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Unexpected Displacement Change Between Studies
Posted 11 nov. 2016, 01:14 UTC−5 Heat Transfer & Phase Change, Simulation Apps, Geometry, Modeling Tools & Definitions, Parameters, Variables, & Functions, Results & Visualization, Studies & Solvers, Structural Mechanics Version 5.2 1 Reply
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Hello everyone,
I recently received plenty of help from Comsol tech support in putting together a model that operates like so:
1st) Heat Transfer in Solids and Solid Mechanics are coupled in order to apply a heat load on a simple geometry which then gives a nice predicted displacement upon executing the first study.
2nd) Within the same component, a second Solid Mechanics interface(not included in the first study) applies a different set of boundary conditions(prescribed displacements/fixed constraints) but no applied force. Eventually I want to apply an edge load to the heat deformed geometry from the first study using a second study which employs only the second Solid Mechanics interface. In order to achieve this, the variables from the first study are entered in to Initial Stress(solid.sx, solid.sxy, etc...) and the second study's stationary solver is set to use variables from the first study/solution under "Values of Variables Not Solved For". The alternative is to export the first geometry and import it back into a second component which is a bit of a headache and has a couple of inconsistencies which I have not resolved.
At any rate, I finally execute the second study and I find that the displacement has changed. Why would the displacement from solution 2 be different than the displacement from solution 1 in the case that there is no applied force in the second study? Somehow, just "holding" the geometry differently with different boundary conditions will induce a deformation? I essentially just want to run the second study without any applied force to make sure that the displacement is the same as given by solution 1 and I am starting from a good place.
Please let me know if you need any more information. I would really appreciate any help in resolving this problem. Thank you.
I recently received plenty of help from Comsol tech support in putting together a model that operates like so:
1st) Heat Transfer in Solids and Solid Mechanics are coupled in order to apply a heat load on a simple geometry which then gives a nice predicted displacement upon executing the first study.
2nd) Within the same component, a second Solid Mechanics interface(not included in the first study) applies a different set of boundary conditions(prescribed displacements/fixed constraints) but no applied force. Eventually I want to apply an edge load to the heat deformed geometry from the first study using a second study which employs only the second Solid Mechanics interface. In order to achieve this, the variables from the first study are entered in to Initial Stress(solid.sx, solid.sxy, etc...) and the second study's stationary solver is set to use variables from the first study/solution under "Values of Variables Not Solved For". The alternative is to export the first geometry and import it back into a second component which is a bit of a headache and has a couple of inconsistencies which I have not resolved.
At any rate, I finally execute the second study and I find that the displacement has changed. Why would the displacement from solution 2 be different than the displacement from solution 1 in the case that there is no applied force in the second study? Somehow, just "holding" the geometry differently with different boundary conditions will induce a deformation? I essentially just want to run the second study without any applied force to make sure that the displacement is the same as given by solution 1 and I am starting from a good place.
Please let me know if you need any more information. I would really appreciate any help in resolving this problem. Thank you.
1 Reply Last Post 11 nov. 2016, 01:31 UTC−5
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Posted:
8 years ago
I thought of initial stress as implementing the first geometry in to the second study when in fact I suppose it is exerting the forces stressed upon the first geometry again but with my new boundary conditions. If this is the case then it defeats the purpose of my model. I need to be able to apply heat deformation under one set of boundary conditions and then apply mechanical force to the heat deformed geometry under a distinctly different set of boundary conditions. Is the only way around this to export/import the geometries in to different components? Thank you.