【新文速递】2024年10月31日固体力学SCI期刊最新文章_ACT_Mechanical_Fluent_Maxwell_System_振动_断裂_复合材料_非线性_通用_航空_航天_建筑_电子_裂纹_理论_材料_多尺度_控制

【新文速递】2024年11月16日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 2 篇，Thin-Walled Structures 1 篇International Journal of Solids and StructuresMinimum energy combined and separated bounds on elastic constants of transversely-isotropic compositesDuc-Chinh Phamdoi:10.1016/j.ijsolstr.2024.113134横向各向同性复合材料弹性常数的最小能量组合界和分离界The considered linearly-elastic transversely-isotropic composite (TIC) is composed of n isotropic, or more generally, transversely-isotropic components sharing the materials’ common symmetry axis with that of the macroscopic material. Using the basic minimum energy and complementary energy principles with certain free-parameter-dependent mixed-longitudinal-transverse-mode strain and stress trial fields, various combination bounds involving some sets of the macroscopic (effective) mixed-mode elastic constants of the composite, which are inter-connected via the constitutive relations, have been established. Choosing the appropriate parameter values of/or optimizing over the free parameters in those inequalities, the separated bounds on the major effective mixed-transverse-longitudinal-mode elastic constants, including the transverse bulk modulus K_eff, the longitudinal Young modulus E_eff, and the longitudinal Poisson’s ratio ν_eff, are derived, beside the classical arithmetic and harmonic average bounds on the pure-mode ones - the transverse shear (μ_eff) and longitudinal shear (μ`_eff) moduli. The separated bounds on 4 remaining effective mixed-mode elastic constants are also obtained. The illustrative numerical comparisons of the bounds, in the two component case, with those for the special subclass of unidirectional transversely-isotropic composites (UTIC), having the unidirectional cylindrical boundaries between the component materials parallel to their symmetry axis, and the exact coated-cylinder assemblage and laminate models are presented. The extreme models cover substantial parts between the bounds for TIC; however the laminate models lie outside the bounds for the subclass UTIC.考虑的线性弹性横向各向同性复合材料（TIC）由n个各向同性或更一般地，横向各向同性组件组成，这些组件与宏观材料的对称轴共享材料的对称性。利用基本的能量最小化和补充能量原理，以及与某些自由参数相关的混合纵向-横向模式应变和应力试探场，建立了涉及复合材料宏观（有效）混合模式弹性常数的一些集合的组合界限，这些常数通过本构关系相互关联。选择这些不等式中的适当参数值或对自由参数进行优化，除了经典的算术和调和平均纯模式界限（横向剪切模量μ_eff和纵向剪切模量μ`_eff）之外，还得出了分离的纯模式界限，包括横向体模量K_eff、纵向杨氏模量E_eff和纵向泊松比ν_eff。还获得了剩余4个有效混合模量边界的分离解。在两组元情况下，将这些边界与具有平行于对称轴的组元材料的单向圆柱形边界之间的特殊子类各向同性复合材料（UTIC）的边界、精确的涂层圆柱体组合模型和层合模型进行了说明性的数值比较。极端模型覆盖了TIC边界的大部分区域，但层合模型则位于子类UTIC的边界之外。Journal of the Mechanics and Physics of SolidsUnraveling the Molecular Mechanisms of Membrane Rupture: Insights from All-Atom Simulations and Theoretical ModelingPanpan Zhu, Ji Lin, Yimou Fu, Chun Shen, Haofei Zhou, Shaoxing Qu, Huajian Gaodoi:10.1016/j.jmps.2024.105958揭开膜破裂的分子机制：来自全原子模拟和理论建模的见解Cell membrane rupture occurs universally and is long thought to be the terminal event of cell death; however, there is an inadequate understanding of the microscopic mechanisms of membrane rupture at the molecular level. In this study, we investigated the rupture mechanism of two model membranes, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and cholesterol bilayer membranes, under surface tension by all-atom molecular simulations and theoretical modeling. Under surface tension, the tail chains of POPC molecules become disordered, leading to ductile membrane deformation, while cholesterol membranes display limited deformation before rupture. We analyzed the orientation of tail chains and the internal stresses within the membranes, revealing that the mutual attraction among different tail chains and the resulting stress peak in the tail region of the membrane play substantial roles in the membrane rupture process. Based on these physical insights, we proposed a theoretical model that incorporates an internal variable of tail chain orientation to capture the variations in strain and orientation of different membrane components under varying surface tensions. The critical rupture threshold predicted by our theoretical model aligns well with the simulation results, demonstrating a brittle to ductile transition for membranes with different cholesterol contents. Our study unravels the impact of tail chain orientation and internal stress on membrane mechanics, which deepens the understanding of the microscale mechanisms underlying membrane rupture.细胞膜破裂是普遍存在的，长期以来被认为是细胞死亡的终末事件；然而，在分子水平上对膜破裂的微观机制了解不足。本研究采用全原子分子模拟和理论建模的方法，研究了1-棕榈酰-2-油酰-磷脂酰胆碱（POPC）和胆固醇双层膜在表面张力作用下的破裂机理。在表面张力作用下，POPC分子尾链变得无序，导致韧性膜变形，而胆固醇膜在破裂前表现为有限变形。我们分析了尾链的取向和膜内的内应力，揭示了不同尾链之间的相互吸引以及在膜尾部区域产生的应力峰值在膜破裂过程中起着重要作用。基于这些物理见解，我们提出了一个理论模型，该模型包含尾链取向的内部变量，以捕捉不同表面张力下不同膜组分的应变和取向变化。我们的理论模型预测的临界破裂阈值与模拟结果很好地吻合，表明具有不同胆固醇含量的膜具有脆性到延性的转变。我们的研究揭示了尾链取向和内应力对膜力学的影响，加深了对膜破裂微观机制的理解。Mechanics of electroadhesion of polyelectrolyte hydrogel heterojunctions enabled by ionic double layersZheyu Dong, Zhi Sheng, Zihang Shen, Shaoxing Qu, Zheng Jiadoi:10.1016/j.jmps.2024.105960离子双层驱动的聚电解质水凝胶异质结电粘附力学In recent years, soft materials with reversible adhesion have come to the fore as a promising avenue of research. Compared to other reversible adhesion methods, electroadhesion enabled by the formation of ionic double layer (IDL) has been widely used due to its simplicity, low energy consumption, fast response, and reversibility. Despite the extensive experimental studies and qualitative mechanistic explanations, there remains a dearth of theoretical studies on this topic, particularly regarding the development of theoretical mechanics models. Our study aims to address this gap by establishing a mechanics model of IDL-enabled electroadhesion between soft materials. We specifically focus on modeling the low-voltage electroadhesion of heterojunctions between two polyelectrolyte hydrogels. The model decomposes the electroadhesion formation into two successive physical processes. First, under appropriate bias conditions, the applied voltage drives the mobile ions in each polyelectrolyte hydrogel to migrate toward the electrode, resulting in the formation of an IDL at the heterojunction interface and the generation of a potent built-in electric field inside the IDL. Second, driven by the strong built-in electric field of IDL, the dangling charged chains of the two polyelectrolyte hydrogels begin to cross the heterojunction interface and penetrate into the opposite hydrogel matrix to form ionic bonds with the oppositely-charged chains, resulting in a bridging network that sutures the interface. As a result, the electrostatic interactions inside the IDL as well as the bridging network across the interface leads to the electroadhesion of polyelectrolyte hydrogel heterojunctions. The modeling results show that the IDL thickness, the IDL electric field density, and the electroadhesion strength increase with the applied voltage. We also experimentally conduct the electroadhesion tests, and the measurements of electroadhesion strength quantitatively match the modeling results well. For the first time, we reveal the underlying mechanism of IDL-driven electroadhesion by establishing a theoretical mechanics model. We anticipate that our mechanics model can shed light on the design, optimization, and control of the electroadhesion of soft-material heterojunctions.近年来，具有可逆性粘附的软质材料作为一种很有前途的研究方向而崭露头角。与其他可逆粘附方法相比，离子双层电粘附（IDL）具有简单、低能耗、响应快、可逆性等优点，得到了广泛的应用。尽管有大量的实验研究和定性的力学解释，但关于这一主题的理论研究仍然缺乏，特别是关于理论力学模型的发展。我们的研究旨在通过建立软材料之间idl驱动的电粘附的力学模型来解决这一差距。我们特别专注于模拟两种聚电解质水凝胶之间异质结的低压电粘附。该模型将电粘附的形成分解为两个连续的物理过程。首先，在适当的偏置条件下，施加的电压驱动每个聚电解质水凝胶中的可移动离子向电极迁移，导致在异质结界面处形成IDL，并在IDL内部产生强大的内置电场。其次，在IDL强大的内置电场的驱动下，两种聚电解质水凝胶的悬空带电链开始穿过异质结界面，并渗透到相反的水凝胶基质中，与相反的带电链形成离子键，形成桥接网络，将界面连接起来。因此，IDL内部的静电相互作用以及界面上的桥接网络导致了聚电解质水凝胶异质结的电粘附。模拟结果表明，随着施加电压的增加，IDL厚度、IDL电场密度和电粘附强度均增加。我们还进行了电粘附实验，电粘附强度的测量结果与模型结果吻合较好。我们首次通过建立理论力学模型揭示了idl驱动电粘附的潜在机制。我们期望我们的力学模型可以为软材料异质结的电粘附设计、优化和控制提供启示。Thin-Walled StructuresEffect of fractal dimension on mechanical behaviour and energy absorption of Menger sponge-inspired fractal structuresMadhusha Bogahawaththa, Damith Mohotti, Paul J. Hazell, Hongxu Wang, Kasun Wijesooriya, Chi King Leedoi:10.1016/j.tws.2024.112704分形维数对Menger海绵状分形结构力学性能和吸能的影响The Fractal Dimension (FD) of Menger Fractal Cubes (MFCs) defines their intricate geometry, making them ideal for lightweight structural applications. However, the effect of FD on their structural behaviour is largely unexplored. This study examines AlSi7Mg MFC geometries formed through a recursive process, with densities ranging from 40 to 1958 kg/m³, corresponding to FDs ranging from 2.35 to 2.73. Compression tests and simulations revealed that higher fractal orders increased densification displacement, achieving up to 80% compressibility, with multi-level extended plateau regions indicating enhanced energy absorption. The fourth-order MFC with an FD of 2.35 and a density of 40 kg/m³ showed a specific energy absorption (SEA) of 6 J/g, demonstrating its potential for weight-efficient, energy-absorbing structures. The outcomes of this study indicate that total energy absorbed increases with an increasing FD, while crush efficiency improves as FD decreases showing better crashworthiness. Moreover, the structures exhibited unique force-displacement responses tailored to their FD. These findings offer valuable insights into optimising thin-walled fractal structures for various engineering applications by adjusting the FD to fine-tune relative density and enhance mechanical performance.门格尔分形立方体（mfc）的分形维数（FD）定义了它们复杂的几何形状，使它们成为轻量化结构应用的理想选择。然而，FD对其结构行为的影响在很大程度上尚未被探索。本研究考察了通过递归过程形成的AlSi7Mg MFC几何形状，其密度范围为40至1958 kg/m³，对应的fd范围为2.35至2.73。压缩试验和模拟表明，更高的分形阶数增加了致密化位移，可达到80%的压缩率，多层次扩展的高原区域表明能量吸收增强。四阶MFC的FD为2.35，密度为40 kg/m³，比能吸收（SEA）为6 J/g，显示了其作为减重吸能结构的潜力。研究结果表明，总能量吸收随FD的增加而增加，粉碎效率随FD的减小而提高，具有较好的耐撞性。此外，结构表现出与其FD相适应的独特的力-位移响应。这些发现为优化各种工程应用的薄壁分形结构提供了有价值的见解，通过调整FD来微调相对密度并提高机械性能。来源：复合材料力学仿真Composites FEM

【新文速递】2024年10月31日固体力学SCI期刊最新文章

International Journal of Solids and Structures

Journal of the Mechanics and Physics of Solids

International Journal of Plasticity

Thin-Walled Structures

【新文速递】2024年11月16日固体力学SCI期刊最新文章