Research on Hydroforming Tubular Parts with Dissymmetrical Structure

A double handles part with dissymmetrical structure used for airplanes was manufactured by hydroforming with the advantage of more even thickness than conventional mechanical method. It is difficulty to form the part with dissymmetrical structure because its biggest section expansion ratio is much higher than the uniform elongation of the tube blank. Three different loading paths were utilized in simulating the forming process of hydroforming the dissymmetrical part and the results of different loading paths were presented. Folding back occurs as the internal pressure ＜65MPa and bursting occurs as the internal pressure ＞75MPa. The most serious thinning occurs in the top of handle. The maximum thickness appears in the area of the opposite to handle. Only as the internal pressure is 70MPa around, A successful part with big expansion ratio up to 73% can be manufactured in the experiment.