FEM simulation of calibration on strain release coefficients in blind hole method

The significant error of the measuring result may arise when measuring welding residual stress by means of the blind hole method.Because the stress around the hole exceed the yield limit,the plastic deformation induces plastic strain.Therefore,based on the principle of the calibration experiment,the strain release coefficients A and B of the steel Q345R are determined.According to the energy parameter S,the strain release coefficient A and B can be revised by the variation formulas;by this method,the result of measuring high residual stress can be more accurate.Based on the strength theory,the strain release coefficients A and B of steel Q345R,which were numerically calculated by the finite element method(FEM),coincide well with the calibration experiment results.So the FEM determination of the strain release coefficients A and B is viable.