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

The connection between fiber microbuckling and dislamination of laminated plate is one problem of interest for discussion about failure mechanism.In this paper,the bifurcation behaviour of laminated plate subjected to longitudinal compressive load is investigated by elastic-plastic finite element method with finite deformation.The laminated plate is composed 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 roaches its bifurcation value, the fiber microbuckling 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 microbuckling,both extensional mode and shear mode exist simultaneously.