Estimating the Process Zone Length of Fracture Tests

Abstract

This paper provides closed-form expressions for theprocess zone lengths and load-displacement responses of cohesive zone modeling,for the popular mode Idou- ble cantileverbeam (DCB) test and the mode II end notched flexure (ENF) testofcom- posite materials. By incorporating traction-separation lawsthat consist of onlyone quasi-brittle softening segment,the problems are formulated and analytically solved for homogenous materialor mid-plane symmetric laminates within the framework of classical laminationtheory(CLT).Th eexpressions indicate that the process zone length isa system parameter that is influenced by themodemixity,the material and interfacial fracture properties as well as the specimen geometry,including the thick- ness and the crack length.Based on the parametric studies and the comparison against finite element(FE)simulations,suggestions for estimating the process zone length are provided.