Abstract In this work, a new criterion to predict fatigue crack initiation in plain Short Fibre Reinforced Thermoplastics is proposed. Several experimental observations in the literature showed that the initiation of a macro crack results from the accumulation of damage in the matrix at the micro-scale. Accordingly, in the proposed criterion the life to crack initiation is predicted through an effective stress acting in the most critical regions in the matrix (close to the fibre ends and lateral surfaces). More precisely, the effective stress is evaluated within a control volume defined as a certain percentage of the matrix volume subjected to the highest stresses. A multi-scale (macro-meso-micro) procedure is adopted for estimating the local stress fields in the polymer. The criterion was proved to successfully predict the influence of the material microstructure (fibre content and orientation distribution) and load orientation.

中文翻译：

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模拟微结构对短纤维增强热塑性塑料中高周疲劳裂纹萌生的影响

摘要 在这项工作中，提出了一种预测普通短纤维增强热塑性塑料疲劳裂纹萌生的新准则。文献中的一些实验观察表明，宏观裂纹的萌生是由微观尺度上基体中损伤的积累造成的。因此，在建议的标准中，通过作用在基体中最关键区域（靠近纤维末端和侧面）的有效应力来预测裂纹萌生的寿命。更准确地说，有效应力是在控制体积内评估的，该控制体积定义为承受最高应力的基质体积的某个百分比。采用多尺度（宏观-中观-微观）程序来估计聚合物中的局部应力场。