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Why my beam idealization doesn't evaluate the shear stress?

Newbie

Why my beam idealization doesn't evaluate the shear stress?

Hello,

I have a simple case of a cylindrical section beam with double all fixed constraint.

I made a straight line in parametric, and in simulate i put an idealization with a circular section beam, as in the picture:

Capture.JPG

The problem are on results, it seems that is not estimated the shear stress, indeed value of Von mises stress is the same of the Beam bending stress!

Capture.JPGCapture.JPG

Thanks!

2 REPLIES 2

Re: Why my beam idealization doesn't evaluate the shear stress?

There are a few limitations with shear stresses and beams, which are considered as possible (not yet implemented) enhancements:

CS99845 : Mechanica/Simulate ignores the transverse shear stress when calculating Von Mises Stress for Beam.

CS201731 : The Max shear stress user defined measure at point on beam element is not computed and available for a dynamic frequency analysis in Creo Simulate

Maybe this is related.

Re: Why my beam idealization doesn't evaluate the shear stress?

I recall from my undergraduate course in solid mechanics, that for a beam in bending, the shear stress is at its maximum at the center of the beam, and zero at the top/bottom, with a parabolic profile. So the bending stress is at its highest where the shear stress is zero. Consequently, for long/slender beam, the shear stress is insignificant, compared to the bending stress. The von Mises equivalent stress is evaluated where it is high, i.e. at the top/bottom.

The shear stress can be of importance, for short beams (but then beam elements are inappropriate), and also for sandwich plates/beams, with a stiff composite/alu shell at the top/bottom, and a soft/light foam in between. The shear stress needs to be verified to be below what the foam can handle. Once again, beam elements are not the ideal choice for such analyses.

/Mats L/