A Simulation Study Of Rotary Draw Bending For Rectangular Section Tubes Of High Strength Steel Based On Dynaform

With the development of the lightweight of bodywork,bodywork materials have been gradually upgraded from traditional aluminum alloy and low strength carbon steel to high-strength steel.The thin-wall rectangular tube of high-strength steel can not only improve the carrying capacity of the bodywork,but also reduce the weight of the bodywork.However,it is easy to produce all kinds of defects in the process of bending due to the low plasticity of high-strength steel and the small window of forming.In order to judge the influence of geometric parameters,material parameters and cross-section parameters of the rectangular tube of high-strength steel on the quality of bending tube forming.At first,the paper establishes a simplified three-dimensional model of bending forming of rectangular tube.Then the simplified model is imported into the Dynaform software to simulate the whole process of bending with different sizes and parameters.Finally,the simulation results of the bending process of rectangular tubes with different relative fillet radius,aspect ratio,yield ratio and bending speed are obtained,drawing the following conclusions:1.When the side length and bending radius of rectangular tube is fixed,its relative fillet radius has larger influence to distortion parameters of bent tube than its relative wall-thickness;moreover,the smaller the two relative values of rectangular tube,the larger its cross-section distortion,the maximum wall-thickness reduction and the maximum height-to-length ratio of longitudinal wrinkling wave in the bottom plate;2.When the section width of a rectangular tube is fixed,the larger the section height,the smaller the aspect ratio,the bigger the cross-section distortion,the larger the maximum wall-thickness reduction and the maximum height-to-length ratio of longitudinal wrinkling wave in the bottom plate;3.The smaller the yield ratio is,the more favorable for most plastic forming,but the smaller the yield ratio,the more serious the maximum wall-thickness reduction;4.With the increase of bending speed,the cross-section distortion and the maximum wall-thickness reduction of tubes and the maximum height-to-length ratio of longitudinal wrinkle wave in the bottom plate are all changed,but this change is not obvious.