Experimental characterization and inverse constitutive parameters identification of tubular materials for tube hydroforming process

This paper deals with an inverse approach strategy to determine the constitutive parameters of tubular materials made of low carbon steel S235 and aluminum alloy AA6063-O. For this purpose, a new self-designed bulge forming machine is manufactured to perform tubular bulge tests. Additionally, tensile tests are carried out on specimens cut from the tube to measure the Lankford anisotropy coefficients. The proposed inverse identification method is developed to identify efficiently the flow stress parameters considering material anisotropy effects. This method is made up of an optimization algorithm that connects experimental free bulge test results and finite element analysis. The comparison between predicted results and experimental data is performed to assess the proposed approach. It is shown that this identification strategy provides appropriate flow stress relationship which can be used to predict accurate plastic deformation behavior during the tube hydroforming process.