von Mises stress/ Worst Case results -Simulation 2009
von Mises stress/ Worst Case results -Simulation 2009
(OP)
Using SW 2009 with Simulation Pro I get some very strange results.
I am modelling a very simple bicycle frame under loads. I have designed it using weldment structural members and meshed using beam meshing. My results have been fairly strange.
The default stress plot is STRMAX- Worst Case stress. This shows an accurate/expected reading of around 40MPa under the load I am subjecting it to. But when I list the results and get the von Mises stress table, my maximum vM stress is a measly 900N/m^2 or so.
My question is... whats wrong? Why such the massive difference between max worst case versus max von Mises?
A second question is, is there any way to refine beam meshing? I only have the option to 'create mesh' with an all beam component. Cheers for any help,
Robert
I am modelling a very simple bicycle frame under loads. I have designed it using weldment structural members and meshed using beam meshing. My results have been fairly strange.
The default stress plot is STRMAX- Worst Case stress. This shows an accurate/expected reading of around 40MPa under the load I am subjecting it to. But when I list the results and get the von Mises stress table, my maximum vM stress is a measly 900N/m^2 or so.
My question is... whats wrong? Why such the massive difference between max worst case versus max von Mises?
A second question is, is there any way to refine beam meshing? I only have the option to 'create mesh' with an all beam component. Cheers for any help,
Robert






RE: von Mises stress/ Worst Case results -Simulation 2009
How many elements are there on each section of the weldment?
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RE: von Mises stress/ Worst Case results -Simulation 2009
How do you have confidence in the results if you can't compare similar studies of different mesh sizes? Perhaps i'm missing something fundamental about beam meshing and its accuracy?
RE: von Mises stress/ Worst Case results -Simulation 2009
Post a screen shot of the mesh menu. I don't have it in front of me right now.
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RE: von Mises stress/ Worst Case results -Simulation 2009
See the screenshot, as soon as I click create mesh, it creates the mesh without further input or adjustment. It only does this on models with all beam elements.
That isn't the real problem though (although I would like more elements), the main problem is the massive difference between the plotted Worst Case stress of around 40MPa, and the tiny von Mises stress of a measly 900Pa at the same node.
Their doesn't seem to be any decent way of producing the results either for an all beam design. If I click 'Create Report', i get a warning that 'Reports cannot be generated for pure beam mesh studies'. I can only assume these problems are due to solidworks being unable to work with beam components properly. What's the reasoning behind not generating a report, just because a design uses beams doesn't make the data/results any less relevant. I'm left with 2 options, a graphical plot, and a inaccurate von Mises stress table.
RE: von Mises stress/ Worst Case results -Simulation 2009
FEMAP has an even nicer presentation in which it shows a virtual outline of the beam and a cock's comb presentation of output values.
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RE: von Mises stress/ Worst Case results -Simulation 2009
Robert
RE: von Mises stress/ Worst Case results -Simulation 2009
A little trick is to edit your .ses file so you can make a parametric model. Save it as a .geo file.
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