【新文速递】2024年2月11日复合材料SCI期刊最新文章

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今日更新：Composite Structures 3 篇，Composites Part A: Applied Science and Manufacturing 1 篇，Composites Part B: Engineering 2 篇

Composite Structures

Dynamics Control of L-shaped Composite Structure in Electric Aircraft: Theoretical Analysis and Experimental Validation

Jian Zang, Lu Liu, Xu-Yuan Song, Zhen Zhang, Ye-Wei Zhang, Li-Qun Chen

doi:10.1016/j.compstruct.2024.117929

电动飞机 L 型复合结构的动力学控制：理论分析与实验验证

This paper focuses on the vibration control of an L-shaped composite structure, which is a simplified part of the motor support structure in an electric airplane. NiTiNOL steel wire rope (NiTi-ST) is employed as the vibration control mechanism. The study begins with a natural frequency and modal analysis using the Rayleigh-Ritz approach, which is subsequently validated using finite element analysis and experimental hammering methods. The dynamical equations are derived through the Lagrange method and then discretized using the Galerkin truncation method (GTM). Vibration responses of the simplified model are obtained through the harmonic balance method (HBM), and these results are confirmed through validation with the Runge-Kutta method (RKM). Based on the theoretical analysis, the experiments are carried out to optimize the vibration control scheme of L-shaped composite beam. The results demonstrates that the NiTi-ST wire rope effectively controls vibrations without affecting the system's natural frequency.

本文主要研究 L 形复合结构的振动控制，该结构是电动飞机电机支撑结构的简化部分。采用镍钛糯钢丝绳（NiTi-ST）作为振动控制机制。研究首先使用 Rayleigh-Ritz 方法进行了固有频率和模态分析，随后使用有限元分析和实验锤击方法进行了验证。通过拉格朗日法推导出动力学方程，然后使用伽勒金截断法（GTM）将其离散化。通过谐波平衡法 (HBM) 获得简化模型的振动响应，并通过 Runge-Kutta 法 (RKM) 验证这些结果。在理论分析的基础上，进行了优化 L 形复合梁振动控制方案的实验。结果表明，NiTi-ST 钢丝绳能有效控制振动，且不会影响系统的固有频率。

Multi-scale FE2 investigation of non linear rate dependent 3D composite structures accounting for fiber-matrix damage

H. Oukfif, E. Tikarrouchine, M-A. Louar, G. Chatzigeorgiou, F. Meraghni

doi:10.1016/j.compstruct.2024.117960

考虑纤维基质损伤的非线性速率相关三维复合材料结构的多尺度 FE2 研究

In the present paper, a two-scale FE2 technique based on periodic homogenization theory is investigated to predict the macroscopic non-linear behavior of polymer matrix composite structures. The computational technique accounts for the fiber/matrix interfacial damage, the matrix ductile damage and the effect of 3D periodic microstructure. The developed approach integrates the geometric description and the non-linear time-dependent local behavior of the different constituents (fibers, matrix and interface). For numerical calculations, advanced User Defined Material and User Element subroutines are developed at the two scales, simultaneously activated to solve macroscopic and microscopic problems through an incremental scheme in the finite element commercial code Abaqus/Implicit The computational efficiency of the developed multi-scale approach is demonstrated by predicting the overall response of 3D composite structures under complex loading paths. The composite structures consist of thermoplastic polymer matrix with elasto-viscoplastic behavior and ductile damage, reinforced by elastic aligned short fibers that are coated by a cohesive zone, which obeys the general unified potential. The numerical results obtained by FE2 simulation with and without accounting for interface effect are analyzed and compared for two examples: Meuwissen-like and 3D corner shape structures. The main benefits of the developed approach lie in accessing the microscopic strain fields, the distributions of the internal variables and the damage evolution in both polymer matrix and interface, as well as identifying their repercussions on the macroscopic response.

本文研究了基于周期均质化理论的双尺度 FE2 技术，以预测聚合物基复合材料结构的宏观非线性行为。该计算技术考虑了纤维/基体界面损伤、基体韧性损伤以及三维周期性微结构的影响。所开发的方法综合了几何描述和不同成分（纤维、基体和界面）的非线性时变局部行为。为了进行数值计算，在两个尺度上开发了先进的用户定义材料和用户元素子程序，通过有限元商业代码 Abaqus/Implicit 中的增量方案同时激活，以解决宏观和微观问题。复合材料结构由具有弹塑性-粘塑性行为和韧性损伤的热塑性聚合物基体组成，并由弹性排列的短纤维加固，短纤维被服从一般统一势能的内聚区包裹。通过 FE2 仿真获得的数值结果，在考虑和不考虑界面效应的情况下，对两个实例进行了分析和比较：类似于 Meuwissen 的结构和三维角形结构。所开发方法的主要优点在于可以获取聚合物基体和界面的微观应变场、内部变量分布和损伤演变，并确定它们对宏观响应的影响。

Long-term creep behavior of novel self-anchored CFRP cable system

Pengcheng Ai, Guozhen Ding, Zhiyuan Li, Peng Feng

doi:10.1016/j.compstruct.2024.117965

新型自锚式 CFRP 电缆系统的长期蠕变行为

Carbon fiber-reinforced polymer (CFRP) cables are an attractive material for bridge cables due to their light weight, high strength, and corrosion resistance properties. However, research on their long-term creep performance is limited. In this study, long-term creep tests were conducted on self-anchored CFRP cables under various stress levels to evaluate their creep performance and residual mechanical properties. Based on experimental data, million-hour creep coefficients and relaxation coefficients were predicted. The results indicated that the self-anchored CFRP cable system had a million-hour creep coefficient ranging from 6.1% to 7.9% at stress levels from 0.3 fu to 0.7 fu (where fu represents the characteristic tensile strength). Additionally, maintaining low and medium stress levels for 1000 h improved the tensile strength and stability of the CFRP cables. The self-anchored CFRP system was also able to provide effective anchorage even after continuous loading. By comparing with the steel cable data in the literature, the self-anchored CFRP system exhibited smaller creep and relaxation, as well as superior residual tensile properties. These findings suggested that the self-anchored CFRP cable exhibited favorable long-term reliability, and finally self-anchored CFRP cables were successfully applied to a bridge in the campus of Tsinghua University.

碳纤维增强聚合物（CFRP）缆绳重量轻、强度高、耐腐蚀，是一种极具吸引力的桥梁缆绳材料。然而，对其长期蠕变性能的研究还很有限。本研究在不同应力水平下对自锚 CFRP 缆索进行了长期蠕变试验，以评估其蠕变性能和残余机械性能。根据实验数据预测了百万小时蠕变系数和松弛系数。结果表明，在 0.3 fu 到 0.7 fu 的应力水平下（其中 fu 代表特征抗拉强度），自锚 CFRP 电缆系统的百万小时蠕变系数介于 6.1% 到 7.9% 之间。此外，保持中低应力水平 1000 小时可提高 CFRP 缆索的抗拉强度和稳定性。自锚 CFRP 系统即使在持续加载后也能提供有效的锚固。与文献中的钢缆数据相比，自锚式 CFRP 系统的蠕变和松弛较小，残余拉伸性能优越。这些研究结果表明，自锚式 CFRP 拉索具有良好的长期可靠性，最终自锚式 CFRP 拉索被成功应用于清华大学校园内的一座桥梁。

Composites Part A: Applied Science and Manufacturing

Through-thickness frontal polymerization: Process development and optimization

S. Vyas, N.A. Parikh, T. Price, D.P. Patel, T.B. Le, P.H. Geubelle, N.R. Sottos

doi:10.1016/j.compositesa.2024.108084

通过厚度正面聚合：工艺开发与优化

Current methods for the manufacture of fiber-reinforced polymer composites (FRPCs) are energy intensive, time consuming, and have adverse effects on the environment. Frontal polymerization (FP) is an out-of-autoclave, self-sustaining cure process garnering significant adoption by enabling rapid and energy-efficient manufacture of FRPCs. Prior FP-based manufacture of FRPCs rely on in-plane triggers to initiate the reaction. In the present study, we adopt through-thickness curing of carbon FRPCs with emphasis on the energy input required and the resulting composite properties. High energy input resulted in high glass transition temperature (Tg=156°C), fiber volume fraction (Vf=65%), and low void content (Vv≈0). Computational modeling and optimization complement the experiments with focus on further reducing the energy whilst maintaining the favorable properties achieved at high energy inputs. A 27.5% reduction in energy resulted while maintaining similar performance.

目前制造纤维增强聚合物复合材料（FRPC）的方法耗能、耗时，并对环境造成不利影响。正面聚合（FP）是一种无需高压釜、可自我维持的固化工艺，可快速、节能地制造 FRPC，因而得到广泛采用。先前基于 FP 的 FRPC 制造依赖于平面内触发器来启动反应。在本研究中，我们采用了碳 FRPC 的通厚固化工艺，重点研究了所需的能量输入和由此产生的复合材料性能。高能量输入带来了高玻璃化转变温度（Tg=156°C）、纤维体积分数（Vf=65%）和低空隙含量（Vv≈0）。计算建模和优化是对实验的补充，重点是进一步降低能量，同时保持高能量输入时实现的有利特性。在保持类似性能的同时，能量降低了 27.5%。

Composites Part B: Engineering

Accuracy enhancement for airbag deployment simulations considering the strain rate and temperature-dependent mechanical properties of thermoplastic olefin and polypropylene

Se-Min Lee, In-Soo Han, Gyu-Won Kim, Jae-Hyun An, Hak-Sung Kim

doi:10.1016/j.compositesb.2024.111292

考虑热塑性烯烃和聚丙烯的应变率和随温度变化的机械特性，提高安全气囊展开模拟的精度

Airbags are essential automotive components that protect occupants from collisions. Airbag covers made of thermoplastic olefin (TPO) material should be deployed quickly without debris under various environments. To accurately predict airbag deployment during a collision, the mechanical properties of polymer materials at high strain rates according to temperature should be considered. In this study, a quasi-static test in the range of 0.0083, 0.0083 s−1 and a medium strain rate tensile test were performed at strain rates of 1, 10, and 100 s−1. Additionally, a split-Hopkinson Pressure bar test was performed to conduct a high strain rate tensile test at 1000, 1500, and 2000 s−1. Through this, tensile strength and failure strain were derived for each strain rate. As the polymer phase moves toward the high strain rate region, the β-transition becomes dominant, resulting in a non-linear increase in tensile strength in the Eyring plot. Based on the strain rate dependent mechanical behavior, an airbag module impact simulation was conducted to verify the effects of strain rate on airbag deployment using the LS-DYNA software. The airbag deployment analysis results showed deployment angle results similar to the actual experiment when strain rate dependent mechanical properties were applied. This is because higher strength was applied at high strain rates compared to low strain rates. Therefore, strain rate dependent mechanical properties are essential in high strain rate simulation such as collision analysis.

安全气囊是保护乘员免受碰撞的重要汽车部件。由热塑性烯烃（TPO）材料制成的安全气囊盖应能在各种环境下快速展开而不产生碎片。为了准确预测碰撞过程中安全气囊的展开情况，应考虑聚合物材料在高应变率下随温度变化的机械特性。在这项研究中，进行了 0.0083、0.0083 s-1 范围内的准静态测试，以及应变速率为 1、10 和 100 s-1 的中等应变速率拉伸测试。此外，还进行了分裂霍普金森压力棒试验，以 1000、1500 和 2000 s-1 的应变速率进行高应变速率拉伸试验。由此得出了每种应变速率下的拉伸强度和破坏应变。随着聚合物相向高应变率区域移动，β 转变成为主导，从而导致艾林图中拉伸强度的非线性增加。根据应变率相关力学行为，使用 LS-DYNA 软件进行了安全气囊模块冲击模拟，以验证应变率对安全气囊展开的影响。安全气囊展开分析结果表明，当应用应变速率相关机械特性时，展开角度结果与实际实验结果相似。这是因为与低应变速率相比，高应变速率下的强度更高。因此，应变速率相关机械特性在碰撞分析等高应变速率模拟中至关重要。

Recycling of CF-ABS machining waste for large format additive manufacturing

Roo Walker, Matthew Korey, Amber M. Hubbard, Caitlyn M. Clarkson, Tyler Corum, Tyler Smith, Christopher J. Hershey, John Lindahl, Soydan Ozcan, Chad Duty

doi:10.1016/j.compositesb.2024.111291

回收 CF-ABS 加工废料，用于大幅面增材制造

Large format additive manufacturing (LFAM) necessitates the use of short fiber thermoplastic composites, such as carbon fiber filled acrylonitrile butadiene styrene, to enable printing. Currently, when LFAM parts are machined into their final shape, the machining scrap (i.e., small flake like particles and offcuts) is landfilled. Previous studies have demonstrated the viability of recycling end-of-life LFAM parts by shredding and optionally re-compounding the material back into pellets. However, there is little understanding of the value and performance of recycled material made from LFAM machining scrap, which if pursued could motivate more broad recycling of this waste stream. In this study, recycled in-process machining scrap is explored as an LFAM feedstock source. Herein, it is found that the primary degradation mechanism of the recycled material is significant fiber length attrition during surface machining. While this fiber attrition negatively impacts the mechanical performance of the material in the print direction, it seems that the changes in processing behaviors and print quality, namely the surface roughness of the printed structure associated with shorter fiber lengths, is beneficial to interlayer adhesion. The tensile strength and elastic modulus of the recycled material, in the print direction, decreased 11% and 31% respectively compared to the pristine material. However, in the layer-wise direction it was found that the recycled material exhibited no significant change in elastic modulus and a significant 21% increase in tensile strength – a surprising result. This work indicates that machining waste could be a viable material stream for recycled LFAM feedstock materials.

大幅面增材制造（LFAM）需要使用短纤维热塑性复合材料（如填充丙烯腈-丁二烯-苯乙烯的碳纤维）来实现打印。目前，当 LFAM 零件被加工成最终形状时，加工废料（即小片状颗粒和下脚料）会被填埋。以前的研究已经证明，通过粉碎和选择性地将材料重新复合成颗粒，回收利用报废的 LFAM 部件是可行的。然而，人们对用 LFAM 加工废料制成的回收材料的价值和性能了解甚少，而如果能对其进行研究，就能推动对这一废物流进行更广泛的回收利用。本研究将回收的加工过程中产生的废料作为 LFAM 原料来源进行了探讨。研究发现，回收材料的主要降解机制是表面加工过程中纤维长度的显著损耗。虽然这种纤维损耗会对材料在印刷方向上的机械性能产生负面影响，但加工行为和印刷质量的变化，即与较短纤维长度相关的印刷结构表面粗糙度，似乎有利于层间粘合。与原始材料相比，再生材料在印刷方向上的拉伸强度和弹性模量分别降低了 11% 和 31%。然而，在层间方向上，回收材料的弹性模量没有明显变化，而拉伸强度却显著增加了 21%--这是一个令人惊讶的结果。这项研究表明，机加工废料可以作为再生 LFAM 原料的可行材料流。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年2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，Mechanics of Materials 1 篇，International Journal of Plasticity 1 篇，Thin-Walled Structures 3 篇International Journal of Solids and StructuresEfficient computational homogenisation of 2D beams of heterogeneous elasticity using the patch schemeThien Tran-Duc, J.E. Bunder, A.J. Robertsdoi:10.1016/j.ijsolstr.2024.112719使用补丁方案对异质弹性二维梁进行高效计算均质化Modern ‘smart’ materials have complex heterogeneous microscale structure, often with unknown macroscale closure but one we need to realise for large scale engineering and science. The multiscale Equation-Free Patch Scheme empowers us to non-intrusively, efficiently, and accurately predict large scale, system level, solutions through computations on only small sparse patches of the given detailed microscale system. Here the microscale system is that of a 2D beam of heterogeneous elasticity, with either fixed-fixed, fixed-free, or periodic boundary conditions. We demonstrate that the described multiscale Patch Scheme simply, efficiently, and stably predicts the beam’s macroscale, with a controllable accuracy, at finite scale separation. Dynamical systems theory supports the scheme. This article points the way for others to use this innovative systematic non-intrusive approach, via a developing toolbox of functions, to model and compute accurately macroscale system-levels of general complex physical and engineering systems.现代 "智能 "材料具有复杂的异质微观结构，通常具有未知的宏观封闭性，但我们需要实现大规模的工程和科学。多尺度无方程补丁方案使我们能够通过对给定详细微尺度系统的稀疏小补丁进行计算，非侵入式地高效、准确地预测大尺度系统级解决方案。这里的微尺度系统是具有固定-固定、无固定或周期性边界条件的异质弹性二维梁。我们证明，所描述的多尺度补丁方案可以简单、高效、稳定地预测梁的宏观尺度，并且在有限尺度分离的情况下精度可控。动力系统理论为该方案提供了支持。这篇文章为其他人使用这种创新的系统化非侵入式方法指明了方向，即通过一个开发中的函数工具箱，对一般复杂物理和工程系统的宏观系统级进行建模和精确计算。Mechanics of MaterialsTailoring electromagnetic interference shielding effectiveness of SiO2-decorated MWCNT/polymer nanocompositesXiaodong Xia, Yang Liu, Juanjuan Zhang, Jianyang Luo, George J. Wengdoi:10.1016/j.mechmat.2024.104949定制二氧化硅装饰的 MWCNT/聚合物纳米复合材料的电磁干扰屏蔽效果While the decorated process has been demonstrated to be a highly efficient method to tailor the electrical conductivity of multi-walled carbon nanotube (MWCNT)-based nanocomposites, the corresponding influences on the agglomeration and electromagnetic interference (EMI) shielding behaviors still remain unknown. In this paper, the decoration-dependent EMI shielding behavior of progressively agglomerated SiO2@MWCNT/polymer nanocomposites is investigated through a hierarchical homogenization scheme of electromagnetic properties in the X-band. Various microstructural features including the MWCNT waviness, progressive agglomeration, hollow structure of MWCNT and decoration-dependent functional interfacial effects have been fully considered. The multiscale theoretical prediction of decorated EMI shielding effectiveness (SE) of progressively agglomerated SiO2@MWCNT/polymer nanocomposites agrees with the experiments along a wide range of decoration thickness. The SiO2 decorated interphase is demonstrated to tune both the nonuniform distribution of MWCNTs and the functional interface effects in the nanocomposites, and therefore tailor the decoration-dependent EMI shielding performance. The effective EMI SE is revealed to first enhance with the decoration thickness, but then decreases with it. The optimal decoration thickness for high EMI SE is obtained numerically. This research provides a guidance to tailor the X-band EMI shielding performance of progressively agglomerated SiO2@MWCNT/polymer nanocomposites by the decoration process.虽然装饰工艺已被证明是一种定制多壁碳纳米管（MWCNT）基纳米复合材料导电性的高效方法，但其对团聚和电磁干扰（EMI）屏蔽行为的相应影响仍然未知。本文通过 X 波段电磁特性的分层均质化方案，研究了逐渐团聚的 SiO2@MWCNT/聚合物纳米复合材料与装饰相关的电磁干扰屏蔽行为。充分考虑了各种微观结构特征，包括 MWCNT 的波浪状、渐进团聚、MWCNT 的中空结构以及与装饰相关的功能界面效应。对渐进团聚的 SiO2@MWCNT/ 聚合物纳米复合材料的装饰电磁干扰屏蔽效能（SE）进行的多尺度理论预测与实验结果在较宽的装饰厚度范围内相吻合。事实证明，SiO2 装饰的中间相可以调整纳米复合材料中 MWCNT 的不均匀分布和功能界面效应，从而定制与装饰相关的 EMI 屏蔽性能。结果表明，有效的 EMI SE 首先会随着装饰厚度的增加而增加，但随后会随着装饰厚度的增加而减少。通过数值计算得到了实现高 EMI SE 的最佳装饰厚度。这项研究为通过装饰工艺定制逐步团聚的 SiO2@MWCNT/ 聚合物纳米复合材料的 X 波段 EMI 屏蔽性能提供了指导。International Journal of PlasticityA forming limit framework accounting for various failure mechanisms: localization, ductile and cleavage fractureFuhui Shen, Yannik Sparrer, Jing Rao, Markus Könemann, Sebastian Münstermann, Junhe Liandoi:10.1016/j.ijplas.2024.103921 考虑到各种破坏机制的成形极限框架：局部破坏、韧性破坏和劈裂破坏The forming limits and failure properties of three distinct advanced high-strength steels (AHSS) have been investigated under various stress states in tensile tests with optimized specimen geometries. In addition to the commonly observed failure patterns governed by localized necking and ductile fracture for two of the AHSS, after substantial plastic deformation at room temperature, cleavage fracture occurs for a large range of stress states in a laboratory quenching and partitioning steel with superior tensile properties. The competition between failure patterns, encompassing ductile and cleavage fractures with and without necking, is governed by the mechanical properties of materials and the stress states, as a transition of failure mechanisms occurs with increasing triaxiality. The forming limit framework is, therefore, further extended to seamlessly integrate cleavage fracture in this study, where the competition between various failure mechanisms is demonstrated using three AHSS in the space of critical strain and principal stress. These findings shed light on the importance of considering cleavage fracture strength as a parameter besides the strength-ductility synergy in advanced high-strength metallic materials, and the proposed framework also gives a more comprehensive guide in designing and conducting the sheet metal forming processes.在采用优化试样几何形状的拉伸试验中，研究了三种不同的高级高强度钢（AHSS）在各种应力状态下的成型极限和破坏特性。除了两种 AHSS 常见的局部缩颈和韧性断裂失效模式外，一种具有优异拉伸性能的实验室淬火分区钢在室温下发生大量塑性变形后，在很大的应力状态范围内出现了劈裂断裂。材料的机械性能和应力状态决定了破坏模式之间的竞争，包括韧性断裂和劈裂断裂（有无缩颈），因为随着三轴度的增加，破坏机制会发生转变。因此，本研究进一步扩展了成形极限框架，以无缝整合劈裂断裂，并使用临界应变和主应力空间中的三种 AHSS 证明了各种破坏机制之间的竞争。这些发现揭示了在先进高强度金属材料中将劈裂断裂强度作为强度-电导率协同作用之外的一个参数考虑的重要性，所提出的框架也为设计和实施金属板材成形工艺提供了更全面的指导。Thin-Walled StructuresUpper-bound Vibration Response Spectrum Computation for Deployable Membrane Structures with Uncertainty EffectsTakashi Iwasa, Shuuta Fujibayashi, Nobuhisa Katsumata, Ken Higuchidoi:10.1016/j.tws.2024.111706具有不确定性效应的可部署膜结构的上界振动响应谱计算Real-time monitoring technology is essential for establishing a control technology for large-sized membrane space structures. However, numerous measurement points are necessary to capture the maximum vibration response, which renders the real-time monitoring technology impractical. Thus, this study proposed an upper-bound vibration spectrum computation approach using a few measurement points samples on a deployable membrane structure. The proposed method exhibits characteristics of applying the standardized upper-bound spectrum, including uncertainty effects for the computations. The experiment results indicated that the upper-bound spectrum calculated from only 30 measured data points appropriately covered the measured spectra, thus confirming the effectiveness of the proposed method.实时监测技术对于建立大型膜空间结构的控制技术至关重要。然而，要捕捉最大振动响应，必须要有大量的测量点，这使得实时监测技术变得不切实际。因此，本研究提出了一种利用可展开膜结构上的少量测量点样本进行上限振动频谱计算的方法。所提出的方法具有应用标准化上界频谱的特点，包括计算的不确定性影响。实验结果表明，仅用 30 个测量数据点计算出的上限值频谱恰当地覆盖了测量频谱，从而证实了所提方法的有效性。Influence of Diverse Boundary Conditions on SH and P-SV Wave Dynamics in Micropolar PlatesSatish Kumar, Vikas Sharmadoi:10.1016/j.tws.2024.111708不同边界条件对微极性板块中 SH 波和 P-SV 波动力学的影响Studying wave propagation characteristics in plates is vital for comprehending the material dynamics to enhance the strength of structures and for optimizing the effectiveness of non-destructive testing devices. Micropolar elasticity displays microcontinuum behavior by integrating rotational and coupling effects through displacements and micro-rotations. The present study thoroughly investigates horizontally polarized shear waves (SH) within a thin micropolar plate by employing diverse boundary conditions namely stress-free, clamped, and mixed conditions. Shear horizontal waves propagate within a plate by shearing the material along the surface, excluding any motion in perpendicular direction. Moreover, for a more comprehensive grasp of wave behavior in a micropolar plate, the study investigates P-SV type waves under plain strain conditions. Analytical techniques are utilized to derive the dispersion relations for SH and P-SV type waves in a micropolar plate. Graphical representations are provided to showcase the impacts of various micropolar parameters such as coupling number, characteristic length, and plate thickness on the phase velocities of SH and P-SV type waves. The study also includes a dispersion analysis of the multimode aspect of SH and P-SV waves. This thorough investigation can significantly augment the comprehension of wave propagation phenomena within plate-like structures.研究板材中的波传播特性对于理解材料动力学以提高结构强度和优化无损检测设备的有效性至关重要。微极性弹性通过位移和微旋转整合了旋转和耦合效应，从而显示出微连续行为。本研究通过采用不同的边界条件，即无应力、夹紧和混合条件，深入研究了薄微波板内的水平极化剪切波（SH）。剪切水平波是通过沿表面剪切材料而在板内传播的，不包括任何垂直方向的运动。此外，为了更全面地掌握微极板中的波行为，研究还探讨了平应变条件下的 P-SV 型波。研究利用分析技术推导出微极板中 SH 波和 P-SV 波的频散关系。研究用图表展示了各种微波参数（如耦合数、特征长度和板厚度）对 SH 波和 P-SV 波相速的影响。研究还包括 SH 波和 P-SV 波多模方面的频散分析。这一深入研究可极大地增强对板状结构内波传播现象的理解。A multistable composite hinge structureChenmin Zhao, Xinyu Lin, Bing Wang, Juncheng Zhu, Chenglong Guan, Shuncong Zhongdoi:10.1016/j.tws.2024.111709 多稳复合铰链结构A composite tape-spring (CTS) structure is a thin-walled open slit tube with fibres oriented at ±45°, which is stable in both extended and coiled configurations. The governing factors of its bistability include composite constitutive behaviour, initial geometrical proportions, and geometrically non-linear structural behaviour. Its bistable principle can be employed to produce a flexible multistable hinge structure with tailorable stability. This is achieved by introducing variable stiffness design within a cylindrical shell structure, where folding stability is dependent on central functional patch region, and then connected to linking ploy regions. Thus, a novel multistable composite hinge structure can be designed with positive Gaussian curvature deformation, and its multistability is highly tailorable: a lengthy one-dimensional mechanical arm can be designed to coil and fold multiple times to enable large folding ratio. An analytical model was established based on the strain energy principle, in order to determine effects from functional tape length; the typical structural stability and stable configurations were then predicted with respect to regional length of the functional layer. It is found that the stability of a multistable composite hinge structure is dependent on geometry and combination of both the functional patch region, and connecting ploy region; the stable criteria are then proposed and show good agreement with experimental observations and FE analysis. These enrich the diversities of functional deployable structures to benefit novel requirements for various deployable mechanisms, and enable customised design, as well as smart driving for flexible and multifunctional mechanical composite hinge applications.复合胶带弹簧（CTS）结构是一种纤维方向为±45°的薄壁开缝管，在伸展和盘绕两种配置下都很稳定。其双稳态性的制约因素包括复合材料的构成行为、初始几何比例和几何非线性结构行为。其双稳态原理可用于制造具有可定制稳定性的柔性多稳态铰链结构。这是通过在圆柱形壳体结构中引入可变刚度设计来实现的，其中折叠稳定性取决于中心功能补丁区域，然后连接到连接犁区域。因此，可以设计出一种具有正高斯曲率变形的新型多稳态复合铰链结构，而且其多稳态性具有很强的可定制性：可以设计出一个冗长的一维机械臂，使其可以多次卷绕和折叠，从而实现较大的折叠率。根据应变能原理建立了一个分析模型，以确定功能带长度的影响；然后预测了与功能层区域长度有关的典型结构稳定性和稳定构型。研究发现，多稳态复合铰链结构的稳定性取决于功能贴片区域和连接杆区域的几何形状和组合；随后提出了稳定标准，并与实验观察和 FE 分析结果表明了良好的一致性。这些研究丰富了功能性可展开结构的多样性，从而满足了各种可展开机构的新要求，实现了定制化设计以及灵活和多功能机械复合材料铰链应用的智能驱动。来源：复合材料力学仿真Composites FEM