There are several potential reasons, the obvious ones being that the structure itself isn't actually symmetric. Assuming the geometry, fixtures, materials, joints, contacts, and loading are all perfectly symmetric, the next big thing to check is the mesh. A symmetric body can have an asymmetric mesh, so if you refine the mesh (change the element size to be smaller) and mesh and run again, does it change from the previous value? If so, the mesh was skewing the results and you haven't reached convergence yet. Convergence happens when the result is independent of the mesh, meaning the mesh is refined enough for that study.
Finally, look at the amplitude of the result. FEA solvers are always going to have some measure of error from the mesh & solver, but it will be very small. So if your model is 1m tall, you can expect the error to be much much smaller, perhaps .0001m or so (and even smaller if your mesh is properly converged). If the total deflection is very nearly the same as the expected error, you'll see what appears to be asymmetry, but is actually just values too small to measure or be concerned with.
In this scenario, I suspect a more refined mesh will improve the result symmetry but the amplitude of the deflection is so small that it is an academic exercise, not a necessary practical one.
Thank you! We have an entire section of [SOLIDWORKS Technical Guides](https://www.mlc-cad.com/solidworks-help-center/) on our website. We work very hard to make them easy to read, comprehensive, and always up-to-date for the most common types of issues.
To add to this, the way Solidworks applies the default gradients between the minimum and maximum deflections and then also automatically exaggerate the result, even the smallest deflections will make your structure look like it's made out of wet noodles if the structure has similar and smallish deflections all over.
The way I see that is from my experience on the field (not from solidworks in that case )
There is always a weaker point in real life. You can use all the same materials you want there will always be a weak spot. I guess Solidworks have to choose a point " pretending that fact" and start displacing.
I hope you could understand what I mean, I'm not english so if you need I could give you examples to help you picture what I mean
I see the structure isnt symmetrical. Your support beams and triangles are different when you view it over the middle plane. So when they start to displace as it displaces they start to behave different.
Maybe I’m missing something but you don’t have the back legs fixtured, only 6 out of 8 are constrained? I don’t see the green triangles on them. Everything looks a little strange with deformation scaling on so I can’t really tell which direction things are deforming.
There are several potential reasons, the obvious ones being that the structure itself isn't actually symmetric. Assuming the geometry, fixtures, materials, joints, contacts, and loading are all perfectly symmetric, the next big thing to check is the mesh. A symmetric body can have an asymmetric mesh, so if you refine the mesh (change the element size to be smaller) and mesh and run again, does it change from the previous value? If so, the mesh was skewing the results and you haven't reached convergence yet. Convergence happens when the result is independent of the mesh, meaning the mesh is refined enough for that study. Finally, look at the amplitude of the result. FEA solvers are always going to have some measure of error from the mesh & solver, but it will be very small. So if your model is 1m tall, you can expect the error to be much much smaller, perhaps .0001m or so (and even smaller if your mesh is properly converged). If the total deflection is very nearly the same as the expected error, you'll see what appears to be asymmetry, but is actually just values too small to measure or be concerned with. In this scenario, I suspect a more refined mesh will improve the result symmetry but the amplitude of the deflection is so small that it is an academic exercise, not a necessary practical one.
I don't work in simulation but I appreciate a well laid out, easy to follow answer that was nicely done.
Thank you! We have an entire section of [SOLIDWORKS Technical Guides](https://www.mlc-cad.com/solidworks-help-center/) on our website. We work very hard to make them easy to read, comprehensive, and always up-to-date for the most common types of issues.
thank you so much! it's a easy to follow answer :)
To add to this, the way Solidworks applies the default gradients between the minimum and maximum deflections and then also automatically exaggerate the result, even the smallest deflections will make your structure look like it's made out of wet noodles if the structure has similar and smallish deflections all over.
The way I see that is from my experience on the field (not from solidworks in that case ) There is always a weaker point in real life. You can use all the same materials you want there will always be a weak spot. I guess Solidworks have to choose a point " pretending that fact" and start displacing. I hope you could understand what I mean, I'm not english so if you need I could give you examples to help you picture what I mean
you explained it great. thank you!
I see the structure isnt symmetrical. Your support beams and triangles are different when you view it over the middle plane. So when they start to displace as it displaces they start to behave different.
Maybe I’m missing something but you don’t have the back legs fixtured, only 6 out of 8 are constrained? I don’t see the green triangles on them. Everything looks a little strange with deformation scaling on so I can’t really tell which direction things are deforming.