Shear vs torsion - difference? 1

[IsTHATbainite]

Hi folks,
Is there a way, via SEM, to tell the difference between a shear failure vs a torsion failure or, are the fractures basically the same? An elongated dimple rupture?

 

[swall]

Your question is vague, given that a ductile torsion failure IS a shear failure.

 

[metengr]

IsTHATbainite;
Have you examined the macrofeatures of the fracture surface to establish service loading conditions? Normally, one begins with observations related to the entire fracture surface before drilling down to higher magnification.
Yes, elongated dimples from ductile rupture can be under shear load or torsional load conditions.

 

[CoryPad]

If I understand your question, you want to tell from a fracture surface if the part fractured due to uniform shear or from torsion. If so, then the idea would be to look at various positions on the fracture surface. Torsion would produce elongated dimples that change orientation as you change position. Uniform shear should product dimples with the sample orientation over the entire surface.

 

[desertfox]

Hi IsTHATbainite

Have a look at this site:-

http://www.pump-zone.com/motors/motors/understanding-factors-that-cause-shaft-failures.html

it gives examples of what to look for.

desertfox