中文摘要：

层合板强度分析若只考虑面内失效而忽略自由边界处的分层失效，往往会高估强度值，得不到合理的预测结果。该文提出了一种层合板强度的数值分析方法，综合考虑了层合板的面内失效（基体失效和纤维断裂）以及层间分层失效。采用有限元方法对层合板进行结构分析得到板的应力响应，结合面内失效判据和分层失效判据对层合板各个单层进行失效判断，采用刚度退化和逐步失效方法求得层合板的最终失效强度。与以往方法相比，该文模型和方法考虑的因素更全面。数值算例表明该方法预测得到的最终失效载荷和分层起始载荷和已有文献实验结果一致。

英文摘要：

Neglecting delamination failure mode owing to free-edge effect, the failure strength of a laminate will be overestimated under the traditional laminate strength analysis which considers only inplane failure. In this paper, a numerical method considering both in-plane failure and delamination failure was proposed to predict the ultimate strength of laminates. For each ply, three major failure modes are considered： matrix failure, fiber breakage and delamination. Finite element method is used to obtain the in-plane stresses and the interlaminar stresses at the free-edge in a laminate under mechanical loads. Stress-based criterions including in-plane failure criterion and delamination failure criterion are adopted to predict the failure mode of laminas. When a lamina is failed, the lamina stiffness is reduced according to the corre-sponding failure mode, and the stresses of the laminate are re-analyzed. This procedure is repeatedly performed until the whole laminate fails and thus the ultimate strength is determined. Numerical examples show that the predicted ultimate failure strengths and delamination onset loads are in good agreement with experimental results in the open literature.