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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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femur modeling

Posted 14.10.2012, 09:59 GMT-4 Geometry, Studies & Solvers, Structural Mechanics Version 4.0a 6 Replies

Aastha Kapoor
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Hi!
I am building a model of femur(thigh bone) and aim at studying their stress and strain distribution on applying a pint load.I have built the model but it doesn't seem to compute,and i can't figure out why.Please check the model and point out the errors that need correction.

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6 Replies Last Post 19.10.2012, 10:15 GMT-4
Mayur
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Posted: 1 decade ago 14.10.2012, 15:04 GMT-4
In your model, mesh is not defined in all domains or on boundaries and also it is not fine enough for solver to converge the solution. And under Prescribed displacement you need to select boundary surfaces.
In your model, mesh is not defined in all domains or on boundaries and also it is not fine enough for solver to converge the solution. And under Prescribed displacement you need to select boundary surfaces.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 15.10.2012, 03:17 GMT-4
Hi

I can only stress: avoid using point or edge constrints, but only 1 level lower than domain => boundary loads. All other make singularities and it far more difficult to analyse your models

--
Good luck
Ivar
Hi I can only stress: avoid using point or edge constrints, but only 1 level lower than domain => boundary loads. All other make singularities and it far more difficult to analyse your models -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago 15.10.2012, 08:32 GMT-4
You are applying the bone material to the boundaries not the domains, and the same for the mesh. Both should be defined at the domain level unless you want to use shell elements.
You are applying the bone material to the boundaries not the domains, and the same for the mesh. Both should be defined at the domain level unless you want to use shell elements.
Aastha Kapoor
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Posted: 1 decade ago 15.10.2012, 09:17 GMT-4
Thank you for your valuable reply Sir.
I am stuck at an error saying "System matrix is zero".Is there a way to rectify it?
Thank you for your valuable reply Sir. I am stuck at an error saying "System matrix is zero".Is there a way to rectify it?
Aastha Kapoor
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Posted: 1 decade ago 19.10.2012, 10:01 GMT-4

Thank you for your valuable reply Sir.
I am stuck at an error saying "System matrix is zero".Is there a way to rectify it?

Though i have changed from point load to a boundary load,and want to plot von-mises stress distribution,the computation shows errors,with the system matrix being zero.Pls let me how to work on it?
[QUOTE] Thank you for your valuable reply Sir. I am stuck at an error saying "System matrix is zero".Is there a way to rectify it? [/QUOTE] Though i have changed from point load to a boundary load,and want to plot von-mises stress distribution,the computation shows errors,with the system matrix being zero.Pls let me how to work on it?
Mayur
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Posted: 1 decade ago 19.10.2012, 10:15 GMT-4
If you would have followed mine and Nagi's suggestions, you should get the solution.
If you would have followed mine and Nagi's suggestions, you should get the solution.

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