An Upper Bound Approach for Analysis of Hydroforming of Sheet Metals

Considering a kinematical velocity admissible field, the upper bound method has beenused for predicting the amount of pressure in hydroforming of sheet metals. The effects of workhardening, friction and blank size have been considered in pressure prediction. Also the effect ofsheet thickness variation has been considered in the present work formulations. The relation betweenpressure and punch stroke has been obtained and optimized by changing the selective parameters inthe velocity components. The results for cylindrical and hemispheric parts have been obtained andcompared with the published experimental results. The effects of work hardening, friction and blanksize on hydroforming pressure have been examined on an elliptical part. Good agreement was foundbetween the experimental and numerical results.