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【新文速递】2023年11月29日复合材料SCI期刊最新文章

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今日更新:Composite Structures 4 篇

Composite Structures

A new mesh-type rail pad with second-order stiffness

Yanbo Bai, Zhenxing He, Nengneng Bao, Peanghao Li

doi:10.1016/j.compstruct.2023.117763

具有二阶刚度的新型网状轨垫

In this paper, a novel mesh-type rail pad with second-order stiffness (MTRPSOS) is proposed, which is comprised of a mesh-type rail pad (MTRP) and multiple filled blocks. By adjusting the height of the filled blocks, the stiffness curves of the MTRPSOS exhibit pronounced second-order stiffness (SOS) characteristics. A finite element (FE) model of the MTRPSOS and a dynamic model were established to investigate the SOS characteristics and their impact on various dynamic indices. The FE calculations reveal that both static and dynamic stiffness of the MTRPSOS increase as the height of the filled blocks decreases. Moreover, as the height of the filled blocks increases, stress distribution becomes more uniform. The dynamic calculations demonstrate that the SOS characteristics of the MTRPSOS significantly affect various dynamic indices. As the SOS of the MTRPSOS decreases, rail displacement correspondingly increases, while vibration acceleration, wheel-rail forces, fastener reaction forces, and derailment coefficient all decrease. This indicates that the MTRPSOS offers superior vibration reduction under the SOS conditions compared to the first-order stiffness conditions. Additionally, a comparative study was conducted to assess the vibration reduction effect of the MTRPSOS in contrast to traditional rail pad, and the results show that the MTRPSOS consistently exhibits lower vibration levels under the same operating conditions, underscoring its superior capacity for vibration reduction.

本文提出了一种具有二阶刚度的新型网状轨道垫(MTRPSOS),它由网状轨道垫(MTRP)和多个填充块组成。通过调整填充块的高度,MTRPSOS 的刚度曲线表现出明显的二阶刚度(SOS)特性。我们建立了 MTRPSOS 的有限元(FE)模型和动态模型,以研究 SOS 特性及其对各种动态指数的影响。有限元计算结果表明,随着填充块高度的降低,MTRPSOS 的静态和动态刚度都会增加。此外,随着填充砌块高度的增加,应力分布也变得更加均匀。动态计算表明,MTRPSOS 的 SOS 特性会显著影响各种动态指数。随着 MTRPSOS 的 SOS 值减小,轨道位移相应增大,而振动加速度、轮轨力、紧固件反作用力和脱轨系数均减小。这表明,与一阶刚度条件相比,MTRPSOS 在 SOS 条件下具有更优越的减振效果。此外,还进行了一项比较研究,以评估 MTRPSOS 与传统轨道垫相比的减振效果,结果表明,在相同的运行条件下,MTRPSOS 始终表现出较低的振动水平,突出了其卓越的减振能力。


Microstructural modeling on electrical conductivities of 3-D carbon/epoxy woven composites along different directions

Zhuodong Liu, Yousong Xue, Baozhong Sun, Bohong Gu, Meiqi Hu

doi:10.1016/j.compstruct.2023.117764

三维碳/环氧编织复合材料不同方向导电性的微观结构建模

Carbon fiber composites have widely been used in aircrafts and high speed vehicles. Electrical conductivity of the carbon fiber composites is critical to electrical safety for the aircrafts and vehicles under high voltage applications. Here we report microstructural modeling on electrical conductivities of three-dimensional (3-D) carbon/epoxy angle-interlock woven composites along on-axis and off-axis directions. A 3-D resistor network model and finite element analysis (FEA) model based on fabric microstructure have been developed to reveal the electric conductivities along different directions. We have found that the conductivity of the woven structure exhibits full anisotropy. The difference of electrical conductivity between in-plane and through-thickness direction decreased due to the existence of through-the-thickness carbon fibers. The electrical conductivity through-thickness direction increases with warp directional length. With increasing off-axis directional length, the conductivity perpendicular to the off-axis direction increases, while the conductivity parallel to the off-axis direction remains basically unchanged. Electric potential distribution and electrical current density are highly related with fabric structure and current directions. Owing to the dependence of mechanical properties are also related with fabric structure and directions, it is expected that both the electrical and mechanical properties of the 3-D woven carbon/epoxy composites could be optimized simultaneously from the composite microstructure designs.

碳纤维复合材料已广泛应用于飞机和高速车辆。碳纤维复合材料的导电性对于高压应用下的飞机和车辆的电气安全至关重要。在此,我们报告了三维(3-D)碳/环氧角交织复合材料沿轴向和离轴向导电性的微观结构模型。我们开发了基于织物微观结构的三维电阻网络模型和有限元分析(FEA)模型,以揭示不同方向的导电率。我们发现,编织结构的电导率表现出完全的各向异性。由于存在穿透厚度的碳纤维,面内和穿透厚度方向的导电率差异减小。厚度方向的导电率随经线方向长度的增加而增加。随着离轴方向长度的增加,垂直于离轴方向的导电率增加,而平行于离轴方向的导电率基本保持不变。电动势分布和电流密度与织物结构和电流方向高度相关。由于力学性能也与织物结构和方向有关,因此预计三维碳/环氧编织复合材料的电气性能和力学性能可以通过复合材料微结构设计同时得到优化。


Experimental and numerical studies on low-velocity impact of laminated C/SiC structures

Bin Liu, Fei Li, Yancheng Liu, Yi Zhang

doi:10.1016/j.compstruct.2023.117765

层状 C/SiC 结构低速冲击的实验和数值研究

Laminated C/SiC(carbon fiber reinforced silicon carbide composites) has the complicated nature of composite failure which include cracks for void defects at the meso and micro scales, complex cracks propagation of tunnel cracks, matrix cracks, delaminations and fiber cracks, orthotropic, and pseudoplastic behavior. It has technical challenge to solve all of them for complicated-mechanics problems by using multi-scale methodology. This paper focused tackling it by a model that lies between macro and meso scales, and proposed a new conceptual 3D FE-PDM(Finite Element - Progressive Damage Method). 3D FE-PDM was validated by the experiments of low-velocity impact of 2D C/SiC and 3D needled C/SiC. Damage initiation and evolution were controlled by strain in order to preventing stress chaos which could occur as cracks leading local stress relief. The multi-linear constitutive relations were adopted in orthotropic directions. The coupled effects of stresses between in-plane and out-of-plane were computed by adding damage coefficients into stiffness matrix. Cohesive Zone Method was used for delamination. The PDM approach was introduced for the 3D elements for intralaminar and cohesive elements for the interfaces. A parametric inversion methodology was put forward to determine the model parameters iteratively by comparing simulation results with the load-time curves, damage CT details of the experiments. Validation implies that, with small number of parameters, 3D FE-PDM is able to predict damage initiation of each phase knee, damage evolution, and load-displacement curve with good convergence for the low-velocity impact case. 2D woven and 3D needled non-woven C/SiC both have impact energy threshold and different damage evolution types.

层状 C/SiC(碳纤维增强碳化硅复合材料)具有复杂的复合材料失效性质,包括中尺度和微尺度的空隙缺陷裂纹、隧道裂纹的复杂裂纹扩展、基体裂纹、分层和纤维裂纹、正交和假塑性行为。使用多尺度方法解决所有这些复杂力学问题是一项技术挑战。本文重点采用介于宏观和中观尺度之间的模型来解决这一问题,并提出了一种新的 3D FE-PDM(有限元渐进损伤法)概念。二维 C/SiC 和三维针 刺 C/SiC 的低速冲击实验验证了 3D FE-PDM。损伤的发生和演变受应变控制,以防止出现应力混乱,导致局部应力释放产生裂纹。在正交方向上采用了多线性组合关系。通过在刚度矩阵中加入损伤系数,计算了平面内和平面外应力的耦合效应。分层采用了内聚区法。层内的三维元素和界面的内聚元素采用了 PDM 方法。通过将模拟结果与实验中的载荷-时间曲线、损伤 CT 细节进行比较,提出了一种参数反演方法来迭代确定模型参数。验证结果表明,在低速冲击情况下,只需少量参数,三维 FE-PDM 就能预测各相膝关节的损伤起始、损伤演变和载荷-位移曲线,且收敛性良好。二维编织和三维针 刺无纺 C/SiC 都具有冲击能量阈值和不同的损伤演变类型。


An adaptive damage monitoring method based on transfer features mapped for advanced composite structures

Yihan Wang, Xiyue Cui, Qijian Liu, Bowen Zhao, Yunlai Liao, Xinlin Qing

doi:10.1016/j.compstruct.2023.117742

基于先进复合材料结构转移特征映射的自适应损伤监测方法

Monitoring damage in advanced composite structures proves challenging due to insufficient transfer and reuse of diagnostic models. Such limitations fail to meet practical monitoring requirements. This paper proposes an innovative method to monitoring damage via Lamb waves based on transfer learning. Firstly, the proposed method utilizes algorithm-centric transfer learning to extract transferable features from the source domain and a limited amount of data from the target domain, using the domain adaptive feature mapping. The aim of this method is to achieve feature adaptation in both the source and target domains by obtaining approximate distribution patterns in the feature space. Subsequently, a fine-tuning method is presented based on data-centric transfer learning for adaptive damage identification. A screening mechanism utilizing a coarse-to-fine strategy is employed to select suitable samples for diagnosing and evaluating damage in the target domain. The proposed method is verified by targeted monitoring cases of advanced composite structures under four monitoring stages, namely, detection of the damage existence, identification of damage types, damage localization and quantification. The results show that the proposed method can present higher monitoring accuracy in general damages for advanced composite structures than nine state-of-the-art methods.

由于诊断模型的转移和再利用不足,监测先进复合材料结构的损坏具有挑战性。这种局限性无法满足实际监测要求。本文提出了一种基于迁移学习的λ波损伤监测创新方法。首先,该方法利用以算法为中心的迁移学习,从源域提取可迁移的特征,并利用域自适应特征映射从目标域提取有限的数据量。这种方法的目的是通过获取特征空间的近似分布模式,实现源域和目标域的特征适应。随后,介绍了一种基于以数据为中心的迁移学习的微调方法,用于自适应损伤识别。利用一种从粗到细的筛选机制,为诊断和评估目标域中的损伤选择合适的样本。在四个监测阶段,即检测损伤是否存在、识别损伤类型、损伤定位和量化阶段,对先进复合材料结构的目标监测案例验证了所提出的方法。结果表明,与九种最先进的方法相比,所提出的方法对先进复合材料结构一般损伤的监测精度更高。




来源:复合材料力学仿真Composites FEM
ACTMechanical振动复合材料CONVERGEUGUM裂纹材料多尺度创新方法控制电气
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首次发布时间:2024-11-03
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【新文速递】2023年11月21日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 3 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 5 篇International Journal of Solids and StructuresHyperspace bounds on mixed mode elastic constants of n-component transversely-isotropic unidirectional materialsPham Duc-Chinhdoi:10.1016/j.ijsolstr.2023.112584n 分量横向各向同性单向材料混合模式弹性常数的超空间界限We consider the general elastic unidirectional composites composed of n transversely-isotropic components (with unidirectional cylindrical boundaries between the phases), which are just macroscopically isotropic in the transverse plane. All 6 mixed-mode elastic constants appear in the complex mixed-mode longitudinal-transverse stress–strain relations (not well-separated into the pure hydrostatic and deviatoric modes as in the usual problems concerning the 3D- or 2D-isotropic bulk and shear moduli). They are subjected to various combination bounds, derived from the minimum energy principles, involving many effective properties simultaneously in the multidimensional-elastic-constant hyperspace. Exploring the possible trial mixed stress–strain modes, we derive from the combination bounds the new sets of bounds, with additional and more refined ones, on all 6 effective mixed-mode longitudinal-transverse constants of the n-component transversely-isotropic unidirectional composites, which improve significantly over the previous results. Refined optimization techniques have been used in conjunction with the iteration procedure. Using Hill relations relating the exact values of some of the effective elastic constants in the two-component case, the bench-mark Paul-Hill-type bounds have also been deduced for all those 6 mixed elastic constants for comparisons with our new bounds (three of them appear to coincide with those of ours, while the others comparatively are near-to-close in numerical examples) in that specific case. Illustrating numerical examples are provided for some two- and multi-component cases. Related to the subject - the matrix approach on bounding elastic anisotropic composites in the literature is critically examined.我们考虑的是由 n 个横向各向同性成分(各相之间的边界为单向圆柱形)组成的一般弹性单向复合材料,它们在横向平面上只是宏观各向同性。所有 6 个混合模式弹性常数都出现在复杂的纵向-横向混合模式应力-应变关系中(并不像通常的三维或二维各向同性体积模量和剪切模量问题那样,被很好地区分为纯静压模式和偏离模式)。它们受制于各种组合约束,这些约束源于最小能量原则,同时涉及多维弹性常数超空间中的许多有效特性。在探索可能的试验混合应力-应变模式的过程中,我们从组合约束中推导出了新的约束集,并对 n 组横向各向同性单向复合材料的全部 6 种有效混合模式纵向-横向常数进行了补充和完善,与之前的结果相比有了显著改善。结合迭代程序使用了改进的优化技术。利用与双组分情况下某些有效弹性常数精确值相关的希尔关系,还推导出了所有这 6 个混合弹性常数的保罗-希尔型基准边界,以便与我们在该特定情况下的新边界进行比较(其中 3 个似乎与我们的边界相吻合,而其他边界在数值示例中相对接近)。我们还提供了一些双组分和多组分情况的数值示例。与本课题相关的是,我们对文献中关于弹性各向异性复合材料边界的矩阵方法进行了批判性研究。New buckling solutions of truncated conical shells incorporating pre-buckling nonlinearityZhou Chao, Gong Guangping, Chen Liang, Wang Bo, Li Ruidoi:10.1016/j.ijsolstr.2023.112587包含预屈曲非线性的截顶锥壳新屈曲解法The pre-buckling nonlinearity is found to have a remarkable effect on both the buckling loads and modes of shells according to the previous studies. In this study, we present a novel accurate buckling analysis of the truncated conical shells under broad boundary constraints incorporating the pre-buckling nonlinearity by a quasilinearization-precise integral method (Q-PIM). Specifically, the nonlinear buckling equations of the shells are transformed into several linear ones by the perturbation and quasilinearization, and they are then solved by the PIM. The produced state transition equations by the PIM are assembled into a global matrix equation, involving the boundary conditions (BCs), to yield the buckling solutions of the shells with or without incorporating the pre-buckling nonlinearity. The convergence study and benchmark buckling solutions verified by the refined finite element method are presented. The quantitative effects of the size parameters and BCs on the nonlinear critical buckling loads as well as the pre-buckling nonlinearity are investigated.以往的研究发现,预屈曲非线性对壳的屈曲载荷和模式都有显著影响。在本研究中,我们采用准线性化-精确积分法(Q-PIM),结合预屈曲非线性,对宽边界约束下的截顶锥形壳体进行了一种新的精确屈曲分析。具体来说,通过扰动和准线性化将壳体的非线性屈曲方程转化为多个线性方程,然后用 PIM 求解。由 PIM 生成的状态转换方程被组合成一个全局矩阵方程,其中涉及边界条件 (BC),从而得到包含或不包含预屈曲非线性的壳体屈曲解。本文介绍了收敛性研究和通过精炼有限元法验证的基准屈曲解。研究了尺寸参数和 BCs 对非线性临界屈曲载荷以及预屈曲非线性的定量影响。Rate-dependent peeling behavior of the viscoelastic film-substrate systemYin Hanbin, Ma Yinji, Feng Xuedoi:10.1016/j.ijsolstr.2023.112588粘弹性薄膜-基底系统随速率变化的剥离行为In contrast to the well-understood peeling behavior of an elastic film-substrate system, the peeling behavior of a viscoelastic film bonded to a rigid substrate remains unclear. This paper established a theoretical peeling model, assuming a uniformly distributed cohesive interfacial interaction, to study the steady-state peeling behavior of a viscoelastic film. The rate-dependent behaviors of the steady-state peeling force and cohesive zone length are mainly analyzed in the present paper. It reveals that there exist 3 typical peeling force-peeling velocity relations relying on the viscous dissipation within the film and the rate-dependent extent of the interfacial adhesion. In addition to the film's viscoelasticity and the peeling velocity, the film thickness, interfacial toughness, and interfacial strength are also identified as factors that influence the steady-state peeling force. For the cohesive zone length of peeling a viscoelastic film, the analytical expression is obtained which demonstrates a dependence on peeling velocity, film viscoelasticity, film thickness, interfacial toughness, and interfacial strength. The present theoretical findings are validated by the finite element simulation and are believed to facilitate the fundamental understandings and practical applications for viscoelastic film-substrate systems.与人们熟知的弹性薄膜-基底系统的剥离行为不同,粘弹性薄膜与刚性基底粘合后的剥离行为仍不清楚。本文建立了一个理论剥离模型,假设界面相互作用为均匀分布的内聚作用,研究粘弹性薄膜的稳态剥离行为。本文主要分析了稳态剥离力和内聚区长度随速率变化的行为。结果表明,存在 3 种典型的剥离力-剥离速度关系,它们分别依赖于薄膜内部的粘滞耗散和与速率相关的界面粘附程度。除了薄膜的粘弹性和剥离速度外,薄膜厚度、界面韧性和界面强度也是影响稳态剥离力的因素。对于粘弹性薄膜剥离时的内聚区长度,得到的分析表达式表明它取决于剥离速度、薄膜粘弹性、薄膜厚度、界面韧性和界面强度。有限元模拟验证了本理论研究结果,相信有助于对粘弹性薄膜-基底系统的基本理解和实际应用。International Journal of PlasticityThe interface effect on crack nucleation under dwell fatigue loading in dual-phase Ti alloyZhang Linglei, Jiang Binbin, Qiu Jianke, Cao Xumeng, Lei Jiafeng, Yang Rui, Du Kuidoi:10.1016/j.ijplas.2023.103816 双相钛合金停留疲劳加载下裂纹成核的界面效应The microstructure of dual-phase Ti alloys crucially influences the nucleation of dwell fatigue cracks, which is of significance in determining the dwell fatigue life of Ti alloys. However, the microstructure effect on crack nucleation in dwell fatigue is still in dispute, and direct experimental investigation is desired. Here, we report that the probability of dwell fatigue cracks nucleating at grain boundaries between colonies and primary α grains is approximately one-fifth of that nucleating at grain boundaries between primary α grains. Three dislocation reaction mechanisms are determined for dislocation transmission through αs/β interfaces in colonies, two of which strongly obstruct and disperse dislocations, while the third mechanism leads to concentrated slip bands of dislocations during dwell cycle loading. As decreasing the localization of dislocation slips can effectively reduce the stress concentration at grain boundaries in colonies, it significantly decreases the possibility of crack nucleation. This demonstrates a quantitative relationship between the localization of dislocation slips and the probability of dwell-fatigue crack nucleation. The results provide insights into the quantitative analysis of the microstructure effect on crack nucleation in Ti alloys.双相钛合金的微观结构对驻留疲劳裂纹的成核有着至关重要的影响,这对决定钛合金的驻留疲劳寿命具有重要意义。然而,微观结构对驻留疲劳裂纹成核的影响仍存在争议,需要进行直接的实验研究。在此,我们报告了驻留疲劳裂纹在鲕粒和原生 α 晶粒之间的晶界成核的概率大约是原生 α 晶粒之间的晶界成核概率的五分之一。确定了位错通过菌落中的αs/β界面传输的三种位错反应机制,其中两种机制强烈阻碍和分散位错,而第三种机制则导致位错在停留循环加载期间形成集中的滑移带。由于降低位错滑移的局部性可有效减少晶胞中晶界的应力集中,从而显著降低裂纹成核的可能性。这证明了位错滑移的定位与驻留疲劳裂纹成核概率之间的定量关系。这些结果为定量分析微观结构对钛合金裂纹成核的影响提供了启示。Thin-Walled StructuresExperimental and numerical investigations towards the lateral torsional buckling of cellular steel beamsBoissonnade Nicolas, Nseir Joanna, Somja Huguesdoi:10.1016/j.tws.2023.111388对蜂窝钢梁横向扭转屈曲的实验和数值研究This paper deals with the response of so-called “cellular members” against lateral torsional buckling. These beams comprising regularly-spaced circular web openings are especially used for their high resistance-to-weight ratio, the possibility to integrate service pipes within their height, and for aesthetics. Such profiles usually exhibit a complex behaviour and many potential failure modes, including interactional local/global instability modes. Regarding global instability, the members are usually designed by means of approximate design rules, which often lead to an unduly conservative solution, with beams sometimes showing up to 150% resistance reserves. The present research works aim at improving this situation, through the development of adequate design formulae. In this respect, the present paper reports on investigations led towards improved solutions for cellular members at the experimental and numerical levels. This first paper focuses on experimental activities and on the development and validation of dedicated shell F.E. models. The results of three bending tests on members spanning from 7.5 m to 11 m are reported. Cross-sectional dimensions, material properties and accurate initial geometrical imperfections were measured for each specimen and further introduced in the corresponding F.E. models, which are shown to provide predictions in close agreement with the experimental results. The companion paper [1] further makes use of the F.E. models within extensive parametric studies and proposes a new set of design rules that could be proposed for integration in Eurocode 3.本文论述了所谓的 "蜂窝构件 "对横向扭转屈曲的响应。这些梁由间隔规则的圆形腹板开口组成,因其阻力重量比高、可在高度范围内集成服务管道以及美观而得到广泛应用。这种型材通常表现出复杂的行为和许多潜在的失效模式,包括交互式局部/整体失稳模式。在全局失稳方面,构件的设计通常采用近似设计规则,这往往会导致解决方案过于保守,梁的抗力储备有时高达 150%。目前的研究工作旨在通过开发适当的设计公式来改善这种状况。在这方面,本文报告了为改进蜂窝构件的解决方案而进行的实验和数值研究。第一篇论文侧重于实验活动以及专用壳体 F.E. 模型的开发和验证。报告了对跨度为 7.5 米至 11 米的构件进行的三次弯曲试验的结果。对每个试样的横截面尺寸、材料特性和精确的初始几何缺陷进行了测量,并将其进一步引入相应的有限元模型,结果表明,这些模型提供的预测结果与实验结果非常吻合。相关论文[1]进一步在广泛的参数研究中使用了 F.E. 模型,并提出了一套新的设计规则,这些规则可纳入欧洲规范 3。On the coupling of data-driven computing and model-driven computing with CUF-based beam modelsHui Yanchuan, Giunta Gaetano, Liu Xiao, Zheng Jie, Yang Jie, Huang Wei, Carrera Erasmodoi:10.1016/j.tws.2023.111394关于数据驱动计算和模型驱动计算与基于 CUF 的波束模型的耦合In this article, Model-driven (MD) computing and Data-driven (DD) computing mechanics are coupled under the framework of Carrera’s Unified Formulation (CUF) for beam structures A DD CUF-based computing is applied for the sub-domains of the beam under investigation where the material constitutive models are challenging to be obtained, whereas a MD CUF-based computing is used to deal with the remaining sub-domains where a constitutive model is available. By using CUF, under the premise of sufficient accuracy, the computational cost of DD-MD CUF-based models could be reduced compared with DD-MD FEM models where solid elements are used. Several static cases are analysed to demonstrate the accuracy and reliability of the proposed DD-MD CUF-based model by comparing the obtained results with those from the finite element commercial software tools.在本文中,模型驱动(MD)计算和数据驱动(DD)计算力学在卡雷拉统一公式(CUF)的框架下对梁结构进行了耦合。通过使用 CUF,在足够精确的前提下,与使用实体元素的 DD-MD FEM 模型相比,基于 DD-MD CUF 模型的计算成本可以降低。我们分析了几个静态案例,通过将获得的结果与有限元商业软件工具的结果进行比较,证明了所提出的基于 DD-MD CUF 的模型的准确性和可靠性。Damage analysis of deployable thin-walled composite shell structure during coiling upChang Zhongliang, Zhao Peng, Zhang Zhijun, Zou Guangping, Zhao Pengyuan, Wu Chenchendoi:10.1016/j.tws.2023.111395 可展开薄壁复合材料壳体结构在卷绕过程中的损伤分析Thin-walled coilable composite shells have been successfully used in deployable space payloads due to their high storage efficiency and stiffness-to-weight ratio. However, in real-life applications the deployable composite shells requiring repeatable coiling up and deployment are easy to be damaged, and their damage or failure behaviors due to large deformations has been rarely studied. This paper aims to investigate their damage and failure behaviors during the snap through, equal-sense and opposite-sense coiling up. First, multiscale models are established to compute the mechanical properties of plain-woven fabrics and unidirectional prepregs with consideration of stiffness reduction of the composites. Then, damages of each ply within the thin-walled shell are studied during snap through and coiling up. Simultaneously, effects of hub diameter on the damage of the thin-walled shell were investigated, followed by experimental verification using strain gauges and a scanning electron microscope (SEM). Simulation and experimental results show that the dominated damage of the thin-walled shell is failure of matrix. The SEMs of the edge damaged show failures of both resin and carbon fibers. Tensile damages of matrix can be relieved as the increment of the hub diameter, and no obvious failure is observed at the hub diameter of 50 mm.薄壁可卷绕复合材料壳体具有较高的存储效率和刚度重量比,已成功用于可展开的空间有效载荷。然而,在实际应用中,需要可重复卷绕和展开的可展开复合材料壳体很容易损坏,而对其因大变形而导致的损坏或失效行为的研究却很少。本文旨在研究其在扣穿、等义和反义卷绕过程中的损伤和失效行为。首先,在考虑降低复合材料刚度的情况下,建立多尺度模型来计算平织织物和单向预浸料的力学性能。然后,研究了薄壁壳体内各层在卡入和卷起过程中的损坏情况。同时,研究了轮毂直径对薄壁外壳损坏的影响,并使用应变仪和扫描电子显微镜(SEM)进行了实验验证。模拟和实验结果表明,薄壁外壳的主要损伤是基体的破坏。边缘损坏处的扫描电子显微镜显示树脂和碳纤维都发生了破坏。基体的拉伸损伤可随着轮毂直径的增大而缓解,在轮毂直径为 50 毫米时未观察到明显的破坏。A dimensionless analytical analysis for buckling and lateral buckling interaction of thin-walled beams with open cross sectionsBakhach Zaenab, Kaimbillah Ahmed El, Hamdaoui Abdellah, Braikat Bouazza, Mohri Foudil, Damil Noureddinedoi:10.1016/j.tws.2023.111396开放截面薄壁梁屈曲和侧向屈曲相互作用的无量纲分析This paper investigates the interaction between buckling and lateral buckling of thin-walled beams with arbitrary open cross-section using nonlinear modeling in large rotation and with warping. First, the equilibrium equations have been transformed into dimensionless ones, and within a nonlinear stability model, various dimensionless parameters are introduced to control the interaction between buckling and lateral buckling. In comparison to a reference of literature, this work focuses on the case of arbitrary sections and includes a greater number of higher-order terms in our analysis. These additions have an impact on the coefficients of the stability formula by expanding its applicability to non- symmetric sections. Then, the effect of the different dimensionless parameters, thus introduced on the stability curve, has been studied. The proposed solutions are validated and compared to numerical solutions obtained by a general finite element package including the warping developed by the authors using Asymptotic Numerical Method (ANM) to solve the initial nonlinear equations.本文利用非线性模型研究了任意开截面薄壁梁在大旋转和翘曲情况下屈曲与侧向屈曲之间的相互作用。首先,将平衡方程转化为无量纲方程,并在非线性稳定性模型中引入各种无量纲参数来控制屈曲和侧向屈曲之间的相互作用。与参考文献相比,本研究侧重于任意截面的情况,并在分析中加入了更多的高阶项。这些新增项扩大了稳定性公式对非对称截面的适用范围,从而对公式系数产生了影响。然后,研究了由此引入的不同无量纲参数对稳定性曲线的影响。提出的解决方案得到了验证,并与作者使用渐近数值法(ANM)求解初始非线性方程的通用有限元软件包(包括翘曲)获得的数值解决方案进行了比较。A novel non-contact measurement strategy for large-size inflatable structures based on numerical predictionsGao Weinan, Song Bo, Chen Xueyan, Lin Guochang, Tan Huifengdoi:10.1016/j.tws.2023.111397基于数值预测的新型大尺寸充气结构非接触测量战略The deformation characteristics of expansive inflatable structures, like airships, provide essential data for their operation in the stratosphere. However, due to rapid configuration changes in these structures with fluctuating air pressure, obtaining accurate morphological data quickly during testing can be challenging. This paper presents a precise method for predicting deformation in large-scale inflatable structures. A finite element method was employed to meticulously model the inflatable structure, underpinned by an inflatable ring skeleton support, and predict its potential maximum deformation points. Leveraging this predictive model as a guide, we proposed utilizing a laser scanning technique for non-contact measurements of the anticipated maximum deformation sites, aiming to discern the deformation patterns of the structure under varying air pressures. A good agreement between the non-contact measurement results and the numerical simulations affirms the efficiency and precision of the proposed methodology. This non-contact measurement strategy, grounded in finite element predictions, streamlines the measurement process, economizing on time and reducing complexity. Such an approach promises to be invaluable for expansive structures like airships. Furthermore, the insights derived from this non-contact method will be pivotal for anticipating the mechanical behaviors of full-scale stratospheric airships during their operations and for refining their design models.膨胀性充气结构(如飞艇)的变形特性为其在平流层中的运行提供了重要数据。然而,由于这些结构会随着气压的波动而迅速发生构型变化,因此在测试过程中快速获取准确的形态数据是一项挑战。本文提出了一种预测大型充气结构变形的精确方法。采用有限元方法对充气结构(由充气环骨架支撑)进行细致建模,并预测其潜在的最大变形点。以这一预测模型为指导,我们建议利用激光扫描技术对预计的最大变形点进行非接触式测量,以辨别结构在不同气压下的变形模式。非接触式测量结果与数值模拟结果之间的良好一致性证实了所建议方法的效率和精确性。这种以有限元预测为基础的非接触式测量策略简化了测量过程,节省了时间并降低了复杂性。这种方法对于飞艇这样的大型结构来说非常有价值。此外,从这种非接触式方法中获得的见解对于预测全尺寸平流层飞艇在运行期间的机械行为以及改进其设计模型至关重要。来源:复合材料力学仿真Composites FEM

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