热塑性复合材料高速冲击时不同失效模式对比分析研究

目的准确地对热塑性复合材料前缘结构进行抗鸟撞冲击设计。方法首先基于刚度退化、材料塑性及应变率影响的复合材料本构关系,通过霍普金森拉-压杆测试得到热塑性复合材料的动力学性能参数。基于不同的失效模式,采用PAM-CRASH显式有限元法,针对运输类飞机热塑性复合材料机翼前缘结构在高速冲击时的破坏形式进行对比分析研究。结果热塑性复合材料较其他复合材料在临界拉伸损伤极限值和纵横向及屈服应力的率相关性上具有更好的性能。冲击分析时,失效应变应考虑材料破坏瞬间的强化效应。剪切应变取值为0.1左右时,前缘结构计算仿真失效的结果与试验结果一致性较高,应变误差仅为6.2%,破坏尺寸误差为4.9%。结论在复合材料失效参数较复杂的情况下,抗冲击设计可将拉伸、压缩、剪切及层间失效等多目标优化设计简化为等效剪切应变失效的单目标优化,此方法可推广应用于其他类型复合材料的抗冲击设计。

Comparative Analysis of Different Failure Modes of Thermoplastic Composites under High Speed Impact

Composite materials are widely used in aircraft design, and their failure modes have been the focus of the industry. Bird strike, as a kind of high-speed impact, is typical foreign material damage to composite materials. Firstly, the dynamic property parameters of thermoplastic composites are obtained by Hopkinson pull-bar test based on the constitutive relationship of composite material with the influence of stiffness degradation, material plasticity and strain rate.,which shows that thermoplastic composite materials have superior critical tensile damage limits and strain rate dependence of longitudinal and transverse and yield stress. Moreover, analysis of different failure modes of thermoplastic composites under high-speed impact is also carried out to study the design of the leading edge of transport aircraft against bird impact. Then the paper studies the failure mode structures on the different failure criteria and obtains the equivalent shear strain of 0.1, which is in good agreement with the experimental results, with a strain error of 6.2% and a failure size error of 4.9%. The methods can be applied to other types of composite materials for impact-resistant design.