Numerical Simulation Of Stretch Bend Forming For Inner Roof Bending Beam With Complex Section

With the aggravation of energy and pollution problem, the concept of lightweightis getting known to people. Aluminum and magnesium alloy taking place of steel ishapping in many areas. Stretch bend forming technology is widely used in light alloybending, due to its excellent mold fitness and small spring-back. However, severalcomplex stretch bending appear in fields like track trains, such as profiles with bigdimension or complicated section, etc. Taking finite element analysis software to doresearch on profile stretch bending is widely used nowadays. Using ABAQUS finiteelement simulation software analyzing profile stretch bending could efficientlyanalyze possible defects during processing. This paper simulates certain profilestretch bend forming with big dimension, large dimension and complex section usingABAQUS simulation software. Followings are some research achievements:Accomplish model of profile, stretch bending mold, upper plate, side plate andjar with CATIA. Introduce the model in ABAQUS and establish a whole completenumerical model through setting parameters as assembling, boundary condition.Which worth noting is that, due to symmetry of the profile, establishing1/2model isappropriate, and mesh of which should be dense. Deduce the jar motion trail equationaccording to the geometry of stretch bending mold and the model is accomplished.Through each five group data simulation on pre-stretch bending, post-stretch bending,stretch radius, profile wall thickness and step during stretch bending, research getscarrying on certain large dimension and complex section. It’s mainly focus on defectsof wall thickness change, wrinkling of bottom part, section distortion and angledeviation of jar part and bending part and spring-back after loading. The result shows that:1. Stretch bending plays little role in wall thickness change:the bigger the stretching, the more obvious thickness change, but the trend is notsevere; The increase of stretch radius or wall thickness also effect the result, andwhich will keep good formability. Increase of step value will improve the wrinklephenomenon greatly.2.The stretch bending also effects sectional distortion, the biggerthe value, the more the distortion will be, and which is not obvious either. Largerradius and wall thickness will improve the sectional dimension. Increase step willdeteriorate sectional distortion.3. Stretch bending effects spring-back too little, thebigger the stretching, the smaller the spring-back. Smaller stretch radius or thickerprofile will do good the formability. Bigger step holds back spring-back greatly.Take the example of a bending beam on a train roof, establish the numericalmodel, and execute the simulation. Through the improvement of pre-stretching andpost-stretching, confirm the optimum stretching range, minimize the effect ofdeviation, distortion and the section narrow effect, and reach the best simulation result.At last, the reliability of simulation software gets proved through the stretch bendingtest.