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Problems computing the volume change of a domain

Posted 2012年3月27日 GMT-4 20:34 Parameters, Variables, & Functions, Results & Visualization, Structural Mechanics Version 4.2 0 Replies

Karen Pascal
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Hello,

I'm modelling a pressurized sphere within an elastic domain, in 2D axi-symmetric Structural Mechanics (v4.2). I'm trying to check the volume change of the sphere.

There are analytic solutions available when the sphere is a cavity so I have set a E_sphere=1 Pa and I have tried several of the methods that were already mentioned in some of the threads in the forum:
-> 1) in Results / Volume integration - expression (1) of the sphere with frame Material / Spatial and calculate the difference

-> 2) same as above with Results / Surface integration - expression (1) of the 'sphere' with "compute volume integral"

-> 3) in Results / Line integration - expression 'solid.disp' of the boundary of the sphere with "compute surface integral"
This option should -as far as I understood- give me the volume change of the sphere directly (please correct me if I'm wrong)

My problem is that there is still quite a lot of discrepancies between this method, even when I'm trying to refine the mesh. The second method (with surface integration) is the best but there is still ~25% error with the analytical result ! Am I doing something wrong ??

What method would you recommend to calculate the change in volume of a domain in 2D axisym. ??

Thanks a lot !

Karen
0 Replies Last Post 2012年3月27日 GMT-4 20:34
COMSOL Moderator

Hello Karen Pascal

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