Investigation of Residual Stress Distribution in Bent Beams by Slitting Method

Slitting method is one of the common methods of residual stress measurement. This method can determine residual stress profile in thick plates and beams. In this article, the residual stress profile and released strains will be compared for two bent steel samples. Two samples are prepared from AISI 4140 steel material. After annealing the samples, they are bent by three roll bending machine to obtain curved beams with specified curvature radiuses. Due to bending process, a considerable residual stresses profile are induced to the samples. The thickness of samples are equals to 10 and 20 mm and they formed to 200 and 400 mm curvature radiuses respectively. A successive slit is created in the samples and released strains are measured using back strain gauge. The residual stress profile is calculated using Legendre polynomial basis function. In spite of different released strains, the residual stress profiles are same as each other’s. The stress profiles are also compared with analytical stress distribution. The results show good agreement between experimentally measured residual stress profiles and analytical solution.