Crack Propagation Study Using Double-K and Double-G Fracture Parameters

Abstract

Recently proposed double-K fracture model and the double-G fracture model belonging to the modified LEFM concept can predict more number of the fracture parameters without needing closed-loop testing system in the experiments such as failure at crack initiation, stable crack propagation, and unstable fracture. The existing analytical method for determining the double-K fracture parameters needs specialized numerical technique because of singularity problem at the integral boundary. For this reason, application of universal form of weight function is introduced and discussed in this chapter to determine double-K fracture parameters using closed-form equations which provide computational efficiency over the existing analytical method. In addition, brittleness of concrete is defined and size-effect study is also carried out using double-K fracture model. Further, equivalency between double-K and double-G fracture models is also studied numerically. Toward the end, a comprehensive study of the influence of size effect, specimen geometry, softening function, loading condition, etc. on these fracture parameters is carried out.