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Calculting Young's modulus of a complex shape using Comsol

Posted Mar 14, 2010, 8:30 a.m. EDT 5 Replies

Amit Finkler
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Hi,

Do you know whether one can calculate Young's modulus of a complex shape using Comsol?

Thanks,

Amit
5 Replies Last Post Mar 14, 2010, 4:23 p.m. EDT
Amit Finkler
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Posted: 1 decade ago Mar 14, 2010, 8:32 a.m. EDT

Hi,

Do you know whether one can calculate Young's modulus of a complex shape using Comsol?

Thanks,

Amit


Sorry, I meant the spring constant of a material assuming it has a homgeneous Young's constant
[QUOTE] Hi, Do you know whether one can calculate Young's modulus of a complex shape using Comsol? Thanks, Amit [/QUOTE] Sorry, I meant the spring constant of a material assuming it has a homgeneous Young's constant
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 14, 2010, 10:06 a.m. EDT
Hi

from my understanding the Young modulus remains a material property that is linked to the stiffness and the inertia of the part, no ?

So if you have the geometry, the density and experimental values for the siffness under known load conditions you should be able to recalculate back (via anoptimisation or a series of parametric sweep solving and the old "abaque" way) to estimate the material Young modulus.

But you must also assume your model is correct and all "important" terms are included

Good luck
Ivar
Hi from my understanding the Young modulus remains a material property that is linked to the stiffness and the inertia of the part, no ? So if you have the geometry, the density and experimental values for the siffness under known load conditions you should be able to recalculate back (via anoptimisation or a series of parametric sweep solving and the old "abaque" way) to estimate the material Young modulus. But you must also assume your model is correct and all "important" terms are included Good luck Ivar
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 14, 2010, 12:53 p.m. EDT
Hi

if it's the stiffness "k[N/m]" you want, then it is straightforward, provided you have correct material data: E, nu, rho, the geometry and the load boundary case:

you load with an Applied force such as 1 or 1000[N] and you calcualte the average displacements of your interface, then

k[N/m] = (Applied_force [N]) / average(dz [m])


Good luck
Ivar
Hi if it's the stiffness "k[N/m]" you want, then it is straightforward, provided you have correct material data: E, nu, rho, the geometry and the load boundary case: you load with an Applied force such as 1 or 1000[N] and you calcualte the average displacements of your interface, then k[N/m] = (Applied_force [N]) / average(dz [m]) Good luck Ivar
Amit Finkler
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Posted: 1 decade ago Mar 14, 2010, 2:08 p.m. EDT

you load with an Applied force such as 1 or 1000[N] and you calcualte the average displacements of your interface, then

k[N/m] = (Applied_force [N]) / average(dz [m])


Calculate with which module/submodule? I can draw the shape using Inventor, for example, and import it into Comsol. Then, which module do I use?

Thanks,

Amit
[QUOTE] you load with an Applied force such as 1 or 1000[N] and you calcualte the average displacements of your interface, then k[N/m] = (Applied_force [N]) / average(dz [m]) [/QUOTE] Calculate with which module/submodule? I can draw the shape using Inventor, for example, and import it into Comsol. Then, which module do I use? Thanks, Amit
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 14, 2010, 4:23 p.m. EDT
Hi

I would use either the basic structural or the "full" structural module, but you have also structural in the MEMS module

If your shape is simple you should use the simplebar in compression k=E*A/L formula (E young modulus, A section area, L length of bar in compression), for bars in flexure it's more the k=3*E*I/L^3 were I=1/12*w*h^3 the inertia with w bar width (defining axis of rotation), h bar height, L bar length that yu should use. Have a look at one of the numerous books on elasticity (i.e. Timoshenko or others)

For complex geometries, the CAD 3D shape and directly the FEM in COMSOL is the best, but always check coherence with the simple formulas above

Good luck
Ivar
Hi I would use either the basic structural or the "full" structural module, but you have also structural in the MEMS module If your shape is simple you should use the simplebar in compression k=E*A/L formula (E young modulus, A section area, L length of bar in compression), for bars in flexure it's more the k=3*E*I/L^3 were I=1/12*w*h^3 the inertia with w bar width (defining axis of rotation), h bar height, L bar length that yu should use. Have a look at one of the numerous books on elasticity (i.e. Timoshenko or others) For complex geometries, the CAD 3D shape and directly the FEM in COMSOL is the best, but always check coherence with the simple formulas above Good luck Ivar

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