首页/文章/ 详情

【新文速递】2024年11月22日复合材料SCI期刊最新文章

1月前浏览469

   

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

Composite Structures

Closed-form analytical solution for local buckling of omega-stringer-stiffened composite panels under compression

Cherine El Yaakoubi-Mesbah, Christian Mittelstedt

doi:10.1016/j.compstruct.2024.118716

受压下欧米茄筋加筋复合材料板局部屈曲的闭型解析解

The use of stiffened thin-walled lightweight structures in e.g. aircraft fuselages requires efficient calculation methods to describe the stability behavior. In this work, a closed-form model for the local buckling analysis of orthotropic composite plates braced by omega-stringers is developed. The problem can be reduced to a plate simply supported at all edges subjected to uniaxial compression with eccentrically attached stringer feet, while the stringer itself is modeled as restraint stiffnesses along the longitudinal edges. The discontinuities in the stiffnesses introduced by the stringer feet result in discontinuities in the curvature behavior and the shear distortion of the structure. In order to map this influence on the local buckling behavior, the reduced model is divided into plate segments of corresponding stiffnesses, for which Ritz-based approach functions for the deformations are defined. Finally, an explicit formulation of the buckling load is derived using the energy method. To validate the model, the Lévy solution is obtained and a finite element analysis is conducted. The results of the parameter studies demonstrate excellent agreement within the design space of the aviation application area.

在诸如飞机机身中使用加筋薄壁轻质结构需要有效的计算方法来描述其稳定性行为。本文建立了正交各向异性欧米茄筋支撑复合材料板局部屈曲分析的封闭模型。该问题可以简化为在单轴压缩下所有边缘都有简单支撑的板,并带有偏心附加的弦脚,而弦本身则被建模为沿纵向边缘的约束刚度。弦脚引入的刚度的不连续导致结构的曲率行为和剪切变形的不连续。为了映射这种对局部屈曲行为的影响,将简化模型划分为相应刚度的板段,并定义了基于ritz的变形逼近函数。最后,利用能量法推导出屈曲载荷的显式表达式。为了验证模型的正确性,得到了lsamvy解,并进行了有限元分析。参数研究的结果表明,在航空应用领域的设计空间内,参数研究的结果非常一致。


Composites Part A: Applied Science and Manufacturing

Nonlinear transient analysis of delaminated composite shell panel under hygro-thermo-mechanical load and experimental validation

Chetan Kumar Hirwani, Naveen Kumar Akkasali, Erukala Kalyan Kumar, Ravi Kumar, Amit Kumar Mehar, Subrata Kumar Panda

doi:10.1016/j.compositesa.2024.108587

湿热机械载荷作用下分层复合材料壳板非线性瞬态分析及实验验证

In this work, the nonlinear time-dependent deflection responses of delaminated composite shell panel structure under the influence of hygro-thermo-mechanical loading have been investigated numerically. To develop a mathematical model, two different higher-order displacement kinematics, Green-Lagrange’s nonlinear strain–displacement relations and two sub-laminate approaches are adopted for delaminated panel structure in association with finite element steps. The delaminated composite shell panel is under the three simultaneous loading, i.e., humidity, temperature, and mechanical loading. The nonlinear time-dependent responses are obtained by solving the governing equation using the direct iterative method and Newmark’s integration technique. The influence of delamination parameters (size, location, and position), geometry and loading on dynamic characteristics have been analyzed. The differences in responses indicated that the kinematic model with higher degrees of freedom generally shows higher deflection values. Further, a detailed discussion of the numerical illustrations and conclusive remarks based on the findings of the numerical illustrations have been provided.

本文对分层复合材料壳板结构在湿热机械载荷作用下的非线性时变挠度响应进行了数值研究。为了建立数学模型,采用格林-拉格朗日非线性应变-位移关系和两种不同的高阶位移运动学方法,结合有限元步骤对分层板结构进行分层。分层复合壳板同时承受湿度、温度和机械三种载荷。采用直接迭代法和Newmark积分法求解控制方程,得到非线性时变响应。分析了分层参数(尺寸、位置和位置)、几何形状和载荷对动态特性的影响。响应的差异表明,自由度越大的运动学模型通常具有较高的挠度值。此外,还提供了数值图解的详细讨论和基于数值图解结果的结论性评论。


Composites Part B: Engineering

N/S co-doped nanocomposite of graphene oxide and graphene-like organic molecules as all-carbonaceous anode material for high-performance Li-ion batteries

Wooree Jang, Jongmin Kim, Seoyun Lee, Seokhoon Ahn, Hyeyoung Koo, Cheol-Min Yang

doi:10.1016/j.compositesb.2024.111994

 

N/S共掺杂氧化石墨烯与类石墨烯有机分子纳米复合材料作为高性能锂离子电池的全碳阳极材料

In this study, to enhance the electrochemical performance of graphene-based anodes for Li-ion batteries (LIBs), we synthesized an all-carbonaceous N/S co-doped nanocomposite of graphene oxide (GO) and graphene-like small organic molecules (GOM) using a mild, eco-friendly, one-step hydrothermal method with thiourea (CH4N2S) (denoted as h-N/S-GO/GOM). The thiourea facilitated N/S co-doping and π−π bonding, which improved the interaction between hydrophilic GO and hydrophobic GOM in aqueous solution. Notably, the formation of π−π bonds between GO and GOM created pathways that enhanced electron transfer, thereby promoting efficient Li-ion transport from the electrolyte through the channels during rapid charge–discharge cycles. Additionally, the functional groups resulting from N/S co-doping increased the number of active sites within the nanocomposite. Consequently, the h-N/S-GO/GOM anode demonstrated superior electrochemical performance, achieving an average reversible capacity of 1265 mAh g−1 at 0.1 A g−1 and retaining 83.0% of its capacity after 200 cycles. Furthermore, the nanocomposite exhibited excellent long-term cycling stability, maintaining a capacity of 688 mAh g−1 even after 1000 cycles at a high current density of 1.0 A g−1. The hierarchical network structure of the all-carbonaceous h-N/S-GO/GOM anode facilitated efficient charge transfer between the electrode and electrolyte through shorter diffusion paths for Li-ion transport and provided additional active sites, contributing to its outstanding electrical performance. The h-N/S-GO/GOM nanocomposite represents a promising alternative to traditional graphite-based anodes, offering a path toward high-performance, eco-friendly LIBs suitable for applications such as electric vehicles and energy storage systems.

在本研究中,为了提高锂离子电池(LIBs)石墨烯基阳极的电化学性能,我们采用温和、环保的一步水热法与硫脲(CH4N2S)合成了氧化石墨烯(GO)和类石墨烯小有机分子(GOM)的全碳共掺杂纳米复合材料(记为h-N/S-GO/GOM)。硫脲促进了N/S共掺杂和π−π成键,改善了水溶液中亲水性GO和疏水性GOM之间的相互作用。值得注意的是,GO和GOM之间π−π键的形成创造了增强电子转移的途径,从而促进了锂离子在快速充放电循环中从电解质通过通道的高效传输。此外,由N/S共掺杂产生的官能团增加了纳米复合材料中活性位点的数量。结果表明,h-N/S-GO/GOM阳极表现出优异的电化学性能,在0.1 A g−1时平均可逆容量达到1265 mAh g−1,并且在200次循环后保持83.0%的容量。此外,该纳米复合材料表现出优异的长期循环稳定性,在1.0 a g−1的高电流密度下,即使在1000次循环后,其容量仍保持在688 mAh g−1。全碳h-N/S-GO/GOM阳极的分层网络结构通过更短的锂离子传输扩散路径,促进了电极和电解质之间有效的电荷转移,并提供了额外的活性位点,有助于其出色的电学性能。h-N/S-GO/GOM纳米复合材料代表了传统石墨基阳极的一个有前途的替代品,为高性能、环保的锂离子电池提供了一条道路,适用于电动汽车和储能系统等应用。


Composites Science and Technology

Sulfur Co-polymer as a Universal Adhesive to Construct Segregated Structure in Cross-linked Rubber toward Improved Conductive and Mechanical Properties

Shu Wang, Zhenghai Tang, Yilin Xiao, Dong Wang, Baochun Guo, Liqun Zhang

doi:10.1016/j.compscitech.2024.110964

 

硫共聚物作为一种通用胶粘剂在交联橡胶中构建分离结构以改善导电性能和力学性能

Creating segregated structure within composites can significantly improve electrical conductivity but usually compromises mechanical properties. In this contribution, we introduced a straightforward and universal method to fabricate segregated rubber composites with a rare integration of high electrical conductivity and mechanical robustness by utilizing an inverse vulcanized copolymer (SP) as an adhesive to bind the segregated domains. Specifically, sulfur-crosslinked butadiene styrene rubber (SBR) granules were mixed with SP and carbon nanotubes (CNTs), followed by compression molding. CNTs embedded within SP are strategically dispersed along the boundaries of SBR granules, and the reaction of SP with SBR granules creates covalent bonding among the segregated domains and increases their crosslinking density. The segregated skeleton constituted by highly interconnected CNTs is robust, which imparts the composites with high electrical conductivity that is stable upon deformations and is able to heal after damage. In addition, the rigid segregated skeleton preferentially ruptures to dissipate enormous energy, and the cohesive interphase facilitates chain finite extensibility in the highly crosslinked segregated domains, resulting in remarkable enhancements on the tensile strength and modulus of the composites. The universality of this strategy is further demonstrated by using ground waste tyre rubber as matrix and boron nitride sheets as filler.

在复合材料中创建分离结构可以显著提高导电性,但通常会损害机械性能。在这篇文章中,我们介绍了一种简单而通用的方法来制造分离橡胶复合材料,通过利用反硫化共聚物(SP)作为粘合剂来结合分离域,该方法具有高导电性和机械稳健性的罕见集成。具体来说,将硫交联丁苯橡胶(SBR)颗粒与SP和碳纳米管(CNTs)混合,然后进行压缩成型。嵌入SP中的CNTs沿着SBR颗粒的边界有策略地分散,SP与SBR颗粒的反应在分离的结构域之间形成共价键,增加了它们的交联密度。由高度互联的CNTs构成的分离骨架是坚固的,这使得复合材料具有高导电性,在变形时稳定,在损伤后能够自愈。此外,刚性偏析骨架优先断裂以耗散大量能量,而内聚界面在高度交联的偏析畴中促进了链的有限扩展,从而显著提高了复合材料的抗拉强度和模量。以磨碎的废轮胎橡胶为基体,氮化硼片为填料,进一步证明了该策略的普遍性。


Vertically Aligned Liquid Metal Thermal Pad with Excellent Electromagnetic Shielding and Ultra-High Compressibility

Yisimayili Tuersun, Pingjun Luo, Xu Huang, Mingdeng Huang, Yilimiranmu Rouzhahong, Chu Sheng

doi:10.1016/j.compscitech.2024.110974

 

具有优异电磁屏蔽和超高压缩性的垂直排列液态金属热垫

With the increasing integration level of modern electronics, flexible highly thermally conductive and electromagnetic interference shielding (EMI) materials were urgently demanded in electronic devices. Traditionally carbon or solid metal fillers are widely used as a reinforcement to fabricate a flexible thermally conductive and EMI shielding materials. However Due to the trade-off between mechanical and thermal properties, it is difficult to further improve the performance of solid filler/polymer composites. Here in this work based on the intrinsic excellent electrical and thermal conductivity of liquid metal (LM), we embedded the LM network structure vertically in the silicone gel and fabricated a vertically aligned LM(VALM) composites. Compared to the randomly dispersed LM composites, VALM composite exhibits high through plane thermal conductivity (κ⊥: 6.08 W/m·K) and excellent EMI shielding efficiency (SE) (minimum and maximum EMI SE for VALM2 were 33.2 dB and 39.5 dB). In addition, due to the fluidic nature of LM, composite materials exhibit excellent softness and flexibility (compression modulus of 0.56 MPa). Practical heat dissipation test results and EMIS efficiencies demonstrate usefulness of VALM composite in next-generation electronics.

随着现代电子产品集成化水平的不断提高,柔性高导热和电磁干扰屏蔽材料在电子器件中的应用日益迫切。传统上,碳或固体金属填料被广泛用作增强材料来制造柔性导热和电磁干扰屏蔽材料。然而,由于力学性能和热性能之间的权衡,固体填料/聚合物复合材料的性能很难进一步提高。本文基于液态金属(LM)固有的优异的导电性和导热性,将液态金属网络结构垂直嵌入有机硅凝胶中,制备了垂直排列的液态金属(VALM)复合材料。与随机分散的LM复合材料相比,VALM复合材料具有高透平面导热系数(κ⊥:6.08 W/m·K)和优异的EMI屏蔽效率(SE) (VALM2的最小和最大EMI SE分别为33.2 dB和39.5 dB)。此外,由于LM的流体性质,复合材料表现出优异的柔软性和柔韧性(压缩模量为0.56 MPa)。实际的散热测试结果和EMIS效率证明了VALM复合材料在下一代电子产品中的实用性。


3D printing lignin carbonized nanotube and cellulose nano fiber aerogel for wearable pressure sensors

Xiaoqing Du, Qi Chen, Qiqi Zhou, Yufan Zhou, Feng Wang, Wangjie Xu, Yulin Zhan, Man Jiang

doi:10.1016/j.compscitech.2024.110976

 

3D打印木质素碳化纳米管和纤维素纳米纤维气凝胶用于可穿戴压力传感器

The nanocellulose represents an important sustainability and chemical stability candidate for conductive 3D aerogel sensors, while introducing additional conductive additives is necessary. Herein, the as developed lignin derived carbonized nanotube (LCNT) in our lab was adopted as conductive ingredient to fabricate cellulose nanofiber (CNF) based composite aerogel by 3D printing. Specifically, the as-prepared LCNT/CNF composite aerogel with ratio of 85:15 in weight presented homogeneous porous morphology with well dispersed and penetrated LCNT in CNF porous matrix, providing a piezoresistive type pressure sensor. Stable signals were achieved under testing range from 0.2 to 9.8 kPa, with response time between 100-200 ms, related to the testing accuracy. The mechanical property of the as-prepared composite aerogel was found to be satisfactory. Under a constant 30% compression strain for 1000 cycles, 92.5% stress retention was maintained, and the ultimate stress was tested to be 16.64 kPa. This work provided a customized wearable pressure sensor with satisfactory comprehensive performance made completely from cellulose and lignin renewable natural polymers.

纳米纤维素代表了导电3D气凝胶传感器的重要可持续性和化学稳定性候选材料,同时引入额外的导电添加剂是必要的。本课题以本实验室开发的木质素衍生碳化纳米管(LCNT)为导电材料,采用3D打印技术制备纤维素纳米纤维(CNF)基复合气凝胶。具体而言,制备的重量比为85:15的LCNT/CNF复合气凝胶具有均匀的多孔形态,LCNT在CNF多孔基质中分散和渗透良好,可提供压阻式压力传感器。在0.2 ~ 9.8 kPa的测试范围内获得了稳定的信号,响应时间在100 ~ 200 ms之间,与测试精度有关。所制备的复合气凝胶的力学性能令人满意。在30%恒定压缩应变下,循环1000次,其应力保持率为92.5%,极限应力为16.64 kPa。本工作提供了一种完全由纤维素和木质素可再生天然聚合物制成的具有满意综合性能的定制可穿戴压力传感器。



来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystemMAGNET断裂复合材料非线性化学通用航空汽车电子材料储能控制
著作权归作者所有,欢迎分享,未经许可,不得转载
首次发布时间:2024-11-27
最近编辑:1月前
Tansu
签名征集中
获赞 6粉丝 0文章 803课程 0
点赞
收藏
作者推荐

【新文速递】2024年11月20日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 3 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 3 篇International Journal of Solids and StructuresDuctile failure by strain localisation: A computational study of materials and structures subjected to highly non-proportional load historiesMartin Kristoffersen, David Morin, Tore Børvik, Odd Sture Hopperstaddoi:10.1016/j.ijsolstr.2024.113128应变局部化的延性破坏:材料和结构在高度非比例载荷历史下的计算研究Ductile failure by the onset of strain localisation after non-proportional load paths is investigated herein by using the imperfection version of the strain localisation theory. A computational framework assuming a planar, porous imperfection band inside a homogeneous solid was used to investigate ductile failure as caused by void nucleation, growth, and coalescence. The localisation analysis framework was calibrated based on a single uniaxial tension test and finite element simulations thereof. Despite the somewhat frugal calibration, the localisation analyses successfully reproduced experimentally measured macroscopic fracture strains from notched tension tests and notched compression-tension tests. The method was subsequently applied to a structural problem involving large deformations and complex load paths, and the results show great promise for future work.本文采用应变局部化理论的缺陷版本,研究了非比例加载路径后应变局部化发生的延性破坏。假设均匀固体内部存在平面多孔缺陷带,采用计算框架来研究由空洞成核、生长和聚并引起的延性破坏。定位分析框架基于单轴拉伸试验及其有限元模拟进行校准。尽管校准成本较低,但定位分析成功地再现了缺口拉伸试验和缺口压缩拉伸试验中实验测量的宏观断裂应变。该方法随后应用于涉及大变形和复杂载荷路径的结构问题,结果显示了未来工作的巨大前景。Journal of the Mechanics and Physics of SolidsThe positioning of stress fibers in contractile cells minimizes internal mechanical stressLukas Riedel, Valentin Wössner, Dominic Kempf, Falko Ziebert, Peter Bastian, Ulrich S. Schwarzdoi:10.1016/j.jmps.2024.105950 应力纤维在收缩细胞中的定位使内部机械应力最小化The mechanics of animal cells is strongly determined by stress fibers, which are contractile filament bundles that form dynamically in response to extracellular cues. Stress fibers allow the cell to adapt its mechanics to environmental conditions and to protect it from structural damage. While the physical description of single stress fibers is well-developed, much less is known about their spatial distribution on the level of whole cells. Here, we combine a finite element method for one-dimensional fibers embedded in an elastic bulk medium with dynamical rules for stress fiber formation based on genetic algorithms. We postulate that their main goal is to achieve minimal mechanical stress in the bulk material with as few fibers as possible. The fiber positions and configurations resulting from this optimization task alone are in good agreement with those found in experiments where cells in 3D-scaffolds were mechanically strained at one attachment point. For optimized configurations, we find that stress fibers typically run through the cell in a diagonal fashion, similar to reinforcement strategies used for composite material.动物细胞的力学在很大程度上是由应力纤维决定的,应力纤维是一种可收缩的纤维束,在响应细胞外信号时动态形成。应力纤维使细胞能够适应环境条件,并保护细胞免受结构损伤。虽然对单个应力纤维的物理描述很发达,但对其在整个细胞水平上的空间分布知之甚少。本文将基于遗传算法的应力纤维形成动态规律与嵌入弹性体介质中的一维纤维的有限元方法相结合。我们假设他们的主要目标是用尽可能少的纤维在大块材料中实现最小的机械应力。该优化任务单独产生的纤维位置和结构与3d支架中的细胞在一个附着点上进行机械拉伸的实验结果非常一致。对于优化的配置,我们发现应力纤维通常以对角线的方式穿过细胞,类似于复合材料的加固策略。Mechanical properties of modular assembled composite lattice architectureCheng Gong, Robert O. Ritchie, Xingyu Wei, Qingxu Liu, Jian Xiongdoi:10.1016/j.jmps.2024.105967 模块化组合复合晶格结构的力学性能The layer-by-layer additive manufacturing approach results in the 3D printed composite lattice structure fails to exploit fiber reinforcement, thereby resulting in inferior mechanical qualities. To address this challenge, this study proposes a novel approach leveraging composite fused filament fabrication (FFF) printing to design modular assembled composite lattice structures. Initially, three high-performance lattice structures were transformed into discrete 2D components and assembled into 3D lattice structures. Subsequently, the mechanical properties of these structures were comprehensively assessed using theoretical, experimental, and finite element analysis methods. Finally, the comparison between the assembled structures and integrated printed lattice structures in terms of surface quality, mechanical properties, and manufacturability revealed significant advantages. The theoretical and finite element analyses accurately predicted the mechanical properties of the lattice structures. The lattice structures that were assembled in a modular way displayed an impressive 74% improvement in surface finish. Additionally, they showed peak strength increases of 140%, 27%, and 26%, respectively, for the mentioned types of topology. The energy absorption also increased significantly by 510.83%, 44.18%, and 30.24%. Furthermore, these assembled structures required less printing support materials, enhancing their manufacturability and cost-effectiveness. This new method of designing modular space structures goes beyond the limitations imposed by equipment by using high-performance topology. It allows for the construction of large-scale, lightweight space structures that offer excellent performance. This study explores innovative opportunities in the field of space manufacturing, offering potential implications for the development of lunar habitats, space telescopes, and space power stations.逐层增材制造方法导致3D打印的复合材料晶格结构无法利用纤维增强,从而导致机械质量较差。为了解决这一挑战,本研究提出了一种利用复合熔丝制造(FFF)打印来设计模块化组装复合晶格结构的新方法。首先,将三个高性能晶格结构转化为离散的二维构件,然后组装成三维晶格结构。随后,采用理论、实验和有限元分析方法对这些结构的力学性能进行了综合评估。最后,将组装结构与集成印刷晶格结构在表面质量、力学性能和可制造性方面进行了比较,显示出显著的优势。理论分析和有限元分析准确地预测了晶格结构的力学性能。以模块化方式组装的晶格结构显示出令人印象深刻的74%的表面光洁度改善。此外,对于上述拓扑类型,它们的峰值强度分别增加了140%,27%和26%。能量吸收也显著提高了510.83%、44.18%和30.24%。此外,这些组装结构需要较少的打印支撑材料,提高了它们的可制造性和成本效益。这种设计模块化空间结构的新方法通过使用高性能拓扑结构,超越了设备所施加的限制。它允许建造大型,轻量级的空间结构,提供卓越的性能。这项研究探索了太空制造领域的创新机会,为月球栖息地、太空望远镜和太空发电站的发展提供了潜在的影响。Latent-Energy-Based NNs: An interpretable Neural Network architecture for model-order reduction of nonlinear statics in solid mechanicsLouen Pottier, Anders Thorin, Francisco Chinestadoi:10.1016/j.jmps.2024.105953 基于势能的神经网络:用于固体力学非线性静力学模型阶数降阶的可解释神经网络结构Nonlinear mechanical systems can exhibit non-uniqueness of the displacement field in response to a force field, which is related to the non-convexity of strain energy. This work proposes a Neural Network-based surrogate model capable of capturing this phenomenon while introducing an energy in a latent space of small dimension, that preserves the topology of the strain energy; this feature is a novelty with respect to the state of the art. It is exemplified on two mechanical systems of simple geometry, but challenging strong nonlinearities. The proposed architecture offers an additional advantage over existing ones: it can be used to infer both displacements from forces, or forces from displacements, without being trained in both ways.非线性力学系统在力场作用下的位移场具有非唯一性,这与应变能的非凸性有关。这项工作提出了一个基于神经网络的代理模型,能够捕捉这种现象,同时在小维的潜在空间中引入能量,保持应变能的拓扑结构;就目前的技术水平而言,这一特点是一种新奇的东西。它在两个简单几何的机械系统上举例说明,但具有很强的非线性。所提出的体系结构比现有的体系结构提供了额外的优势:它可以用来从力中推断位移,或者从位移中推断力,而无需以两种方式进行训练。Mechanics of MaterialsConstitutive Modeling of Transformation-Induced Plasticity Steels Considering Strength-Differential EffectJaebong Jung, Hyeonil Park, Seung Wook Lee, Ji Hoon Kimdoi:10.1016/j.mechmat.2024.105207考虑强度差效应的相变塑性钢本构建模Transformation-induced plasticity (TRIP) steels undergo martensitic phase transformations due to their austenite phase. In this study, using 1-mm-thick TRIP steel at room temperature, the phase transformation behaviors under tensile and compressive modes were measured using a ferrite scope based on the detection of the magnetic volume. A strength differential (SD) effect was observed, where the tensile strength was lower than the compressive strength. The rate of tensile transformation was faster than that of compressive transformation. To account for the SD effect in finite-element analysis, a martensitic kinetics-based constitutive model was developed, which was decomposed into elastic, plastic, Bain, and transformation parts. A larger transformational strain was generated in the tensile mode, and the asymmetric SD effect was captured well by the proposed model.相变诱发塑性(TRIP)钢由于其奥氏体相而发生马氏体相变。在本研究中,使用1 mm厚的TRIP钢在室温下,使用基于磁体积检测的铁氧体示波器测量拉伸和压缩模式下的相变行为。观察到强度差(SD)效应,其中抗拉强度低于抗压强度。拉伸转变速率大于压缩转变速率。为了考虑有限元分析中的SD效应,建立了基于马氏体动力学的本构模型,将其分解为弹性、塑性、贝恩和变形部分。在拉伸模式下产生较大的转换应变,且该模型较好地反映了非对称SD效应。Thin-Walled StructuresSeismic Performance of hollow section concrete-filled GFRP tubular columns under monotonic loads and cyclic loadsZi-Ming Yang, Ju Chendoi:10.1016/j.tws.2024.112705单调荷载和循环荷载作用下中空截面GFRP钢管混凝土柱的抗震性能The experimental investigation and analytical reporting in this paper focus on the behavior of HS-CFGT members, specifically their response to both monotonic loads and cyclic loads. A total of 8 specimens, divided into two groups, each group with 2 kinds in loading type, including 6 columns under cyclic horizontal loads and 2 columns under monotonic lateral loads, were tested. The details of the experimental setups, procedures, significant observations encompassing failure modes, maximum bearing capacities, displacement corresponding to the peak load, load-displacement hysteretic curves, skeleton curves, stiffness degradation curves, and energy dissipation curves and were truthfully reported. The inspection of the experimental data has yielded several important conclusions regarding the effect of column parameters on the behavior of HS-CFGT columns. The most significant finding is that the influence of concrete strength and FRP tube thickness on the seismic performance of HS-CFGT columns is not independent of each other. Furthermore, the findings additionally suggest that HS-CFGT columns made of high-strength concrete demonstrate commendable ductility. The initial flexural stiffness for the preliminary design of HS-CFGT columns is also provided to facilitate the implementation of this innovative technology.本文的试验研究和分析报告侧重于HS-CFGT构件的性能,特别是它们在单调荷载和循环荷载下的响应。试验共8个试件,分为两组,每组2种荷载类型,包括循环水平荷载作用下的6根柱和单调侧向荷载作用下的2根柱。详细的实验设置,程序,重要的观察结果,包括破坏模式,最大承载能力,峰值荷载对应的位移,载荷-位移滞后曲线,骨架曲线,刚度退化曲线和能量耗散曲线,并如实报告。通过对试验数据的检验,得出了关于柱参数对HS-CFGT柱性能影响的几个重要结论。最重要的发现是混凝土强度和FRP管厚度对HS-CFGT柱抗震性能的影响不是相互独立的。此外,研究结果还表明,由高强混凝土制成的HS-CFGT柱具有良好的延性。本文还提供了HS-CFGT柱初步设计的初始抗弯刚度,以促进这一创新技术的实施。Active shovel spinning process: plastic deformation behavior, microstructure, and propertiesLijun Zhang, Lukuan Li, Ning Yang, Su Liu, Hong Chi, Jiayi Xu, Shuai Zhang, Fazhe Sun, Jian Zhong, Qingqiang He, Yulei Andoi:10.1016/j.tws.2024.112714主动铲纺丝工艺:塑性变形行为、微观结构和性能In response to the challenges of traditional casting and welding processes for thin disc with cylinder, characterized by excessive weight, complex procedures, and variable seam quality, a novel active shovel spinning (ASS) process is proposed. This technique utilizes a spinning roller to lift the sheet metal radially, gradually forming the cylindrical wall into a monolithic structure. A finite element (FE) analysis model for the ASS of SPHE material is established, with the optimization goals set as the outer diameter ellipticity O¯r, the precision of the outer generatrix L¯I, and the maximum forming force F_max of the spinning roller. Using extreme difference analysis and the Grey Relational Analysis (GRA), multi-objective optimization under various conditions of rotational speed ratio η, feed rate v, and friction coefficient f is conducted to identify the optimal combination of process parameters as η=1.6, v=2, and f=0.15. The plastic flow behavior under these parameters is analyzed, and experimental studies are conducted. The findings reveal extensive metal flow in radial, axial, and circumferential directions. The bulging of the cylinder primarily relies on the deformation of the metal at the upper ends of the inner and outer sides, with greater stress and strain on the outer wall than the inner. The disparity between the deformed and undeformed areas is mainly reflected in the position and diameter of the stress Mohr's circle and the size of the strain Mohr's circle diameter. Due to the increased aspect ratio, refinement, and uniformity of the grains, the ultimate tensile strength σ_UTSi in all directions within the forming area has significantly improved, with a 48% increase in the reduced thickness area σ_UTS1-CD and a 31% increase in the σ_UTS2-CD. These results enhance the understanding of the forming mechanism in the ASS process, thereby providing crucial guidance for optimizing the quality of the formed components.针对传统铸造和焊接工艺在加工薄壁圆筒时存在的重量过大、工艺复杂、焊缝质量不稳定等问题,提出了一种新型的主动铲刮旋压(ASS)工艺。该工艺利用旋转辊将金属板材向上抬起,逐渐将圆筒形壁板形成为一个整体结构。建立了ASS加工SPHE材料的有限元(FE)分析模型,优化目标设定为外径椭圆度O¯r、外轮廓线精度L¯I和旋压辊的最大成形力F_max。采用极差分析和灰色关联分析(GRA),在不同的旋转速度比η、进给速度v和摩擦系数f条件下进行多目标优化,确定了最佳工艺参数组合为η=1.6、v=2和f=0.15。分析了在这些参数下金属的塑性流动行为,并进行了实验研究。研究结果表明,金属在径向、轴向和周向方向上发生了广泛的流动。缸体凸起主要依靠内、外侧上部金属的变形,外壁的应力和应变大于内壁。变形和未变形区域之间的差异主要体现在应力莫尔圆的位置和直径以及应变莫尔圆直径的大小上。由于晶粒的尺寸、均匀性和精细度的提高,成形区内所有方向上的极限抗拉强度σ_UTSi都有显著提高,其中减薄区域的σ_UTS1-CD提高了48%,σ_UTS2-CD提高了31%。这些结果有助于加深对ASS工艺成形机制的理解,从而为优化成形零件的质量提供关键指导。Fatigue fracture mechanism and life prediction of steel-aluminium clinched joints under different stress ratiosYue Zhang, Jianbiao Peng, Ruitao Peng, Bei Lei, Jiachuan Jiangdoi:10.1016/j.tws.2024.112721 不同应力比下钢-铝夹紧接头疲劳断裂机理及寿命预测Vehicle bodies are subject to complex random loads during travelling, making it imperative to investigate the effects of different stress ratios on the body joining structure. To investigate the fatigue performance of steel-aluminium clinched joints under different stress ratios, fatigue experiments were conducted on these joints subjected to different load levels at stress ratios of -0.4, 0.1, and 0.4. The fracture mechanism of steel-aluminium clinched joints under different stress ratios was investigated through analysis of the joint's fracture morphology and the composition of abrasive chips using Scanning Electron Microscope and Energy Dispersive Spectroscopy. A fatigue life prediction model for steel-aluminium clinched joints was developed by employing the modified Paris formulation of the Wallker equation. The results indicate that joint failure can be classified into three main forms: lower sheet fracture, upper sheet pull-off accompanied by lower sheet fracture and reaching infinite life (2 million times). The lower sheet of a fatigue failure specimen in a steel-aluminium clinched joint exhibited a novel form of fretting damage known as lower sheet inter-plate fretting wear. Furthermore, the application of Walker's improved Paris formula proved to be highly effective in accurately predicting the fatigue life of steel-aluminium clinched joints under different stress ratios, with the predicted results demonstrating excellent agreement with experimental findings.汽车车身在行驶过程中承受复杂的随机载荷,研究不同应力比对车身连接结构的影响是十分必要的。为了研究不同应力比下钢-铝锁接接头的疲劳性能,在应力比为-0.4、0.1和0.4的情况下,对钢-铝锁接接头进行了不同载荷水平的疲劳试验。利用扫描电镜和能谱分析了钢-铝绞合接头的断口形貌和磨屑组成,探讨了不同应力比下钢-铝绞合接头的断裂机理。采用Wallker方程的修正Paris公式,建立了钢-铝铰接疲劳寿命预测模型。结果表明:节理破坏可分为三种主要形式:下片材断裂、上片材脱落并伴随下片材断裂、达到无限寿命(200万次)。钢-铝铰接疲劳破坏试样的下片表现出一种新的微动损伤形式,即下片板间微动磨损。应用改进的Walker’s Paris公式对不同应力比下钢-铝锁接接头的疲劳寿命进行了准确预测,预测结果与试验结果吻合良好。来源:复合材料力学仿真Composites FEM

未登录
还没有评论
课程
培训
服务
行家
VIP会员 学习计划 福利任务
下载APP
联系我们
帮助与反馈