Employment of finite element analysis and Response Surface Methodology to investigate the geometrical factors in T-type bi-layered tube hydroforming

Bi-layered tubing which consists of two different metallic layers is recommended to use in complex working environments as it offers combined properties that single layer structure does not have. However, in this wok, producing of T-shape bi-layered components using the tube hydroforming process is investigated. In this regard, the bulge height and the wall thickness reduction of the bi-layered hydroformed parts (responses) are modelled as functions of the geometrical factors using the combination of the finite element modelling (FEM) and Response Surface Methodology (RSM) for design of experiments (DOE). The geometrical factors effects and their interactions on the responses were determined and discussed. Based on the resultant models, a multi-response optimization study was conducted. Furthermore, for the optimum solutions, a significant agreement was indicated between the predicted and numerical values.