Modeling the R-curve effects in laminate composites using the interface thick level set method

Abstract

This paper presents a new model for simulating delamination growth in composites in presence of the resistance curve (R-curve) effects. This model is extended from the interface thick level set (ITLS) method which is developed recently. In this approach the common definition of damage in the constitutive relationship of the interface elements is replaced with a new damage definition based on the thick level set (TLS) method. This new damage definition provides a direct link between fracture and damage mechanics that allows use of interface elements without a predefined cohesive law. In this paper the ITLS method is adopted to incorporate the R-curve effects caused by extended bridging, in modeling delamination. The fracture energy in the developed model is defined as a function of the crack length which allows simple use of experimentally measured R-curve as a direct input of this model. This is in contrast with the popular cohesive models that need to develop some mathematical relationships to extract the cohesive law parameters from experimental R-curve. The proposed 3D model is validated against experimental data obtained from literature to support the accuracy of obtained results.