今日更新:Composite Structures 2 篇,Composites Part A: Applied Science and Manufacturing 3 篇,Composites Science and Technology 1 篇
Automatic assembly of tensegrity chain structures along axes based on NURBS curves
Yongcan Dong, Xingfei Yuan, Yiqian Chen, Akram Samy, Shilin Dong
doi:10.1016/j.compstruct.2024.118465
基于NURBS曲线的张拉整体链结构轴向自动装配
Tensegrity chain structures (TCS) are emerging as a promising structural form and have gradually garnered increasing attention across a wide range of applications. However, designing large-scale tensegrity chains, particularly those with complex geometric shapes, remains a challenging endeavor. To address this issue, this study proposes a fully parametric design method, termed the Modular Growth Assembly (MGA), to facilitate the automatic construction of TCS. Leveraging Non-Uniform Rational B-Splines (NURBS) curves, this method can directly capture the desired structural shapes and guide the assembly of numerous elementary tensegrity units into the overall structure along their axes. For assembly, some existing tensegrities are exemplarily introduced to serve as the elementary units, forming an elementary unit library. To adopt to various packing spaces, two transformation techniques are employed to explore different shape transformation patterns. Subsequently, the parametric determinations of nodal coordinates, topology, and prestress for the overall structure are investigated, respectively. A number of fascinating design examples, including both 2D and 3D cases, are then presented to demonstrate the effectiveness of the proposed method. This research will pave the way for the convenient production of customized TCS for diverse applications and might be beneficial to provide a comprehensive optimization framework for such systems.
张拉整体链结构(TCS)作为一种新兴的结构形式,在广泛的应用中逐渐受到越来越多的关注。然而,设计大规模的张拉整体链,特别是那些具有复杂几何形状的,仍然是一个具有挑战性的努力。为了解决这一问题,本研究提出了一种全参数化设计方法,称为模块化生长装配(MGA),以促进TCS的自动构建。利用非均匀有理b样条(NURBS)曲线,该方法可以直接捕获所需的结构形状,并引导许多基本张拉整体单元沿其轴线组装到整体结构中。对于装配,一些现有的张拉整体被范例地引入作为基本单元,形成一个基本单元库。为了适应不同的填充空间,采用了两种变换技术来探索不同的形状变换模式。随后,分别研究了节点坐标、拓扑结构和整体结构预应力的参数确定。一些迷人的设计实例,包括二维和三维的情况下,然后提出,以证明所提出的方法的有效性。本研究将为方便生产各种应用的定制TCS铺平道路,并可能有助于为此类系统提供全面的优化框架。
A micromechanics perspective on the intralaminar and interlaminar damage mechanisms of composite laminates considering ply orientation and loading condition
Zhengtao Qu, Cong Zhao, Luling An
doi:10.1016/j.compstruct.2024.118454
考虑层向和加载条件的复合材料层内和层间损伤机理的细观力学研究
A comprehensive understanding of the complex damage mechanisms in composite laminates is of great importance for establishing material failure models and designing structural damage tolerance. This paper proposed a combined numerical computation and in-situ experimental study to comprehensively investigate the influence of ply orientation and loading conditions on the microscopic damage behaviors of composite laminates. In terms of numerical computation, to overcome the limitations of current monolayer Representative Volume Element (RVE) models, 3-D two-layer RVE models were developed to characterize the intra-ply and inter-ply damage behavior of composite laminates. In-situ tests were conducted on orthotropic laminates under transverse tensile and out-of-plane shear loads, and the physical processes of crack initiation and propagation were analyzed in conjunction with numerical simulation results. The research findings revealed the contributions of the matrix, fibers, and their interfaces to the damage behavior dominated by matrix cracking in composite laminates. The extension processes and final morphologies of matrix cracks were analyzed and a summary of the propagation patterns of matrix cracks was provided. The proposed 3-D two-layer RVE model effectively captured transient failure processes that cannot be observed in in-situ tests, and the numerical computation results were consistent with ex-situ observations after specimen failure.
全面了解复合材料层合板的复杂损伤机理,对于建立材料失效模型和设计结构损伤容限具有重要意义。本文提出了数值计算与现场试验相结合的方法,全面研究了铺层取向和加载条件对复合材料层合板微观损伤行为的影响。在数值计算方面,为了克服现有单层代表体积元(RVE)模型的局限性,建立了表征复合材料层合板层内和层间损伤行为的三维双层代表体积元模型。对正交各向异性层合板进行了横向拉伸和面外剪切试验,并结合数值模拟结果分析了裂纹萌生和扩展的物理过程。研究结果揭示了基体、纤维及其界面对复合材料层合板中以基体开裂为主的损伤行为的影响。分析了基体裂纹的扩展过程和最终形貌,总结了基体裂纹的扩展模式。提出的三维两层RVE模型有效捕捉了原位试验无法观测到的瞬态破坏过程,数值计算结果与试样破坏后的离地观测结果一致。
Automatic yarn path extraction of large 3D interlock woven fabrics with confidence estimation
Yuriy Sinchuk, Yanneck Wielhorski, Arturo Mendoza, Samy Blusseau, Santiago Velasco-Forero
doi:10.1016/j.compositesa.2024.108396
基于置信度估计的大型三维互锁机织物纱线路径自动提取
Modeling realistic textile composite structures remains a challenging task due to their complex geometry. In this paper, a novel method for reconstructing yarn paths based on micro-computed tomography is proposed. A deep learning approach is employed to convert μ-CT scan into an appropriate distance map, which is used for extracting yarn paths with a tracking algorithm. An ablation study is performed to understand the hyperparameters that matter the most. This study includes variation of the target images, selection of spatial dimension of the U-Net (2D, 2.5D and 3D), dataset sampling strategies and loss terms weighting. Additionally, a robust method for estimating the quality of the predictions without the need for annotation is introduced. The accuracy of the reconstruction method is demonstrated through the analysis 15 test μ-CT images, with 5 devoted to the optimal post-processing evaluation and 10 for assessing the final test results.
由于复杂的几何形状,现实纺织复合结构的建模仍然是一项具有挑战性的任务。本文提出了一种基于微型计算机断层扫描重建纱线路径的新方法。该方法采用深度学习方法将 μ-CT 扫描转换为适当的距离图,然后利用跟踪算法提取纱线路径。为了解最重要的超参数,进行了一项消融研究。这项研究包括目标图像的变化、U-Net 空间维度的选择(2D、2.5D 和 3D )、数据集采样策略和损失项加权。此外,还介绍了一种无需注释即可估算预测质量的稳健方法。通过分析 15 张测试 μ-CT 图像(其中 5 张用于优化后处理评估,10 张用于评估最终测试结果),证明了重建方法的准确性。
A deep learning framework based on attention mechanism for predicting the mechanical properties and failure mode of embedded wrinkle fiber-reinforced composites
Chen Liu, Xuefeng Li, Jingran Ge, Xiaodong Liu, Bingyao Li, Zengfei Liu, Jun Liang
doi:10.1016/j.compositesa.2024.108401
基于注意机制的深度学习框架预测嵌入式褶皱纤维增强复合材料力学性能和失效模式
To avoid the expensive computational costs process of high-fidelity simulation, a deep learning (DL) framework based on attention mechanism and three-dimensional stress state is proposed to predict the compressive mechanical properties and failure modes of embedded wrinkle thick-section composites in this paper. The deep learning framework includes strength and stiffness, stress–strain curves and failure mode prediction networks respectively using convolutional neural networks based on wrinkle angle distribution and material distribution. The attention-based loss function is considered in the failure mode network to accurately predict the local high damage areas. The high-fidelity three-dimensional finite element simulations based on progressive damage method are used to compute the datasets for training and validating. The results show that the deep learning framework can accurately predict the compressive mechanical properties and failure modes of embedded wrinkle composites. Meanwhile, the DL framework also reveals the influence rule of wrinkle parameters on mechanical properties and failure modes.
为了避免高保真仿真过程中昂贵的计算成本,本文提出了一种基于注意机制和三维应力状态的深度学习框架来预测嵌入式褶皱厚截面复合材料的压缩力学性能和破坏模式。深度学习框架包括基于皱褶角分布和材料分布的卷积神经网络的强度和刚度、应力-应变曲线和失效模式预测网络。在失效模式网络中考虑基于注意力的损失函数,以准确预测局部高损伤区域。采用基于渐进损伤法的高保真三维有限元模拟,计算训练和验证数据集。结果表明,深度学习框架能够准确预测嵌入褶皱复合材料的压缩力学性能和破坏模式。同时,DL框架还揭示了起皱参数对力学性能和破坏模式的影响规律。
Hierarchical carbonaceous modified carbon fiber reinforced polyether ether ketone and reusing reclaimed carbon fiber for sustainable photocatalysis: An experimental and numerical analysis
R. Sasikumar, Saritha Kanoth, Shubra Singh, Kumaran Rengaswamy, V. Subramanian, R. Jayavel
doi:10.1016/j.compositesa.2024.108403
分级碳基改性碳纤维增强聚醚醚酮及再生碳纤维可持续光催化的实验与数值分析
A strategic one-step design of fiber-film multifunctional carbonaceous (Graphene Nano Platelets (GNPs)/amine-Multiwalled Carbon Nanotubes (MWCNTs) modified carbon fiber reinforced Polyether ether ketone (PEEK) has been fabricated to explore its synergism in mechanical, electromagnetic, and photocatalytic applications. The dispersive surface energy compatibility between PEEK (γsd-36.2 mJ/m2), NH2-MWCNTs (γsd-29.9 mJ/m2), and GNPs (γsd-39 mJ/m2) exhibits unique reinforcement mechanism. The mesoscale modeling using Digimat-FE and Abaqus FEA predicts interlaminar shear behavior, which agrees with the experimental results. The multifarious assembly features of GNP/MWCNT reinforcement enable the improved shielding effectiveness of 42.99 dB. The 0.1 % TiO2-RCF is found to have a degradation efficiency of 99.9 %. A reactor model was developed in COMSOL Multiphysics, and the degradation rate of MB was fitted with the Langmuir-Hinshelwood kinetic model. The estimated parameters included an intrinsic reaction rate of 1.37 × 10−6 mol m−3 min−1 and an adsorption constant of 1.728 × 1018 m3 mol−1.
为了探索其在机械、电磁和光催化应用中的协同作用,我们采用战略性的一步法设计了一种纤维薄膜多功能碳质(石墨烯纳米板(GNPs)/胺-多壁碳纳米管(MWCNTs)改性碳纤维增强聚醚醚酮(PEEK))。聚醚醚酮(PEEK)(γsd-36.2 mJ/m2)、NH2-MWCNTs(γsd-29.9 mJ/m2)和 GNPs(γsd-39 mJ/m2)之间的分散表面能相容性表现出独特的增强机制。利用 Digimat-FE 和 Abaqus FEA 建立的中尺度模型预测了层间剪切行为,与实验结果一致。GNP/MWCNT 增强材料的多种组装特性使屏蔽效果提高了 42.99 dB。0.1 % TiO2-RCF 的降解效率为 99.9 %。在 COMSOL Multiphysics 中开发了反应器模型,并用 Langmuir-Hinshelwood 动力学模型拟合了甲基溴的降解率。估计参数包括 1.37 × 10-6 mol m-3 min-1 的固有反应速率和 1.728 × 1018 m3 mol-1 的吸附常数。
Experimental and numerical study on failure mechanisms of tapered laminates: Effects of ply thickness and taper ratio
Xin Lu, Ryo Higuchi, Xiawan Hua, Toshio Nagashima, Tomohiro Yokozeki
doi:10.1016/j.compscitech.2024.110784
锥形层压板破坏机理的实验与数值研究:厚度和锥度比的影响
Although the variable ply drop-off strategy in tapered laminates offers design flexibility for composite components, it introduces significant challenges to structural reliability due to the discontinuity and stress concentration caused by ply termination. In light of this, we present an integrated experimental and numerical investigation into the failure mechanisms of tapered composite laminates. Interrupted tensile tests are employed to analyze the progressive damage processes of these laminates, considering the effects of taper ratio and ply thickness. Comprehensive failure examinations are conducted alternately using optical microscopy, X-ray radiography, and X-ray computed tomography. In parallel, a generic failure model is developed within the framework of finite element method. It enables the prediction of failure loads and damage patterns in the laminate specimens, allowing for comparison with test results. A strong correlation between numerical modeling and experimental reference has been achieved, which clarifies the interdependence of failure behavior on ply thickness and taper ratio. For identical structural compositions, it is demonstrated that the utilization of thin plies and shallow tapers enhances the damage resistance of laminate structures with ply drop-offs.
尽管锥形层压板的可变厚度下降策略为复合材料组件提供了设计灵活性,但由于厚度终止引起的不连续和应力集中,它给结构可靠性带来了重大挑战。鉴于此,我们对锥形复合材料层合板的破坏机制进行了综合实验和数值研究。考虑锥度比和厚度的影响,采用间断拉伸试验分析了复合材料的渐进损伤过程。综合故障检查交替使用光学显微镜、x射线摄影和x射线计算机断层扫描进行。同时,在有限元框架内建立了通用的失效模型。它能够预测层压试样的失效载荷和损伤模式,允许与测试结果进行比较。数值模拟结果与实验结果具有较强的相关性,阐明了层厚和锥度比对破坏行为的影响。在相同的结构成分下,薄层和浅锥层的使用均能提高具有层数下降的层压结构的抗损伤能力。