单向纤维增强复合材料的压缩弹塑性微屈曲

本文讨论单向纤维增强复合材料在沿纤维纵向承压时的贯穿型细观失稳。文中提出纤维弹塑性微屈曲的观点,并由弹塑性稳定理论导出层状周期排列的纤维复合材料的临界失稳载荷参数式。结合压缩应力应变关系可进一步确定弹塑性失稳点的位置,从而导出压缩强度的理论公式。所得理论预测值与4种主要纤维增强复合材料的实验结果均能定量符合。借助该理论公式,可分别对由脆性和由韧性纤维增强的压缩折带破坏模式作出定性解释。

ELASTOPLASTIC COMPRESSIVE MICROBUCKLING OF UNIDIRECTIONAL FIBRE REINFORCED COMPOSITES

The spontaneous mierobuckling of unidirectional fibre reinforced composites subjected to longitudinal compression is examined in the present paper. The problem is approachel from the elastoplastic microbuckling viewpoint, which leads to a formula on the critical instability load for periodically assembled layered composites. Further determination of the elasto-plastic instability point is facilitated by the compressional stress strain relation, which then gives rise of the final formula of the compressive strength. Our theoretical predictions quantitatively agree with the experimental data of four representative fibre reinforced composites. Qualitative explanations for different compressional kink are band failure modes associated with brittle and ductile fibre reinforcements are given by means of the present theory.