Mathematical and numerical modelling of large axisymmetric creep strains and damage

摘要

The paper presents a simulation model for the creep process of rotating disks under radial tensional pressure subjected to of body force. The finite strain theory is applied. The material is described by the Norton-Bailey law generalized for true stresses and logarithmic strains. The mathematical model is formulated in form of set of four partial differential equations with respect to radial coordinate and time. Necessary initial and boundary conditions are also given. To make the model complete, the numerical procedure for solving this set is proposed. What is worth noticing the classical FEM is not applicable, because not only geometry, but also loading (body forces) change in time during the creep process. It would demand redefinition of finite elements at each time step. In uniaxial problem similar model was presented in [4], but now it is developed for complex stress state. Possible different formulations of initial and boundary conditions may be found in [5]. The procedure may be useful in problems of optimal design of full disks in [6].