I trying to do a simple analysis of a large steel cylinder resting on an aluminum frame. The can is free to slide on the frame, all weldments are bonded. The analysis runs and show a stress range from 0 to 28 ksi but the entire frame is colored blue, i.e. 0 ksi. There should clearly be some high stress areas where the frame bends and around the welds. What might be the cause for just seeing a uniform stress state? The deflections show so that's not an issue.
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Solved by zhuangs. Go to Solution.
Hi Buckeye81,
Based on what I see, it looks as if the cylinder is not restrained. You should check that it is making contact with the rollers. You may need to put a small "flat" section on the rollers and cylinder so that you have contact over an area instead of a line (or point depending on the profile of the rollers).
It has been a few years since I used Inventor's stress analysis (I presume that is what you are using, right?), but chances are the stresses are being shown properly based on the analysis setup (garbage in -> garbage out). If you display where the maximum stress occurs, it is probably at a single point, and the rest of the model has low enough stress that it appears blue (somewhere between 0 and a couple ksi).
When you write that the displacements show, you're implying that they are correct. Are they? The stresses are shown, too, but they are not correct.
Actually the cylinder is restrained and is tangent to the rollers. I have since modifed the model to remove the cylinder, create flats at the proper angle on the rollers, and apply the equivalent load on those flats. Same result. Doesn't matter if I modify the scale of the color bars, the structure remains entirely blue...constant stress everywhere.
To check this, can you pick a node in the conact area and then check the results of that node, to see whether the result is still zero.
Next, activate the gravity option, and then run the analysis. After that, check whether the model is blue for stress result.
-Shoubing
buckeye81,
You may ultimately need to post your problem to the Inventor discussion group instead of this one (Simulation Mechanical is separate from Inventor), but here are a few other thoughts that may help determine what's going on.