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modeling of stresses in a brace
Posted Apr 25, 2017, 4:23 p.m. EDT Modeling Tools & Definitions, Parameters, Variables, & Functions, Structural Mechanics 1 Reply
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For a project, we have to make a mechanical simulation of the stresses in a brace. We already have a CAD-model of the brace, which is an elliptic cylinder with an excision on the side of the spine (see figure attached). The dimensions are: height=380mm, width outside (long diameter of ellipse)=270mm, depth outside (short diameter of ellipse)=220mm, thickness=4mm.
The aim of our project is to model the stresses present in the brace and to remove redundant material in order to make the brace lighter.
In the geometry toolbar, we already have divided the CAD-model in small squares using work planes and we have applied forces on those squares. Actually we applied these forces as pressures on the inside of the brace. Not on all squares are pressures applied. On the dorsal side of the brace, the applied pressures are much higher than those applied on the ventral side.
In the physics tree, we selected structural mechanics -> solid mechanics. As we have never worked before with Comsol, we are not sure that we made the right choice here. The results we get after building a mesh and computing, is not the stress distribution that we expected to obtain. We have already tried to change our constraints, but the result doesn’t become better. Also, when we make our E-modulus much higher, the result stays the same. Our question is now: What should we select? Is it correct to select solid mechanics in our situation or do we need something else?
Thank you very much for your time!
Mathilde and Heleen
The aim of our project is to model the stresses present in the brace and to remove redundant material in order to make the brace lighter.
In the geometry toolbar, we already have divided the CAD-model in small squares using work planes and we have applied forces on those squares. Actually we applied these forces as pressures on the inside of the brace. Not on all squares are pressures applied. On the dorsal side of the brace, the applied pressures are much higher than those applied on the ventral side.
In the physics tree, we selected structural mechanics -> solid mechanics. As we have never worked before with Comsol, we are not sure that we made the right choice here. The results we get after building a mesh and computing, is not the stress distribution that we expected to obtain. We have already tried to change our constraints, but the result doesn’t become better. Also, when we make our E-modulus much higher, the result stays the same. Our question is now: What should we select? Is it correct to select solid mechanics in our situation or do we need something else?
Thank you very much for your time!
Mathilde and Heleen
1 Reply Last Post Apr 25, 2017, 5:28 p.m. EDT
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Posted:
8 years ago
Quick remark: changing the Young's modulus will change the magnitude of the displacements but not the stresses in a part.
Jeff
Jeff