Numerical analysis of the hydro forming process involving an automobile rear subframe by finite element methods

Abstract

Background: The hydroforming process has been extended and applied widely among automotive companies over the last 20 years. It has many advantages such astubular parts offering improved structural integrity, fewer vehicle frame components, mass savingsin material usage and weight reduction as well aslessspringback, higher stiffness, and better design freedom. Aim: In the present study, a process for generatingrear subframe components has been developed usingthe tube hydroforming process.Carbonated steel tube material,havingultimate tension strength over 440 MPa,wasadapted for improved performance. At the initial design step, a feasibility investigation, aided by the finite element method,was employed to meet detailed hydro-formability. Variables like an inner pressure, axial direction feed, and designpatternwere investigated in the rear subframe for vehicle chassis systemthrough hydro-forming. Overall, hydroformablesubframe parts were established by cross-sectional investigation. Results: All expansion rates were designed to be capable of forming.Detailed simulations showed that the final thickness, due to hydroforming, exceeded the standards for component development. Application: It is necessary to verifythat the workability of the pipe material at each stepevery forming process, like as prebending, preforming, and hydro-forming, is defined accurately. To dothis, more efficient section design criterion wasoptimized through an analysis of both the shape and the thickness of the hydroformed components.