An enriched element‐failure method (REFM) for delamination analysis of composite structures

Abstract

SUMMARYThis paper develops an enriched element-failure method for delamination analysis of composite structures. This method combines discontinuous enrichments in the extended finite element method and element-failure concepts in the element-failure method within the finite element framework. An improved discontinuous enrichment function is presented to effectively model the kinked discontinuities; and, based on fracture mechanics, a general near-tip enrichment function is also derived from the asymptotic displacement fields to represent the discontinuity and local stress intensification around the crack-tip. The delamination is treated as a crack problem that is represented by the discontinuous enrichment functions and then the enrichments are transformed to external nodal forces applied to nodes around the crack. The crack and its propagation are modeled by the 'failed elements' that are applied to the external nodal forces. Delamination and crack kinking problems can be solved simultaneously without remeshing the model or re-assembling the stiffness matrix with this method. Examples are used to demonstrate the application of the proposed method to delamination analysis. The validity of the proposed method is verified and the simulation results show that both interlaminar delamination and crack kinking (intralaminar crack) occur in the cross-ply laminated plate, which is observed in the experiment.

Modelling delamination migration in angle-ply laminates

“…It has origins from the Hansbo's method [16] and its variants [17][18][19][20][21][22]. When it comes to modelling crack propagations, the above-mentioned methods, together with many others such as the meshless methods [23][24][25][26][27], the XFEM-based methods [12,[28][29][30][31][32][33], the phase-field method [34][35][36][37] and the thick level-set method [38][39][40][41], all belong to the broad family of methods which do not rely on remeshing.…”

Mesh independent modelling of tensile failure in laminates using mixed-time integration in explicit analysis

“…As an alternative to pre-insertion of interface elements, cracks can be initiated adap-based modelling methods introduces strong discontinuities in a mesh with enrichment provided by Heaviside step functions [26,27,28,29,30,31], called the extended finite element method (XFEM). In the absence of enrichment to shape functions, the features of adaptive modelling can also be obtained using standard finite element shape functions.…”