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针对钎焊钢质蜂窝夹芯梁开展高温三点弯曲疲劳实验研究.结果表明芯子排列方向显著影响结构疲劳性能,高温下W向试件易于承受循环载荷.提出基于疲劳模量退化的寿命预测经验函数方法,其参数与材料性质、载荷环境等因素有关.该方法可以预测结构疲劳寿命而避免大量重复性实验.结果表明:对于L向试件,剩余模量退化规律可用二阶多项式拟合;而W向试件则倾向于用指数型函数描述.从刚度退化方程中得到非线性累积损伤模型,并与线性Miner准则和试验结果进行了比较,合理解释了蜂窝夹芯梁的高温损伤问题.
The experimental study on three-point bending fatigue test of high temperature brazed steel honeycomb sandwich beam was carried out. The results show that the direction of core arrangement significantly affects the structural fatigue performance, and the W specimen tends to bear cyclic loading under high temperature. Empirical function method, whose parameters are related to material properties, load environment and other factors, can predict the fatigue life of structures and avoid a large number of repetitive experiments.The results show that for L-shaped specimens, the residual modulus degradation can be fitted by second order polynomial While W direction specimen tends to be described by exponential function.The nonlinear cumulative damage model is obtained from the stiffness degradation equation and compared with the linear Miner criterion and the experimental results to reasonably explain the high temperature damage of the honeycomb sandwich beam .