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Echeban's blog

How to extract angle of twist and shear stress due to torque in Workbench

Submitted by Echeban on

I set up this model of a shaft with to opposing torque simulating a shaft and pulley system. 

The supports and loads are shown here: Ex-3-9-LoadsAndSupports.png

Note that the origin (top left) has the rotation X constrained to eliminate rigid body motion and to set a reference of zero twist at that point. 

I requested every result that I can imagine, see the Outline here: Ex-3-9-Outline2.png

The torque is shown here: Ex-3-9-TorsionalMoment.png

ANSYS terminology... confusing

Submitted by Echeban on

Why ANSYS calls the well known "element coordinate system" with their own term, "solution" coordinate system? 

Why ANSYS calls  the well know method of applying a "bias" for mesh refinement with their own term, "inflation"? -- I looked it up. INFLATION: to cause to expand or distend with air or gas.

Why ANSYS calls  the well know method of "partitioning" a solid model with their own term, "slice"? OK, may be "slice" is descriptive, but "inflation"? and "solution cs"?   

 

How can I avoid stress concentration at fixed support

Submitted by Echeban on

I have a cantilever beam, 8 in long, rectangular cross section W=0.75 in, H=1.5 in, E=29 msi, Poisson's=0.3, under uniform line load qy = -50 lbf/in (y direction) entire length, bending around strong axis (zz). Beam theory solution M*c/I gives max. stress = 5687 psi.

I model with ANSYS Workbench, uniform mesh Ex-3-6-3D-Normal-Stress.PNG attached.

If I refine the mesh I only get more and more stress concentration. Expected but how to avoid? I just want to get the same result as M*c/I to show how FEA can predict the same as beam theory. 

Are shear-moment diagrams wrong in ANSYS Workbench 16.1 ?

Submitted by Echeban on

I think I found an ERROR in ANSYS Workbench 16.1 and I hope someone can either CONFIRM or show me what I did wrong. 

This is very important because I am teaching this material, but I do not have support from ANSYS, so I am asking for your help. 

beam_static_structural.jpg : shows a cantilever beam 8 in long under line load -50 lb/in, E=29 msi, cross section 0.75 in wide by 1.5 in tall.

beam_triads.jpg: element triads clearly show cross section coordinates are aligned with global x-y-z coords

Portuguese version of cadec-online available

Submitted by Echeban on

The Protuguese version of http://cadec-online.com/ is available. Previous versions include English, Spanish, and Farsi. English is the base version for the developement of the app. I did the Spanish translation. Farsi and Portuguese were done by volunters. We are looking for volunteers for other translations. pls contact me if interested.