今日更新：Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 3 篇Journal of the Mechanics and Physics of SolidsChallenging the paradigm for reactive material's ignition from shear to pressure: Thermomechanical study of Al-PTFEG.G. Goviazin, R. Ceder, S. Kalabukhov, S. Hayun, D. Ritteldoi:10.1016/j.jmps.2024.105581 挑战反应材料从剪切到压力的点火范式：Al-PTFE 的热力学研究Structural reactive materials (SRMs) are attracting growing interest in the warheads industry, while the Al-PTFE system is probably the most popular. Due to their final application, high-strain rate (impact) testing is the most realistic method for SRMs. For this purpose, a synchronized Split Hopkinson (Kolsky) Pressure Bar with high-speed infrared and optical cameras is used to characterize the sintered Al-PTFE system, thus enabling the simultaneous investigation of its thermal energy release and mechanical properties under impact. The characteristic specimen heating rates during such experiments are of the order of 3.85 × 108 °C/min, which most likely caused evaporation of the reaction products, that were therefore not identified in a post-mortem analysis of the remaining fragments. Whereas the conventional wisdom has it that shear loading causes SRM ignition, the main result of this work just points to the opposite, showing unambiguously that pressure is the reaction-triggering loading mode, with the potential involvement of a pore collapse mechanism.结构反应材料（SRM）在弹头工业中越来越受到关注，而 Al-PTFE 系统可能是最受欢迎的。由于其最终用途，高应变率（冲击）测试是 SRM 最现实的方法。为此，我们使用了带有高速红外和光学相机的同步分体式霍普金森（Kolsky）压力棒来表征烧结 Al-PTFE 系统，从而能够同时研究其在冲击下的热能释放和机械性能。在此类实验中，试样的特征加热速率约为 3.85 × 108 °C/分钟，这很可能会导致反应产物的蒸发，因此在对剩余碎片进行死后分析时无法确定这些产物。传统观点认为剪切加载会导致 SRM 起火，而这项工作的主要结果恰恰相反，明确显示压力是引发反应的加载模式，孔隙塌缩机制也可能参与其中。Mechanics of MaterialsChirality in topologically interlocked material systemsDong Young Kim, Thomas Siegmunddoi:10.1016/j.mechmat.2024.104956拓扑互锁材料系统中的手性The present study focuses on the mechanical chirality in plate-type topologically interlocked material systems. Topologically interlocked material (TIM) systems are a class of dense architectured materials for which the mechanical response emerges from the elastic behavior of the building blocks and the contact-frictions interactions between the blocks. The resulting mechanical behavior is strongly non-linear due to the stability-instability characteristics of the internal load transfer pattern. Two tessellations are considered (square and hexagonal) and patches from each are used as templates. While individual building blocks are achiral, chirality emerges from the assembly pattern. The measure of microstructure circulation is introduced to identify the geometric chirality of TIM systems. TIM systems identified as geometrically chiral are demonstrated to possess mechanical chiral response with a force-torque coupling under transverse mechanical loading of the TIM plate. The chiral length is found to be constant during the elastic response, yet size-dependent. During nonlinear deformation, the chiral length scale increases significantly and again exhibits a strong size dependence. The principle of dissection is introduced to transform non-chiral TIM systems into chiral ones. In the linear deformation regime, the framework of chiral elasticity is shown to be applicable. In the non-linear deformation regime, chirality is found to strongly affect the mechanical behavior more significantly than in the linear regime. Experiments on selected TIM systems validate key findings of the main computational study with the finite element method.本研究的重点是板型拓扑互锁材料系统的机械手性。拓扑互锁材料（TIM）系统是一类致密结构材料，其机械响应源于构件的弹性行为和构件之间的接触摩擦相互作用。由于内部载荷传递模式的稳定性-不稳定性特征，由此产生的机械行为具有很强的非线性。我们考虑了两种棋盘格（正方形和六边形），并将每种棋盘格中的斑块用作模板。单个构件是非手性的，而手性则来自于组装模式。引入微观结构循环度量来识别 TIM 系统的几何手性。在 TIM 板的横向机械负载下，被确定为几何手性的 TIM 系统具有力矩耦合的机械手性响应。研究发现，手性长度在弹性响应期间保持不变，但与尺寸有关。在非线性变形过程中，手性长度尺度显著增加，并再次表现出强烈的尺寸依赖性。我们引入了剖分原理，将非手性 TIM 系统转化为手性系统。在线性形变机制中，手性弹性框架被证明是适用的。在非线性变形机制中，手性对机械行为的影响比线性机制中更为显著。在选定的 TIM 系统上进行的实验验证了使用有限元方法进行的主要计算研究的主要发现。Thin-Walled StructuresClassification of fiber metal laminates (FMLs), adhesion theories and methods for improving interfacial adhesion: A reviewMin Xie, Lihua Zhan, Bolin Ma, Shengmeng Huidoi:10.1016/j.tws.2024.111744纤维金属层压板 (FML) 的分类、粘附理论和改善界面粘附的方法：综述Fiber metal laminates (FMLs) have the advantages of both metals and composite materials, making them highly promising materials in the aviation industry. The metal-polymer interfacial adhesion has an extremely important impact on the overall performance of FMLs. The present review provides a comprehensive review on the classification of FMLs, interfacial adhesion theories and methods for improving metal-polymer interfacial adhesion. First, the development history of FMLs is briefly reviewed and different types of FMLs are discussed in detail in terms of metal, reinforcement and matrix. Then, several currently known interfacial adhesion theories are elaborated. Finally, a comprehensive discussion on methods of surface treatment and nanoparticle addition is presented for improving metal-polymer interfacial adhesion.金属纤维层压板（FML）兼具金属和复合材料的优点，是航空工业中极具发展前景的材料。金属-聚合物界面附着力对 FML 的整体性能有着极其重要的影响。本综述全面回顾了 FML 的分类、界面附着力理论以及改善金属-聚合物界面附着力的方法。首先，简要回顾了 FML 的发展历史，并从金属、增强材料和基体的角度详细讨论了不同类型的 FML。然后，阐述了目前已知的几种界面粘附理论。最后，全面讨论了改善金属-聚合物界面粘附力的表面处理和纳米粒子添加方法。Effect of void defects on mechanical behavior and failure features of C/C honeycomb structureLijia Guo, Fangchao Zhang, Weijie Li, Xiaoyan Liang, Zhongwei Zhangdoi:10.1016/j.tws.2024.111745空隙缺陷对 C/C 蜂窝结构力学行为和失效特征的影响The combination of honeycomb structure and carbon/carbon (C/C) composites offers unique high load-bearing and light-weight advantages in satellite-bearing platforms. However, the defects generated by the imperfect preparation process are inevitable. This paper employs the chemical vapor infiltration (CVI) technique to fabricate novel C/C honeycomb structures and considers the presence of internal void defects. Based on micro-computerized tomography (μ-CT) images, the void distribution and porosity as well as the micro-structure characteristics are acquired. Meso-scale representative volume element (RVE) models is established to predict the performance of honeycomb wall material. A secondary development of ABAQUS is performed to establish a model of honeycomb structure containing void defects. Multi-scale models are developed for investigating the mechanical performance of the C/C honeycomb structure. Experimental methods and finite element simulations are utilized to examine the effects of porosity and different weave structures on the compression and shear properties, as well as damage modes of C/C honeycomb structures in detail. The results demonstrate that the presence of low porosity ρ = 1 % severely diminishes the load-bearing capacity of the honeycomb and affects its damage pattern. Twill-2 weave C/C honeycomb inherits the advanced performance of the composites and exhibits superior comprehensive properties compared to plain weave and twill-1 weave honeycomb structures.蜂窝结构与碳/碳（C/C）复合材料的结合为卫星承载平台提供了独特的高承重和轻质优势。然而，不完善的制备工艺不可避免地会产生缺陷。本文采用化学气相渗透（CVI）技术制造新型碳/碳蜂窝结构，并考虑了内部空隙缺陷的存在。基于微计算机断层扫描（μ-CT）图像，获得了空隙分布和孔隙率以及微结构特征。建立了中尺度代表体积元素（RVE）模型，用于预测蜂窝壁材料的性能。对 ABAQUS 进行二次开发，以建立包含空隙缺陷的蜂窝结构模型。为研究 C/C 蜂窝结构的机械性能开发了多尺度模型。利用实验方法和有限元模拟，详细研究了空隙率和不同编织结构对 C/C 蜂窝结构的压缩和剪切性能以及破坏模式的影响。结果表明，低孔隙率 ρ = 1 % 会严重降低蜂窝的承载能力，并影响其损坏模式。斜纹-2 织法 C/C 蜂窝结构继承了复合材料的先进性能，与平纹织法和斜纹-1 织法蜂窝结构相比，具有更优越的综合性能。Manufacture of honeycomb core sandwich structures by hybrid approaches: Analysis using lab scale experiments and numerical simulationA. Kumar, R. Ganesh Narayanan, N. Muthudoi:10.1016/j.tws.2024.111739采用混合方法制造蜂窝芯夹层结构：利用实验室规模实验和数值模拟进行分析In the present work, the novel sandwich structures with honeycomb core are fabricated by a solid-state joining process — friction stir spot welding (FSSW), without and with disc inserts (abbreviated as FSSW and FSSW_D) and hybrid joints without and with disc inserts (abbreviated as FSSW_AB and FSSW_D_AB). Their mechanical performance was compared with adhesive-bonded (AB) joints through the lap-shear, peel, bend, and scaled-up forming tests. Further, numerical simulations of a few FSSW strategies and AB joints are performed in Abaqus to predict the load-displacement response and Mises stress during bending. Proposing the fabrication stretegies, implementation and testing, along with numerical prediction of behavior of such joints, are the novel contributions. The peel tests showed substantial improvement in load capacity from 232% to 705% for FSSW, FSSW_AB, FSSW_D, and FSSW_D_AB joints, compared to AB joints. In the lap-shear tests, all joint types displayed significantly enhanced peak load over AB joints, ranging from 568% to 1015%. The hybrid joints, such as FSSW_AB and FSSW_D_AB, consistently outperformed the corresponding spot-welded joints, FSSW and FSSW_D, due to the sharing of load between the AB and metallurgical bonding. The FSSW_D_AB joints demonstrated exceptional peak load-to-weight ratio and fracture energy. The failure modes were consistent, with disc-inserted structures showing failure at the front-side welds for lap-shear and peel tests. During bending, the numerical modelling results were in good agreement up to the peak load. Bending panels made by FSSW_D_AB demonstrated improvement in specific stiffness and peak load by 46% and 6.12%, respectively, compared to the AB panel. Lastly, the scaled-up hybrid sandwich panel (FSSW_D_AB) showed significant improvement in deliverables when compared with the AB panel.本研究采用固态连接工艺--摩擦搅拌点焊（FSSW），制造出了带蜂窝芯的新型夹层结构，包括无圆盘插入件和有圆盘插入件的夹层结构（缩写为 FSSW 和 FSSW_D），以及无圆盘插入件和有圆盘插入件的混合连接结构（缩写为 FSSW_AB 和 FSSW_D_AB）。通过搭接-剪切、剥离、弯曲和放大成形试验，将它们的机械性能与粘合剂粘接（AB）接头进行了比较。此外，还在 Abaqus 中对一些 FSSW 策略和 AB 接头进行了数值模拟，以预测弯曲过程中的载荷-位移响应和米塞斯应力。提出制造方法、实施和测试，以及对此类接头行为的数值预测，都是我们的新贡献。剥离试验表明，与 AB 接头相比，FSSW、FSSW_AB、FSSW_D 和 FSSW_D_AB 接头的承载能力大幅提高了 232% 至 705%。在搭接-剪切试验中，所有类型接头的峰值载荷都比 AB 型接头明显提高，从 568% 到 1015%不等。FSSW_AB 和 FSSW_D_AB 等混合接头的性能始终优于相应的点焊接头（FSSW 和 FSSW_D），这是因为 AB 和冶金粘接分担了载荷。FSSW_D_AB 接头显示出优异的峰值载荷重量比和断裂能量。在搭接剪切和剥离测试中，圆盘插入式结构在正面焊缝处出现断裂，其断裂模式是一致的。在弯曲过程中，直到峰值载荷为止，数值建模结果都非常吻合。与 AB 面板相比，FSSW_D_AB 制作的弯曲面板在比刚度和峰值载荷方面分别提高了 46% 和 6.12%。最后，与 AB 面板相比，按比例放大的混合夹芯板（FSSW_D_AB）在可交付成果方面有显著改善。来源：复合材料力学仿真Composites FEM
