Numerical evaluation of cohesive fracture parameters from a wedge splitting test

Direct determination of the parameters describing the popular cohesive crack model from experimental results, such as would be obtained from standard three-point bending or wedge splitting tests, poses a challenging problem. This paper describes a numerical method for obtaining key fracture parameters describing the softening behavior of quasibrittle materials in mode I failure. The identification problem is formulated as a special type of constrained optimization problem known in the mathematical programming literature as a mathematical program with equilibrium constraints. Experimental results of a wedge splitting test recently conducted at the Laboratory of Construction Materials, Swiss Federal Institute of Technology (LMC/EPFL) are used to illustrate applicability of the proposed method.