一种FRP累积损伤模型及其在结构疲劳寿命估算中的应用  

A FRP Cumulative Damage Model and Its Application to Fatigue Life Evaluation of Composite Laminates

作　　者：李亚智[1] 张开达[1] 张博平[1] 

机构地区：[1]西北工业大学,西安710072

出　　处：《应用力学学报》2003年第1期54-58,共5页Chinese Journal of Applied Mechanics

基　　金：航空基金 (98B530 2 0 )资助

摘　　要：推荐了一种应变损伤累积模型 ,能够考虑单向板面内多轴应力和平均应力的影响。只需要单向板在确定应力比下的若干典型疲劳试验结果 ,就可以预测相同材料体系多向层压结构在不同应力比的循环载荷下的疲劳寿命 ,有助于降低试验成本和工作量。研究了适用于多向层压结构剩余强度估算和疲劳寿命预测的步骤和程序。针对碳纤维 树脂基T3 0 0 QY891 1复合材料 ,试验测定了三组典型单轴循环应力 ([0 ]1 6拉 拉、[90 ]1 6拉 拉和 [0 90 ]4S剪 剪 )下的S—N曲线。以此为输入 ,预测四种多向铺层板在各种拉 -拉循环应力下的疲劳寿命 ,寿命预测结果和相应的试验结果吻合良好。采用了保持计算和试验的载荷 /强度比相对等值的方法来近似抵消层合效应对疲劳寿命的影响。强调了进一步发展能够定量估计层间应力影响与分层扩展过程的疲劳损伤模型的重要性。A cumulative damage model is proposed, which can be us ed to consider the influence of in plane bi-axial stresses and mean stress on the fatigue behavior of unidirectional laminates. With only minimum typical fatigue tests at certain stress ratio for unidirectional laminates, it is possible to p redict the fatigue life of multi-directional laminates subjected to cyclic stre sses of different stress ratios. This would significantly reduce test costs for laminate structures. The procedure and the correspondent computer codes have bee n developed to evaluate the residual strength and fatigue life of multi-directi onal laminates. For T300 /QY8911 Carbon/Bismalimide composites, three kinds of t ypical tests (fatigue of 16 tension-tension, 16 tension-tension an d 4s shear-shear) are performed to obtain the S-N curves for unidirect ional laminates, which are used as input for the above procedure. Both tests and calculations are performed to get the fatigue lives for four kinds of multi-di rectional laminate coupons with different tensile cyclic stress applied. The pre diction lives agree well with the experimental results. It is also realized that an analytical model is essential to simulate the effect of stacking sequence an d the subsequent inter-lamina stresses on fatigue behavior of laminates. In vie w of the resultant fatigue life, a relative load/strength ratio technique is int roduced in the present analysis to diminish this effect.

关 键 词：疲劳寿命估算 损伤模型 多向层压板 

分 类 号：V214.8[航空宇航科学与技术—航空宇航推进理论与工程]