Experimental and numerical investigation of through-thickness residual stress of laser-bent Ti samples

Abstract

One of the important parameters that can influence on performance of a part and its life is residual stress. All manufacturing processes can create residual stress in different ranges. Laser bending is one of the thermoforming processes that has been used in different industries. The aim of this study is investigation of through-thickness residual stress profile of Grade 2 titanium samples that were subjected to laser bending process. Slitting method was used to measure the residual stress profile experimentally. Both series expansion and pulse-regularization methods that are common computational techniques in the slitting method were employed to calculate the residual stress. Besides, finite element simulation of the laser bending process was done to study the through-depth residual stress distribution numerically. The results of two computational techniques were compared to each other and with the finite element method results. Furthermore, the effect of laser bending process on surface roughness and microhardness of the samples at the heat-affected zone was investigated. The results showed that laser bending process can induce considerable residual stress in the heat-affected zone of the part. Comparing the experimental and finite element method results showed good agreement between them. In comparison with the control sample, both surface roughness and microhardness of the samples increased after the laser bending process.