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Effective Young's modulus of multistack
Posted Dec 7, 2010, 11:33 a.m. EST Structural Mechanics Version 3.5a 1 Reply
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Good day,
I am new in Comsol and I am trying to simulate the "effective" Young's modulus and Tensile strength of a stack with two layers (rectangle shape 10mmx30mm).
So first of all, I tried with just one layer and applied different displacements (from 0 to 3mm) to one side (the opposite side is fixed) and calculated the reaction forces at the fixed side, but I dont find a linear relation to find the Young's modulus with the slope of the line. The Young's modulus that I wrote for the material was 4.9GPa.
What is my mistake? I guess that after doing it for one layer I can do the same for the two layers, is that right?
Thanks for your help!!
Andres
I am new in Comsol and I am trying to simulate the "effective" Young's modulus and Tensile strength of a stack with two layers (rectangle shape 10mmx30mm).
So first of all, I tried with just one layer and applied different displacements (from 0 to 3mm) to one side (the opposite side is fixed) and calculated the reaction forces at the fixed side, but I dont find a linear relation to find the Young's modulus with the slope of the line. The Young's modulus that I wrote for the material was 4.9GPa.
What is my mistake? I guess that after doing it for one layer I can do the same for the two layers, is that right?
Thanks for your help!!
Andres
1 Reply Last Post Dec 7, 2010, 3:27 p.m. EST
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Posted:
1 decade ago
Hi
first of all its always best to start simple (hence one layer at the time is the "good" way).
Then are you in 2D or 3D ? and which displacement direction did you act on ?
Do not forget that if you have an isotropic material you also have the Poisson value to define and that you should rather talk of a tensor and not a just scalar Young modulus, no ?
Furthermore, 4.9GPa is a rather low value, sound more like some hard rubber, as well as 3mm displacement for a 10-30 mm object that is >=10% strain we are far outside yeld limits for most metals, hence we are no longer in a "small displacements model", so I'm not sure the standard physics are realy representatif here, Iwould at lesat turn on large displacements.
Then cehck the structural user guide, there is far more on the theory therein, try to write out the expected equations and results for your simplest case, then compare. COMSOL calculates rather correctly, when using coherent material values and when setting up your model in a mathematically and physicsally way
--
Good luck
Ivar
first of all its always best to start simple (hence one layer at the time is the "good" way).
Then are you in 2D or 3D ? and which displacement direction did you act on ?
Do not forget that if you have an isotropic material you also have the Poisson value to define and that you should rather talk of a tensor and not a just scalar Young modulus, no ?
Furthermore, 4.9GPa is a rather low value, sound more like some hard rubber, as well as 3mm displacement for a 10-30 mm object that is >=10% strain we are far outside yeld limits for most metals, hence we are no longer in a "small displacements model", so I'm not sure the standard physics are realy representatif here, Iwould at lesat turn on large displacements.
Then cehck the structural user guide, there is far more on the theory therein, try to write out the expected equations and results for your simplest case, then compare. COMSOL calculates rather correctly, when using coherent material values and when setting up your model in a mathematically and physicsally way
--
Good luck
Ivar