【新文速递】2023年12月23日固体力学SCI期刊最新文章_ACT_Mechanical_System_Flux_Abaqus_断裂_复合材料_非线性_通用_海洋_裂纹_理论_材料_控制

【新文速递】2023年12月6日复合材料SCI期刊最新文章

今日更新：Composite Structures 7 篇Composite StructuresComparison of local, gradient-enhanced and integral form of continuum damage approaches to strain localization in fiber reinforced compositesG. Gopinath, R.C. Batradoi:10.1016/j.compstruct.2023.117737纤维增强复合材料应变定位的局部、梯度增强和连续损伤积分形式方法比较Structures often have inserts and notches that cause stress concentration and consequent reduction in the load bearing capacity. The literature on numerical implementation of continuum damage mechanics (CDM) has generally focused on using local theories of damage.However, their use to analyze deformations of notched laminates that are prone to strain localization can cause numerical convergence issues that can be alleviated by employing a non-local theory. There are a few studies using a non-local damage theory for fiber-reinforced polymeric composites (FRPCs) and even fewer for strain localization in FRPCs. The non-local theories employ an equivalent (or effective or von Mises) strain often used in metal plasticity while most theories for studying failure of FRPCs use individual strain/stress components.Here, we compare predictions from local and nonlocal CDM approaches that are effective in studying strain localization in FRPCs. For the local approach, we employ a rate-dependent evolution relation. For the non-local approach, we either compute damage at a point as the weighted sum of damage at its neighbors that introduces a length scale into the problem, or employ a gradient-enhanced approach that also introduces a length scale. It is shown that numerical predictions from both the rate-dependent and the non-local theory alleviate to different degrees sensitivity of results to the finite element mesh used and the strain localization issues.Of these, a local rate-type approach is more convenient and cost effective.结构中经常会有嵌入物和缺口，这些嵌入物和缺口会导致应力集中，从而降低承载能力。有关连续损伤力学（CDM）数值实施的文献通常侧重于使用局部损伤理论。然而，使用局部损伤理论分析容易产生应变局部化的缺口层压板的变形会导致数值收敛问题，而采用非局部理论则可以缓解这些问题。针对纤维增强聚合物复合材料（FRPCs）使用非局部损伤理论的研究很少，而针对 FRPCs 中应变局部化的研究则更少。非局部理论采用金属塑性中常用的等效应变（或有效应变或冯米塞斯应变），而研究 FRPC 失效的大多数理论则采用单个应变/应力成分。对于局部方法，我们采用了与速率相关的演化关系。对于非局部方法，我们要么将某点的损伤计算为其邻近点损伤的加权和，从而在问题中引入长度尺度，要么采用同样引入长度尺度的梯度增强方法。结果表明，依赖速率理论和非局部理论的数值预测都在不同程度上缓解了结果对所使用的有限元网格和应变局部化问题的敏感性。Long-term bolt preload relaxation and contact pressure distribution in clamping anchorages for CFRP platesGuozhen Ding, Peng Feng, Yu Wang, Pengcheng Ai, Qinyu Wangdoi:10.1016/j.compstruct.2023.117780CFRP 板材夹紧锚固件中螺栓预紧力的长期松弛和接触压力分布Clamping anchorages are commonly used to anchor CFRP (carbon fiber reinforced polymer) plates, and the anchoring performance is significantly impacted by bolt preload. This research presents experimental and numerical investigations of long-term bolt preload relaxation in clamping anchorages for CFRP plates. First, a compression test was conducted to obtain the elastic modulus in the thickness direction of CFRP plates. Then, four types of relaxation tests (single bolt, planar and curved anchorage, external load effect, and thickened anchorage) were conducted, considering the effects of the number of CFRP plates, anchorage type, external load, and initial preload. The elastic interaction during the tightening process was also investigated. The contact pressure distribution was simulated through the finite element method, which is in good agreement with the results obtained from pressure papers. To fit relaxation test results and predict million-hour relaxation, different theoretical models were employed. The results indicate that the number of CFRP plates is crucial to preload relaxation, and the presence of CFRP plates introduces strong elastic interactions between bolts in the anchorage. Preload relaxation also increases under external loads and with the increase in initial preload. Curved anchorage has less bolt preload relaxation in the long term under external loads. Furthermore, thickened anchorages have a more uniform contact pressure distribution due to the improved pressure diffusion mechanism.夹紧锚固装置通常用于锚固 CFRP（碳纤维增强聚合物）板，而螺栓预紧力对锚固性能影响很大。本研究对 CFRP 板材夹紧锚固件中螺栓预紧力的长期松弛进行了实验和数值研究。首先，通过压缩试验获得 CFRP 板厚度方向的弹性模量。然后，考虑到 CFRP 板的数量、锚固类型、外部载荷和初始预紧力的影响，进行了四种松弛试验（单螺栓、平面和曲面锚固、外部载荷效应和加厚锚固）。此外，还研究了拧紧过程中的弹性相互作用。通过有限元方法模拟了接触压力分布，与压力论文获得的结果十分吻合。为了拟合松弛测试结果和预测百万小时松弛，采用了不同的理论模型。结果表明，CFRP 板的数量对预载松弛至关重要，CFRP 板的存在会在锚固件中的螺栓之间产生强烈的弹性相互作用。在外部荷载作用下，预紧松弛也随着初始预紧的增加而增加。在外部荷载的长期作用下，弧形锚固件的螺栓预紧松弛较小。此外，由于压力扩散机制得到改善，加厚锚固件的接触压力分布更加均匀。A new method of preparing lattice structures of continuous carbon fiber-reinforced thermoplasticsBaosheng Liu, Yulin Wang, Ruishen Lou, Yunxiang Yao, Xianglin Chen, Huimin Lidoi:10.1016/j.compstruct.2023.117781制备连续碳纤维增强热塑性塑料晶格结构的新方法The three-dimensional lattice sandwich structure of composite has attracted extensive attention in the engineering field due to its superior mechanical property and multifunctional designability. Developing technology that can guarantee both production cycle and cost remains challenging. In this work, an innovative forming technology based on 3D printing and hot folding process is presented to fabricate lattice sandwich structures of continuous fiber-reinforced thermoplastics. The prepared lattice sandwich structures show obvious competitiveness and superior material efficiency, which is reflected in high compressive strength (23.55 MPa/(g/cm3)) and specific compressive modulus (457.82 MPa/(g/cm3)). The simplified theoretical model and 3D progressive failure model are carried out to predict the compressive behaviors of the lattice sandwich structures, and the results are consistent with the experimental results. Additionally, the flexibility of the proposed method is demonstrated by fabricating various 3D structures.三维晶格夹层结构复合材料以其优越的机械性能和多功能设计性在工程领域受到广泛关注。开发既能保证生产周期又能降低成本的技术仍具有挑战性。本研究提出了一种基于三维打印和热折叠工艺的创新成型技术，用于制造连续纤维增强热塑性塑料的格子夹层结构。所制备的格子夹层结构具有明显的竞争力和优异的材料效率，具体表现为较高的抗压强度（23.55 兆帕/（克/立方厘米））和比压缩模量（457.82 兆帕/（克/立方厘米））。通过简化理论模型和三维渐进破坏模型来预测格子夹层结构的抗压行为，结果与实验结果一致。此外，还通过制造各种三维结构证明了所提方法的灵活性。Expanding the Mechanical and Mass-Transport combination for Bone Scaffolds: Through Stretched StructureXing Peng, Shiyu Li, Dongyang He, Junyan Li, Shuxin Qu, Zhongmin Jindoi:10.1016/j.compstruct.2023.117783扩展骨支架的机械和质量传输组合：通过拉伸结构Optimizing the mechanical and mass-transport properties of porous biomaterials simultaneously can be challenging, as they often correspond one-to-one through structure. For instance, increasing permeability by reducing relative density frequently leads to lower mechanical properties. In this study, we introduced a stretched structure to optimize the two properties simultaneously. Initially, the stretched scaffolds were evaluated at the same porosity, revealing that the elastic modulus and permeability of the stretched scaffold are approximately twice that of the original type. Subsequently, the orientation dependence of these properties was investigated. The results suggest that the stiffness of the stretched structure in the width direction is compromised, aligning with the mechanical properties of cortical bone in shaft bones. The permeability of the stretched structure exhibits significant anisotropy, with values much higher than those of original structure. Moreover, our biological experiments demonstrate that extremely stretched structures exhibit low and uneven curvature, potentially impeding cell growth. Hence, striking a balance between curvature and the stretching method employed is crucial. The stretching method can also be applied to other strut-based structures, enabling greater design flexibility in achieving a desirable mechanical and mass-transport combination, providing a foundation for high-performance artificial bone prostheses.同时优化多孔生物材料的机械性能和质量传输性能是一项挑战，因为它们往往通过结构一一对应。例如，通过降低相对密度来增加渗透性往往会导致机械性能降低。在这项研究中，我们引入了一种拉伸结构来同时优化这两种特性。首先，在相同孔隙率下对拉伸支架进行评估，结果表明拉伸支架的弹性模量和渗透性大约是原始支架的两倍。随后，研究了这些特性的取向依赖性。结果表明，拉伸结构在宽度方向上的刚度受到影响，这与轴骨中皮质骨的机械特性一致。拉伸结构的渗透性表现出明显的各向异性，其值远高于原始结构。此外，我们的生物实验证明，极度拉伸的结构会表现出较低且不均匀的曲率，可能会阻碍细胞生长。因此，在曲率和拉伸方法之间取得平衡至关重要。拉伸方法还可应用于其他基于支柱的结构，从而在实现理想的机械和质量传输组合方面具有更大的设计灵活性，为高性能人工骨假体奠定基础。Meso-viscoelastic modeling of solid propellant using XCT technology and virtual element methodBo Jin, Huiru Cui, Hualin Fandoi:10.1016/j.compstruct.2023.117784利用 XCT 技术和虚拟元素法建立固体推进剂的介观弹性模型This paper proposes a scheme to develop 2D mesoscale propellant models from X-ray computed tomography (XCT) images, including digital image processing (DIP)-based models and molecular dynamics (MD)-based models. In the MD-based approach, parametric models can be constructed by presuming that the particles are discs that satisfy the size distribution and volume fraction derived from XCT images of propellant. Based on the advantages of the virtual element method (VEM) for simulating the deformation of composite materials, this study obtains statistical information from XCT images to generate mesostructural models and compare their mechanical behaviors. Under the assumption of small deformation, the mesoscopic behaviors predicted by both mesostructural models are in good agreement, indicating that simpler MD-based models are adequate to characterize the overall viscoelastic properties of propellant. The impacts of propellant mesostructure parameters were addressed by using MD-based models.本文提出了一种从 X 射线计算机断层扫描（XCT）图像开发二维中尺度推进剂模型的方案，包括基于数字图像处理（DIP）的模型和基于分子动力学（MD）的模型。在基于 MD 的方法中，可以通过假定粒子为圆盘来构建参数模型，这些圆盘满足从推进剂 XCT 图像中得出的尺寸分布和体积分数。基于虚拟元素法（VEM）在模拟复合材料变形方面的优势，本研究从 XCT 图像中获取统计信息，生成中观结构模型，并比较其力学行为。在小变形假设下，两种介观结构模型预测的介观行为非常一致，表明基于 MD 的较简单模型足以表征推进剂的整体粘弹特性。利用基于 MD 的模型研究了推进剂介观结构参数的影响。Damage evolution in flax fibre composite under creep loadJianqun Hao, Alexandros Prapavesis, Stepan V. Lomov, C.A. Fuentes Rojas, Aart Willem Van Vuuredoi:10.1016/j.compstruct.2023.117786蠕变载荷下亚麻纤维复合材料的损伤演变This work aims to reveal the damage mechanisms and evolution in unidirectional flax fibre biocomposites when subjected to creep load. X-ray micro computed tomography and acoustic emission (AE) was used to monitor the failure progress during flexural creep tests. A correlation between the event clusters and directly observed damage modes was established based on coupons with expected failure mechanisms and then validated by computed tomography observations. The damage initiated from matrix cracking in the primary creep stage, and then fibre-matrix interface debonding combined with fibre pull-out occurred sequentially during the steady creep stage. In the tertiary creep stage, the explosive fibre fracture emerged and eventually triggered catastrophic failure. Considerably more AE events were detected during creep tests compared to those in quasi-static tests, which indicates that intensive damage is generated under creep load, and therefore causes the strength degradation. A good agreement was observed between the cumulative number of AE events and the increasing damage volume fraction over time determined by X-ray micro computed tomography during multi-step creep tests.这项研究旨在揭示单向亚麻纤维生物复合材料在承受蠕变载荷时的破坏机制和演变过程。在挠曲蠕变试验中，采用 X 射线显微计算机断层扫描和声发射（AE）技术监测破坏过程。根据具有预期破坏机制的试样，建立了事件群与直接观察到的破坏模式之间的相关性，然后通过计算机断层扫描观察进行验证。在一级蠕变阶段，损坏从基体开裂开始，然后在稳定蠕变阶段，纤维-基体界面脱粘与纤维拉出相继发生。在三级蠕变阶段，出现了爆炸性纤维断裂，并最终引发了灾难性破坏。与准静态试验相比，蠕变试验中检测到的 AE 事件要多得多，这表明在蠕变载荷作用下会产生密集的损伤，从而导致强度下降。在多步蠕变试验中，通过 X 射线显微计算机断层扫描测定的 AE 事件累积数量与随时间增加的损伤体积分数之间存在良好的一致性。Normal Contact Mechanism of Flexible Film/Substrate Bilayer Structure: Experimental and Numerical InsightShouyao Liu, Jian Wu, Shixue He, Bohan Yang, Benlong Su, Xuebo Yuan, Youshan Wangdoi:10.1016/j.compstruct.2023.117791柔性薄膜/基底双层结构的正常接触机制：实验与数值分析The film/substrate bilayer structure design plays a crucial role in enhancing the adaptability of flexible tactile sensors in complex environments. Nonetheless, as the cornerstone for machine tactility, the normal contact mechanism of the film/substrate bilayer structure remains elusive. Herein, the normal contact characteristics of polydimethylsiloxane film/sponge bilayer structure (PF/SBS) with different structural parameters, including substrate porosity, film mass ratio, and relative thickness between film and substrate, are investigated by experimental and numerical methods. The roles of the film and substrate structure parameters of PF/SBS in the normal contact process are analyzed by a cohesive contact model from the energy perspective. The results demonstrate that PF/SBS not only modulates the maximum normal force by substrate porosity but also exerts a substantial impact on the critical contact state by the film mass ratios. The contribution of film thickness to the critical separation state can be enhanced up to 90% with increasing relative thickness.薄膜/基板双层结构设计在增强柔性触觉传感器在复杂环境中的适应性方面发挥着至关重要的作用。然而，作为机器触感的基石，薄膜/基底双层结构的正常接触机制仍然难以捉摸。本文通过实验和数值方法，研究了具有不同结构参数（包括基底孔隙率、薄膜质量比、薄膜与基底的相对厚度）的聚二甲基硅氧烷薄膜/海绵双层结构（PF/SBS）的正常接触特性。通过内聚接触模型，从能量角度分析了 PF/SBS 的薄膜和基底结构参数在正常接触过程中的作用。结果表明，PF/SBS 不仅能通过基底孔隙率调节最大法向力，还能通过薄膜质量比对临界接触状态产生重大影响。随着相对厚度的增加，薄膜厚度对临界分离状态的贡献率最高可达 90%。来源：复合材料力学仿真Composites FEM

【新文速递】2023年12月23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

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International Journal of Plasticity

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【新文速递】2023年12月6日复合材料SCI期刊最新文章