单向承压层合板纤维微屈曲的有限元分析

FINITE ELEMENTE ANALYSIS FOR FIBER MICRO- BUCKLING IN LAMINATED PLATE UNDER UNIFORM COMPRESSION

本文应用分叉理论对单向承压层合板作有限变形、弹塑性有限元分析,得到纤维微屈曲现象及由此而引起的纤维层表面波动形态,并给出微屈曲发生后剪应力等的数值和分布。在层合板剪切强度薄弱处,有可能因纤维微层曲而引起层间剥离破坏。

The connection between fiber microbuckling and dislamination of la-minated plate is one problem of interest for discussion about failure mech-anism. In this paper, the bifurcation behaviour of laminated plate sub-jected to longitudinal compressive load is investigated by elastic-plastic finite element method with finite deformation.The laminated plate is com-posed of elastic layers with higher modulus (which simulate the fiber) and elastic-plastic layers with lower modulus(which simulate the matrix). When the compressive strain reaches its bifurcation value, the fiber micro-buckling phenomenon takes place. After that small amplitude waves of deformation arise in interface plane, then also shear stress and transverse normal stress vary from zero to an obvious value with the compressive strain increase. Under this shear stress a dislamination can occur in the local interface of laminated plate, where the shear strength is quite low. In the numerical example of symmetric laminate fiber micro-buckling, both extensional mode and shear mode exist simultaneously.