今日更新：International Journal of Solids and Structures 3 篇，Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 5 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 5 篇International Journal of Solids and StructuresOn the use of multidimensional differential geometry to model covariant behaviors of viscoelastic or hyperelastic structures, illustrated with numerical simulations using spacetime finite element analysisBenoît Panicaud, Emmanuelle Rouhauddoi:10.1016/j.ijsolstr.2024.112803利用多维微分几何建立粘弹性或超弹性结构的协变行为模型，并通过时空有限元分析的数值模拟加以说明In the present article, a covariant spacetime formalism is used to model the behavior of viscoelastic and hyperelastic solids, within a thermodynamical framework. The latter aims to ensure the validity of thermodynamics second principle and to derive reversible or irreversible models for thermomechanics. The use of the Lie derivative is of particular interest to achieve such goals. Covariance enables to address finite deformation. Coupled to a covariant finite element analysis, it allows numerical simulations that simultaneously ensure the physical balance of energy and momentum for thermomechanical applications. Different mechanical loadings are considered, bending or uniaxial extension ones, with quasi-static or time exponential or time cyclic evolution. We also provide quantification of the different performances of the numerical simulations, and show the advantages and drawbacks of the spacetime approach.本文采用协变时空形式主 义，在热力学框架内模拟粘弹性和超弹性固体的行为。后者旨在确保热力学第二原理的有效性，并推导出热力学的可逆或不可逆模型。要实现这些目标，使用列导数尤其重要。协变能够解决有限变形问题。结合协变有限元分析，可以进行数值模拟，同时确保热力学应用中能量和动量的物理平衡。我们考虑了不同的机械负载，如弯曲或单轴拉伸负载，以及准静态、时间指数或时间循环演变。我们还对数值模拟的不同性能进行了量化，并展示了时空方法的优缺点。Continuum-molecular modeling of planar micropolar media: Anisotropy, chiral properties and length-scale effectsVito Diana, Andrea Bacigalupo, Luigi Gambarottadoi:10.1016/j.ijsolstr.2024.112810平面微波介质的连续分子建模：各向异性、手性和长度尺度效应This paper presents a continuum-molecular formulation for bi-dimensional micropolar media within the mathematical formalism of a revised peridynamic theory with oriented material points. A variational procedure is considered to derive the fundamental governing equations of the model, which postulates that material points interact through pair potentials allowing generalized pairwise actions to be derived as energy conjugates to properly defined pairwise deformation measures. While continuity of mass is assumed, constitutive laws are produced for long-range micro-interactions to reproduce the effective behavior of the material at the macro-scale. The definition of proper micromoduli functions respecting material symmetries and invariance properties allows then to obtain a non-local micropolar continuum based on pseudo-discrete kinematics, while providing a mechanism-based description of material anisotropy and coupling behaviors uncovered by classical elasticity. An analytic micro-macro moduli correspondence procedure is also established, based on the formal analogy with the constitutive tensor of centrosymmetric planar micropolar continua. As an important result of this research, we show that distinctive chiral effects of micropolar elasticity can be reproduced by introducing a directional independent pseudo-scalar pair potential, which turns out to be analytically vanishing when the rotationally invariant part of the corresponding continuum elastic tensor is invariant to mirror reflections as well. Moreover, the proposed formulation demonstrates sensitivity to elastic bending size-effect as specific property of structured materials homogenized as micropolar continua, and related to the characteristic length of their underlined microstructure. The resulting constitutive non-locality, which plays an important role in fracture problems, is conceptually separated with respect to the intrinsic non-local character of the model related to the integral nature of its governing equations, and then does not vanish when the horizon reduces to zero. The theoretical findings and the effectiveness of the model are successfully verified through illustrative examples referred to representative cases of structured materials homogenized as micropolar continua, including length-scale dependent quasi-static crack propagation as well as the mechanism-based description of the coupling between bulk strain and pure rotation in elastic bi-dimensional homogenized chiral lattices.本文提出了一种双维微波介质的连续分子公式，该公式采用了具有定向材料点的修正周动理论的数学形式。该模型假定材料点通过成对电势相互作用，从而可以将广义的成对作用推导为适当定义的成对变形量的能量共轭。在假定质量连续性的同时，还为长程微观相互作用制定了构成法则，以再现材料在宏观尺度上的有效行为。在尊重材料对称性和不变性的基础上定义适当的微观模量函数，可以获得基于伪离散运动学的非局部微观连续体，同时对经典弹性所揭示的材料各向异性和耦合行为进行基于机理的描述。根据与中心对称平面微观连续体的构成张量的形式类比，还建立了微观-宏观模量的解析对应程序。作为这项研究的一项重要成果，我们证明了微观弹性的独特手性效应可以通过引入与方向无关的伪标度对势能来重现，当相应连续弹性张量的旋转不变部分对镜面反射也不变时，该势能就会在解析上消失。此外，所提出的公式还证明了对弹性弯曲尺寸效应的敏感性，这是均匀化为微极性连续体的结构材料的特定属性，并与其下划微结构的特征长度相关。由此产生的构成非局部性在断裂问题中起着重要作用，这种非局部性在概念上与模型的内在非局部性相分离，而模型的内在非局部性又与其控制方程的积分性质相关，因此当水平线降为零时，这种非局部性并不会消失。该模型的理论发现和有效性通过一些具有代表性的例子得到了成功验证，这些例子涉及作为微极性连续体均匀化的结构材料，包括与长度尺度相关的准静态裂纹扩展，以及基于机制的弹性二维均匀化手性晶格中体应变与纯旋转之间的耦合描述。A new honeycomb design strategy for favoring pattern transformation under uniaxial loadingXiuhui Hou, Feng Xie, Tianhao Sheng, Zichen Dengdoi:10.1016/j.ijsolstr.2024.112812有利于单轴载荷下图案变形的新型蜂窝设计策略Pattern transformation, as one of the special properties of mechanical metamaterials, is widely found in elastic porous structures and gradually expanding to honeycomb structures. Inspired by the higher-order flower-like buckling pattern of hexagonal honeycomb, and generalizing the geometry of structures that pattern transformation occurs under uniaxial compression, this paper proposes a Modified Hexagonal Honeycomb(MHH) structure by adjusting the thickness ratio α and the deflection extension angle θ of the cell wall to topologically reconstruct the honeycomb structure to initiate the first-order quasi-flower-like buckling pattern under uniaxial loading. Results show that the quasi-flower-like pattern transformation appears directly for the MHH structure under uniaxial compression, accompanied with a transition of the Poisson’s ratio, from positive to negative. And the butterfly pattern, which appears for traditional hexagonal honeycomb only under biaxial loading, is also observed for the MHH under uniaxial compression. The relative size of the nodes among cell walls is believed to play a crucial role on the appearance of the pattern transformation of the honeycomb structure. This work has revealed the underlying physical mechanism for pattern transformation of honeycomb structures, and would also extend the application range of honeycomb structures to the design of elastic dampers, bending/torsion actuators, or robot drive joints.图案变换作为机械超材料的特殊性质之一，广泛存在于弹性多孔结构中，并逐渐扩展到蜂窝结构中。受六边形蜂窝的高阶类花朵屈曲形态的启发，并对单轴压缩下发生形态转变的结构的几何形状进行了归纳，本文提出了一种修正六边形蜂窝（MHH）结构，通过调整细胞壁的厚度比α和挠度扩展角θ，拓扑重构蜂窝结构，从而在单轴加载下引发一阶准类花朵屈曲形态。结果表明，单轴压缩下的 MHH 结构直接出现了准花朵状模式转变，并伴随着泊松比由正变负的转变。传统六边形蜂窝仅在双轴载荷下出现的蝴蝶图案，在单轴压缩下的 MHH 结构中也出现了。细胞壁之间节点的相对大小被认为对蜂窝结构的图案变化起着至关重要的作用。这项研究揭示了蜂窝结构模式转换的基本物理机制，并将蜂窝结构的应用范围扩展到弹性阻尼器、弯曲/扭转致动器或机器人驱动关节的设计。Journal of the Mechanics and Physics of SolidsHigh-cycle shakedown, ratcheting and liquefaction behavior of anisotropic granular material with fabric evolution: experiments and constitutive modellingYi Hong, Xuetao Wang, Lizhong Wang, Guozheng Kang, Zhiwei Gaodoi:10.1016/j.jmps.2024.105638各向异性颗粒材料的高循环抖动、棘轮和液化行为：实验和构造模型Although the mechanical response of granular materials strongly depends on the interplay between their anisotropic internal structure (fabric) and loading direction, such coupling is not explicitly considered in existing high-cycle experimental datasets and models. High-cycle experiments on granular specimens specifically prepared with various fabric orientations are presented. It is found that the high-cycle strain accumulation behavior can change remarkably, from shakedown to ratcheting, when the fabric orientation deviates more from the loading direction. Inspired by the experimental observations, a fabric-dependent anisotropic high-cycle model is proposed, by proper recasting of an existing model formulated within Critical State Theory, into the framework of Anisotropic Critical State Theory. The model explicitly accounts for the fabric evolution, which is linked to plastic modulus, dilatancy and kinematic hardening rules. The model can quantitatively reproduce the high-cycle strain accumulation (i.e., shakedown and ratcheting) under drained conditions, as well as pre-liquefaction and post-liquefaction responses granular materials having widely ranged fabric anisotropy, densities and cyclic loading types using a unified set of constants. It exhibits a unique feature of simulating the distinct high-cycle strain accumulation and liquefaction of granular material with various fabric anisotropy, while the existing high-cycle models treat them equally. The successful reproduction of the anisotropic sand element response under high-cycle drained and undrained conditions makes it possible to perform whole life analysis of various foundations on granular soil subjected to high-cycle loading events.尽管颗粒材料的机械响应在很大程度上取决于其各向异性的内部结构（织物）和加载方向之间的相互作用，但现有的高循环实验数据集和模型并未明确考虑这种耦合。本文介绍了专门制备的具有不同织物方向的颗粒试样的高循环实验。实验发现，当织物方向与加载方向偏差较大时，高循环应变累积行为会发生显著变化，从抖动到棘轮。受实验观察结果的启发，通过将临界状态理论中制定的现有模型适当重铸到各向异性临界状态理论框架中，提出了一个与织物有关的各向异性高循环模型。该模型明确考虑了与塑性模量、扩张性和运动硬化规则相关的织物演变。该模型可定量再现排水条件下的高循环应变累积（即抖动和棘轮），并可使用一套统一的常数再现具有广泛织物各向异性、密度和循环加载类型的颗粒材料的液化前和液化后反应。它的独特之处在于能模拟具有不同结构各向异性的颗粒材料的不同高循环应变累积和液化，而现有的高循环模型对它们一视同仁。由于成功再现了各向异性砂元素在高循环排水和不排水条件下的响应，因此可以对承受高循环荷载事件的各种粒状土地基进行全寿命分析。Mechanics of MaterialsFluid convection driven by surface tension during free-surface frontal polymerizationYuan Gao, Justine E. Paul, Manxin Chen, Aarev Seth, Qibang Liu, Liu Hong, Leonardo P. Chamorro, Randy H. Ewoldt, Nancy R. Sottos, Philippe H. Geubelledoi:10.1016/j.mechmat.2024.104987自由表面锋聚合过程中由表面张力驱动的流体对流Frontal polymerization (FP) is an efficient method to manufacture thermoset polymers and composites, and is usually modeled as a reaction–diffusion (RD) process. In this study, we investigate numerically and experimentally how fluid convection ahead of the propagating front can impact the reaction–diffusion balance in the free-surface FP of dicyclopentadiene (DCPD) and 5-ethylidene-2-norbornene (ENB). Multiphysics finite element analyses reveal how the velocity of the surface-tension-driven flow described by the dimensionless Marangoni number can be modulated by varying the processing temperature and the viscosity of the monomer resin. The surface-tension-driven fluid velocity exhibits two distinct regimes, which arise from the interplay and competition between thermal and chemical advection. The dispersion of the reaction heat by the Marangoni flow leads to a reduction in the velocity of the front. The presence of fluid convection during FP can lead to instabilities in the front propagation and generate reaction patterns, which can be adjusted by controlling the initial temperature and degree of cure. The numerical findings are corroborated by experiments that combine FP and particle image velocimetry (PIV).正面聚合（FP）是制造热固性聚合物和复合材料的一种有效方法，通常被模拟为反应-扩散（RD）过程。在本研究中，我们通过数值和实验研究了在双环戊二烯（DCPD）和 5-亚乙基-2-降冰片烯（ENB）的自由表面 FP 中，传播前沿的流体对流如何影响反应-扩散平衡。多物理场有限元分析揭示了如何通过改变加工温度和单体树脂的粘度来调节无量纲马兰戈尼数所描述的表面张力驱动流体的速度。表面张力驱动的流体速度呈现出两种截然不同的状态，这源于热平流和化学平流之间的相互作用和竞争。马兰戈尼流对反应热的分散导致了前沿速度的降低。在 FP 过程中，流体对流的存在会导致前沿传播的不稳定性，并产生反应模式，这可以通过控制初始温度和固化程度来调整。结合 FP 和粒子图像测速仪 (PIV) 进行的实验证实了数值研究结果。Interface temperature evolution and bonding characteristics analysis induced by microparticle impactWei Wang, Shufan Wu, Zhongcheng Mu, Jiyuan Yi, Zhicong Wangdoi:10.1016/j.mechmat.2024.104989微粒撞击引起的界面温度演变和粘接特性分析The energy conversion and heat production resulting from plastic deformation induced by microparticle impact affects a change in interface temperature, which varies with the initial state of the microparticle. Due to the instantaneous and microscopic characteristics of microparticle impact process, interface temperature has not been fully studied. Thus, evolution theory of the impact interface temperature with initial velocity is proposed based on the Hugoniot equation, and the predictive outcomes of the evolution theory are verified by numerical model. Furthermore, it is demonstrated that microparticle bonding occurs below the melting point by comparing theoretical bonding temperature with melting temperature. Notably, the trend of the difference between interface temperature and melting point with varying impact velocity reveals disparate driving mechanisms for bonding and melting. The interface temperature evolution theory and bonding characteristics analysis facilitate understanding the heat generation mechanism and temperature action of microparticle impact, and provides a new perspective for the interface regulation and bonding state determination.微粒撞击引起的塑性变形所产生的能量转换和热量会影响界面温度的变化，而界面温度会随微粒的初始状态而变化。由于微颗粒撞击过程的瞬时性和微观特性，界面温度尚未得到充分研究。因此，基于休格诺方程提出了冲击界面温度随初速度变化的演化理论，并通过数值模型验证了演化理论的预测结果。此外，通过比较理论粘合温度与熔点温度，证明了微粒粘合发生在熔点以下。值得注意的是，界面温度与熔点之差随冲击速度变化的趋势揭示了粘合与熔化的不同驱动机制。界面温度演化理论和结合特性分析有助于理解微颗粒撞击的发热机制和温度作用，为界面调节和结合状态的确定提供了新的视角。Mechanics of membrane targeting antimicrobials - Pore nucleation in bacterial membranesGuijin Zou, Wooseong Kim, Huajian Gaodoi:10.1016/j.mechmat.2024.104991膜靶向抗菌剂的机理 - 细菌膜的孔核形成The lipid bilayer membrane is increasingly recognized as a promising target for medicine, as exemplified by the recent surge in the development of membrane targeting antimicrobials (MTAs) against methicillin-resistant Staphylococcus aureus (MRSA), a superbug posing significant challenges to public health. Interestingly, the effectiveness of MTAs seems to vary markedly between the exponential growth and stationary phases of bacteria, a phenomenon that remains poorly understood. Here, we perform molecular dynamics (MD) simulations of the lipid bilayer membrane of S. aureus across different phases of bacteria growth, examining equilibrium properties and free energies associated with pore nucleation, the initial stage of membrane perforation preceding pore expansion and rupture. Our findings reveal that pore nucleation in the stationary phase bacterial membrane requires more energy compared to the exponential phase due to the increased concentration of cardiolipin, a type of mechanically resilient lipids, in the former, which provides a physical explanation for why the stationary phase is more tolerant of MTAs. The insights gained from this study not only deepen our understanding of the mechanics of bacterial membrane but can also help lay a foundation for simulation-assisted discovery and evaluation of MTAs for optimized treatments.脂质双分子层膜越来越被认为是一个很有前景的药物靶点，最近针对耐甲氧西林金黄色葡萄球菌（MRSA）的膜靶向抗菌剂（MTAs）的研发激增就是一个例证，MRSA 是一种对公共卫生构成重大挑战的超级细菌。有趣的是，MTAs 的效果似乎在细菌的指数生长期和静止期之间有明显差异，这一现象至今仍鲜为人知。在此，我们对金黄色葡萄球菌在不同生长阶段的脂质双层膜进行了分子动力学（MD）模拟，研究了与孔核（孔扩张和破裂前膜穿孔的初始阶段）相关的平衡特性和自由能。我们的研究结果表明，与指数期相比，静止期细菌膜的孔核形成需要更多的能量，这是因为前者中的心磷脂（一种具有机械弹性的脂质）浓度增加了。本研究获得的见解不仅加深了我们对细菌膜力学的理解，还有助于为模拟辅助发现和评估 MTAs 以优化治疗奠定基础。Traction-separation law for bridged cracks at immiscible polymers interfaceM. Perelmuterdoi:10.1016/j.mechmat.2024.104998 不相溶聚合物界面桥接裂缝的牵引-分离定律A traction-separation law for bonds at cracks bridged zones at immiscible polymers interface is developed. It is assumed that bonds at the crack bridged zone between different polymers are formed by bundles of the polymer molecules-promoter of adhesion. It is taken into account that molecules of the polymer-promoter can form one-stitch and many-stitch bonds between polymers. Nonlinear deformation curves of bonds at the crack bridged zone were obtained on this basis. The model of different materials joint with bridged interface crack is used to simulate immiscible polymers adhesive bonding. The system of singular integral-differential equations is applied for evaluation of bonds traction for the polymers interface bridged crack. The analysis of the bond traction-separation law parameters influence on the numerical iterative solution convergence of the integral-differential equations system has been performed. Evaluations of the polymer joint fracture toughness were performed using the non-local two-parameter criterion for quasi-static growth of bridged cracks.针对不相溶聚合物界面裂缝桥接区的粘结，提出了牵引分离定律。假设不同聚合物之间裂缝桥接区的键是由聚合物分子束--粘合促进剂形成的。考虑到聚合物促进剂分子可在聚合物之间形成单缝和多缝粘合。在此基础上得出了裂缝桥接区粘接处的非线性变形曲线。利用不同材料接合处的桥接界面裂缝模型模拟不相溶聚合物的粘合。应用奇异积分微分方程系统评估聚合物界面桥接裂缝的粘结牵引力。分析了粘接牵引力分离定律参数对积分微分方程系统数值迭代求解收敛性的影响。使用桥接裂纹准静态增长的非局部双参数准则对聚合物接头断裂韧性进行了评估。Creep-recovery deformation of 304 stainless-steel springs under low forcesMing-Yen Tsai, Shou-Yi Chang, Yulin Zhang, Fuqian Yang, Sanboh Leedoi:10.1016/j.mechmat.2024.105003304 不锈钢弹簧在低力作用下的蠕变-恢复变形The deformation behavior of materials at high temperatures determines the structural stability of mechanical structures under high-temperature service conditions. In this work, we prepare helical springs from 304 stainless-steel wires and study creep-recovery deformation of the helical springs under low forces at temperatures of 475–575 °C. In contrast to most methods reported in the literature, we use Kelvin representation of the Burgers model with a nonlinear dashpot in series connection to analyze the creep-recovery deformation of the helical springs and suggest the deformation mechanisms of the diffusion of interstitial atoms and dislocation generation/annihilation in transient creep and recovery of the helical springs under low forces. For the creep deformation, the stress exponent and activation energy for the plastic flow of the nonlinear dashpot are 2 and 57.8 kJ/mol, respectively, and the activation energy for the deformation flow of the linear dashpot is 41.8 kJ/mol. The nonlinear dashpot does not play any role in the recovery deformation, and the formation energy of defects for the recovery deformation of the helical springs is 51.4 kJ/mol. The approach used in this work provides a simple method to use a phenomenological model with a nonlinear dashpot to capture the power-law creep deformation of metallic materials.材料在高温下的变形行为决定了机械结构在高温服役条件下的结构稳定性。在这项工作中，我们用 304 不锈钢丝制备螺旋弹簧，并研究了螺旋弹簧在 475-575 °C 低力条件下的蠕变恢复变形。与文献报道的大多数方法不同，我们采用开尔文表示的布尔格斯模型与非线性达斯锅串联来分析螺旋弹簧的蠕变-恢复变形，并提出了在低力条件下螺旋弹簧瞬态蠕变和恢复的变形机制，即间隙原子扩散和位错生成/消能。在蠕变变形中，非线性仪表盘塑性流动的应力指数和活化能分别为 2 和 57.8 kJ/mol，而线性仪表盘变形流动的活化能为 41.8 kJ/mol。非线性达斯盆在恢复变形中不起作用，螺旋弹簧恢复变形的缺陷形成能为 51.4 kJ/mol。这项工作中使用的方法提供了一种简单的方法，利用带有非线性达什波特的现象学模型来捕捉金属材料的幂律蠕变变形。International Journal of PlasticityDiscontinuous coarsening leads to unchanged tensile properties in high-entropy alloys with different recrystallization volume fractionsZhongsheng Yang, Xin Liu, Jiajun Zhao, Qionghuan Zeng, Kengfeng Xu, Yue Li, Chuanyun Wang, Lei Wang, Junjie Li, Jincheng Wang, Hyoung Seop Kim, Zhijun Wang, Feng Hedoi:10.1016/j.ijplas.2024.103963 不连续粗化导致具有不同再结晶体积分数的高熵合金的拉伸性能保持不变Heterogeneous microstructure alloys provide a possibility for the combination of strength and ductility. As a typical heterogeneous microstructure, a partially recrystallized microstructure is attractive because of the convenient processing route and great potential for industrial applications. However, the mechanical properties of this microstructure vary dramatically with different morphology factors, especially the recrystallization fraction, which restricts the processing window and the property consistency. In this study, we found that the yield strength (∼1.3 GPa) and ductility (∼20%) of the partially recrystallized Ni2CoCrFeTi0.24Al0.2 do not change when the recrystallization fraction increases from 21% to 72%. This novel phenomenon is attributed to an additional hetero-deformation induced (HDI) strain hardening effect produced by heterogeneous precipitates. With the increased recrystallization fraction, this additional HDI stress keeps the ductility unchanged by offsetting the decreased HDI stress arising from the hetero-deformation between recrystallized (RX) and non-recrystallized (NRX) areas. The unchanged yield strength comes from the increased strengthening effects of the lamellar precipitates and grain boundaries. We also confirmed that the discontinuous coarsening contributes to the formation of heterogeneous precipitates. These findings would open a new pathway for enhancing the consistency and processability of hetero-structured alloys and thus promote their broader industrial applications.异质微结构合金为强度和延展性的结合提供了可能。作为一种典型的异质微观结构，部分再结晶微观结构因其便捷的加工路径和巨大的工业应用潜力而颇具吸引力。然而，这种微结构的力学性能会随着形态因素（尤其是再结晶分数）的不同而发生巨大变化，从而限制了加工窗口和性能一致性。在这项研究中，我们发现当再结晶分数从 21% 增加到 72% 时，部分再结晶 Ni2CoCrFeTi0.24Al0.2 的屈服强度（∼1.3 GPa）和延展性（∼20%）并没有发生变化。这种新现象归因于异质析出物产生的额外异质变形诱导（HDI）应变硬化效应。随着再结晶比例的增加，这种额外的 HDI 应力抵消了再结晶 (RX) 和非再结晶 (NRX) 区域之间的异质变形所产生的 HDI 应力下降，从而保持了延展性不变。屈服强度不变的原因是片状析出物和晶界的强化作用增强了。我们还证实，不连续粗化有助于异质析出物的形成。这些发现将为提高异质结构合金的一致性和可加工性开辟一条新途径，从而促进其更广泛的工业应用。Thin-Walled StructuresExperimental and simulation investigation for prismatic lithium-ion battery cells under impact loadingZhongwei Xu, An Liu, Lizhong Mao, Hongsheng Tian, Bengang Yi, Heping Ling, Xishu Wang, Kang Xudoi:10.1016/j.tws.2024.111864冲击载荷下棱柱形锂离子电池芯的实验和模拟研究In the current work, prismatic lithium-ion battery (LIB) cells were impacted in various rigid cylinder loading speeds (v = 1, 5, 10, 2000 and 5000 mm/s), which provided the data basis for establishing a practical and reasonable LIB cell damage assessment method. Based on thermal-runaway cell safety borders (TCSB) and undamaged cell safe borders (UCSB), the deformed cells can be classified into safe, risk and failure regions. With the increment of the v values, the UCSB and TCSB of cells decreased linearly along a logarithm axis. Moreover, the relationships between key cell parameters (cell thickness, separator thickness and separator fracture strain) and the cell deformation limits (DL) under rigid cylinder impact loads were also revealed. A DL prediction method was newly introduced for the prismatic LIB cells with different sizes. Finally, the tensile mechanical data of cell components (anodes, cathodes and separators) were also measured for cell local detailed simulation models. By the simulations, the effect of the frictional behaviors between cell components on the deformation processes and failure mechanisms of LIB cells were deeply discussed.在当前工作中，棱柱形锂离子电池（LIB）电芯在不同的刚性圆柱体加载速度（v = 1、5、10、2000 和 5000 mm/s）下受到冲击，这为建立实用合理的 LIB 电芯损伤评估方法提供了数据基础。根据热失控电池安全边界（TCSB）和未损坏电池安全边界（UCSB），可将变形电池分为安全区、风险区和失效区。随着 v 值的增加，电池的 UCSB 和 TCSB 沿对数轴线性下降。此外，还揭示了在刚性圆柱体冲击载荷下，电池关键参数（电池厚度、隔板厚度和隔板断裂应变）与电池变形极限（DL）之间的关系。新引入的 DL 预测方法适用于不同尺寸的棱柱形 LIB 电池。最后，还为电池局部详细模拟模型测量了电池组件（阳极、阴极和隔膜）的拉伸机械数据。通过模拟，深入讨论了电池组件之间的摩擦行为对锂电池变形过程和失效机制的影响。Crashworthiness of hierarchical multi-cell circular tubesZhipeng Gao, Jian Zhao, Hai Zhang, Dong Ruandoi:10.1016/j.tws.2024.111857分层多孔圆管的耐撞性Bio-inspired and hierarchical concepts are demonstrated to be effective in enhancing the compressive performance of tubes. The bio-inspired hierarchical multi-cell circular (BHMC) tubes with different numbers of ribs were investigated in this paper. The effects of hierarchical order, tube mass, the number of ribs, outer circle tube and inner structure with non-uniform thicknesses were explored. The results show that the SEA of BHMC tubes with four, five and six ribs (i.e. BHMC-R4, BHMC-R5 and BHMC-R6) is greater than that of conventional hollow circular tube with the same mass. The SEA of the third order of BHMC tube with four ribs (i.e. BHMC-R4-3) is approximately twice that of conventional hollow circular tube with the same mass. As the tube mass increases, the SEA of BHMC-R4, BHMC-R5 and BHMC-R6 tubes increases. Moreover, BHMC-R4 tubes with different hierarchical orders present the highest SEA among BHMC-R4, BHMC-R5 and BHMC-R6 tubes. In addition, theoretical models were proposed and their predictions of plateau forces aligned well with those obtained through numerical simulations.事实证明，生物启发和分层概念可有效提高管材的抗压性能。本文研究了具有不同肋数的生物启发分层多孔圆管（BHMC）。探讨了分层顺序、管子质量、肋数、外圆管和厚度不均匀的内部结构的影响。结果表明，具有四条、五条和六条肋骨的 BHMC 管（即 BHMC-R4、BHMC-R5 和 BHMC-R6）的 SEA 比相同质量的传统空心圆管大。三阶四肋 BHMC 管（即 BHMC-R4-3）的 SEA 大约是相同质量的传统空心圆管的两倍。随着管道质量的增加，BHMC-R4、BHMC-R5 和 BHMC-R6 管道的 SEA 也随之增加。此外，在 BHMC-R4、BHMC-R5 和 BHMC-R6 管材中，不同层级的 BHMC-R4 管材的 SEA 值最高。此外，还提出了一些理论模型，这些模型对高原力的预测与数值模拟的结果非常吻合。A three-dimensional progressive failure analysis of filament-wound composite pressure vessels with void defectsLei Ge, Jikang Zhao, Hefeng Li, Jingxuan Dong, Hongbo Geng, Lei Zu, Song Lin, Xiaolong Jia, Xiaoping Yangdoi:10.1016/j.tws.2024.111858具有空隙缺陷的丝状缠绕复合材料压力容器的三维渐进失效分析Composite pressure vessels are promising solution for storing compressed gas with the high strength/stiffness to weight ratio, but the accurate modeling of mechanical behavior under high pressure remains a huge challenge considering manufacturing-induced void defects. The void generating method is developed to construct the finite element model with voids explicitly constructed. A three-dimensional(3D) progressive damage model complied with the user-defined material subroutine (UMAT) is performed to predict the void defect introduced damage behavior and burst pressure of composite pressure vessels. It indicates that the predicted burst strength agrees well with experimental value, and with the pressure increasing, the damage of composite layers initially appears in the matrix of middle cylinder section and region near the equator. The matrix damage is dominant at the outset, then achieves a balance with the fiber damage, and finally comes in second until the burst failure of the composite pressure vessels. The void defects will result in the damage initiation, evolution and final failure of composite layers, and the clustered voids will deteriorate the local damage status, but will not change the general damage trend. The present damage failure analysis scheme can provide theoretical guidance for reliability evaluation of composite pressure vessels with void defects.复合材料压力容器具有较高的强度/刚度重量比，是存储压缩气体的理想解决方案，但考虑到制造过程中引起的空隙缺陷，高压下机械行为的精确建模仍然是一个巨大的挑战。我们开发了空隙生成方法，以构建明确存在空隙的有限元模型。利用用户自定义材料子程序（UMAT）建立的三维（3D）渐进损伤模型预测了空隙缺陷引起的损伤行为和复合材料压力容器的爆破压力。结果表明，预测的爆破强度与实验值吻合良好，随着压力的增加，复合材料层的损伤最初出现在圆筒中段的基体和赤道附近区域。基体损伤一开始占主导地位，然后与纤维损伤达到平衡，最后居第二位，直至复合材料压力容器爆破失效。空隙缺陷将导致复合材料层的损伤开始、演变和最终失效，集群空隙会恶化局部损伤状况，但不会改变总体损伤趋势。本损伤失效分析方案可为存在空隙缺陷的复合材料压力容器的可靠性评估提供理论指导。Inverse Finite Element Method with Energy-Based Regularization for Deformation Reconstruction and Structural Health MonitoringWu Maoqi, Tan Shujundoi:10.1016/j.tws.2024.111859基于能量正则化的反有限元法用于变形重建和结构健康监测Distributed Fiber Optical Sensing (DFOS) can be used to perform compact, low-invasive and large-scale strain measurements, providing an important tool for strain-based deformation reconstruction and Structural Health Monitoring (SHM). However, most current deformation reconstruction methods are difficult to apply to the sparse uniaxial strain measurement conditions associated with DFOS, especially for structures with complex geometries. This work introduces an energy-based regularization method, i.e., a priori assumption that the actual deformation state is close to the state with the minimum deformation energy under the premise of satisfying the strain constraints, into inverse finite element method to perform load-independently deformation reconstruction under the condition of sparse uniaxial strain measurement. The Inverse Finite Element Method with Energy-based Regularization (iFEM-EBR) can naturally construct the DFOS-based deformation reconstruction model with quasi-forward finite element analysis without introducing additional mathematical processing. The sensitivity of this method to structural characteristics, such as material parameters, makes it a unique prospect in SHM.分布式光纤传感（DFOS）可用于进行紧凑、低侵入性和大规模应变测量，为基于应变的变形重建和结构健康监测（SHM）提供了重要工具。然而，目前大多数变形重建方法都难以适用于与 DFOS 相关的稀疏单轴应变测量条件，尤其是对于具有复杂几何形状的结构。本研究在逆有限元法中引入了基于能量的正则化方法，即在满足应变约束的前提下，先验地假设实际变形状态接近于变形能量最小的状态，从而在稀疏单轴应变测量条件下进行与载荷无关的变形重建。基于能量正则化的反有限元法（iFEM-EBR）可以在不引入额外数学处理的情况下，通过准正向有限元分析自然构建基于 DFOS 的变形重构模型。这种方法对材料参数等结构特性的敏感性使其在 SHM 领域具有独特的前景。Determining residual stress profile induced by end milling from measured thin plate deformationJinhua Zhou, Qi Qi, Qiangqiang Liu, Zongyuan Wang, Junxue Rendoi:10.1016/j.tws.2024.111862根据测量的薄板变形确定端铣引起的残余应力曲线Lots of residual stress data is usually required to support the machining process optimization of the thin-walled component. In this work, an inverse method to determine the residual stress profile for end milling titanium alloy Ti-6Al-4V is developed based on the measured thin plate deformation. Firstly, the hyperbolic tangent function is introduced to parameterize the residual stress profile of end milling. Then the mapping relationship between the residual stress profile and the bending deflection of thin plate is established. Furthermore, a solution algorithm to determine the characteristic coefficients of the residual stress profile from the measured deflection is proposed. And the residual stress profiles under different cutting conditions are inversely solved. Finally, six groups of end milling verification experiments are conducted and a high average prediction accuracy of 90.19% is obtained. The proposed reverse method can quickly obtain the residual stress profile by measuring the machining deformation of thin plate.通常需要大量残余应力数据来支持薄壁部件的加工工艺优化。在这项工作中，根据测量到的薄板变形，开发了一种确定钛合金 Ti-6Al-4V 端铣残余应力曲线的反演方法。首先，引入双曲正切函数对端铣残余应力曲线进行参数化。然后，建立了残余应力曲线与薄板弯曲挠度之间的映射关系。此外，还提出了根据测量挠度确定残余应力轮廓特征系数的求解算法。并对不同切削条件下的残余应力曲线进行了反求解。最后，进行了六组端铣验证实验，获得了 90.19% 的高平均预测精度。所提出的逆向方法可以通过测量薄板的加工变形快速获得残余应力曲线。来源：复合材料力学仿真Composites FEM
