# Stress analysis for the same configuration but different material

The same geometry and the same free body diagram. However, if we replace the material from steel to glass, for example. How does that influence the analysis?

Two things I think are 1. steel is ductile and glass is brittle. This means the cross section when it fails will be different. 2. glass has lower yield stress, which means it is much easier to fail.

Is there anything else that I omit? Thank you very much.

• What would you have to change if you replaced steel with aluminium or titanium? Sep 22 '18 at 21:13
• One: Steel is not always ductile, so the statement 'steel is ductile' is false. Two: The distribution of stresses would remain the same, hint think about photoelasticity, however the results would not be same. Sep 22 '18 at 21:39
• in addition, if you replace glass, then you'll see three different regions after failure, one is the origine, it is spherical, two is mist or hackle region if remember correctly , and then a very smooth region, mirror region, not all are visible with naked eye, but a magnifier is enough. Sep 22 '18 at 21:46

• … as a well known analogous situation to the sensitivity to Poisson's ratio, consider the difference between plane stress and plane strain boundary conditions in 2D analysis. The effective value of Youngs modulus changes by a factor of $(1-\nu)$. Sep 22 '18 at 23:55