【新文速递】2024年11月19日固体力学SCI期刊最新文章

今日更新：Composite Structures 9 篇，Composites Part A: Applied Science and Manufacturing 1 篇，Composites Science and Technology 1 篇Composite StructuresA DG-VLM framework for computational static aeroelastic analysis of composite wingsDario Campagna, Vincenzo Gulizzi, Ivano Benedettidoi:10.1016/j.compstruct.2024.118697复合材料机翼静力气动弹性计算分析的DG-VLM框架A computational framework for static aeroelastic analysis of composite laminated plates is proposed, whose novelty is the conjoined use of a structural discontinuous Galerkin (DG) formulation and an aerodynamic vortex lattice method (VLM), suitably coupled for the monolithic solution of the aeroelastic problem. The structural method is built on variable-order generalized kinematics, which allows the seamless adoption of either beam or plate modelling strategies, with on-demand order of polynomial approximation over the transverse and in-plane dimensions of the structural elements. The underlying DG formulation also simplifies the coupling between the structural and aerodynamic grids, thus providing a versatile tool for the aeroelastic analysis of either low or high aspect-ratio composite wings. Several numerical tests have been performed to assess the convergence features of the proposed framework as well as its accuracy with respect to available computational and experimental benchmark data. The obtained results confirm its robustness and highlight its potential for aeroelastic assessments in early aircraft conceptual design.提出了一种复合材料层合板静力气动弹性分析的计算框架，其新颖之处在于将结构不连续伽辽金（DG）公式与气动涡流点阵法（VLM）相结合，适合于气动弹性问题的整体求解。结构方法建立在变阶广义运动学的基础上，允许无缝采用梁或板建模策略，对结构单元的横向和平面尺寸按需进行多项式逼近。潜在的DG公式还简化了结构网格和气动网格之间的耦合，从而为低或高展弦比复合材料机翼的气动弹性分析提供了一个通用工具。已经进行了几次数值测试，以评估所提出框架的收敛特性及其相对于现有计算和实验基准数据的准确性。得到的结果证实了它的鲁棒性，并突出了它在早期飞机概念设计中的气动弹性评估潜力。Inertial and elastic properties of general composite beamsWenbin Yudoi:10.1016/j.compstruct.2024.118690一般组合梁的惯性和弹性特性Slender composite structures can be modeled using engineering beam models with properties computed through a cross-sectional analysis, such as VABS. These properties are given in terms of the mass matrix, stiffness matrix, and compliance matrix in a general coordinate system. The invariance of strain energy and kinetic energy is employed to rigorously transform sectional properties into different coordinate systems with parallel shifts and rotations. Additionally, the computation of commonly used inertial properties (mass center, principal inertial axes, mass moments of inertia, etc.) from the mass matrix, and commonly used elastic properties (extension stiffness, bending stiffness, torsion stiffness, tension center, shear center, principal bending axes, principal shear axes, etc.) from the compliance matrix, is elucidated. The elastic properties are given for both the Timoshenko model and the Euler–Bernoulli model. The definitions for shear center and twist center are clarified and consistently generalized for composite beams. Isotropic homogeneous beams are used to illustrate how to relate commonly used engineering beam properties with the compliance matrix and the stiffness matrix for composite beams. Finally, engineering beam properties necessary for general-purpose aeromechanical analysis programs such as CAMRAD II are derived from the properties computed by VABS.细长复合结构可以使用工程梁模型建模，并通过截面分析（如VABS）计算其性能。这些性质以一般坐标系下的质量矩阵、刚度矩阵和柔度矩阵的形式给出。利用应变能和动能的不变性，将截面性质严格转换为具有平行位移和旋转的不同坐标系。此外，还阐述了从质量矩阵中计算常用的惯性特性（质量中心、主惯性轴、质量惯性矩等）和从柔度矩阵中计算常用的弹性特性（拉伸刚度、弯曲刚度、扭转刚度、拉伸中心、剪切中心、主弯曲轴、主剪切轴等）。给出了Timoshenko模型和Euler-Bernoulli模型的弹性性质。对组合梁的剪切中心和扭转中心的定义进行了澄清和一致的推广。以各向同性均匀梁为例，说明了如何将常用工程梁的特性与复合梁的柔度矩阵和刚度矩阵联系起来。最后，通过VABS计算得到了通用气动力学分析程序（如CAMRAD II）所需的工程梁特性。Low-velocity impact damage characteristics of flax/glass epoxy hybrid laminates on the influence of different temperatures: Experimental and numerical analysisMuneer Ahmed Musthaq Ahamed, Hom Nath Dhakal, Zhongyi Zhang, Antigoni Barouni, John Regan Pillai, Saleh Elkelani Babaadoi:10.1016/j.compstruct.2024.118704 不同温度对亚麻/玻璃环氧复合层合板低速冲击损伤特性的影响：实验与数值分析This study investigated the effects of different temperatures on the low-velocity impact damage behaviour of flax fibre-reinforced epoxy composites and their glass/flax hybrids. Composites reinforced with flax, glass, and hybrid flax/glass onto epoxy matrix Subjected to low-velocity drop weight impact tests at 5 J of incident impact energy at sub-zero temperatures (−10 °C and −20 °C) and at room temperature (RT) are presented. Under the different temperatures, the experimental findings showed a beneficial hybrid effect where the temperature played a significant role. At RT, the Lam-GFGFGFG exhibit improved impact resistance, with enhanced energy absorption capabilities compared to glass-only laminates (Lam-G). Besides, Lam-GFFFFG laminates exhibit a significant difference in the force–displacement curves at − 20 °C, with a maximum load of 801.95 N in contrast to RT and − 10 °C resulting in a gradual increase in force with increasing displacement. This indicates that Lam-GFFFFG laminates can resist the impact and maintain structural integrity at sub-zero temperatures. The alternation of glass and flax layers in the hybrid structure contributes to the synergistic effects, resulting in improved damage resistance and tolerance. Also, the highest impact tolerance in a laminate is achieved through the hybridisation of flax fibre-reinforced composites with glass-reinforced layers on the outer surfaces (Lam-GFFFFG) at − 10 °C. Subsequently, experimental results were compared with finite element analysis (FEA) results, derived from a model built using a VUMAT subroutine integrated with ABAQUS/Explicit for a more accurate representation of the damage characterisation of the composite laminates under low-velocity impact.研究了不同温度对亚麻纤维增强环氧复合材料及其玻璃/亚麻杂化材料低速冲击损伤行为的影响。以亚麻、玻璃和亚麻/玻璃混合增强环氧基复合材料为材料，在零下温度（- 10 °C和- 20 °C）和室温（RT）下进行了5 J入射冲击能的低速落重冲击试验。在不同的温度下，实验结果显示出有利的杂交效应，其中温度起着显著的作用。在RT测试中，Lam-GFGFGFG表现出更好的抗冲击性，与纯玻璃层压板（Lam-G）相比，具有增强的能量吸收能力。此外，Lam-GFFFFG层压板在- 20 °C时的力-位移曲线差异显著，与RT和- 10 °C相比，最大载荷为801.95 N，随着位移的增加，力逐渐增加。这表明Lam-GFFFFG层压板可以在零下温度下抵抗冲击并保持结构完整性。混合结构中玻璃层和亚麻层的交替有助于协同效应，从而提高抗损伤性和耐受性。此外，通过亚麻纤维增强复合材料与外表面玻璃增强层（Lam-GFFFFG）在- 10 °C下的杂交，层压板的最高抗冲击能力得以实现。随后，将实验结果与有限元分析（FEA）结果进行了比较，该分析结果来自使用VUMAT子程序与ABAQUS/Explicit集成建立的模型，以更准确地表示复合材料层合板在低速冲击下的损伤特征。Comparative study of toughness and energy evaluation of laminated bamboo composites and toughening mechanismYao Wu, Shengjie Liu, Zhi Li, Jinjun Xu, Weihang Xudoi:10.1016/j.compstruct.2024.118706竹材层合复合材料韧性、能量评价及增韧机理对比研究As toughness becomes an important mechanical property of construction materials, scientific toughness assessment is vital to the development of new materials and helpful for material innovation. For laminated bamboo composites in which the failure modes are relatively uncertain, different methods were applied to evaluate the toughness of bamboo laminate. A comparative study of various toughness evaluation methods was conducted for laminated bamboo. The meaning and error of the toughness expressed by the energy release rate or J-integral determined by different methods were interpreted and analyzed. Based on the calculated toughness, the toughening mechanism of bidirectional laminated bamboo was explored. The results show that the ratio of transverse bamboo strip volume Vf vertical to the initial notch direction has a positive impact on the initial stiffness, maximum load, and energy release rate. Besides that, the layup or arrangement of bamboo strips would also affect the mechanical properties and fracture toughness of laminated bamboo, of which the effect is investigated by dividing the fracture parameters by Vf. It is concluded that the major mechanism for increasing the ductility and the toughness before the maximum load (expressed by D2/D1 and GIcun/Vf or GIc0.8d/Vf) is the crack deflection caused by the hierarchical structure composed of vascular bundles (fiber) and parenchyma tissue (matrix) in a single layer of bamboo laminae. However, the ductility and the toughness after the maximum load (expressed by D3/D2 and GIc0.8d/GIcun) are mainly enhanced by the alternatively arranged bamboo laminae of different fiber directions.随着韧性成为建筑材料的重要机械性能之一，科学地评估材料的韧性对于新材料的发展和材料创新至关重要。对于其失效模式相对不确定的层压竹复合材料，采用不同的方法评估竹层压板的韧性。对层压竹材的韧性评估方法进行了比较研究，并解释了由不同方法确定的能量释放率或J积分所表达的韧性含义和误差。基于计算的韧性，探讨了双向层压竹材的增韧机理。结果表明，垂直于初始裂纹方向的横向竹条体积Vf垂直与初始刚度、最大载荷和能量释放率呈正相关。此外，竹条的铺设或排列也会影响层压竹材的机械性能和断裂韧性，其中影响通过将断裂参数除以Vf进行研究。结论认为，在最大荷载前（用D2/D1和GIcun/Vf或GIc0.8d/Vf表示）提高韧性和韧性的主要机制是单层竹片中由维管束（纤维）和薄壁组织（基质）组成的分级结构引起的裂纹偏转。然而，在最大荷载后（用D3/D2和GIc0.8d/GIcun表示）的韧性和韧性主要通过不同纤维方向排列的交替竹片增强。Shape recovery effect and energy absorption of reusable honeycomb structuresYangzuo Liu, Changfang Zhao, Cheng Xu, Jie Rendoi:10.1016/j.compstruct.2024.118708可重复使用蜂窝结构的形状恢复效果及能量吸收When using auxetic honeycomb structures to create repeatable energy-absorbing components, a key challenge is selecting the appropriate unit configuration for effective functional integration. In this work, four typical honeycomb structures were prepared, and the mechanical behaviors, shape recovery effects, and energy absorption properties of three types of auxetic honeycomb structures re-entrant honeycomb (RH), arrow honeycomb (AH), and star honeycomb (SH) were compared with those of hexagonal honeycomb (HH) through quasi-static loading–unloading tests. The findings indicate that the 3D printed polyurethane (TPU) honeycomb structures demonstrate robust shape recovery, stable energy absorption, notable stress softening characteristics. The recovery behaviors can be characterized by three distinct phases, namely hyperelastic, transitional, and viscoelastic. The unit configuration significantly influences the shape recovery capability, with apparent elastic modulus and stability of the energy absorption efficiency determining the overall shape recovery capability. The loading method also affects the energy absorption and dissipation patterns in different honeycomb structures. In terms of specific energy absorption (SEA), AH has the highest rating, with RH and SH at 86 % and 50 % of the SEA of AH respectively. The number of reusable cycles is primarily dictated by the specific configuration of the unit type. In scenarios involving reusability, the energy absorption capacity of the TPU honeycomb can only reach 70 % of its original energy absorption capacity. This study may inform the application of auxetic materials in reusable energy absorbers.当使用消声蜂窝结构来制造可重复的吸能部件时，一个关键的挑战是选择合适的单元配置来实现有效的功能集成。本文制备了4种典型的蜂窝结构，并通过准静态加载-卸载试验，比较了3种消声蜂窝结构的力学性能、形状恢复效果和吸能性能，分别为再入式蜂窝（RH）、箭头式蜂窝（AH）和星形蜂窝（SH）。结果表明，3D打印聚氨酯（TPU）蜂窝结构具有良好的形状恢复、稳定的能量吸收和显著的应力软化特性。其恢复行为可分为超弹性、过渡和粘弹性三个阶段。单元结构对形状恢复能力有显著影响，表观弹性模量和能量吸收效率的稳定性决定了整体形状恢复能力。载荷方式对不同蜂窝结构的能量吸收和耗散规律也有影响。在比能量吸收（SEA）方面，AH的评级最高，RH和SH分别为AH SEA的86 %和50 %。可重复使用周期的数量主要由单元类型的特定配置决定。在涉及重复使用的场景下，TPU蜂窝的吸能能力只能达到原有吸能能力的70 %。本研究可为增塑剂在可重复使用吸能材料中的应用提供参考。Additively manufactured plate lattice interpenetrating composites with high yield strength and energy absorbing capabilityXiaobo Wang, Bo Song, Hanxing Zhu, Zhi Zhang, Lei Zhang, Yusheng Shidoi:10.1016/j.compstruct.2024.118709增材制备的板点阵互穿复合材料具有较高的屈服强度和吸能性能Mechanical metamaterials with plate lattice architectures have been proven to possess specific stiffness and strength superior to that of traditional truss lattice structures. Current research mainly focuses on the mechanical properties of plate lattice skeletons, leaving interpenetrating composites with plate lattice architectures unexplored. In this work, plate lattice interpenetrating composites have been prepared by filling epoxy resin matrix to additively manufactured stainless steel plate lattice skeletons. By conducting uniaxial quasi-static compression tests and performing finite element analysis, mechanical performance and deformation patterns of plate lattice interpenetrating composites have been revealed. Results show that Young’s modulus and yield strength of plate lattice skeletons can be greatly enhanced by introducing an epoxy resin matrix to form interpenetrating composites. In addition, interpenetrating composites have been observed to deform stably without shear damage or fracture, facilitating the increase of energy-absorbing capability. Specific energy absorption of interpenetrating composites is up to three times higher than that of corresponding pure skeletons, which could extend the potentials of plate lattice metamaterials in energy-absorbing applications.具有板晶格结构的机械超材料已被证明具有优于传统桁架晶格结构的刚度和强度。目前的研究主要集中在板晶格骨架的力学性能上，对具有板晶格结构的互穿复合材料的研究还不够深入。本文通过在增材制造的不锈钢板晶格骨架中填充环氧树脂基体，制备了板晶格互穿复合材料。通过单轴准静态压缩试验和有限元分析，揭示了板点阵互渗复合材料的力学性能和变形规律。结果表明，引入环氧树脂基体形成互穿复合材料可显著提高板晶格骨架的杨氏模量和屈服强度。此外，互穿复合材料变形稳定，无剪切损伤或断裂，有利于吸能能力的提高。互穿复合材料的比能吸收是纯骨架材料的3倍以上，可以拓展板晶格超材料在吸能方面的应用。Stress-driven nonlocal integral model with discontinuities for transverse vibration of multi-cracked non-uniform Timoshenko beams with general boundary conditionsPei Zhang, Peter Schiavone, Hai Qing, Qi Lidoi:10.1016/j.compstruct.2024.118712具有一般边界条件的多裂纹非均匀Timoshenko梁横向振动的非连续应力驱动非局部积分模型We present a formulation for the size-affected vibration study of multi-cracked non-uniform Timoshenko beams based on the well-posed stress-driven nonlocal elastic theory with discontinuities. The beam ends are assumed to be constrained by elastic springs with translational and rotational stiffness to simulate general boundary conditions. The presence of cracks divides the beam into segments connected by translational and rotational springs, and compatibility conditions are established to address the geometric discontinuities introduced by these cracks. The stress-driven constitutive equations are integrated into an equivalent differential form, equipped with a set of constitutive boundary conditions at the two ends of the entire structure and multi-sets of constitutive continuity conditions at the junctions of the sub-structures. To solve the equations of motion, the constraint conditions and the integrals involved, we employ the differential quadrature method (DQM) alongside an interpolation quadrature formula, which allows us to efficiently compute the frequencies of the cracked beams across various boundary types. After validating our approach against results in the existing literature, we present numerical studies that examine the effects of the nonlocal parameter, the slope of the beam’s thickness variation, crack location, severity, number, and the stiffness of the springs on the vibrational behavior of the beams.基于带不连续点的定常应力驱动非局部弹性理论，提出了多裂纹非均匀Timoshenko梁的尺寸影响振动研究公式。为了模拟一般的边界条件，假定梁端受到具有平移和转动刚度的弹性弹簧的约束。裂缝的存在将梁分成由平移弹簧和旋转弹簧连接的部分，并建立了相容条件来解决这些裂缝引入的几何不连续。将应力驱动本构方程积分为等效微分形式，在整个结构两端设置一组本构边界条件，在子结构连接处设置多组本构连续性条件。为了求解运动方程、约束条件和所涉及的积分，我们采用微分正交法（DQM）和插值正交公式，这使我们能够有效地计算出各种边界类型的裂纹梁的频率。在验证了我们的方法与现有文献的结果之后，我们提出了数值研究，研究了非局部参数、梁的厚度变化斜率、裂缝位置、严重程度、数量和弹簧刚度对梁的振动行为的影响。Nonlinear large strain mechanics and failure of 45° woven CFRP laminates characterized by Full-Field measurementsBehrad Koohbor, Nicholas B. Mennie, Addis Kidanedoi:10.1016/j.compstruct.2024.11871545°编织CFRP层合板的非线性大应变力学和破坏特征的现场测量The nonlinear mechanical response of 45° woven composites is studied using full-field strain measurements. First, carbon fabric samples without an epoxy matrix are prepared and tested to evaluate the deformation response of the fiber tows in the absence of internal resistance imposed by the epoxy matrix. Next, the effect of the epoxy matrix is examined by fabricating and testing 45° single-ply carbon fiber reinforced composite laminas. Homogeneous strain fields with minimal resistance against external loads are observed in fabric samples without epoxy. The in-plane rotation of fiber tows in the carbon fabric samples varies linearly with the applied global strain. On the other hand, the development of scissoring action in single-ply composite laminas is shown to cause severe shearing of the epoxy entrapped between the orthogonal fiber tows, leading to the outward protrusion of epoxy from the surface of the lamina. The scissoring effect is correlated with different stages of deformation in a highly nonlinear stress–strain response. Finally, similar tests performed on three-ply laminates reveal that the abovementioned matrix protrusion leads to accelerated delamination in 45° laminates at global strains lower than those in single-ply laminas. The underlying mechanisms for scissoring-induced matrix protrusion are discussed using a simple analytical model.采用全场应变法研究了45°编织复合材料的非线性力学响应。首先，制备了不含环氧基的碳织物样品，并对其进行了测试，以评估纤维束在没有环氧基内阻时的变形响应。其次，通过制作和测试45°单层碳纤维增强复合材料层板，考察了环氧基的影响。在不含环氧树脂的织物样品中观察到具有最小外部负载阻力的均匀应变场。碳纤维织物样品中纤维束的平面内旋转随施加的总应变呈线性变化。另一方面，在单层复合材料层板中，剪切作用的发展导致夹闭在正交纤维束之间的环氧树脂发生严重剪切，导致环氧树脂从层板表面向外突出。在高度非线性的应力-应变响应中，剪切效应与变形的不同阶段有关。最后，在三层板上进行的类似试验表明，上述基质突出导致45°层板在整体应变低于单层层板的情况下加速分层。本文用一个简单的解析模型讨论了剪切诱导基质突出的潜在机制。Composites Part A: Applied Science and ManufacturingPhenyl group-based fluorinated polymer dispersed liquid crystal composite films with high contrast ratio and low driving voltageJing Qin, Chao Chen, Baohua Yuan, Longxiang He, Xian He, Zuowei Zhang, Luoning Zhang, Cheng Zou, Yanzi Gao, Meina Yu, Huai Yangdoi:10.1016/j.compositesa.2024.108591 高对比度、低驱动电压的苯基氟化聚合物分散液晶复合薄膜Polymer dispersed liquid crystal (PDLC) are composite materials which usually obtained by the phase separation during polymerization of liquid crystal/monomer mixtures, and it have shown potential applications in smart windows. In this work, the rigidity and flexibility of phenyl acrylate monomers were regulated by varying the number of benzene rings and the influences on the morphology and electro-optical properties of PDLC were discussed. The results showed that the PDLC films formed by monomers with one benzene ring possessed better performance. In addition, fluorination of monomers with a benzene ring could further enhance overall performance. The CR was significantly improved from 138 to 175, but the driving voltage is maintained at a lower value (6.9 V). This work provides a choice for optimizing electro-optical properties of PDLC films.聚合物分散液晶（PDLC）是一种通常由液晶/单体混合物聚合过程中相分离得到的复合材料，在智能窗口中具有潜在的应用前景。本文研究了苯环数对丙烯酸苯酯单体刚性和柔韧性的影响，并讨论了苯环数对丙烯酸苯酯单体形貌和电光性能的影响。结果表明，单苯环单体形成的PDLC膜具有较好的性能。此外，带苯环的单体氟化可以进一步提高整体性能。CR从138显著提高到175，但驱动电压维持在较低的值（6.9 V）。这项工作为优化PDLC薄膜的电光性能提供了选择。Composites Science and TechnologySafe and Negligible-Loss Overcurrent Protection: A Novel Macromolecular Voltage Stabilizer for Conductive Polymer CompositesXuhuang Chen, Jiaqi Gao, Yinghao Qi, Chuanchuan Dai, Zhaoxin Li, Yu Wu, Peng Yu, Siwen Bidoi:10.1016/j.compscitech.2024.110965 安全可忽略损耗的过流保护：一种用于导电聚合物复合材料的新型高分子稳压器The balance between safety issues and low loads remains a major obstacle toward large-scale applications of conductive polymer composites (CPCs) based over-current protection. Elevating the conductive filler concentration in CPCs is a potential strategy to reduce initial resistivity for decreased load, but compromise positive temperature coefficient (PTC) performance and voltage breakdown strength. Here, a novel type of macromolecular voltage stabilizer is synthesized by fluorine rubber and ferrocene to optimize the comprehensive properties of CPCs with low resistivity. The voltage stabilizer provides CPCs with a high voltage breakdown strength of up to 54V with maintaining an extremely low initial resistivity. Such CPCs also have an enhanced PTC intensity, improved instability voltage threshold, suppressed NTC effect, and good reproducibility up on/off switching. Based on tunnel effect, these improved properties can be interpreted by the reduction of charge transfer impact on the degradation of the polymer matrix. This work suggests the great potential of using these unique additives and theoretical investigations for overcurrent protection or insulating material.安全问题和低负载之间的平衡仍然是导电聚合物复合材料（cpc）过流保护大规模应用的主要障碍。提高导电填料浓度是降低负载时降低初始电阻率的潜在策略，但会损害正温度系数（PTC）性能和电压击穿强度。本文以氟橡胶和二茂铁为原料合成了一种新型的大分子稳压器，以优化低电阻率聚氯乙烯的综合性能。电压稳定器为cpc提供高达54V的高压击穿强度，并保持极低的初始电阻率。这种cpc还具有增强的PTC强度，改进的不稳定电压阈值，抑制NTC效应，以及良好的上/下开关再现性。基于隧道效应，这些性能的改善可以通过减少电荷转移对聚合物基体降解的影响来解释。这项工作表明，使用这些独特的添加剂和理论研究的过流保护或绝缘材料的巨大潜力。来源：复合材料力学仿真Composites FEM