Three-point bending straightening algorithm and verification for I-type seamless welded rail

The straightness of seamless welded rail (SWR) is very important for high speed railways. To improve the straightness of SWR, in this paper, we propose a three-point bending straightening algorithm for I-type SWR. It has been verified by theoretical analysis, finite element simulation, and experiments. The three-point bending straightening algorithm for I-type SWR has three steps: (1) three-point bending straightening prediction models are established based on simplified cross-section; (2) shape compensation coefficients are proposed to reduce the influence of simplified cross-section on the accuracy of the prediction models; (3) effective simplified cross-section dimensions are determined by optimizing shape coefficients with the Trust-Region-Reflective Least Squares method. The three-point bending straightening algorithm, which meets the needs of prediction precision in the industrial application, is stable and convergent, and could be the basis of further intelligent straightening.