【新文速递】2024年7月26日固体力学SCI期刊最新文章

 

今日更新：International Journal of Solids and Structures 2 篇，Journal of the Mechanics and Physics of Solids 1 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Uniform stretching behavior of single crease origami arrays

Qian Zhang, Hui Qiu, Qiuhong Lin, Jian Feng, Jianguo Cai

doi:10.1016/j.ijsolstr.2024.112993

单折纸阵列的均匀拉伸行为

Origami arrays featuring ideal purely rotational creases inherently possess multiple kinematic degrees of freedom. The incorporation of crease rotational stiffness introduces additional constraint relations to the kinematic morphology of the origami array, due to the interaction between the plate and the crease. This paper concentrates on elucidating the coupling effect, employing two theoretical models to systematically analyze the uniform stretch process of a single crease origami array. The validity of our theoretical approaches is substantiated through verification in the finite element method. Firstly, the mechanical equations of the origami unit, together with the length and angle constraint equations of the origami array, are amalgamated to formulate a comprehensive set of morphological computational equations specific to the single crease origami array. This set enables the realization of morphological analysis for general origami arrays. Moreover, energy equations for the origami array are computed using an equivalent rigid plate nonlinear creasing element. When combined with constraint equations corresponding to horizontal stretch displacement, these energy equations contribute to the establishment of a nonlinear optimization framework for determining the morphology of uniform single crease origami arrays. Notably, our investigation reveals that during the early stages of the unfolding process for a single crease origami array, even a small relative horizontal stretch displacement can induce a drastic change in the center crease. Through finite element analysis of general origami arrays, it is shown that the proposed theoretical analysis method applies to different crease stiffness, both unfolding and folding processes, and different plate types. The research method in this paper can provide ideas for systematically analyzing the influence mechanism of crease properties on the morphological features of origami structures.

具有理想的纯旋转折痕的折纸阵列固有地具有多个运动自由度。由于板与折痕之间的相互作用，折痕旋转刚度的结合为折纸阵列的运动学形态引入了额外的约束关系。本文着重阐述了耦合效应，采用两种理论模型系统地分析了单折纸阵列的均匀拉伸过程。通过有限元方法的验证，证实了理论方法的有效性。首先，将折纸单元的力学方程与折纸阵列的长度和角度约束方程合并，形成一套完整的单折纸阵列形态计算方程;该集 合可以实现一般折纸阵列的形态分析。此外，利用等效刚性板非线性压痕单元计算了折纸阵列的能量方程。将这些能量方程与水平拉伸位移的约束方程相结合，建立了确定均匀单折纸阵列形态的非线性优化框架。值得注意的是，我们的研究表明，在单折痕折纸阵列展开过程的早期阶段，即使是很小的相对水平拉伸位移也会引起中心折痕的剧烈变化。通过对一般折纸阵列的有限元分析，表明所提出的理论分析方法适用于不同的折痕刚度、展开和折叠过程以及不同的板型。本文的研究方法可以为系统分析折纸结构的折痕特性对形态特征的影响机理提供思路。

Multimodal self-operation of a liquid crystal elastomer spring-linkage mechanism under constant light

Yunlong Qiu, Yuntong Dai, Kai Li

doi:10.1016/j.ijsolstr.2024.112998

恒光条件下液晶弹性体弹簧连杆机构的多模态自运行

Multimodal self-operating systems can provide abundant functionality and adaptability, efficiently handling various tasks and offering enhanced capabilities for complex applications. To suit various application scenarios, it is necessary to build a wider variety of multimodal self-operating systems. Inspired by the classic spring-linkage mechanism, we proposed a multimodal self-operating liquid crystal elastomer spring-linkage mechanism, consisting of a liquid crystal elastomer fiber, rigid rod and mass block under constant light. To explore the dynamic behavior of the spring-linkage mechanism, we propose a nonlinear dynamic model derived from a photothermally responsive liquid crystal elastomer model. The numerical calculation shows that four self-operation states of the spring-linkage mechanism are discovered with a supercritical Hopf bifurcation condition existing between the states. The liquid crystal elastomer fiber utilizes thermal energy provided by ambient light to compensate for damping dissipation during its motion. Furthermore, we perform a comprehensive analysis of the Hopf bifurcation condition of the spring-linkage mechanism, examining the key parameters that impact the frequency and amplitude of the self-operation. The structural simplicity of the spring-linkage mechanism and its multimodal self-operation distinguish it from many existing self-operation systems, holding promise for intriguing applications in the fields of micro-electro-mechanical systems, sensing and actuation.

多模式自操作系统可以提供丰富的功能和适应性，有效地处理各种任务，并为复杂的应用程序提供增强的功能。为了适应不同的应用场景，需要构建种类更多的多式联运自操作系统。在经典弹簧连杆机构的启发下，我们提出了一种由液晶弹性体纤维、刚性杆和质量块组成的多模态自动液晶弹性体弹簧连杆机构。为了探索弹簧连杆机构的动力学行为，我们提出了一个由光热响应液晶弹性体模型导出的非线性动力学模型。数值计算表明，发现了弹簧连杆机构的4种自运行状态，状态之间存在一个超临界Hopf分岔条件。液晶弹性体纤维利用环境光提供的热能来补偿其运动过程中的阻尼耗散。此外，我们对弹簧连杆机构的Hopf分岔条件进行了全面的分析，研究了影响自动频率和幅值的关键参数。弹簧连杆机构的结构简单，其多模态自操作使其区别于许多现有的自操作系统，在微机电系统、传感和驱动领域有着有趣的应用前景。

Journal of the Mechanics and Physics of Solids

Intrinsic Fracture Toughness of a Soft Viscoelastic Adhesive

Xingwei Yang, Michael J. Wald, Ryan Birringer, Jonathan Kemling, Aaron Hedegaard, John Martin, Jason Clapper, Rong Long

doi:10.1016/j.jmps.2024.105797

一种软粘弹性胶粘剂的内在断裂韧性

The fracture toughness of inelastic materials consists of an intrinsic component associated with the crack tip fracture process and a dissipative component due to bulk dissipation. Experimental characterization of the intrinsic component of fracture toughness is important for understanding the fracture mechanism and predictive modeling of the fracture behavior. Here we present an experimental study on the intrinsic toughness of a soft viscoelastic adhesive. We first obtained full-field and full-history data of the displacement and deformation fields in pure shear fracture tests using a particle tracking method. By combining these data with a nonlinear constitutive model, we extracted the intrinsic toughness through an energy balance analysis. A two-stage crack propagation behavior was observed in our fracture experiments: under monotonic loading the crack first underwent a slow propagation stage and then suddenly entered a fast propagation stage. We found that the intrinsic toughness was highly scattered for the slow propagation stage, but remained consistent for the fast propagation stage. Further examination of the fracture surface and the onset of fast propagation revealed that transition from the slow to the fast propagation stage was governed by the applied stretch and was likely due to a change in the crack tip fracture process.

非弹性材料的断裂韧性由与裂纹尖端断裂过程有关的固有分量和由于体积耗散而产生的耗散分量组成。断裂韧性固有成分的实验表征对于理解断裂机理和断裂行为的预测建模具有重要意义。本文对软粘弹性胶粘剂的固有韧性进行了实验研究。我们首先利用颗粒跟踪方法获得了纯剪切断裂试验中位移和变形场的全场和全历史数据。将这些数据与非线性本构模型相结合，通过能量平衡分析提取固有韧性。在我们的断裂实验中观察到两阶段的裂纹扩展行为:在单调加载下，裂纹先经历缓慢扩展阶段，然后突然进入快速扩展阶段。研究发现，在缓慢扩展阶段，本征韧度高度分散，而在快速扩展阶段，本征韧度保持一致。对断口表面和快速扩展开始的进一步检查表明，从缓慢扩展到快速扩展阶段的转变是由施加的拉伸控制的，可能是由于裂纹尖端断裂过程的变化。

Mechanics of Materials

A high-rate, impact-driven biaxial fragmentation experiment for ductile materials

Gary Simpson, Justin Moreno, Matthew Shaeffer, K.T. Ramesh

doi:10.1016/j.mechmat.2024.105102

一种高速率、冲击驱动的延性材料双轴破碎实验

The experimental investigation of high strain rate fragmentation has generally been limited to one of two cases: analytically powerful but simple one-dimensional loading configurations, or complicated multiaxial experiments more closely approximating use applications. The former, exemplified by Mott-style ring fragmentation, promotes simple and confident analysis—forming the backbone of the field and revealing the basic nature of dynamic fragmentation in solids—but ignores some critical mechanisms in order to achieve that simplicity. The latter, while informing applications of interest such as ballistic impact, may provide limited insight and is often difficult to access diagnostically. This work presents an attempt to help bridge the gap between 1D ring expansion and 3D fragmentation experiments in the form of impact driven, high-strain-rate biaxial tensile fragmentation experiments. The impact target system consists of a thin specimen plate and a thick polymer impact buffer. The latter serves as a fluid-like medium allowing momentum transfer between an impacting projectile and a rapidly growing near-hemispherical bulge in the specimen plate. The deformation of the specimen and fragmentation pattern are observed using ultra-high-speed optical imaging as well as flash x-ray imaging, and individual fragments are recovered and characterized post-mortem. Using this method, the fragmentation behavior of 6061-T6 Aluminum is investigated at tensile strain rates exceeding 10^5s−1 and at higher stress triaxiality than that commonly achieved.

对高应变速率破碎的实验研究通常局限于两种情况之一：分析能力强但简单的一维加载配置，或更接近使用应用的复杂多轴实验。前者以莫特式环破碎为例，促进了简单而可靠的分析，成为该领域的支柱，并揭示了固体动态破碎的基本性质，但为了实现这种简单性，忽略了一些关键机制。后者虽然为弹道撞击等相关应用提供了信息，但可能提供的洞察力有限，而且往往难以进行诊断。本研究试图通过冲击驱动的高应变率双轴拉伸碎裂实验，弥合一维环形膨胀和三维碎裂实验之间的差距。冲击目标系统由薄试样板和厚聚合物冲击缓冲器组成。后者是一种类似于流体的介质，允许撞击弹丸和试样板上迅速增大的近半球形凸起之间进行动量传递。使用超高速光学成像和闪光 X 射线成像技术观察试样的变形和碎裂模式，并在死后回收和鉴定单个碎片。利用这种方法，可以研究 6061-T6 铝在拉伸应变速率超过 10^5s-1 和应力三轴度高于通常情况下的碎裂行为。

Thin-Walled Structures

Localized loading behavior of cold-formed stainless steel RHS under Interior-One-Flange load case at elevated temperatures

Chen-Yu Xu, Hai-Ting Li

doi:10.1016/j.tws.2024.112265

高温下冷弯不锈钢RHS内单法兰局部加载行为

The localized loading behavior of cold-formed stainless steel (CFSS) rectangular hollow section (RHS) members at elevated temperatures is investigated in this paper. Fifteen localized loading tests conducted at various temperatures up to 800°C were reported. The tests were carried out under the Interior-One-Flange (IOF) load case as specified in American Specification for the design of cold-formed stainless steel structural members. Tensile coupon tests were performed to obtain the material properties of the CFSS RHS at various temperatures. Detailed information on dimensions, temperature history, failure modes, load-deformation curves, localized loading capacities of specimens at various temperatures were presented. In addition, a numerical investigation was supplemented, where a total of 192 finite element (FE) analyses were undertaken after validation of developed FE model against the elevated-temperature test results. The influence of various parameters on the localized loading capacities of CFSS RHS at different temperatures under IOF load case was revealed. The obtained results were utilized to assess the applicability of the localized loading design provision for CFSS RHS under IOF load case codified in the American Specification to elevated temperature conditions. Moreover, the results were also compared with predictions based on existing design rules in literatures for cold-formed RHS at elevated temperatures. Furthermore, reliability analyses were carried out to assess the reliability levels of the assessed design methods. It is shown that the existing design rules can generally provide conservative and reliable predictions of the localized loading capacities for the CFSS RHS under IOF load case at elevated temperatures.

研究了冷弯不锈钢(CFSS)矩形空心截面构件在高温下的局部加载行为。报告了在800°C的不同温度下进行的15次局部加载试验。试验是在美国冷弯不锈钢结构构件设计规范中规定的内单法兰(IOF)荷载工况下进行的。对CFSS RHS材料在不同温度下的性能进行了拉伸试验。给出了试件在不同温度下的尺寸、温度历史、破坏模式、荷载-变形曲线、局部加载能力等详细信息。此外，还补充了一项数值研究，在将开发的有限元模型与高温试验结果进行验证后，进行了总共192次有限元分析。揭示了在IOF工况下，不同温度下各参数对CFSS RHS局部承载能力的影响。利用获得的结果来评估CFSS RHS在美国规范中规定的IOF荷载情况下局部加载设计条款在高温条件下的适用性。此外，还将结果与基于现有设计规则的高温冷弯RHS预测结果进行了比较。此外，还进行了可靠性分析，以评估所评估的设计方法的可靠性水平。结果表明，现有设计规则一般能保守可靠地预测高温工况下CFSS RHS局部载荷能力。