FE Simulation-based process design for manufacturing structural members of commercial vehicle using pipes with rectangular Cross-Sections

Bent pipes are key components employed in vast quantities and diversities for satisfying the increasing demand for lightweight and high-strength products. Consequently, pipe bending has become an attractive manufacturing technology for lightweight product forming. This study examined the roll-bending process using a computer numerically controlled (CNC) profile bending machine equipped with three driving rolls. In this process, process design variables should be precisely designed to obtain smoothly curved pipes with high precision and without defects. Specifically, the central roller position must be precisely determined by considering springback?which is inevitable in the cold-forming process. A numerical approach was applied to calculate the central roller position for producing the required curvature. The established FE model was compared with experimental results for validation and then used to obtain the relationship between the central roller stroke and the final curvature of the bent pipe for various pipe material properties and cross-sections. The central roller position for producing the desired curvature was determined using a pipe deformation database obtained from a series of forming simulations, and the usefulness of the proposed numerical approach was evaluated.