基于修正剪滞模型的竹纤维/基体界面应力理论

A modified shear-lag model for interface stress transfer in bamboo fiber/matrix composites

竹维管束鞘中竹纤维/基体界面力学问题对分析竹维管束在微观尺度下的力学行为起着重要作用。本文针对竹纤维排布方式,并结合竹纤维锥形尖端几何特征,提出了适用于对竹维管束鞘做分析的修正剪滞理论模型,推导出了纤维轴向应力及纤维/基体界面位置处剪应力计算公式,在此基础上讨论了竹纤维长径比和纤维锥形尖端对复合材料内部应力分布的影响。分析发现,竹纤维较大长径比和细长锥形尖端可以实现纤维/基体界面间应力的有效传递。

The interface stress between bamboo fiber and matrix plays an important role in controlling the micromechanical behavior of bamboo vascular bundles.Based on the staggered alignment pattern and conical-end geometrical character of bamboo fiber,a modified shear-lag model was developed to study the stress transfer problem in bamboo vascular bundle sheath,with which the axial average stresses of bamboo fiber and fiber/matrix interface shear stress were derived.Then the effects of fiber-aspect ratio and fiber tip-length ratio on the stress distribution along the fiber length were investigated.The analysis results show that the large aspect ratio and sharp tapered-end of bamboo tiny fiber can make the interfacial stress transfer effectively.