This work presents a framework that allows designers to accurately estimate the fatigue lifetime of injection molded short fiber reinforced parts. The framework and its calibration are demonstrated on a large set of experimental data, increasing the complexity in loading conditions, anisotropy, and stress state, and demonstrated on two demonstrator parts. By step-by-step increasing complexity in both experiments and simulations, the features that are essential for accurate lifetime prediction are discussed in detail. It is shown that it is essential to accurately capture the influence of load ratio and anisotropy on fatigue lifetime. Subsequently, one needs to consider the correct local stress state by compensating for plasticity and the resulting non-linearity either by a plasticity correction method in the case of local plasticity or by employing an elastoplastic material model. In addition, to be accurate in the presence of stress concentrations, one needs to correct for the stress gradient, here demonstrated using a highly stressed volume concept, automatically offering potential to reduce sensitivity to mesh size. The accuracy of the lifetime predictions on complex shaped parts, with realistic loading conditions, shows that it is crucial to consider the load ratio at the local level.

中文翻译：

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用于精确预测注塑成型短玻璃纤维增强塑料零件疲劳寿命的框架

这项工作提出了一个框架，使设计人员能够准确估计注射成型短纤维增强部件的疲劳寿命。该框架及其校准在大量实验数据上进行了演示，增加了加载条件、各向异性和应力状态的复杂性，并在两个演示部件上进行了演示。通过逐步增加实验和仿真的复杂性，详细讨论了准确寿命预测所必需的功能。结果表明，准确捕捉载荷比和各向异性对疲劳寿命的影响至关重要。随后，在局部塑性的情况下，通过塑性校正方法或采用弹塑性材料模型，通过补偿塑性和由此产生的非线性，来考虑正确的局部应力状态。此外，为了在应力集中的情况下准确，需要校正应力梯度，这里使用高应力体积概念进行了演示，自动提供了降低对网格尺寸的敏感性的潜力。在实际载荷条件下，对复杂形状零件的寿命预测的准确性表明，在局部水平考虑载荷比至关重要。