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116 Views, 4 Replies

06/12/2017 7:59 PM

Load viewer shows incorrect graph for the z coordinate(it should look like one on the y), but it works fine if i switch z for x. I thought it displays incorrectly only on viewer, but it also shows wrong results after analysis. What might be the problem here?

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Message 1 of 4 ( Views: 116 ) 06/13/2017 4:31 PM

Hi @Vorx2013 Welcome to the Sim Mech forum.

It is hard to know what is wrong from the images alone, but here are some questions or things to try. If these ideas do not help to fix the problem, please feel free to create an archive ("app button > Archive > Create") and attach the archive (.ACH file) to your reply.

- What version of Sim Mech are you using?
- The problem could be related to the use of a comma (",") for the decimal separator instead of a period ("."). Just as a test, what happens if you round the values off, such as changing 4.803E6 to 4E6? (For testing purposes, you might want to drop the "E6" and try 4.803 and 4 so that the numbers on the graph do not overlap.)
- From the first image, I can see that the range of Y coordinates on the selected surface is -4.2 to 4.2 mm. It looks like the range of Z coordinates is 0 to 0 mm. Is that correct? Is the selected surface flat and located at Z=0?

Technical Support Specialist

Customer Service & Support

Autodesk, Inc.

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Message 2 of 4 ( Views: 95 ) 06/13/2017 5:23 PM

"1.What version of Sim Mech are you using?"

Autodesk Simulation Mechanical 2017

"2.The problem could be related to the use of a comma (",") for the decimal separator instead of a period ("."). Just as a test, what happens if you round the values off, such as changing 4.803E6 to 4E6? (For testing purposes, you might want to drop the "E6" and try 4.803 and 4 so that the numbers on the graph do not overlap.)"

Graphs show nothing if i switch (",") for (".")

I tried this version -4*t^2+86-4,8*s^2.The results are still same.

"3.From the first image, I can see that the range of Y coordinates on the selected surface is -4.2 to 4.2 mm. It looks like the range of Z coordinates is 0 to 0 mm. Is that correct? Is the selected surface flat and located at Z=0?"

It should be located at X=0, since i chose other coordinate system that starts at the center of the ring.

The equasion should represent paraboloid that defines pressure on the ring. It supposed to go from 21E06 Pa at 3,7 mm radius to 0 Pa at 4,5 mm radius.

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Message 3 of 4 ( Views: 89 ) 06/13/2017 6:30 PM

Hi @Vorx2013

It looks like you have that variable pressure load assigned to a local coordinate system, and all of the nodes are at a **local** Z coordinate of 0. So the graph is correct to show that all of the nodes have a Z value of 0 (the horizontal axis of the graph), and over that range of coordinates and at a constant value of local Y, the pressure is constant.

Your equation should be in terms of local X and Y coordinates (see the attached image). Your equation will be a parabola in terms of "radius" when the form is pressure = a*(X^2+Y^2) + b*SQR(X^2+Y^2)+c. (except you need to substitute r for local X and s for local Y. It looks like the constant a=-4.803E6, b=0, and c=86.75E6 in your case.)

Alternatively, you could define your local coordinate system to be a cylindrical system instead of a rectangular system. Then the equation would be written in terms of one variable, the radius, as pressure = a*r^2 + b*r + c.

Technical Support Specialist

Customer Service & Support

Autodesk, Inc.

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Message 4 of 4 ( Views: 75 )