Abstract: In order to discuss the effect of tensile specimen section shape on void damage of metal materials, notch tensile tests and pre-tensile impact crack tests under low temperature are conducted on specimens with round, rectangular section. Fracture surface of SEM is observed. Finite element method is used to simulate the elasto-plastic deformation of the specimens. The distribution of void damage rates along fracture surface , the situation of fracture origin and void growth around the situation of fracture origin are simulated by using mecromechanical model. Results show that section shape of notch specimens have significant influence on void evolution, There exists noticeable difference in void damage rates along fracture surface between round and rectangular section, which means that critical void damage rates is not material constant. There is more error in simulating void growth under unaxisymmetry triaxial stress conditions using R-T model and GTN model.

Key words: Plastic strain Void Cell model Stress triaxiality, High-speed track, Measure, Wheel hollow wear, Wheel/rail relationship, High-speed train