WRINKLING BEHAVIOR IN HYDROFORMING OF UNSYMMETRICAL TUBULAR PART

Geometrical analysis, numerical simulation and experiment were conducted to investigate wrinkling behavior in hydroforming of unsymmetrical tubular part. The influence of wrinkle parameters on the average thickness reduction rate was demonstrated using geometrical analysis. The wrinkling process and forming results of different loading paths were analyzed especially by means of FE simulation. It is shown from the experiment and simulation results that the unsymmetrical tubular part could be formed through the method of useful wrinkles. The thickness of the sound part is not uniform along the axial direction in the forming area. The internal pressure is the key factor to form the useful wrinkle. The axial stress is near zero in the expanding zone for useful wrinkles. By the method of useful wrinkle, process window of unsymmetrical tubular part can be enlarged for tube hydroforming.