Experimental and Numerical Study on the Accuracy Residual Stress Measurement by Incremental Ring-Core Method

In this study, the calibration constants of incremental step method have been determined by finite element analysis to calculate the residual stresses by the ring-core method. The calibration coefficients have been determined by simulation the uniaxial and biaxial loading. It is indicated that the loading approach has not effect on the calibration constants and they are unique. The uniaxial condition has been used to determine the calibration coefficients in the experimental method. To verify the determined constants, the calibration factors have been used to calculate the residual stresses in the case of uniform and non-uniform residual stresses. The axial and biaxial conditions have been studied and the results are in good accordance with applied stresses in simulations. In the uniaxial loading the measured residual stresses in finite element model completely accommodated by the applied stresses and presented formula and calibration constants determined the direction of the maximum principal stress by clearance less than 0.7%. Clearance of the measures stresses and applied stresses in the non-uniform case was about 1 %. An experimental test has been used to show the effectiveness of the obtained calibration coefficient by finite element analysis. Also, it is indicated that the results of the experimental test are satisfactory.