Study Of Various Initial Blank Shapes To Minimize The Earing In The Different Shaped Formed Parts Using Finite Element Analysis

Abstract

In deep drawing process planar anisotropy is found to be a major problem. A high planar anisotropy causes earing in the formed cup (formation of wavy edge at the top). In this paper anisotropic behavior of stainless steel sheet is studied for drawn rectangular, circular and octagonal shaped parts. Finite element based simulation software PAMSTAMP2G is used to simulate the forming of the octagonal deep drawn cup. It is well known that the blank shape and size greatly affects the strain distribution in deep drawing process. Earing is a major problem due to highly anisotropic behavior of the selected material. To optimize the initial blank shape to minimize earing, the flow of material was observed at various steps during the forming and accordingly blank shapes were modified. Four blank shapes were considered to minimize earing for the forming of octagonal product. Finally a circular blank was used for forming of the octagonal part which gave minimum earing. The thickness strain distribution for circular shaped blank is better as compared to other blank shapes

Numerical optimization of the blank shape in order to minimize the earring defect in the deep drawing process of square sections

“…Sharwari et al [7] researched on minimizing the earring defect in polyhedral parts and reported that the initial blank with a circular cross-section creates the least earring defect in forming 8-sided cups. Chen and Sowerby [8] predicted the behavior of earring defects of the cylindrical cups' deep drawing process by studying the slip field pattern that does not deny Hencky equations.…”

Blank Shape Optimization on Deep Drawing of a Twin Elliptical Cup Using the Reduced Basis Technique Method

“…Earring height minimization can be performed using blank shape optimization to obtain better stress distribution and also to reduce the number of production stages. [ 3,7].…”

“…Since the earring defect is generated by the sheet metal anisotropy, it is greatly influenced by the initial blank shape. Earring height minimization can be performed using blank shape optimization to obtain better stress distribution and also to reduce the number of production stages [1][2][3][4][5][6][7]. A theoretical analysis was presented for minimizing earing behavior in cylindrical deep drawing, They used the different blank shape optimization for reducing earings.…”

“…Several methods were developed for the optimum blank design [3,7] the optimum blank shape was designed using the slip-line field theory The method is capable of predicting an optimal blank shape within few seconds but assumes the blank material as isotropic, rigid and perfectly plastic [12].…”

“…Since the earring defect is generated by the sheet metal anisotropy, it is greatly influenced by the initial blank shape. Earring height minimization can be performed using blank shape optimization to obtain better stress distribution and also to reduce the number of production stages [3,7].…”