Application of a nonlocal grid model for analysis of the creep damage of metals

摘要

The paper presents a model of creep damage development in polycrystalline material. The model operates at two scales: micro and macro. The microscale is appropriate for simulation of the damage development phenomenon. Engineering structures operate and experimental tests are performed at the macroscale. For a polycrystalline material, damage development is strictly dependent on the structure of the material. At the microscale, the model uses a tool called cellular automata that enables the description of this dependence. The macroscopic results, required for comparison with the experimental results and for the analysis of engineering structures, are achieved by means of the finite element method. The model connects the cellular automata damage model with the deformation model implemented in the finite element system to realize the multiscale cellular automata finite element model. This connection is made using a nonlocal approach to avoid a solution dependence on the finite element mesh. The nonlocal grid method is considered the most suitable for the discrete cellular automata model. The model has been verified with the experimental results of a uniaxial tension test for copper at elevated temperature. The effectiveness and different variants of the nonlocal grid method for creep crack growth problems have been examined.