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How is this torsion?by Femme_physics
Tags: torsion 
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#19
Dec312, 02:43 PM

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#20
Dec512, 12:16 PM

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That's an awful lot of correspondence and really it's just the use of terms and a point of view. The weld group is subjected to a tension, a shear and a moment about the centroid of the weld group, about the axis perpendicular to the paper. If someone wants to call that moment a torsion, why shouldn't they? It's not a bad use of the term in this case, because it causes shear stresses in the welds, and shear stress is usually associated with torsion in a solid member. What it does not represent is a torsion on the beam itself. That is bending. But we are discussing the weld group...



#21
Dec712, 01:11 AM

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#22
Dec712, 05:28 AM

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Going back to your original problem in post 1, there is some confusion as to
1.) whether you are looking at loads and streses on the on the weld group or the beam, 2.) whether the beam is an I beam, an open channel 'U' tube, a semicircular open tube, etc.,, and 3) whether the load at the end is applied at the center of the crosssection or eccentrically applied at the right side of the cross section. looking at the beam and assuming it is an I beam withthe load applied at the center of the crosssection, there is bending and vertical shear and axial loading in the beam, no torsion; looking at the weld for this load case, it is subject to vertical shear, horizontal shear, and torsion. This appears to be the most likely scenario. If the load was applied off center along the edge of the cross section, there is still bending, vertical shear, and axial load in the beam, as well as torsional shear stresses in the beam from the eccentrically applied load that causes a twisting moment. Important thing here is that there is still bending....must be. For the weld group for this case, we have vertical shear, horizontal shear, and torsion in 2 directions. 


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