Research on the Shrink-expand Forming Law of Variable Cross-section Tubes for Automobiles
To determine the influencing factors of the shrink-expansion forming process for the variable cross-section hollow pipe for vehicles and improve the preparation quality of the shrink-expansion forming process,numerical simulations were performed using Abaqus software.The study investigated the effects of different process parameters(mold closing force,lubrication scheme,forming rate)on the forming process and identified the optimal process parameters,indicating that a die closing force of 20 kN,combined lubrication of oil and grease,and a forming rate of 1 mm/s resulted in good uniformity in the shrinking-expanding forming process of variable-section hollow tubes,with no occurrences of necking or wrinkling.The variable cross-section shrink-expansion forming experiment of the hollow pipe is carried out according to the simulation results,and the experimental results are basically consistent with the simulation results,which verifies the accuracy of this combination of process parameters and provides assistance for the high-performance manufacturing of the variable cross-section hollow pipe for vehicles.