Effect of Die Velocity on Tube Deformation Mechanics During Low Pressure Tube Hydroforming Process Sequence Variation

Abstract Tube hydroforming is one of the successful manufacturing processes to create a variety of shapes using fluid pressure. The process fills the tube with fluid and pressurizes it to deform in various cross-sections. The method is categorized in three types: high pressure, pressure sequencing and low-pressure tube hydroforming. Tube hydroforming has gained popularity due to its many advantages such as part consolidation, uniform deformation, quality of the formed part and the possibility of unique shapes with indents or angles. Due to uniform thinning in the formed part, the parts can be lower weight and thus proven to be the technology to create light-weight parts for automotive and aerospace industries to increase the fuel economy. This paper focuses on low-pressure tube hydroforming. In low-pressure tube hydroforming, during the closing of the die the tube is marginally pressurized to a fixed volume. The previous study which was published in IMECE2019 and 2020 was focused on to investigate the effect of variation of thickness on deformation mechanics of the tube with variation in the process sequence during low-pressure tube hydroforming. In this part of the research, the study focused on how the velocity of the die effect the deformation mechanics with variation of the process sequence during low-pressure tube hydroforming. The circular tube was formed in a square shape. The four sides of die edges were considered as individual edges and the motion of these edges will be varied to achieve the final shape. The deformation mechanics in each condition was presented and analyzed. The die velocity effect on die filling, thickness and strain distribution were studied. It was found that the die velocity effects the tube deformation for the thinner tube and buckling could be eliminated using low pressure with tight die filling.