Micromechanical analysis of composite materials considering material variability and microvoids
参考中译:考虑材料变异性和微空隙的复合材料微观力学分析


          

刊名：International Journal of Mechanical Sciences
作者：O. Vallmajo（AMADE, Polytechnic School, University of Girona, C/Universitat de Girona 4）
A. Arteiro（DEMec, Faculdade de Engenharia, Universidade do Porto）
J. M. Guerrero（AMADE, Polytechnic School, University of Girona, C/Universitat de Girona 4）
A. R. Melro（Bristol Composites Institute (ACCIS), University of Bristol）
A. Pupurs（Laboratory of Experimental Mechanics of Materials, Riga Technical university）
A. Turon（AMADE, Polytechnic School, University of Girona, C/Universitat de Girona 4）
刊号：780C0005
ISSN：0020-7403
出版年：2024
年卷期：2024, vol.263
页码：108781-1--108781-14
总页数：14
分类号：TH111
关键词：Fiber reinforced polymers (FRP)；Microvoids；Mechanical properties；Micro-mechanics
参考中译：纤维增强聚合物（玻璃钢）;微空洞;机械性能;微观力学
语种：eng
文摘：One of the main challenges for fiber-reinforced polymers (FRP) is the difficulty to predict their mechanical behavior. At the microscale, the properties of the constituents, their spatial distribution and the defects arising from manufacturing affect the mechanical behavior. In this work, statistically representative volume elements (SRVEs) are proposed based on a micromechanical finite element model to determine the effect of content, distribution and size of microstructural defects and, material uncertainties on the elastic mesoscale properties of FRPs. To that end, different cylindrical void sizes are considered as well as irregular shaped voids between fiber tows (inter-fiber voids). Fibers and voids are randomly distributed in a SRVE. An uncertainty quantification and management analysis is employed to obtain statistical descriptors of the effective mesoscale mechanical properties of FRPs. The results obtained are compared with analytical models. It is demonstrated that, for carbon fiber/epoxy composites, SRVEs with lateral dimensions equivalent to 15 times the average fiber diameter and a length of 0.01 mm along the longitudinal direction remain statistically representative with or without the presence of voids. The results show that the presence of voids reduces the transverse and shear elastic properties of FRPs. The smaller the voids are, the bigger is the reduction. Regarding the presence of inter-fiber voids, the reduction is lower. This trend is well predicted by the Mori-Tanaka mean field theory. However, the relative difference between the numerical and the analytical predictions increases for high void volume fractions. Regarding the effective longitudinal Young's modulus, the rule of mixtures, the Mori-Tanaka mean field theory and the concentric cylinder assembly model provide similar predictions for the mean value, but the uncertainty is overestimated by the analytical models because the properties of the fibers take a single value for each calculation with the analytical model, while they more realistically change from fiber to fiber in the numerical SRVEs.
参考中译：纤维增强聚合物(FRP)的主要挑战之一是难以预测其力学行为。在微观尺度上，成分的性质、空间分布以及制造过程中产生的缺陷会影响材料的力学行为。本文提出了基于细观力学有限元模型的统计代表性体积元，以确定微结构缺陷的含量、分布和尺寸以及材料不确定性对玻璃纤维增强塑料弹性细观性能的影响。为此，考虑了不同的圆柱形空隙大小以及光纤丝束之间的不规则形状空隙(光纤间空隙)。纤维和空隙在SRVE中随机分布。通过不确定性量化和管理分析，获得了FRPS有效细观力学性质的统计描述子。将所得结果与解析模型进行了比较。结果表明，对于碳纤维/环氧复合材料，横向尺寸相当于平均纤维直径的15倍，纵向长度为0.01 mm的复合材料在有或没有孔洞存在的情况下仍具有统计代表性。结果表明，孔洞的存在降低了FRPS的横向和剪切弹性性能。空隙越小，减少的幅度越大。对于纤维间空隙的存在，缩减率较低。森田中平均场理论很好地预测了这一趋势。然而，对于较高的空泡体积分数，数值预测和分析预测之间的相对差异增大。对于有效纵向杨氏S模数，混合物规则、Mori-Tanaka平均场理论和同心圆柱体组装模型对平均值提供了类似的预测，但分析模型高估了不确定性，因为解析模型每次计算纤维的性质都取一个值，而在数值模型中，它们更接近于从纤维到纤维的变化。



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