在文献中,提出了一个预测复合材料中裂纹扩展方向的比应变能密度准则(Strain energy density ratio criterion)。用一个短纤维复合材料层合板中Ⅰ-Ⅱ型复合型裂纹扩展方向的预测为例子与实验结果进行了对比。结果表明,该准则对预测复合材料中裂纹扩展方向是成功的。那么,这个准则可否用来预测复合材料的破坏强度呢,本文将研究这个问题。 In the literature, a new Strain energy density ratio criterion is proposed to predict the direction of crack propagation in composites. The prediction of the type Ⅰ-Ⅱ composite crack growth direction in a short fiber composite laminate was taken as an example to compare with the experimental results. The results show that this criterion is successful in predicting crack propagation in composites. So, this criterion can be used to predict the failure strength of composite materials, this article will study this issue.