【新文速递】2023年10月3日固体力学SCI期刊最新文章

今日更新：Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇Journal of the Mechanics and Physics of SolidsBending the rules: Strain accommodation in layered crystalline solids through nanoscale buckling over dislocationsGruber Jacob, Plummer Gabriel, Tucker Garritt J.doi:10.1016/j.jmps.2023.105450弯曲规则：通过纳米级位错屈曲实现层状晶体固体的应变容纳Basal dislocations and ripplocations both offer explanations for the deformation of layered crystalline solids in response to compressive strain. Existing work, however, presents no clear definition of a ripplocation and the distinction between these two mechanisms remains unclear. Molecular dynamics simulations in graphite and modified graphitic models reveal that equivalent additional half-planes of material can induce both dislocations and ripplocations. In this work, we find that ripplocations are essentially an elastic buckling phenomenon operating at the atomic scale, rather than a discrete crytallographic defect. Dislocation core confinement produces incommensurate planar elastic strains with sufficient energy to trigger a buckling instability that transfers strain energy to the surrounding lattice. The interplay between incommensurate strain and buckling is a quasi-continuum phenonemon where both mechanisms may accommodate arbitrary disregistry, not only the discrete values accommodated by perfect or partial basal dislocations. The mechanistic transition depends critically on the atomic-scale interfacial energies between layers and the continuum elastic behavior of the bulk material. Buckling is possible, though unfavorable, in the MAX phase Ti3AlC2 and systems of multiple layers buckle at lower strains than only a single layer. These extensions of the ripplocation model in van der Waals layered solids suggest that nanoscale elastic buckling potentially plays a role in the deformation of a wide range of layered crystalline systems in response to common mechnical configurations.基底位错和波状位错都能解释层状晶体固体在压缩应变作用下的变形。然而，现有研究并未给出涟漪位错的明确定义，这两种机制之间的区别仍不清楚。石墨和改良石墨模型的分子动力学模拟显示，等效的附加半平面材料既能诱发位错，也能诱发波纹位错。在这项工作中，我们发现波状位错本质上是一种在原子尺度上运行的弹性屈曲现象，而不是一种离散的晶体学缺陷。位错核心束缚会产生具有足够能量的不可比平面弹性应变，从而引发屈曲不稳定性，将应变能量传递到周围晶格。不相称应变和屈曲之间的相互作用是一种准连续现象，在这种现象中，两种机制都可以容纳任意的偏析，而不仅仅是完全或部分基底位错所容纳的离散值。机理转换在很大程度上取决于层间原子尺度的界面能量和块体材料的连续弹性行为。在 MAX 相 Ti3AlC2 中，屈曲是可能的，尽管是不利的。而多层体系在较低应变下的屈曲程度要低于单层体系。范德瓦尔斯层状固体中波纹定位模型的这些扩展表明，纳米级弹性屈曲可能在各种层状晶体系统的变形中发挥作用，以应对常见的技术配置。Mechanics of MaterialsImpact and adhesion mechanics of block copolymer micro-particles with a silicon substrateDuran Salih, Kim Ara, Lee Jae-Hwang, Muftu Sinandoi:10.1016/j.mechmat.2023.104817嵌段共聚物微颗粒与硅衬底的冲击和粘附力学原理Deformation of a two-phase block copolymer (BCP) during high velocity impacts is studied experimentally and theoretically with an aim to use this material in cold spray (CS) additive manufacturing. Micron scale (10–20 μm) spherical particles of polystyrene-block-polydimethylsiloxane (PS-b-PDMS) are impacted on a silicon substrate by using a laser-induced projectile impact test (LIPIT) setup with impact velocities in the range of 50–600 m/s. Experiments indicate that polymer particles adhere to the substrate when their impact velocities fall within the range of 140–500 m/s. A constitutive model that accounts for the effects of both strain rate and temperature on the mechanical behavior of such materials is developed. A critical energy release rate function which depends on the surface temperature and rate of separation is formulated and used in a cohesive zone model (CZM) to model bonding of the BCPs on the substrate. The model parameters are calibrated by comparing the deformed and computed deformed particle shapes and coefficient of restitution values of the rebounding particles. Simulations show that the particles experience ultra-high strain rates (>104 s−1), large deformation, and temperature elevation due to plastic dissipation and interfacial friction. The outer rim of the contact interface is predicted to experience temperature levels above the glass transition temperature of the PS-domain of the BCP. Bonding is correlated with increase of contact area, plastic dissipation and temperature rise in the interface.通过实验和理论研究了双相嵌段共聚物（BCP）在高速冲击过程中的变形，目的是将这种材料用于冷喷（CS）快速成型制造。微米级（10-20μm）使用激光诱导弹丸冲击试验（LIPIT）装置，以 50-600 m/s 的冲击速度将聚苯乙烯-块状-聚二甲基硅氧烷（PS-b-PDMS）球形颗粒冲击到硅基底上。实验表明，当冲击速度在 140-500 米/秒范围内时，聚合物颗粒会粘附在基底上。我们建立了一个应变率和温度对这种材料的机械行为都有影响的构成模型。制定了一个取决于表面温度和分离率的临界能量释放率函数，并将其用于内聚区模型（CZM），以模拟 BCP 在基体上的粘合。通过比较变形颗粒和计算变形颗粒的形状以及反弹颗粒的恢复系数值，对模型参数进行了校准。模拟结果表明，由于塑性耗散和界面摩擦，颗粒经历了超高应变率（>104 s-1）、大变形和温度升高。据预测，接触界面外缘的温度水平将高于 BCP 的 PS 域的玻璃化转变温度。粘合与接触面积增加、塑性耗散和界面温度升高相关。来源：复合材料力学仿真Composites FEM