Abstract Chopped carbon fiber sheet molding compound has a great potential in lightweight automotive, marine, and aerospace applications. One of the most challenging tasks is to predict the failure strength of the material due to its anisotropy and heterogeneity, as well as complex stress states in real-world working conditions. In this paper, a novel constitutive model of carbon fiber chip is proposed to capture the pre- and post-failure behaviors under different loading modes. On this basis, we propose a new computational micromechanics model, which is calibrated and validated by uniaxial tensile, compressive, and in-plane shear experiments. Furthermore, a set of microstructures representative volume element (RVE) models under complex loading conditions are reconstructed to understand the relationship between the microstructure characteristics and the failure envelopes. Finally, several modified versions of classical failure criteria are proposed for anisotropic materials with consideration of the fiber orientation tensor. The modified Tsai-Wu failure criterion, which shows the best accuracy among all failure criteria, is highlighted in the comparative study.

中文翻译：

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基于计算微力学模型的短切碳纤维片状模塑料复合材料失效准则

摘要 短切碳纤维片状模塑料在轻量化汽车、船舶和航空航天应用中具有巨大的潜力。最具挑战性的任务之一是预测材料由于其各向异性和异质性以及实际工作条件下的复杂应力状态而导致的失效强度。在本文中，提出了一种新的碳纤维芯片本构模型，以捕获不同加载模式下的失效前和失效后行为。在此基础上，我们提出了一种新的计算微力学模型，该模型通过单轴拉伸、压缩和面内剪切实验进行校准和验证。此外，重构复杂载荷条件下的一组微观结构代表体积元 (RVE) 模型，以了解微观结构特征与失效包络之间的关系。最后，考虑到纤维取向张量，针对各向异性材料提出了经典失效准则的几种修改版本。比较研究中强调了修改后的 Tsai-Wu 失效准则，它在所有失效准则中显示出最佳的准确性。