Modeling of cyclic material deformations of the homogeneous and notched materials and the finite element analysis

MODELING OF CYCLIC MATERIAL DEFORMATIONS OF THE HOMOGENEOUS AND NOTCHED MATERIALS AND THE FINITE ELEMENT ANALYSIS SUMMARY Keywords: Hardening types, kinematic hardening, isotropic hardening, cyclic plasticity, circumferentially notched bar In this study, notch root strains of a circumferentially notched bar have been investigated under proportional and nonproportional loadings. After determining the dimensions of the tension test specimen according to ASTM standarts, modeling of the test specimen has been realized using a finite element software. Respectively the tension, the cyclic tension – compression, the torsion and the cyclic torsion tests of the specimen have been simulated by FEM. Material has been deterimed as 16MnCr5 steel and to determine materials plastic behavior, two different hardening types which are Mises isotropic hardening and Chaboche kinematic hardening rules have been used. The results obtained according to the hardening types have been compared. According to the results, under cyclic loading kinematic hardening type could capture the Bauschinger effect unlike isotropic hardening. Under monotonic loadings, the results obtained from different hardening types have been accord with each other. The circumferentially notched bar of Barkey has been modeled using the same finite element software. The material of the notched bar has been determined as SAE 1070 steel. First, under axial loading and torsial loading sepereately, axial stress concentration factor and the torsial stress concentration factor have been determined. Axial and torsial stress concentration factors obtained have been accord with the results obtained form the experiments which realized before. Finally under proportional and nonproportional loading the notch root strains have been investigated and assessed. According to the findings obtained in this research, it was concluded that under cyclic loadings materials plastic behaviour can be