Abstract:

     A perturbance method to analyze the process of stretchbending is introduced in this paper. For the convexoconvex workpiece with small curvature in across to the pull direction, it is divided into two areas, one is the area contacting the die surface and the other is the free area restricted on the one end by gripper jaws. Based on the assumption that the components of stressstrain state in the two areas are different from those in stretchbending over cylinder die and strip stretching by additional small values, the perturbed solution is build and the deformation is analyzed. Using the numerical simulation software, the stretchbending process of the roof curve beam of the stainless steel body of subway cars is studied and the technological parameters are optimized, the forming defect is eliminated and the stretchbending die with high precision is developed, and quality stainless steel parts are made finally.

Key words: stretch bend forming, perturbance method, steel profiles, numerical simulation