【新文速递】2024年1月6日复合材料SCI期刊最新文章

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

Composite Structures

Planar-thick panels and 3D-printed gap fillers: A hybrid digital fabrication approach to curved surface approximations

Ting-Uei Lee, Yuanpeng Liu, Yi Min Xie

doi:10.1016/j.compstruct.2024.117875

平面厚板和 3D 打印间隙填充物：曲面近似的混合数字制造方法

Curved surfaces may be approximated using polygonal panels to simplify complex architectural designs, yet their constructions can be expensive due to single-use moulds producing unique panels. To reduce costs, strategies like planarizing and reducing the number of different panels have been suggested, which are increasingly achievable with advancing digital fabrication technologies. However, current subtractive and additive manufacturing techniques face challenges in producing complex 3D shapes and large volumes, respectively. Combining these two techniques has been attempted, mainly with small 3D-printed nodes, leaving the direct realization of curved surface approximations unexplored. This paper extends the thick-panel origami theory to introduce planar-thick panels and 3D-printed gap fillers for cost-effective constructions. It presents a computational workflow to transform meshes into non-intersecting panels while preserving edge connectivity and frame-like gap fillers with minimized volumes. Physical prototypes demonstrate significant cost savings compared to direct 3D printing. All prototypes are accurate within a 10 mm material thickness due to the guidance of the gap fillers. The finite element analysis shows that structural performance is greatly influenced by the material properties, especially of panels, due to their relatively larger volume. Numerical examples are also presented using the k -means clustering-optimization method to reduce the number of different panels.

曲面可以使用多边形面板来近似，以简化复杂的建筑设计，但由于生产独特面板的模具是一次性使用的，其建造成本可能很高。为了降低成本，有人提出了平面化和减少不同面板数量等策略，随着数字制造技术的发展，这些策略越来越容易实现。然而，目前的减法和增法制造技术分别在生产复杂的三维形状和大批量产品方面面临挑战。将这两种技术结合在一起的尝试主要是使用小型三维打印节点，而直接实现曲面近似的技术尚未得到探索。本文扩展了厚板折纸理论，引入了平面厚板和三维打印间隙填充物，以实现具有成本效益的结构。它提出了一种计算工作流程，可将网格转化为不相交的面板，同时保留边缘连接和体积最小的框架式间隙填充物。与直接三维打印相比，物理原型展示了显著的成本节约。由于间隙填充物的引导作用，所有原型的材料厚度都精确到 10 毫米以内。有限元分析表明，结构性能在很大程度上受到材料特性的影响，尤其是面板，因为其体积相对较大。此外，还介绍了使用 k -means聚类优化法减少不同面板数量的数值示例。

Shear strength damage model and damage removal FE modeling of stud shear connectors embedded in UHPC

Jianan Qi, Weihao Zou, Jie Liu, Shuai Li, Jingquan Wang

doi:10.1016/j.compstruct.2024.117880

嵌入超高强度混凝土中的螺柱剪切连接件的剪切强度损伤模型和损伤消除有限元模型

The study conducted a series of push-out tests to study the shear strength of studs as shear connectors in steel-UHPC (ultra high-performance concrete) composite structures. The damage removal modeling was developed and utilized to simulate stud damage caused by welding defects, concrete cracking, and lifting effects. The study investigated the impact of stud damage on the static performance and shear strength of studs. Results indicated that when the root area of the stud was damaged, the shear strength and stiffness of the stud decreased with the damage degree. When the stud root was damaged within 5%h (h is the height of stud shank), it had a significant effect on the shear strength of the stud. Damage outside the 5%h range of the stud root had no significant effect on the shear strength of the stud. And a shear strength damage model was firstly proposed to reveal the damage mechanism of studs. A reduction factor K was proposed to account for the loss in shear strength caused by stud damage. Two methods for calculating K, namely the area reduction method and the equivalent area method, were developed. The calculated values of shear strength considering stud damage were obtained and verified by comparing the calculated values with the test results. The proposed method offers a better prediction of shear strength for damaged studs in UHPC.

该研究进行了一系列推出试验，以研究钢-UHPC（超高性能混凝土）复合结构中作为剪切连接件的螺柱的剪切强度。开发并使用了损伤消除模型来模拟由焊接缺陷、混凝土开裂和提升效应造成的螺柱损伤。研究调查了螺柱损坏对螺柱静态性能和抗剪强度的影响。结果表明，当螺柱根部区域受损时，螺柱的剪切强度和刚度会随着受损程度的增加而降低。当螺柱根部的损坏程度在 5%h（h 为螺柱柄的高度）范围内时，对螺柱的抗剪强度有显著影响。在螺柱根部 5%h范围之外的损坏对螺柱的抗剪强度没有明显影响。为了揭示螺柱的损坏机制，首先提出了一个剪切强度损坏模型。并提出了一个折减系数 K 来计算因螺栓损坏而造成的剪切强度损失。提出了两种计算 K 的方法，即面积缩减法和等效面积法。通过将计算值与测试结果进行比较，获得了考虑到螺柱损坏的剪切强度计算值，并对其进行了验证。所提出的方法能更好地预测超高强度混凝土中受损螺柱的抗剪强度。

Three-dimensional finite element modelling OF the fire response of passive and prestressed near-surface mounted (NSM)–cfrp-strengthened reinforced concrete slab strips

Adriana S. Azevedo, João P. Firmo, João R. Correia

doi:10.1016/j.compstruct.2023.117872

被动和预应力近表面安装（NSM）-cfrp 加固钢筋混凝土板条火灾响应的三维有限元建模

This paper presents a numerical study about the fire behaviour of reinforced concrete (RC) slab strips strengthened with passive and prestressed carbon fibre reinforced polymer (CFRP) laminates installed according to the Near-Surface Mounted (NSM) technique. 3D finite element models were developed to simulate fire resistance tests in which the NSM-CFRP-strengthened-RC slab strips were simultaneously subjected to a service load and the ISO834 fire. The CFRP-concrete interface was modelled through temperature-dependent bi-linear bond-slip laws. In addition to the prestress levels applied to the CFRP (0%, 25% and 50% of their tensile strength), the presence/geometry of fire protection (calcium silicate boards) was also assessed. The comparison between numerical and previous experimental results showed the models accuracy in predicting the thermo-mechanical response of fire exposed passive and prestressed NSM-CFRP-strengthened-RC slab strips, presenting a fire resistance decrease when the prestress increased from 0% to 50%, from 13to 6min when no fire protection was used, and from 152to 127min with fire protection. The numerical results allowed predicting the decrease of critical temperature in the CFRP anchorages with the prestress increase: 3.4-3.6Tg, 3.0Tg , and 2.1-2.4Tg respectively for prestress levels of 0%, 25% and 50% (Tg– adhesive’s glass transition temperature).

本文对采用近表面安装（NSM）技术安装的被动和预应力碳纤维增强聚合物（CFRP）层压板加固的钢筋混凝土（RC）板条的火灾行为进行了数值研究。开发了三维有限元模型来模拟耐火试验，在试验中，NSM-CFRP 加固的 RC 板条同时承受使用荷载和 ISO834 火灾。CFRP - 混凝土界面通过与温度相关的双线性粘结滑移定律进行建模。除了应用于 CFRP 的预应力水平（拉伸强度的 0%、25% 和 50%）外，还评估了防火保护（硅酸钙板）的存在/几何形状。数值结果与之前实验结果的对比显示，模型在预测受火的无源和预应力 NSM-CFRP 加固 RC 板条的热机械响应方面非常准确，当预应力从 0% 增加到 50%，耐火性下降；在未使用防火保护时，耐火性从 13 分钟下降到 6 分钟；在使用防火保护时，耐火性从 152 分钟下降到 127 分钟。数值结果可以预测 CFRP 锚固件的临界温度会随着预应力的增加而降低：在预应力水平为 0%、25% 和 50% 时，临界温度分别为 3.4-3.6Tg、3.0Tg 和 2.1-2.4Tg（Tg为粘合剂的玻璃转化温度）。

Composites Part A: Applied Science and Manufacturing

Pseudo-ductile behaviour of fibrous composite Z-pins

E. Santana de Vega, G. Allegri, B. Zhang, I. Hamerton, S.R. Hallett

doi:10.1016/j.compositesa.2024.108009

纤维状复合材料 Z 形销的伪电导行为

This paper describes the development and characterisation of a novel type of composite Z-pin able to accommodate large deformation without exhibiting fibre failure. Three types of pseudo-ductile Z-pins are fabricated by means of micro-pultrusion of polybenzoxazole (PBO) fibres. Namely, unidirectional PBO fibre (uPBO) Z-pins in combination with a ductile (uPBO/DCT) and a brittle (uPBO/BT) matrix system are developed, together with a twisted PBO fibre Z-pin in combination with a ductile matrix (tPBO/DCT). Single pin bridging tests are carried out across the full mode mixity range from mode I (Φ= 0) to mode II (Φ = 1). The tests reveal that uPBO-based pins are able to pull out throughout the full mode mixity range, regardless of the ductility of the pin matrix. uPBO/DCT pins exhibit a 20-fold increase in energy dissipation per pin than traditional carbon fibre/bismaleimide (CF/BMI) pins at load mode mixities higher than Φ = 0.9. The mode I behaviour of all pins considered is comparable. All PBO pins exhibit an apparent delamination toughness enhancement superior to CF/BMI at mode mixities above Φ = 0.2, with a ductile matrix increasing the average energy dissipated per pin by a further 2-8%.

本文介绍了一种新型复合材料 Z 形销的开发和特性分析，这种销能够承受大变形而不会出现纤维断裂。通过对聚苯并恶唑（PBO）纤维进行微拉伸，制造出了三种假韧性 Z 形销。即，结合韧性（uPBO/DCT）和脆性（uPBO/BT）基体系统的单向 PBO 纤维（uPBO）Z 形销，以及结合韧性基体的扭曲 PBO 纤维 Z 形销（tPBO/DCT）。在从模式 I（Φ= 0）到模式 II（Φ= 1）的整个混合模式范围内进行了单针桥接测试。测试结果表明，无论插针基体的延展性如何，基于 uPBO 的插针都能在整个混合模式范围内拔出。当负载模式混合度高于 Φ = 0.9 时，uPBO/DCT 插针的单位能量耗散比传统碳纤维/双马来酰亚胺（CF/BMI）插针增加了 20 倍。所有引脚的模式 I 行为都具有可比性。所有 PBO 销针在模式混合度超过 Φ = 0.2 时，分层韧性明显优于 CF/BMI，韧性基体使每个销针的平均耗散能量再增加 2-8%。

Composites Science and Technology

Epoxy composites with satisfactory thermal conductivity and electromagnetic shielding yet electrical insulation enabled by Al2O3 platelet-isolated MXene porous microsphere networks

Fanjun Guo, Yuying Wang, Kangle Xue, Li Liu, Jun Li, Yudong Huang

doi:10.1016/j.compscitech.2023.110425

通过 Al2O3 板块隔离 MXene 多孔微球网络实现具有令人满意的导热性、电磁屏蔽性和电气绝缘性的环氧树脂复合材料

The development of highly integrated electronic devices has placed higher demands on the thermal conductivity, electromagnetic interference (EMI) shielding, and electrical insulation properties of electronic packaging materials. In this work, a facile strategy for the fabrication of epoxy composites with Al2O3 platelet-isolated MXene porous microsphere networks was proposed. The composites were prepared by a simple salt-template method under vortex conditions and showed effective electric insulation as well as satisfactory EMI shielding and thermal conductivity properties. Particularly, the EMI shielding performance is enhanced by MXene porous microspheres with multi-interfacial conductive networks. Moreover, Al2O3 platelets (Al2O3p) with shell-like arrangement enrich the thermal conductivity paths on one hand and synergistically interact with the epoxy matrix to intercept the electron transfer between the MXene porous microspheres on the other hand. As a result, the obtained MXene/Al2O3p/Epoxy composites exhibit excellent thermal conductivity (2.1 W/mK) and satisfactory EMI shielding performance (22.3 dB at 8.6 GHz), while maintaining high electrical insulation (1.2 × 109 Ωcm). This paper provided a new idea to synergistically improve the electrical insulation, thermal conductivity and EMI shielding properties of epoxy composites.

高度集成电子设备的发展对电子封装材料的导热性、电磁干扰（EMI）屏蔽和电绝缘性能提出了更高的要求。本研究提出了一种简便的环氧树脂与 Al2O3 板状隔离 MXene 多孔微球网络复合材料的制备方法。复合材料是在涡流条件下通过简单的盐模板法制备的，具有有效的电绝缘性能、令人满意的电磁干扰屏蔽性能和导热性能。特别是，具有多界面导电网络的 MXene 多孔微球增强了 EMI 屏蔽性能。此外，具有贝壳状排列的 Al2O3 小板（Al2O3p）一方面丰富了导热路径，另一方面与环氧基质协同作用，拦截了 MXene 多孔微球之间的电子转移。因此，所获得的 MXene/Al2O3p/Epoxy 复合材料具有优异的导热性（2.1 W/mK）和令人满意的电磁干扰屏蔽性能（8.6 GHz 时为 22.3 dB），同时还保持了较高的电绝缘性（1.2 × 109 Ωcm）。本文为协同改善环氧树脂复合材料的电绝缘性、导热性和 EMI 屏蔽性能提供了一个新思路。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年1月14日复合材料SCI期刊最新文章

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 1 篇Composite StructuresvAnalysis of cure kinetics of CFRP composites molding process using incremental thermochemical information aggregation networksBo Yang, Haoping Huang, Fengyang Bi, Liqiong Yin, Qi Yang, Hang Shendoi:10.1016/j.compstruct.2024.117904基于增量热化学信息聚合网络的CFRP复合材料成型过程固化动力学分析This work focuses on addressing the pain points of poor generalization performance and difficulty in continuous learning that exist in the phenomenological and neural network surrogate models. Therefore, this study proposes a lightweight adaptive thermochemical information aggregation networks (ATANets) to overcome the gradient conflict challenge, and combines the generative knowledge distillation (GKD) algorithm to compress the model to capture finer-grained and enriched information on kinetics behaviors, which yields a thermochemical feature information extraction networks (FENets) with incremental learning capability. The experimental results demonstrated that as the complexity of the learning task deepened, the FENets models obtained by incremental training with ATANets and GKD still had excellent continuous learning capability, with the relative variations of the coefficients of determination and the mean square error being smaller than 6.7×10-3 and 0.3860×10-3, respectively. Meanwhile, the accurate characterization of cure kinetics behaviors was achieved in the thermochemical coupling analysis of CFRP, with the maximum values of the average and maximum temperature differences of 0.0176 °C and 0.2538 °C, respectively. Overall results show that our proposed incremental model is remarkably preferable to existing models and is beneficial in promoting the widespread reuse of the existing knowledge of cure kinetics behavior of resins in this domain.这项工作的重点是解决现象学和神经网络代理模型中存在的泛化性能差和持续学习困难的痛点。因此，本研究提出了一种轻量级的自适应热化学信息聚合网络(ATANets)来克服梯度冲突挑战，并结合生成知识蒸馏(GKD)算法对模型进行压缩，以捕获更细粒度和更丰富的动力学行为信息，从而产生具有增量学习能力的热化学特征信息提取网络(FENets)。实验结果表明，随着学习任务复杂度的加深，使用ATANets和GKD增量训练得到的fenet模型仍然具有优异的连续学习能力，决定系数和均方误差的相对变化量分别小于6.7×10-3和0.3860×10-3。同时，在CFRP的热化学偶联分析中，实现了固化动力学行为的准确表征，平均温差最大值为0.0176℃，最大温差最大值为0.2538℃。总体结果表明，我们提出的增量模型明显优于现有模型，有利于促进该领域树脂固化动力学行为现有知识的广泛重用。Composites Part A: Applied Science and ManufacturingA self-supervised learning framework based on physics-informed and convolutional neural networks to identify local anisotropic permeability tensor from textiles 2D images for filling pattern predictionJohn M. Hanna, José V. Aguado, Sebastien Comas-Cardona, Yves Le Guennec, Domenico Borzacchiellodoi:10.1016/j.compositesa.2024.108019基于物理信息和卷积神经网络的自监督学习框架，从纺织品二维图像中识别局部各向异性渗透率张量，用于填充图案预测In liquid composite molding processes, variabilities in material and process conditions can lead to distorted flow patterns during filling. These distortions appear not only within the same part but also from one part to another. Notably, minor deviations in the dry fibrous textiles cause local permeability changes, resulting in flow distortions and potential defects. Traditional permeability models fall short in predicting these localized fluctuations, especially for anisotropic textiles, whereas reliance on homogeneous permeability models creates substantial discrepancies between forecasted and observed filling patterns. This study presents a self-supervised framework that determines in-plane permeability tensor field of textiles from an image of that textile in dry state. Data from central injection experiments is used for training, including flow images and pressure inlet data. This work demonstrates that this model proficiently predicts flow patterns in unobserved experiments and captures local flow distortions, even when trained on a relatively small dataset of experiments.在液体复合成型过程中，材料和工艺条件的变化会导致填充过程中流动模式的扭曲。这些扭曲不仅出现在同一部分，而且从一个部分到另一个部分。值得注意的是，干燥纤维纺织品中的微小偏差会导致局部渗透性变化，从而导致流动扭曲和潜在缺陷。传统渗透率模型在预测这些局部波动方面存在不足，特别是对于各向异性纺织品，而依赖均质渗透率模型会在预测和观察到的填充模式之间产生巨大差异。本研究提出了一种自监督框架，从纺织品干燥状态的图像中确定纺织品的面内渗透率张量场。中心注射实验数据用于训练，包括流动图像和入口压力数据。这项工作表明，即使在相对较小的实验数据集上训练，该模型也能熟练地预测未观察到的实验中的流动模式，并捕获局部流动扭曲。Composites Part B: EngineeringConcerns in tension-tension fatigue testing of unidirectional composites: Specimen design and test setupBabak Fazlali, Stepan V. Lomov, Yentl Swolfsdoi:10.1016/j.compositesb.2024.111213单向复合材料拉伸-拉伸疲劳试验中的问题:试样设计和试验设置Tension-tension fatigue of unidirectional (UD) composites is often used to represent the fatigue behavior of composites. The standard proposes to use end tabs for UD composites. However, obtaining a reliable S–N curve requires avoiding premature failure, which in turn requires minimizing stress concentrations near the grips and end tabs. This work examines the fatigue life of different specimen and end tab designs. Conventional end tabs and other well-known designs, along with novel arrow end tabs, are tested to identify the method that is least influenced by the stress concentrations and yields the highest and the most valid fatigue life. Rectangular specimens with rectangular and tapered end tabs, which is the standard configuration, yielded the highest fatigue life. This differs from the preferences in the quasi-static test, where arrow end tabs performed the best. Moreover, the effect of parameters in the manufacturing process and test setup on the fatigue life of two different carbon fiber/epoxy prepregs material systems are discussed. The results reveal the significant effect of the test setup on tension-tension fatigue of UD composites and will inform the community on how to perform more reliable fatigue tests.单向复合材料的拉伸-拉伸疲劳常被用来表示复合材料的疲劳行为。该标准建议在UD复合材料中使用结束标签。然而，获得可靠的S-N曲线需要避免过早失效，这反过来又需要最小化握把和末端卡箍附近的应力集中。本工作考察了不同试样和端片设计的疲劳寿命。测试了传统的端卡和其他知名的设计，以及新型的箭头端卡，以确定受应力集中影响最小的方法，并产生最高和最有效的疲劳寿命。具有矩形和锥形端片的矩形试样是标准配置，产生了最高的疲劳寿命。这与准静态测试中的首选项不同，在准静态测试中，箭头结束选项卡表现最好。此外，还讨论了制造工艺参数和试验设置对两种不同碳纤维/环氧预浸料材料体系疲劳寿命的影响。研究结果揭示了试验设置对UD复合材料拉伸-拉伸疲劳的显著影响，并将为如何进行更可靠的疲劳试验提供指导。Composites Science and TechnologyBayesian optimization-based prediction of the thermal properties from fatigue test IR imaging of composite couponsMartin Demleitner, Rodrigo Q. Albuquerque, Ali Sarhadi, Holger Ruckdäschel, Martin A. Ederdoi:10.1016/j.compscitech.2024.110439 基于贝叶斯优化的复合材料疲劳红外成像热性能预测The prediction of the prevailing self-heat transfer parameters of a glass/epoxy composite coupon during fatigue testing in general and the distinction between viscoelastic- and frictional crack growth-related energy dissipation in particular, are not trivial problems. This work investigates the feasibility of predicting the convective film coefficient, the total work loss as well as the ratio between viscoelastic and fracture-induced damping from thermal images using Bayesian optimization in conjunction with 3D FE thermal analysis. To this end, glass fiber/epoxy biax coupons are pre-damaged by means of a drop weight impact machine and subsequently tested under uniaxial tension-tension high cycle fatigue conditions. IR images are taken of the self-heating thermal profile at steady-state conditions. Synthetic surface thermal images are generated by numerical thermal analysis of the damage distribution obtained byμ-CT scanning prior to testing. Bayesian optimization of the aforementioned parameters is conducted by minimizing the loss function between the as-measured and the synthetic IR image. The predicted work-loss is consequently validated against the measured hysteretic response, from which a very good agreement is found.预测玻璃/环氧复合材料在疲劳试验中普遍存在的自传热参数，特别是区分粘弹性和摩擦裂纹扩展相关的能量耗散，不是一个简单的问题。本研究研究了利用贝叶斯优化结合三维有限元热分析，从热图像中预测对流膜系数、总功损失以及粘弹性和裂缝诱导阻尼之间的比率的可行性。为此，采用落锤冲击试验机对玻璃纤维/环氧双轴材料进行预损伤，并在单轴拉伸-拉伸高周疲劳条件下进行试验。对稳态条件下的自热热廓线进行了红外成像。对得到的损伤分布进行数值热分析，生成合成的表面热图像μ-测试前的ct扫描。上述参数的贝叶斯优化是通过最小化实测图像与合成红外图像之间的损失函数来实现的。因此，预测的工作损失与测量的滞后响应进行了验证，从中发现了非常好的一致性。来源：复合材料力学仿真Composites FEM