Numerical and experimental studies on wrinkling control methods of sheet metal part with high curvature and large flange in rubber forming

Abstract

Wrinkling is one of the main failure modes in sheet metal forming process and may lead to assembly problems of the parts. Control of wrinkling is difficult due to the complex deformation behavior of the sheet metal. A finite element model for side blankholder method to control wrinkling was established and used for the simulation. Trials and simulations were conducted to analyze the parameters of wrinkling characteristics. Results show that with the increase in the angle of the side blankholder, the resistance force of the side blankholder decreases. The blank length on the side blankholder should be small enough. The fillet radius of the side blankholder should be large enough to reduce the deformation. The bottom gap between the die and the side blankholder cannot be too large because the support of the blank will decrease in the forming process. In order to verify the simulation results, three blank lengths (20, 15, and 5 mm) over the side blankholder were used in the experiment. The results of the comparison tests testify the reliability of the simulation. The optimal parameter of the blank length is 5 mm. A new clamp method was designed for wrinkling control to overcome the shortcomings of the side blankholder method. The precision of the part met the requirement using soft rubber and two layers of rubber plates.

Theory, Method and Practice of Metal Deformation Instability: A Review

“…Chen et al [ 121 , 122 ] investigated the wrinkling behavior of high curvature, large flange sheet metal stampings by experiment. They found that if the blank holder was not used, the larger the gap between mold and side blank, and the more serious the wrinkling of the flange.…”

“… Wrinkling behavior of sheet metal stamping: ( a ) sheet metal stamping of a high curvature large flange [ 121 , 122 ]; ( b ) wrinkling of GPa-grade steel, comparison analysis of representative wrinkle area (wrinkling area b, c and d) with the simulation results [ 123 ]; ( c ) failure mode of a AA2024-T3 thin plate [ 124 ]. …”

Research on wrinkling in rubber forming of the convex flange with 2A12 aluminum alloy sheet

“…Chen et al(2012) conducted finite element analysis of the rubber forming process of high shrinkage bending edges in ABAQUS software, where the results showed that the greater the distance between the side blank holder and the die, the easier the material to wrinkle. According to Chen et al(2019), the finite element analysis of rubber forming wrinkle defects of large curvature and high-flip sheet metal parts was carried out by PAMSTAMP software to determine the optical parameters of side blank holder, the structure of the die, hardness of the rubber, etc., providing a rubber forming method that can directly use the complete machining of convexly curved parts without margin unfolding blanks. explored the consequences of the rubber forming for the simplified models of different convex curved edge by finite element method.…”

Sheet thinning prediction method based on localized friction effect in deep-drawing

“…One of the commonly used tools is Finite Element Analysis (FEA) that can simulate and analyze the forming behaviors under different conditions. [18][19][20][21][22][23] In addition, the optimization methods have also been applied to predict forming behaviors in the deep-drawing process. [24][25] This paper integrated FEA and optimization methods to predict the effects of VCOF on formability in deepdrawing.…”