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When to turn the 'Large Deformation' on?

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If I have a structure with total length about 300um, the deflection in one direction under the actuation is 100um (with Large Deformation = OFF) which has obviously exceeded the linear region.

I should not trust this 100um result, correct?

Instead, I should turn on the Large Deformation and re-run the model, correct?

Thanks.

C.M.S.

4 Replies Last Post 13 apr 2017, 03:18 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 12 feb 2010, 01:53 GMT-5
Hi

From what I read, my first reaction would be to say "Yes", and to compare the results, perhaps in steps starting with smaller loads to follow the on-linear the trend.

And, in anycase I can only suggest that you also do a couple of simplified hand calculations to check that your results seems correct.

Good luck
Ivar
Hi From what I read, my first reaction would be to say "Yes", and to compare the results, perhaps in steps starting with smaller loads to follow the on-linear the trend. And, in anycase I can only suggest that you also do a couple of simplified hand calculations to check that your results seems correct. Good luck Ivar

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Posted: 1 decade ago 19 ago 2010, 15:44 GMT-4
Hi Ivar,
I that case are you saying that the large deformation on is mainly used when the results are non linear?

Assuming that I have a pre-stress condition that will linearize the results should I still use the Large Deformation on?

And lastly, in my condition if I have a circular membrane of 8 micron thickness and a 1 mm radius and clamped at the circumference, should I still set the large deformation to be on or off? I am still new at this and the manual does not seem to suggest on how shall I deal with this issues.

Hope that you could help in this matter.
Hi Ivar, I that case are you saying that the large deformation on is mainly used when the results are non linear? Assuming that I have a pre-stress condition that will linearize the results should I still use the Large Deformation on? And lastly, in my condition if I have a circular membrane of 8 micron thickness and a 1 mm radius and clamped at the circumference, should I still set the large deformation to be on or off? I am still new at this and the manual does not seem to suggest on how shall I deal with this issues. Hope that you could help in this matter.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 20 ago 2010, 02:01 GMT-4
Hi

for me (in my understanding) I use large deformation for non-linear effects to get the cross elements 2nd order of the deformation in the calculations (see the structural doc)

but if I have a doubt (and in anycase wile setting up my models I work first WITHOUT large deformations as it's much quicker to solve) I run a "large deformation" case at the end, just to compare my results, in case of large diferences, I investigate further

--
Good luck
Ivar
Hi for me (in my understanding) I use large deformation for non-linear effects to get the cross elements 2nd order of the deformation in the calculations (see the structural doc) but if I have a doubt (and in anycase wile setting up my models I work first WITHOUT large deformations as it's much quicker to solve) I run a "large deformation" case at the end, just to compare my results, in case of large diferences, I investigate further -- Good luck Ivar

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Posted: 8 years ago 13 apr 2017, 03:18 GMT-4
Hi
I would like to ask , set the large deformation switch where? or how to set the large deformation of the vertical cantilever beam?

Thank you in advance!
Hi I would like to ask , set the large deformation switch where? or how to set the large deformation of the vertical cantilever beam? Thank you in advance!

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