复合材料强度准则中参数α_1和α_2对可靠性指标的影响

The Influence of Parameters α_1 and α_2 on Reliability Index in the Strength Criterion of Composite Material

运用随机有限元法 ,对单向纤维复合材料组成的层合板结构进行了可靠性分析 .给出了复合材料强度准则中待定参数α1和α2 对结构可靠性指标 β的影响 ,其结果是α1和α2 对 β的影响作用正好相反 .即不论对改进的还是简化的蔡—吴失效准则 ,都会得到下面的结论 :当固定α2 变化α1时 ,如果 β随α1的增加而增加 ,则在相同情况下 ,当固定α1变化α2 时 ,该 β却随着α2 的增加而减小 ,反之亦然 .将上述规律运用到实际工程中 ,既可使材料的性能得到充分发挥 ,又可使某些具体复合材料结构的可靠性得到保证 .

The stochastic finite element method is used to analyze the composite structural reliability. Here the laminate structure is made of unidirectional fiber composites. The unknown parameters α 1 and α 2 , which appear in the strength criterion of composite, affect the structural reliability index β . At the same time, the affected result is similar both for improved and for simplified Tsai_Wu strength criterion. The influences of α 1 on β and of α 2 on β are reversed. In other words, when α 2 is a known constant and α 1 is a changed number, β is increasing while α 1 is increasing; in the same situation, while α 1 is a known constant and α 2 is a changed number, β is decreasing while α 2 is increasing, vice verse. If this law is used in the engineering structure, not only the material character can be brought into full play, but also the composite structural reliability can be ensured.