An elastic-plastic finite element procedure considering nonlinear deformation behavior is used to study ductile fracture mechanics problems. A global secant relaxation-based acceleration method is used to improve a modified Newton-Raphson iteration in carrying out the numerical solutions of discrete nonlinear algebraic systems. Since this computational procedure possesses good numerical stability and convergency rate performance, well converged results can be efficiently obtained. The converged finite element results include fracture parameters of integral, differential and displacement models. These parameters can be used to study the nonlinear fracture behavior of structures. The influence of nonlinear deformation on ductile fracture mechanics problems is investigated. A study regarding correlations between two different models of fracture parameters is carried out, which shows certain types of linear relations for the load being above a certain level under which the plastic deformation around crack tip is up to a certain degree of severity. This tendency of correlations between different fracture parameters holds good for model problems with and without considering nonlinear deformation behavior. Based on this result, a conclusion can be drawn that the considered fracture parameters have the same effect in expressing the fracture level of structures although their mechanics properties and related fracture laws are different. The establishment of this theoretical conclusion is largely the result of proper finite element modeling and converged iterative computations.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering