复合材料层合板刚度降理论模型研究

复合材料在静态和动态载荷作用下的损伤形式是十分复杂的，精确的模型能更深刻地揭示复合材料的损伤机理。以Hahn和Tsai提出的单向损伤模型为基础建立了刚度递降关系，运用上述刚度递降关系给出了一个疲劳寿命算例，计算数据与试验结果较为吻合，相对误差分别为7．72％和8．79％。结果表明：材料在循环加载作用下的损伤过程大体上可以分为两个阶段；通过保留泰勒级数展开二次项，能准确模拟出材料的“突然死亡”行为。

On Stiffness Reduction of Composite Laminates

No matter composite laminates is subjected to static or dynamic load,damage is significantly complex. Accurate modeling for fatigue damage can reveal the damage mechanism of composite laminates. Firstly,a model based on Hahn and Tsais unidirectional damage model is established,showing the relationship between stiffness reduction ratios and applied maximum loads. Secondly,an example of fatigue life calculating with above model is given. Compared with the test results,the relative errors of calculating are 7.72% and 8.79% respectively. The results show that the damage process of material subjected to cycle load is able to be divided two phases. Withholding Second-Order Terms of Taylor Series Expansion,the model can exactly simulate abruptly death behavior of composites.