XFEM modeling of short microfiber reinforced composites with cohesive interfaces

• A new extended finite element formulation and implementation is presented for progressive failure in random short microfiber reinforced composites.
• A new debonding enrichment function is proposed to incorporate cohesive traction–separation behavior between the fiber inclusions and the matrix.
• Fiber inclusions are modeled as elastic objects of zero measure using the XFEM approach.

This manuscript presents the formulation and implementation of a failure model for random short microfiber reinforced composite materials based on the Extended Finite Element Method (XFEM). Elastic and deformable microfiber inclusions modeled as objects with zero measure are incorporated into the XFEM framework. A new debonding enrichment function is proposed to idealize the progressive debonding between the fiber–matrix interfaces. The proposed manuscript provides a modeling strategy particularly suitable for very high aspect ratio inclusions. The fiber deformation is approximated as axial and directly incorporated into the Lagrangian. The progressive failure within the matrix material is idealized using an integral-type nonlocal damage model. The performance of the proposed XFEM model is assessed by comparing model predictions to the direct finite element method for various fiber configurations. The numerical verification studies point to high accuracy characteristics of the proposed approach. The computational efficiency of the approach provides the capability to evaluate the failure response of microstructures that include a large number of short fiber inclusions.