| The bending and forming process is an important method of profile bending,and the bending and bending products are mainly used in the fields of automobiles and aerospace.The bending of the profile will inevitably occur,and accurately predicting the bounce volume has always been a difficult problem in actual production.In recent years,new products have been emerging in an endless stream,and the quality standards have been continuously improved.Only by predicting the rebound more accurately can the development cycle be shortened and the forming precision improved.Due to the reciprocating tensile and compressive deformation of the inner layer of the profile during the bending and forming process,considering the effect of the material,this paper is based on the new proportional follower strengthening material model,and the bending under the plastic pre-stretching and bending loading path is carried out.Modeling and theoretical analysis.Taking arbitrary section profiles as the research object,based on the assumption of flat section and the assumption of one-way stress,the stress and strain distribution of the cross-section of the profile under the deformation type of "inner layer without reverse plastic compression deformation" and "inner reverse plastic compression deformation" are analyzed.The expressions of the radius of curvature and the total bending moment expression of the strained neutral layer after loading are derived.The judgment conditions of the bending deformation type are given,and the complex equation of the simultaneous bending and bending is established.Analytic method.The ST12 rectangular section profile was selected and the proportional coefficient of the reverse loading yield point in the proportional follower reinforcement material model was determined by the tensile-compression cycle loading experiment.A quantitative elastic analysis was performed on the plastic pre-stretching and re-bending loading path pull-down buckling.The influence of different tensile forces and different bending radii on the radius of curvature of the buckling elastic is obtained.The law shows that under the plastic prestretching and bending loading path,as the tensile force increases gradually,the radius of curvature of the tensile buckling is gradually reduced.For the same pulling force,the larger the bending radius,the larger the pulling buck.The finite element model of the bending and bending was established by ABAQUS finite element software,and the experimental verification was carried out on the jib bending and bending machine.The results show that the analytical results obtained by the proportional follow-up reinforced model are better than those of the classical follower reinforced model.The results of the elastic analysis are more accurate.It is proved that the scale-dependent reinforcement material model has certain theoretical significance and application prospects. |
