Kurkin Evgenii, Spirina Mariia, Espinosa Barcenas Oscar Ulises, Kurkina Ekaterina
Joint Russian-Slovenian Laboratory Composite Materials and Structures, Samara National Research University, 34 Moskovskoe Shosse, Samara 443086, Russia.
Polymers (Basel). 2022 Apr 27;14(9):1781. doi: 10.3390/polym14091781.
Short-fiber reinforced composites are widely used for the mass production of high-resistance products with complex shapes. Efficient structural design requires consideration of plasticity and anisotropy. This paper presents a method for the calibration of a general material model for stress-strain curve prediction for short-fiber reinforced composites with different fiber mass fractions. A Mori-Tanaka homogenization scheme and the J2 plasticity model with layered defined fiber orientation were used. The hardening laws: power, exponential, and exponential and linear were compared. The models were calibrated using experimental results for melt front, orientation tensor analysis, fiber length, and diameter and tension according to ISO 527-2, for samples of PA6 which were either non-reinforced, or reinforced with 10%, 15%, 20%, and 30% carbon fiber mass fractions. The novelty of this study lies in the transition from the strain-stress space to the strain-stress-fiber fraction space in the approximation of the material model parameters. We found it necessary to significantly reduce the fiber aspect ratio for the correct prediction of the mechanical characteristics of a composite using the Mori-Tanaka scheme. This deviation was caused by the ideal solution of ellipsoidal inclusion in this homogenization scheme. The calculated strength limits using Tsai-Hill failure criteria, based on strain, could be used as a first approximation for failure prediction.
短纤维增强复合材料广泛应用于复杂形状的高抗性产品的大规模生产。高效的结构设计需要考虑塑性和各向异性。本文提出了一种校准通用材料模型的方法，用于预测不同纤维质量分数的短纤维增强复合材料的应力-应变曲线。采用了Mori-Tanaka均匀化方案和具有分层定义纤维取向的J2塑性模型。比较了幂硬化定律、指数硬化定律以及指数和线性硬化定律。根据ISO 527-2，使用未增强或用10%、15%、20%和30%碳纤维质量分数增强的PA6样品的熔体前沿、取向张量分析、纤维长度、直径和拉伸的实验结果对模型进行校准。本研究的新颖之处在于在材料模型参数近似中从应变-应力空间过渡到应变-应力-纤维分数空间。我们发现，使用Mori-Tanaka方案正确预测复合材料的力学特性时，有必要显著降低纤维长径比。这种偏差是由该均匀化方案中椭圆形夹杂的理想解引起的。基于应变使用Tsai-Hill失效准则计算的强度极限可作为失效预测的一阶近似。
