Study of tube hydroforming in a trapezoid-sectional die

Trapezoid-sectional parts are used in many areas. In the present paper, the hydroforming process of the tube in a trapezoid-sectional die is investigated experimentally. Effects of loading paths on the hydro-formability of trapezoid-sectional parts are studied and the design principle of loading paths for trapezoid-sectional parts is put forward. Through numerical simulations, the effects of die angles and friction coefficients on the hydroforming process and the final parts are explored. The variation regularity of thickness on the unsupported wall along the cross-sections is analyzed and the simulation results show good agreement with the analytical conclusions. The present study provides a knowledge base for hydroforming die and process parameter design and helps to further understand the corner-filling process.