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对层合复合材料自由角附近的层间高应力问题,提出了一种三维有限差分法方案计算层合复合材料在变温下的自由角附近的应力场。对文中给出的[90°/0°]s对称铺层和Ni/Al层合复合材料及两个算例,有限差分方案的结果以前所提供的半解析解结果更接近三维有限元计算结果。同时对纤维任意铺设的碳纤维增强塑料的算例进行了计算,发现有限差分方案的结果也和三维有限元计算结果符合的很好。这种有限差分方案所得的解是稳定的、收敛的。文中还就所计算的例子的应力场和层间破坏之间的关系进行了讨论,发现层间剥离应力,即正应力可能是层间破坏的主要因素。
For the problem of high interlayer stress near the free corner of the laminated composite, a three-dimensional finite difference scheme is proposed to calculate the stress field near the free angle of the laminated composite under varying temperature. For the [90 ° / 0 °] s symmetric lay-up and the Ni / Al laminated composites given in the paper and the two examples, the results of the finite difference scheme provided earlier are closer to the results of the three-dimensional finite element analysis . At the same time, an example of CFRP which is randomly laid on the fiber is calculated. The result of finite difference scheme is also found to be in good agreement with the 3D FEM. The solution to this finite difference scheme is stable and convergent. The paper also discusses the relationship between stress field and interlayer failure in the calculated examples. It is found that the delamination stress, that is, the normal stress, may be the main factor of interlayer failure.