Fatigue model of steel honeycomb sandwich beams at high temperature
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摘要: 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.
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关键词:
- 损伤演化
Abstract: In this work fatigue behaviors of steel honeycombsandwich beams at high temperature are investigated through three-pointbending tests. The results show that fatigue properties are significantlyinfluenced by different core configurations. Specimens with W-direction arefit for fatigue loads. A fatigue modulus reduction approach is adopted whichis based on the interpolation by the empirical functions of experimentalresults, whose coefficients depends on the material properties and loadingconditions. This approach permits to predict the fatigue life of the steelsandwich structures while avoiding a large number of experiments. Theresults show a second-order polynomial function is fit for describingresidual modulus degradation rules of L-direction specimens, whileexponential function for W-direction specimens. Two non-linear cumulativedamage models, derived from the chosen stiffness degradation equation, areexamined in context with the linear Miner damage rule and compared withexperimental results. The developed models give a reasonable explanation forthe damage of steel honeycomb sandwich beam under high temperature.-
Key words:
- damage evolution
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