MFE 201 Lecture Notes - Lecture 3: Process Variable, Flanging, Deep Drawing
31 Mar 2016
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Document Summary
In drawing and stretching operations the material will see metal displacement from the original shape, changing thicknesses and geometries signi cantly. In simple tension, such as a tensile test, even ductile materials stretch about a practical 40%. In stretching and drawing processes the material is often formed more than that, and frequently by mechanisms other than stretching. In addition the stress conditions are very di erent than simple stretching. Tests to predict the performance of materials for these processes have been developed. (a) A cupping test (the erichsen test) to determine the formability of sheet metals. (b) bulge-test results on steel sheets of various widths. The specimen farthest left is subjected to, basically, simple tension. The specimen farthest right is subjected to equal biaxial stretching. These specimens are deformed until failure to get an idea of their limits. Forming limit diagrams also allow for predictive performance of a material.
