複合材料積層板中の多重層間剥離伝播挙動の非線形有限要素解析

抄録

Propagation process of multiple penny-shape interlaminar delaminations in circular axisymmetric nonlinear plates under a quasi-static transverse load, which is an idealized problem of damage accumulation in composite laminates due to low velocity impact loading, is numerically studied through a finite element analysis. A fracture element, which was proposed to simulate the crack propagation (Majima & Suemasu, 1999), is modified for elements with mid-node. The condition for crack propagation is also changed to make the convergence of the solution with element size smoother. Both failures related to strength and the fracture mechanical instability are possible to be considered by using the present element. The element is applied to a fundamental problem of fracture mechanics. The solution converges quickly with the decrease of element size and the results are consistent with the theoretically predicted solution. The sufficiently accurate solution is obtained even with the fairly rough element division. Then the element is used to simulate the propagation of multiple delaminations in a composite laminate, considering nonlinearity due to finite deflection. The early stages of the damage propagation depend on the initial delamination size. The finite element results are consistent with the failure process inferred from the energy release rate distribution theoretically obtained in the precedent study (Suemasu & Maiima. 1998).