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 toa sudden increase in the usage of automotive vehicles. Thisresults in an increase in air pollution. Due to which a stricterregulation applied by the federal government to decrease airpollution. To escape from the pollution penalty innovations arebeen pushed. The industry has been looking at many innovativemanufacturing processes like electric assisted manufacturing,single point incremental forming, high-speed forming, andmany. All these innovative processes promise more uniformdeformation and increases formability in the part. One suchprocess is tube hydroforming for tubular parts. Tubehydroforming is the successful manufacturing process to createa variety of shapes using fluid pressure. The fluid medium canbe water with preventive additives, oil, or viscous liquid. In thisprocess, the tube was filled with the fluid medium and furtherpressurized to deform to various shapes. Tube hydroforming iscategorized into three types: high pressure, pressure sequencingand low-pressure tube hydroforming. Ferrous and non-ferrousmetals are formed using these processes. Due to uniformthinning in the formed part, the parts can be lower weight andthus proven to be the technology to create light-weight parts forautomotive and aerospace industries to increase the fueleconomy. Tube hydroforming has gained popularity due to itsmany advantages such as part consolidation, quality of theformed part and the possibility of unique shapes with indents orangles. This paper focuses on low-pressure tube hydroforming.In low-pressure tube hydroforming, during the closing of thedie the tube is marginally pressurized to a fixed volume. Theprevious study which was published in IMECE2019 wasfocused on investigating the deformation mechanics of the tubedue to variation in the process sequence during low-pressuretube hydroforming. In the second part of this research focus onhow the thickness of the tube affect the deformation mechanicsin the variation of the process sequence during low-pressuretube hydroforming. The circular tube was formed in a squareshape. The four sides of die edges were considered asindividual edges and the motion of these edges will be varied toachieve the final shape. The deformation mechanics in eachcondition was presented and analyzed. The relative thicknessand strain distribution were studied. The change of tube profilepattern from the start to the end of the process were presentedand compared. It was found that the deformation mechanicswas mostly influenced by the variation of movement by punchand die side with no internal pressure case. The buckling in thetube wall also depended on which side of the die moves todeform the tube.