EFFECT OF THICKNESS ON TUBE DEFORMATION MECHANICS DURING LOW PRESSURE TUBE HYDROFORMING PROCESS SEQUENCE VARIATION

A rapid increase in fuel consumption has been seen due to a sudden increase in the usage of automotive vehicles. This results in an increase in air pollution. Due to which a stricter regulation applied by the federal government to decrease air pollution. To escape from the pollution penalty innovations are been pushed. The industry has been looking at many innovative manufacturing processes like electric assisted manufacturing, single point incremental forming, high-speed forming, and many. All these innovative processes promise more uniform deformation and increases formability in the part. One such process is tube hydroforming for tubular parts. Tube hydroforming is the successful manufacturing process to create a variety of shapes using fluid pressure. The fluid medium can be water with preventive additives, oil, or viscous liquid. In this process, the tube was filled with the fluid medium and further pressurized to deform to various shapes. Tube hydroforming is categorized into three types: high 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 light-weight parts for automotive and aerospace industries to increase the fuel economy. Tube hydroforming 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 previous study which was published in IMECE2019 was focused on investigating the deformation mechanics of the tube due to variation in the process sequence during low-pressure tube hydroforming. In the second part of this research focus on how the thickness of the tube affect the deformation mechanics in the 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 relative 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. It was found that the deformation mechanics was mostly influenced by the variation of movement by punch and die side with no internal pressure case. The buckling in the tube wall also depended on which side of the die moves to deform the tube.