Experimental Investigation and Integration of Finite Element Analysis and Response Surface Method to Multi-objective Optimization of Geometrical Factors in Bi-layered Al-Cu Tubes Hydroforming

Tube hydroforming process is an unconventional method to deform tubular components to the desired shape of die cavity by applying high pressure and axial feed displacement. Bi-layered tubing which consists of two different metallic layers (such as aluminum and copper) is recommended to use in complex working environments as it offers combined properties that single layer structure does not have. Using of this tubes are suggested in transferring high-temperature corrosive fluids, aerospace and aviation industries, oil production and nuclear power plants. In this paper, thickness reduction and wrinkle height of the bi-layered hydroformed tube are modeled in terms of geometrical factors (lengths, diameter and thickness of inner and outer tubes, lengths and heights of bulge, Chamfer lengths) using finite element method and design of experiments (DOE) with surface response method (RSM). As well, finite element model was built and experimentally validated. The geometrical factors effects and their interactions on the responses were determined and discussed. Optimum geometrical factors are obtained by minimizing thickness reduction and wrinkle height using multi-objective optimization. The optimization results are in good agreement with the experimental test.