Ductile fracture behavior of low carbon high strength steel using continuum damage mechanics

Abstract

Abstract In this paper ductile fracture of low carbon high strength steel is estimated following the phenomenological approach of continuum damage mechanics (CDM) evolved by Lemaitre. This assumes damage, corresponding to void growth and their coalescence during large deformation, to be isotropic and ductile in nature. The CDM formalism allows estimating the ductile behavior by a damage variable D. This is evaluated from elastic modulus degradation measurement of uniaxial tensile tests with loading–unloading cycles. The result obtained in terms of D C, the critical value of damage, is found to be 0.44. This gives a measure of ductile fracture from the CDM approach. Respective average D values corresponding to every elastic modulus degradation estimate are used for simulation of ductile behavior of the material. The simulation result closely approximates the experimental flow curve up to about 15 % of strain with minor deviation beyond this strain level up to fracture. The method shown provides a way to evaluate ductile behavior of a material conveniently.