Mixed Finite Element Method for End‐Notched Flexure Test

Abstract

To permit more efficient use of the experimental data in the end‐notched flexure (ENF) test, a mixed finite element method is used to model the macromechanical situation with a small number of four‐noded quadrilateral elements. This small number of elements is made possible by the development of two types of specialty finite elements (constant shear‐strain bending element and delamination bending element) within the Hu‐Washizu variational principle. With these elements it is possible to satisfy exactly the kinematic boundary conditions of the ENF test—especially at the point of zero slope. Assuming linear elastic fracture mechanics, the critical interlaminar fracture toughness