加速冲击疲劳寿命模型。以BGA焊点为例，计算了BGA焊点的冲击疲劳损伤等效边界。结果表明，预测边界与实际边界的误差在−5% ~ 7%之间，验证了模型的有效性。

引用次数: 0

Molecular insights of acoustic softening mechanism in ultrasonic vibration-assisted tensile deformation of SiC/Al composites 超声振动辅助SiC/Al复合材料拉伸变形声软化机理的分子研究

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-30 DOI: 10.1016/j.mechmat.2025.105539

Ben An, Jiaqi Li, Zhenshun Li, Diping Wu, Rui Li

Ultrasonic vibration (UV) has been widely utilized in metal forming processes owing to its ability to enhance material formability. However, the microscopic mechanism governing the plastic deformation of SiC/Al composites under UV remains unclear, thereby significantly restricting their implementation in ultra-precision machining applications. To address this gap, a particle-reinforced composite model was developed using the Random Sequential Adsorption (RSA) algorithm, and molecular dynamics simulations were conducted to compare the tensile behavior of SiC/Al composites under UV and non-UV conditions. The effects of SiC volume fraction and particle size on mechanical properties were systematically evaluated and the mechanism of UV-induced acoustic softening was discussed. The results showed that the increase of SiC particle size from 16 Å to 32 Å and the decrease of volume fraction from 13.8 % to 8.3 % diminished both tensile strength and elastic modulus. UV enhanced atomic kinetic energy and grain boundary potential energy, thereby facilitating dislocation annihilation and suppressing dislocation pile-ups, ultimately reducing flow stress. The stress reduction due to acoustic softening was correlated with dislocation evolution dynamics and increases with ultrasonic amplitude. This work sheds light on theoretical framework for optimizing the efficient processing of particle-reinforced SiC/Al composites under UV.

超声振动（UV）由于能够提高材料的成形性，在金属成形工艺中得到了广泛的应用。然而，控制SiC/Al复合材料在UV下塑性变形的微观机制尚不清楚，从而极大地限制了其在超精密加工中的应用。为了解决这一问题，研究人员利用随机顺序吸附（RSA）算法建立了颗粒增强复合材料模型，并进行了分子动力学模拟，比较了SiC/Al复合材料在紫外线和非紫外线条件下的拉伸行为。系统评价了碳化硅体积分数和粒径对力学性能的影响，探讨了紫外光声软化的机理。结果表明：SiC粒径从16 Å增大到32 Å，体积分数从13.8%减小到8.3%，拉伸强度和弹性模量均降低；UV提高原子动能和晶界势能，从而促进位错湮灭，抑制位错堆积，最终降低流动应力。声软化引起的应力减小与位错演化动力学相关，并随超声振幅的增大而增大。本研究为优化UV下颗粒增强SiC/Al复合材料的高效加工提供了理论框架。

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引用次数: 0

A sole-material hierarchical lattice structure with simultaneous tunable thermal expansion and low-frequency bandgap properties 具有同时可调热膨胀和低频带隙特性的鞋底材料分层晶格结构

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-30 DOI: 10.1016/j.mechmat.2025.105537

Yunhao Zhang , Hao Xia , Zhendong Sha

Hierarchical lattice structures (HLSs) characterized by multiscale and self-similar geometries have attracted increasing attention due to their exceptional mechanical and functional performance. However, almost HLSs focus on bi-material systems, which often suffer from interfacial mismatches. Herein, we propose an HLS composed of a sole-material system of Ti₅Si₃ with an anisotropic characteristic. This design eliminates interfacial mismatches inherent in bi-material systems and leverages geometry-anisotropy coupling to achieve tunable behavior with reliable and predictable performance. A theoretical framework is established to derive the expressions of thermal expansion coefficient (α). Bloch wave theory and eigenfrequency simulations are employed to evaluate bandgap characteristics and wave propagation behavior. Our results demonstrate that the α is significantly reduced at a small internal angle of 30° and high aspect ratio of 15, achieving a minimum value of 2.56 ppm K⁻¹ at the third hierarchical level. Accompanied by the decrease in α values, low-frequency bandgaps below 1000 Hz occur. It is also demonstrated that with the increase in hierarchical level, multiple narrower bandgaps are observed due to altered vibration mode patterns. In contrast with previous bi-material HLSs, our sole-material HLS exhibits not only simple manufacturability but also multi-functionalization.

层次晶格结构具有多尺度和自相似的几何特征，由于其优异的力学和功能性能而受到越来越多的关注。然而，几乎所有的hss都集中在双材料系统上，这些系统经常受到界面不匹配的影响。在此，我们提出了一个由具有各向异性特征的Ti5Si3鞋底材料体系组成的HLS。这种设计消除了双材料系统固有的界面不匹配，并利用几何各向异性耦合来实现具有可靠和可预测性能的可调行为。建立了推导热膨胀系数（α）表达式的理论框架。采用布洛赫波理论和特征频率模拟来评估带隙特性和波的传播行为。结果表明，在30°的小内角和15的高长宽比下，α显著降低，在第三层次上达到最小值2.56 ppm K−1。伴随着α值的减小，出现了低于1000hz的低频带隙。结果还表明，随着分层水平的增加，由于振动模式的改变，观察到多个更窄的带隙。与以前的双材料HLS相比，我们的鞋底材料HLS不仅具有简单的可制造性，而且具有多功能。

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引用次数: 0

Soft orthotropic hyperelastic lattice structures: Numerical homogenization and experimental validation 软正交各向异性超弹性晶格结构：数值均匀化和实验验证

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-28 DOI: 10.1016/j.mechmat.2025.105534

Dror Raf, Itay Magen, Amit Ashkenazi, Lee Jordan, Dana Solav

Lattice structures have become increasingly popular in various applications due to their lightweight and wide range of effective properties that can be locally tailored by adjusting their geometric features. Finite element (FE) simulations are commonly used to predict their mechanical response and inform inverse design algorithms. However, these simulations pose significant computational demands due to the large number of elements needed for meshing lattice geometries. This challenge can be addressed by replacing lattice geometries with a homogeneous solid of equivalent mechanical properties, a process known as homogenization. However, determining a suitable constitutive model and parameters is difficult, particularly when the response is nonlinear and anisotropic. To this end, this study presents a method for numerically homogenizing orthotropic lattice structures subjected to large elastic deformations. FE simulations of lattice unit cells are employed to quantify their nonlinear elastic response under large uniaxial tension, compression, and simple shear deformations. The simulation results are then used to fit the constitutive model parameters for the effective behavior of the unit cells, employing a Fung orthotropic hyperelastic formulation. The proposed homogenization method is validated through comparisons with full-geometry simulations and compression experiments on beam-based cubic lattice structures manufactured from thermoplastic polyurethane (TPU) using selective laser sintering (SLS). Furthermore, we compare the response of a beam with orthotropic unit cells under bending, which activates multiple deformation modes. The results demonstrate the feasibility and computational efficiency of the proposed homogenization method, highlighting the potential of this approach for efficient modeling and design of lattice structures in engineering applications.

晶格结构由于其轻量化和广泛的有效特性，可以通过调整其几何特征进行局部定制，因此在各种应用中越来越受欢迎。有限元（FE）模拟通常用于预测其力学响应并为反设计算法提供信息。然而，由于网格几何所需的大量元素，这些模拟提出了显著的计算需求。这一挑战可以通过用具有等效力学性能的均匀固体取代晶格几何来解决，这一过程被称为均质化。然而，确定一个合适的本构模型和参数是困难的，特别是当响应是非线性和各向异性的。为此，本研究提出了一种大弹性变形下正交各向异性晶格结构的数值均匀化方法。采用有限元模拟的方法，量化了晶格单元胞在大单轴拉伸、压缩和简单剪切变形下的非线性弹性响应。然后利用模拟结果拟合单元胞的有效行为的本构模型参数，采用Fung正交各向异性超弹性公式。通过对热塑性聚氨酯（TPU）采用选择性激光烧结（SLS）制备的梁基立方晶格结构进行全几何模拟和压缩实验，验证了所提出的均匀化方法。此外，我们比较了正交各向异性单元格梁在弯曲作用下的响应，这激活了多种变形模式。结果证明了所提出的均匀化方法的可行性和计算效率，突出了该方法在工程应用中高效建模和设计晶格结构的潜力。

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引用次数: 0

Quantification of the influence of laser shock peening parameters on residual stresses in thick AA 7050 specimens: An experimental and explainable machine learning-based approach 激光冲击强化参数对AA 7050厚试样残余应力影响的量化：一种基于实验和可解释的机器学习方法

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-28 DOI: 10.1016/j.mechmat.2025.105536

Claudia Barile, Simone Carone, Caterina Casavola, Giovanni Pappalettera

Laser Shock Peening (LSP) is a mechanical treatment capable of inducing a compressive residual stress field in the surface of a component, thereby improving its fatigue behavior. However, the selection of process parameters and the component geometric factors, such as thickness, are of paramount importance in the optimization of the final residual stresses, which exhibit a complex response due to the interaction between the process variables. An explainable machine learning framework has the potential to model the LSP treatment with high accuracy, while concurrently providing interpretations on the results and the process parameters' influence and interrelation. In this study, the effect of LSP on residual stresses in thick AA 7050-T7451 was experimentally investigated using incremental hole drilling with a Gaussian Process Regression-based approach to minimize user influence. Subsequently, experimental data was used to construct a robust ensemble machine learning model, namely a Random Forest, which achieved high generalization power by utilizing a rigorous K-Folds cross-validation with 100 repetitions. Finally, a critical comparative analysis of different approaches to determine feature importance was conducted. In this context, the SHapley Additive exPlanation (SHAP) framework emerged as a significant tool, providing reliable results and interpretations at both global and local levels. In this way, a quantitative assessment of the contributions of the LSP variables for each individual residual stress measurement was achieved. This allowed a deeper understanding of the effects of these parameters and their mutual interactions.

激光冲击强化（LSP）是一种机械处理，能够在部件表面诱导压缩残余应力场，从而改善其疲劳性能。然而，工艺参数的选择和零件的几何因素，如厚度，在最终残余应力的优化中是至关重要的，由于工艺变量之间的相互作用，最终残余应力表现出复杂的响应。一个可解释的机器学习框架有可能以高精度建模LSP处理，同时提供对结果和过程参数的影响和相互关系的解释。在本研究中，通过基于高斯过程回归的增量钻孔方法，实验研究了LSP对厚AA 7050-T7451残余应力的影响，以尽量减少用户的影响。随后，利用实验数据构建了一个鲁棒的集成机器学习模型，即随机森林，该模型通过100次重复的严格k - fold交叉验证获得了很高的泛化能力。最后，对确定特征重要性的不同方法进行了批判性的比较分析。在这种背景下，SHapley加性解释（SHAP）框架作为一种重要的工具出现，在全球和地方层面提供了可靠的结果和解释。通过这种方式，可以定量评估LSP变量对每个单独残余应力测量的贡献。这使我们能够更深入地了解这些参数的影响及其相互作用。

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引用次数: 0

A thermo-order-mechanical coupled model for main-chain isotropic-genesis polydomain liquid crystal elastomers 主链各向同性多畴液晶弹性体的热序-力学耦合模型

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-27 DOI: 10.1016/j.mechmat.2025.105531

Baihong Chen , Lingrui Zhu , Huxiao Yang , Rui Xiao

Polydomain liquid crystal elastomers (LCEs) are composed of numerous micron-scale domains, each with a distinct director orientation, resulting in macroscopic isotropy. In recent years, main-chain polydomain LCEs crosslinked in the isotropic state (I-PLCEs) have obtained increasing scientific and technological interest due to their complex thermo-order-mechanical coupling behaviors, which include the polydomain–monodomain (PM) transition, energy dissipation capability and stimuli-responsive actuation. In this work, we develop a constitutive model to describe these coupled behaviors in I-PLCEs. The model incorporates internal state variables to represent mesogen orientation. The free energy consists of the elastic energy arising from the deformation of the polymer networks and a residual energy due to the incompatibilities within the microscope nematic domain. The temperature affects both the rate of mesogen orientation and the order parameter. Under quasi-static loading conditions, an energy minimization approach governs the evolution equations, enabling the prediction of the extremely small equilibrium threshold stress required for the PM transition in I-PLCEs. Comparisons between model predictions and experimental data demonstrate that the model accurately reproduces the stress response of I-PLCEs at different temperatures and effectively captures the thermal actuation stretch under constant nominal stress. This work provides an efficient modeling framework for describing the coupled thermo-mechanical response of main-chain I-PLCEs.

多畴液晶弹性体（LCEs）由许多微米级结构域组成，每个结构域具有不同的取向，从而形成宏观各向同性。近年来，各向同性交联的主链多畴LCEs （I-PLCEs）由于其复杂的热序-力学耦合行为，包括多畴-单畴（PM）跃迁、能量耗散能力和刺激响应驱动，得到了越来越多的科学和技术关注。在这项工作中，我们开发了一个本构模型来描述I-PLCEs中的这些耦合行为。该模型结合内部状态变量来表示介元取向。自由能由聚合物网络变形产生的弹性能和显微镜向列域内不相容引起的残余能组成。温度对介观取向速率和序参量都有影响。在准静态加载条件下，能量最小化方法控制演化方程，能够预测i- plce中PM转变所需的极小平衡阈值应力。模型预测与实验数据的对比表明，该模型准确再现了I-PLCEs在不同温度下的应力响应，并有效捕获了恒定名义应力下的热致动拉伸。这项工作为描述主链I-PLCEs的热-力学耦合响应提供了一个有效的建模框架。

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引用次数: 0

Mesoscale finite element modeling of EPS bead size effect on the strength and failure of lightweight concrete EPS头尺寸对轻量化混凝土强度和破坏影响的中尺度有限元模拟

IF 4.1 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Mechanics of Materials

Pub Date : 2025-10-26 DOI: 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.

EPS混凝土的力学性能受粉粒含量和粒径的影响较大，粉粒越小，强度越高。本研究开发了一个连续力学框架，明确地结合砂浆、骨料和EPS珠。砂浆模型采用塑性损伤规律，增强了新的压缩损伤-应变关系和应变位移过程，以降低网格敏感性，而EPS珠则由实验校准的各向同性可破碎泡沫模型表示。在单轴压缩和三点弯曲的情况下，进行了一套全面的中尺度有限元分析，从而预测了抗压强度和破裂模量。该框架再现了实验强度-尺寸相关性，阐明了孔隙率驱动的损伤起裂和演化，并引入了一种新的抗压强度与EPS体积比之间的数学关系。

引用次数: 0