Analysis of Strain Non-uniformity Index (SNI) for different geometries of drawn sheet metal parts

This paper explores the effect of the part geometry on the variation of the Strain NonUniformity Index (SNI) at failure in shapes drawn from a single material. Forming of different shapes, namely, a square cup, an equibiaxially stretched sample was performed experimentally as well as simulated using AUTOFORM 5.2 Plus software. Failure predictions were made using the SNI based methodology and the FLD, and compared with experimental outcomes. Forming of the cross draw (FTF benchmark), was simulated and corresponding critical SNI was established based on the failure predicted with reference to the FLD. The SNI values so obtained are discussed in light of different component shapes and draw depths during forming of various geometries.