Displacement Stress Range

[mohammad7777]

Hi all ...
I have a question in displacement stress range formula ... Please help me.
Can someone tell me what is the exact derivation of the formula "Se={(Sb^2+4St^2)^0.5} ??
Many thanks ...

 

[aaloui]

Hi Mohammed,

this is simply the formula of the equivalent stress or stress intensity acc. to Tresca (shear stress theory). Here are just the moments considered, namely bending and torsional moments, stresses caused by direct forces are neglected, nevertheless you can add the longitudinal stresses from axial forces to the bending stress Sb since they act in same direction, but generaly this last one is neglected.

Greetings,

Ali.