Modeling and Analysis of Crack Initiation in a Cylindrical Specimen

Abstract

In an engineering component subjected to variable loading/cyclic stressing, the stress and stress state, particularly the plastic strain and the triaxiality, play an important role in determining its life. Ductile materials predominantly fail by void growth, and crack initiation in ductile material can be associated with a specified volume of voids. Estimation of this crack initiation life and the remaining life through analytical modeling and comparing it through experimental testing in a cylindrical specimen made by EN-8 steel are the major objectives of this work. An investigation on ductile crack initiation in structural steel has been made, based on the concept of Garson’s yield function. First, the condition of ductile crack initiation in the uniform stress field has been investigated. A critical value of the damage variable is determined based on the stress and crack initiation parameter. Damage per cycle/rate is estimated using a crack growth parameter and the remaining life is based on these two parameters. A verification test is conducted on standard tensile test specimen using an MTS test system.