Experimental and numerical benchmark study of mode II interlaminar fracture toughness of unidirectional GFRP laminates under shear loading using the end-notched flexure (ENF) test

The paper deals with experimental and numerical analysis of end-notched flexure (ENF) test of GRFP unidirectional laminates. The numerical analyses were performed in the ANSYS (R) program based on the finite element method. The fracture zone under mode II shear loading was modelled with the application of Virtual Crack Closure Technique (VCCT) associated with Linear Fracture Criterion and with the use of Cohesive Zone Method (CZM) coupled with bilinear delamination law. The problem of ENF test was solved with the use of one- and three-dimensional models with the implementation of linear interface element or contact element and by modelling the test in an accurate way (support and load rollers) and simplified by using boundary conditions. The benchmark studies confirmed the usefulness of several data reduction schemes and ruled out the Corrected Beam Theory as ineffective for determining the mode II critical energy release rate as well as highlighted the superiority of the CZM method over the VCCT has been confirmed by: (i) the possibility of applying the method for coarse meshes; (ii) convergence of results achieved for both two- and three-dimensional models; (iii) significantly shorter CPU time; and (iv) no need of the initial delamination front assumption.

Automated summary

This paper discusses experimental and numerical analysis of the ENF test of GRFP unidirectional laminates. The use of VCCT and CZM methods for modelling the fracture zone under mode II shear loading has shown the superiority of CZM over VCCT in terms of applicability for coarse meshes, convergence of results, shorter CPU time, and no need for initial delamination front assumption.