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

• Published in: International journal for numerical methods in engineering Vol. 79; no. 6; pp. 639 - 666
• Main Authors: Sun, X. S., Tan, V. B. C., Liu, G., Tay, T. E.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 06-08-2009; Wiley
• Subjects: composite structure; Computational techniques; Computer simulation; Delaminating; Delamination; delamination analysis; Discontinuity; discontinuous enrichment; enriched element-failure method (REFM); Enrichment; Exact sciences and technology; external nodal forces; Fracture mechanics; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Mathematical analysis; Mathematical methods in physics; Mathematical models; Physics; Solid mechanics; Structural and continuum mechanics; X-FEM; Interfacial layer; Enrichment; Stiffness matrix; composite structure; Modeling; Crack propagation; Finite element method; X-FEM; Crack tip; Delamination; Mesh generation; Damaging; Discontinuity; enriched element-failure method (REFM); Stratified material; Kinking; Rupture; delamination analysis; discontinuous enrichment; Experimental study; external nodal forces; Plate; Matrix method; Asymptotic approximation; Structural analysis; Crack; eXtended Finite Element Method
• ISSN: 0029-5981; 1097-0207
• DOI: 10.1002/nme.2567

This 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. Copyright © 2009 John Wiley & Sons, Ltd.