Complex U-shape Parts Of High Strength Steel Springback Analysis And Process Parameters Optimization

Bend stamping parts accounted for a large proportion of total automotive stamping parts, therefore the vehicle assembly and quality are affected by the bending process. But the spring-back is the flaw problem that is ordinary but is also difficult to solve in sheet metal stamping forming. Due to it, the precision of part is hard to achieve, especially for the U-shaped part. How to effectively control the spring-back and guarantee the quality have always been the keys and difficulties in stamping forming.With the analysis of the stress-strain and deformation mechanism in different deformation stages of the U-shaped parts bending stamping, this paper focuses on the causing mechanism of spring-back, and summed up the influence of the entire bending process on the spring-back of final forming, In consideration of the advantages in cost savings, improve efficiency and software development is relatively complete, using the finite element simulation of sheet metal forming software--DYNAFORM for U-bending forming simulation.In this paper, the object of study is a vehicle U-shaped fuel tank strap provided by the enterprise. Using DYNAFORM software to carry on multigroup numerical simulations emphasize on the wrinkling and spring-back defects after stamping. And an analysis of the parameters settings in bending spring-back finite element simulation is presented. Then optimize the structural shape of sheet blank by UG software in order to research the function of reinforcing rib and the effect of its layout.Based on orthogonal experiment, the material properties parameters and mold surface parameters are analyzed in detail. Combining the range analysis and variance analysis can give out more accurate result on the impact extent of parameters. And the trend of various parameters impacting on the spring-back is also summarized. Combining the significant parameters of material properties and mold surface with blank thickness, stamping speed to do the comprehensive analysis based on orthogonal experiment. Then obtain a preliminary optimization of controlling spring-back in sheet metal forming. Spring-back compensation method is brought forward to solve the difficulty of U-shaped fuel tank strap assembly. Finally the paper gives the final optimized parameters which can meet the manufacturers and automotive assembly requirements. Aimed at the problem of angle changing due to the damage on the die surface, a specific limit scope of angle changing is given to guide the manufacturer for repairing the die and thus play a guiding role model.