Variationally consistent eXtended FE model for 3D planar and curved imperfect interfaces

• A variationally consistent 3D XFEM model for planar and curved thin imperfect interfaces is proposed.
• Bulk mesh size independent results are obtained.
• The implementation in standard XFEM models is straightforward.
• Blending and quadrature subdomains are avoided.
• Comparisons with spring-like models show that the asymptotic behavior is consistently recovered.

We propose an eXtended Finite Element Method convergent to the asymptotic solution of a thin interface problem for both planar and curved imperfect interfaces in three dimensions. The main advantage over standard cohesive-zone models is the bulk-mesh size independence. With respect to standard eXtended Finite Element Method, in the proposed procedure, blending and quadrature sub-domains are not required. The focus is on the evaluation of the accuracy of the proposed approach in solving three-dimensional benchmark tests. The numerical results are compared with those available from analytical solutions and spring-like interface models.