A comparative study on the modeling of matrix cracking in fiber-reinforced polymer laminates under transverse compression - XFEM versus a smeared crack approach

Abstract

As the number of applications for fiber-reinforced polymers (FRP) is growing, the importance of understanding the failure behavior of this material is rising. This is merely conceivable by developing precise computational material models, which saves time, material, and energy. In general, the polymer matrix is the constitute with the lowest strength against failure in a FRP; hence the matrix requires additional attention especially under transverse compression where it is considered as the principal load carrying component of the FRP. In the present work, a comparative study on the modeling of matrix cracking in FRP laminates under transverse compression is carried out. To do so, an eXtended Finite Element Method (XFEM) approach is developed for discrete crack modeling, and the conventionally used smeared crack approach is applied via an existing Abaqus/Explicit implementation for continuum crack modeling. The comparison of the results illustrates that despite different kinematics behind the models, they both successfully predict a near identical material degradation and energy dissipation in the material response, but with differing predictions when considering frictional tractions and the predicted maximum stress levels. XFEM is established to be mesh-objective and the smeared crack method predicts the material response optimally when the mesh discretization is one element per ply with reduced integration excluding non-linear geometry effects. Moreover, the wedge effect described by geometrical deformation is distinctly represented as cracks are studied explicitly in XFEM, which provides the possibility of further study for inter-laminar effects such as delamination, crack propagation and crack migration. Key words: XFEM, smeared crack model, progressive damage analysis, transverse compression, friction, fiber-reinforced polymer