Numerical modeling of creep in metals: numerical results

A 2-dimensional initial strain direct boundary element method was proposed to numerically model the creep behaviour of metals. The boundary of the body was discretized into quadratic elements and the domain into quadratic quadrilaterals. The variables were also assumed to have a quadratic variation over the elements. Due to the time-dependent nature of creep, the solution was derived over increments of time. Backward Euler method and automatic time incrementation technique for updating the variables were implemented to assure stability and accuracy of results. An algorithm had been developed to implement this method. The results for a square plate under biaxial load were compared to analytical solutions and showed to be in good agreement with errors of 4.17% and 1.91% for effective creep strain and creep strain in the xx-direction, respectively. Parametric study of the effects of varying the initial time step, tolerance range and convergence criteria on the numerical results were also carried out. (Author)