Quantitative evaluation of specimen geometry effect on bending deformation of laser peen forming

Abstract

Quantitative evaluation of geometry effect on the bending in laser peen forming (LPF) is of particular importance to achieve complex shaping and distortion correction accurately. In this study, analytical modeling, numerical simulation and experiments are carried out to investigate the geometry effect with a simplified single-curved shape characterized by the generatrix length, the sectional arc length, the sheet thickness and the sectional radius. The normalized deviation of arc height is defined to describe the difference of bending deformation between a flat specimen and a specimen with certain geometry. The normalized deviation is insensitive to the specimen length when the generatrix length is twice as the arc length. The proposed analytical model can provide a consistent prediction of geometry effect with the results from both simulation and experiments under its applicable condition. Bending deformation is increased by increasing sectional radius. A dimensionless quantity, composed of overall geometry parameters, is proposed to quantitatively evaluate the geometry effect. The relationship between the normalized deviation of arc height and the proposed dimensionless quantity is revealed with a single functional curve, which is well validated by the simulation and experimental results. The proposed simple functional relationship can provide an effective way to quantitatively evaluate the geometry effect on bending deformation for process planning of LPF for shape control.