Tube hydro forming process design for SUV long member using numerical simulation technique

SUV long members are expected to carry the weight of the vehicle and it should act as a energy absorbing member during the course of crash. To satisfy these functional requirements of long member, it should have good strength, crash properties/energy absorbing capability and light weight in order to save cost. Typically long members are fabricated structures. In fabrication process, standard shapes obtained from the conventional forming process are welded together all along their length. Due to welding along the length, the component is prone for fatigue failure and the strength is comparatively reduced.

It has been found from literature that many of automotive structural components are produced from hydro forming process for specific advantages. In this paper, an attempt has been made to study the feasibility of hydro forming process for the long member. This will eliminate the weld along the length and improve the strength in addition to weight reduction.

One of the major challenges was to decide the joining locations for the multiple hydro formed pieces. Since the long member is 4 m in length, it was very difficult to form it as a single piece. The joining locations were arrived at based on numerical analysis and brain storming. On the basis of joining locations, tube diameters were decided. Process simulation was carried to optimise the pressure time and axial feed time and to validate the design. The present study successfully demonstrated the feasibility of the hydro forming of the component.