An interface element with continuous traction to analyze delamination propagation

Abstract

An interface element which accounts for the properties of both material strength and fracture mechanics is proposed to numerically simulate the damage propagation process in composite laminates. Several element refinements, which ensure the smooth convergence of the solution during the calculation of damage, are incorporated through a user subroutine in the commercially available finite element package program (MARC). The element was successfully applied to the fundamental problems of stable crack propagation and crack initiation. The propagation process of multiple interlaminar delaminations in circular axisymmetric nonlinear plates subjected to a quasi-static transverse load has been solved to demonstrate the applicability and efficiency of the present element in a complex delamination propagation problem. Because a continuous stress distribution with respect to surface separation along the crack path is assumed on the interface, smooth and stable convergence of the solution of crack propagation can be realized with a fairly coarse mesh compared to the mesh of the model when a discrete interface traction force is assumed only at the nodes on the interface. Since the interface element considers the energy dissipated during the formation of the crack surface, it may be applied to the simulation of a dynamic failure process.

Keywords:

• COMPOSITE LAMINATE
• DELAMINATION
• INTERFACE ELEMENT
• FINITE ELEMENT METHOD
• SIMULATION OF DAMAGE PROPAGATION