【新文速递】2024年6月4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 2 篇

Composite Structures

Reinforced crack propagation in a prestressed and prepolarized piezoelectric material

Gilbert Marius Daniel Ghita, Eduard-Marius Craciun

doi:10.1016/j.compstruct.2024.118248

预应力和预极化压电材料中的增强裂纹扩展

In this paper the problem of an antiplane reinforced crack in prestressed and prepolarized piezoelectric materials is considered. Using the boundary conditions of the reinforced crack we get the homogeneous and a nonhomogeneous Riemann-Hilbert problems. Nonhomogeneous linear complex differential equations having the unknown complex potentials are obtained. For a constant value of the applied incremental forces can be obtained the complex potentials, incremental displacement and stress fields corresponding to the third mode of the classical fracture. Extending Sih’s strain energy density failure criterion for prestressed and prepolarized piezoelectric materials we study the antiplane reinforced crack propagation in a PZT type piezoelectric material. Using numerical results and the graphical representation of incremental strain energy density, the direction of antiplane reinforced crack initiation can be predicted versus different values of stiffness constant and for different small values of initial mechanical and electrical fields.

本文研究了预应力和预极化压电材料中的反平面增强裂纹问题。利用加筋裂纹的边界条件，得到了齐次和非齐次黎曼-希尔伯特问题。得到了具有未知复势的非齐次线性复微分方程。当施加的增量力为一定值时，可以得到与经典断裂第三模态相对应的复势场、增量位移场和应力场。推广Sih的预应力和预极化压电材料应变能密度破坏准则，研究了PZT型压电材料的反平面增强裂纹扩展。利用数值结果和增量应变能密度的图形表示，可以预测不同刚度常数值和不同初始电场和电场小值下反平面增强裂纹的起裂方向。

Composites Part A: Applied Science and Manufacturing

Fibre geometry and its contribution to the global unidirectional tensile properties of enset fibre-reinforced epoxy composites

Mengstu Ashebre Arefe, Mulualem G. Gebreslassie, Aart Willem Van Vuure

doi:10.1016/j.compositesa.2024.108294

纤维几何形状及其对enset纤维增强环氧复合材料整体单向拉伸性能的影响

This study investigated the potential forms of enset fibres and their tensile properties. Microscopic images of the fibre cross-section were collected, and image analysis was carried out in MATLAB. As a result, four distinct fibre shapes were identified and their likelihood of occurring as well as- their area contribution to the fibre bundle were determined. These fibres have distinct tensile strength, Young’s modulus, and strain-to-failure values, distinguishing the strongest and weakest fibres. The strength distribution of these fibre shapes does not conform to the Weibull theory. However, it follows the scenario that fibres with the biggest perimeter-to-area ratio provide the weakest values and vice versa. This shows that the tensile properties of fibres are influenced not only by their material properties but also by their geometric shape. As a result, fibres of different shapes contribute differently to the global tensile properties of the fibre-polymer composites.

本研究探讨了嵌套纤维的潜在形式及其拉伸性能。采集了纤维截面的显微图像，并在MATLAB中进行了图像分析。结果，确定了四种不同的纤维形状，并确定了它们发生的可能性以及它们对纤维束的面积贡献。这些纤维具有不同的拉伸强度、杨氏模量和应变破坏值，从而区分出最强和最弱的纤维。这些纤维形状的强度分布不符合威布尔理论。然而，它遵循这样一种情况，即具有最大周长面积比的纤维提供最弱的值，反之亦然。这表明纤维的拉伸性能不仅受其材料特性的影响，而且受其几何形状的影响。因此，不同形状的纤维对纤维-聚合物复合材料的整体拉伸性能有不同的贡献。

Electrical curing of carbon fibre composites with conductive epoxy resins

Yunlong Tang, J. Patrick A. Fairclough

doi:10.1016/j.compositesa.2024.108296

导电环氧树脂碳纤维复合材料的电固化

Direct electric cure (DEC) was used to cure carbon fibre-reinforced polymers (CFRPs). We show that the energy consumption for curing is significantly reduced, with the judicious placement of contact electrodes, by almost twelve-fold, compared to autoclave curing, and threefold compared to oven curing (0.84, 10.0, and 2.64 kW). CFRP samples of an epoxy matrix with 0-3 wt% carbon black (CB) was used to increase matrix conductivity, and the effect of this variation on the curing and mechanical properties was determined. Subsequently, the concentration with the highest flexural strength, a CFRP with 2 wt% CB was prepared, to study the effects of four different contact arrangements (Top-Bottom, Outside-Outside, Outside-Inside, Inside-Inside) under high pressure (about 2 MPa). Top-Bottom mode shows the best performance, here the electrical current flows through the ply stack perpendicular to the fibre direction. This CFRP has similar mechanical properties as samples manufactured by a range of traditional curing methods. Although the degree of cure (DOC) was reduced by 3–7 %, dependent on the placement of the electrical contacts, the through ply cures showed uniform and high degrees of cure. We show that DEC, thus provides a low capital investment solution to high-quality composite manufacture, facilitating market access for small enterprises, as part sizes and curing times are not limited by oven size nor oven thermal mass.

采用直接电固化(DEC)技术对碳纤维增强聚合物(CFRPs)进行固化。我们表明，与高压罐固化相比，明智地放置接触电极，固化的能耗显着降低了近12倍，与烘箱固化相比降低了3倍(0.84,10.0和2.64 kW)。采用0-3 wt%炭黑(CB)的环氧基CFRP样品提高基体电导率，并测定了这种变化对固化和力学性能的影响。随后，制备了具有最高抗弯强度浓度的CFRP，即2 wt% CB的CFRP，研究了高压(约2 MPa)下Top-Bottom、Outside-Outside、Outside-Inside、Inside-Inside四种不同接触方式对CFRP抗弯强度的影响。顶-底模式表现出最好的性能，在这里电流流过垂直于纤维方向的堆叠层。这种碳纤维增强塑料具有类似的机械性能样品制造的一系列传统的固化方法。虽然根据电触点的位置，固化度(DOC)降低了3-7 %，但通过层的固化表现出均匀和高度的固化。我们表明，DEC因此为高质量复合材料制造提供了低资本投资的解决方案，促进了小型企业的市场准入，因为零件尺寸和固化时间不受烤箱尺寸和烤箱热质量的限制。