Deformation mechanics of tube in variation of process sequence during low pressure tube hydroforming

Tube hydroforming is the successful manufacturing process to create a variety of shapes using fluid pressure. In this process, the tube was filled with the fluid and further pressurized to deform to various shapes. Tube hydroforming is categorized into three types: higher pressure, pressure sequencing and low-pressure tube hydroforming. Ferrous and non-ferrous metals are formed using these processes. Due to uniform thinning in the formed part, the parts can be lower weight and thus proven to be the technology to create lightweight parts for automotive and aerospace industries. This process has gained popularity due to its many advantages such as part consolidation, quality of the formed part and the possibility of unique shapes with indents or angles. 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 focus of this paper is to investigate the deformation mechanics of the tube due to variation in 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 thickness and strain distribution were studied. The change of tube profile pattern from the start to the end of the process were presented and compared.