A stiffness degradation model with two parameters is presented to describe the composite laminate's characteristic stiffness degradation rule under cyclic loading. The normalized stiffness degradation curves processed by this model agrees well with each other for different specimens under the same fatigue loading. Therefore a new fatigue life prediction method is presented considering the specimen' s individual historical fatigue information and the stiffness degradation rule. Four kinds of E-glass/Epoxy laminates and five kinds of laminates with central holes are tested to verify the presented method. Results show that the fatigue life of composite specimen can be accurately predicted when considering its individual historical information. The prediction results agree fairly well with the experimental results by adopting the residual stiffness data about the characteristic damage state (CDS) only.%通过疲劳试验获得了复合材料层合板刚度退化的两参数模型,基于此模型提出了复合材料结构剩余疲劳寿命监测的剩余刚度方法,它以实验室中获得的归一化的剩余刚度曲线为基准,结合复合材料结构疲劳危险点的实测剩余刚度值,预测该危险部位的剩余疲劳寿命.该方法抓住了复合材料结构刚度退化的本质,借助实测刚度值,消除了疲劳性能分散性的大部分影响.通过4种玻璃/环氧复合材料光滑试验件和中心孔试验件的疲劳试验结果对该方法进行了验证.结果显示,本方法可以准确地预测复合材料结构的剩余寿命,且仅需利用前20％左右的剩余刚度数据,预测结果便与试验结果吻合较好.
展开▼
