1. (a) Calculate Ravg for a metal where the R values for the 0, 45, and 90 directions are 1.2, 1, and 0.8, respectively. (b) What is the limiting drawing ratio (LDR) for this material? (c) If we have a blank with a diameter of 18 cm with LDR-3, how many deep drawing passes should we do at least to reach a can with a bottom diameter of 1.8 cm? (30 point) Limited drawing ratio (LDR) 4.0 3.0 2.0 1.0 Zinc 0.2 Copper, brass, aluminum Steel O Titanium 0.4 0.6 1.0 2.0 Average strain ratio (Ravg) Fig. 1. The relationship between average anisotropy and LDR for various sheet metals. 4.0 6.0