Solving the cohesive zone model analytic function for concrete based on wedge-splitting test on a compact tension specimen

In this paper, the cohesive zone of concrete is investigated using wedge-splitting test on a compact tension specimen. First, the stress function of the wedge-splitting test on a specimen was obtained by the boundary collocation method. Followed by the actual the wedge-splitting test on a compact tension specimen, the cohesive zone length and the crack opening displacement (COD) in the cohesive zone were obtained by using the digital image correlation method (DICM). Based on the stress function and test data, the weight function that satisfied the conditions of COD in the cohesive zone was determined by superposition of analytic functions with the same crack length but different cohesive zone lengths. Next, the cohesive zone model analytic solutions was determined by the weighted integral method, and the tensile strain softening curve and the fracture energy were obtained. Finally, by comparing the results, it was found that the COD obtained from the cohesive zone model analytic solution was close to the experimental COD, and in addition, the fracture energy was very close to the fracture energy determined using softening curve forms those are frequently used, and the calculated fracture energy was very close to the measured fracture energy. The work shows that the method of determining cohesive zone model analytic solutions using the COD works, revealing a new method for solving the tensile strain softening curve.