A simulation method for fatigue-driven delamination in layered structures involving non-negligible fracture process zones and arbitrarily shaped crack fronts

Abstract

Most of the existing methods for fatigue-driven delamination are limited to two-dimensional (2D) applications or their predictive capabilities have not been validated in three-dimensional (3D) problems.This work presents a new cohesive zone-based computational method for simulating fatigue-driven delamination in the analysis of 3D structures without crack migration. The method accurately predicts fatigue propagation of non-nelgigible fracture process zones with arbitrarily shaped delamination fronts.The model does not require any kind of fitting parameter since all the input parameters are obtained experimentally from coupon tests. The evaluation of the energy release rate is done using two new techniques recently developed by the authors (the growth driving direction and the mode-decomposed J-integral) leading to an accurate prediction of delamination propagation under mixed-mode and nonself-similar growing conditions. The new method has been implemented as a UEL for Abaqus and validated against an experimental benchmark case with varying crack growth rate and shape and extension of the fracture process zone.

Benchmark test for mode I fatigue-driven delamination in GFRP composite laminates: Experimental results and simulation with the inter-laminar damage model implemented in SAMCEF

“…One exception is the method presented by Carreras et al [26]. The method was implemented as a user-defined cohesive element in Abaqus, and the predicting capabilities of this method were demonstrated by comparison with experimental benchmark tests on carbon fibre reinforced polymer (CFRP) specimens [27].…”

“…In all cases, the simulation results matched the experimental data very well. All the input parameters introduced in the simulations presented in [26] were obtained experimentally from fatigue propagation tests on coupon specimens, thus avoiding calibrating the method to adjust any kind of fitting parameter. This, together with the demonstrated accuracy in predicting the delamination front evolution, make the method the perfect candidate to be integrated into the libraries of commercial FE codes as a built-in simulation function.…”

“…Moreover, this paper describes the implementation of the simulation method for fatigue-driven delamination presented in [26] into the commercial finite element software Simcenter Samcef software package version 2021.2 [33]. Additional validation of the method against the presented benchmark test was done.…”

“…The paper is structured as follows. In Section 2, the main theoretical concepts related to the 3D progressive delamination method [26] are presented. In Section 3.1, the methodology to characterize the input mode I interface properties is provided.…”

Composites fatigue delamination prediction using double load envelopes and twin cohesive models

“…Locally, cohesive elements follow a fatigue constitutive law that is usually an extension of a bilinear static cohesive law [11][12][13][14][15][16][17][18], taking into account an assumed number of fatigue cycles in a given time increment. The number of cycles elapsed in a fatigue model over one second is here defined as 'numerical fatigue frequency', which is usually much larger than the fatigue frequency of actual tests.…”