The Research Of Straightening Mechanism And Experiment Considering Stress Superposition

Straightening is an important working procedure of ensure the straightness of metal bars,which the essence of is to change the bending level of parts.In the process of straightening bending deformation,the internal residual stress of part must be generated that will influence the straightening precision.Therefore,this paper is on the basis of parts' stress evolution,researching the superposition rules between residual stress and load stress,exploring multiple straightening mechanism depend on stress evolution rules of strengthen material,analyzing internal mechanical behavior of deformation how to influence straightening precision,and carrying on the straightening contrast experiment.The main contents are as follows:(1)According to the elastic-plastic deformation theory,analyzing the deformation behavior and residual stress mechanism of strengthen material in the initial straightening,and proposing stroke prediction method considering stress evolution rule in the multiple straightening.The results show that section stress evolution in multiple straightening processes depends on deformation history,and the bending analysis method considering stress superposition is more suitable for multiple straightening processes.(2)Depended on stress linear superposition principle,the stress distribution model in multiple straightening processes is built.Comparing the differences of the resilience property and residual stress between strengthen material and ideal elastic-plastic material in two-step straightening process that proving the necessity of reinforcement.On this basis,the iterative stroke prediction model of multiple straightening is deduced.The research shows that in the multiple straightening processes,the stroke prediction model is real-time corrected by straightening history.(3)Based on the discretization numerical solution,using Workbench and MATLAB to analyze section stress distribution in the simulation.Through comparing the FEA solution based on the post-processing result of simulation and the numerical analytical solution based on the stress distribution model,verify the correctness of the stress distribution model in the multiple straightening processes.(4)Select the LG guide rail to conduct straightening experiment,and respec-tively using simple stroke prediction model and iterative stroke prediction model to do straightening experiment.The result shows that the precision and efficiency of the stroke prediction model which this paper proposes is better.