Injection-moulded short-fibre composites are lightweight materials suitable for high-volume applications; however, current simulation methods (based on failure initiation criteria) to design components using these materials cannot yet accurately predict failure. This work presents a methodology to predict failure of injection-moulded short-glass-fibre reinforced thermoplastic (IM-SFRP) composite subcomponents, based on experimentally measured properties. The material's fracture toughness was characterized by Compact Tension tests for different fibre orientations and environmental conditions. These fracture toughnesses were used as the input for cohesive zone modelling in Finite Element simulations of subcomponents representative of automotive applications, coupled with fibre orientation fields predicted by an injection-moulding process simulation. These coupled simulations presented excellent agreement with the experimental results for subcomponents both in terms of (i) the peak load (highlighting the importance of accounting for the finite fracture toughness of the material to accurately predict the ultimate failure of the subcomponents), and (ii) the pre- and post-peak sequence of failure events (verified using fractographic analyses). This work also verified the applicability of temperature-moisture equivalence, not only for material characterisation using coupons including the material's fracture toughness, but also for the mechanical response of subcomponents until final failure. The methodology demonstrated in this paper contributes to designing safer and more efficient damage-tolerant IM-SFRP components.

中文翻译：

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通过断裂力学预测注射成型短纤维子组件在不同环境条件下的失效

注塑短纤维复合材料是适合大批量应用的轻质材料；然而，当前使用这些材料设计组件的模拟方法（基于故障引发标准）尚无法准确预测故障。这项工作提出了一种基于实验测量的性能来预测注塑短玻璃纤维增​​强热塑性塑料 (IM-SFRP) 复合材料子组件故障的方法。通过针对不同纤维取向和环境条件的紧凑拉伸测试来表征材料的断裂韧性。这些断裂韧性被用作代表汽车应用的子部件的有限元模拟中粘性区建模的输入，再加上注塑工艺模拟预测的纤维取向场。这些耦合模拟在以下方面与子部件的实验结果非常吻合：(i) 峰值载荷（强调考虑材料的有限断裂韧性以准确预测子部件的最终失效的重要性），以及 (ii) ) 故障事件的峰值前和峰值后序列（使用断口分析进行验证）。这项工作还验证了温度-湿度等效性的适用性，不仅适用于使用试样（包括材料的断裂韧性）进行材料表征，而且适用于子部件直至最终失效的机械响应。本文演示的方法有助于设计更安全、更高效的耐损伤 IM-SFRP 组件。