A cohesive model for stick–slip behavior in mode-I fracture during double cantilever beam tests: A dynamic process with static loading

There is a chance that laminate composite materials could exhibit discontinuous fracture behaviors with varied energy release rate as crack propagates in mode-I, known as stick–slip fracture. The current work focuses on modeling such mechanical behaviors by proposing a cohesive model with adapted traction-separation mechanical behavior for crack propagation. The fracture surface from experiments were divided into energy accumulation zone and rapid cracking zone to capture the stick–slip fracture. The mathematical relationships between crack length and crack opening displacement at loading tips during double cantilever beam tests were built based on fracture mechanism to determine critical parameters for proposed cohesive model. Both analytical and finite element models with user subroutine were developed for the validation of the proposed cohesive models with two different experimental cases. As a result, the proposed cohesive model can accurately predict the stick–slip fracture, indicating the mode-I fracture behavior with stick–slip can be a quasi-static process but with dynamic propagation.