Constitutive Modeling of Dissipative Solids for Postcritical Behavior and Fracture

The paper aims at the description of the postcritical behavior and fracture of dissipative solids during tensile test. The ductile fracture is understood as the final stage of the necking process and is preceded by the nucleation and growth of voids mostly due to plastic deformations and yield stress state and by the linkage of voids. An elastic-viscoplastic model of solids with internal imperfections parameter interpreted as the void volume fraction is postulated. Elastic-plastic response of the matetrial is also discussed. The material functions and constants are determined based on available mechanical test data as well as on metallurgical observation results. The theory of ductile fracture based on the evolution of internal imperfections is presented. Influence of different effects is examined and synergetic nature of fracture phenomenon is investigated. The criterion of fracture is deduced. The initial-boundary-value problem is discussed.