Hi,

It depends of your material.

For an isotropic material (such as Steel), you have the same E, same G and same nu.

For an anisotropic material (such as composite) you have 3 E modulus (E1, E2, E3), 3 G modulus (G12, G13, E23) and 3 nu (nu12, nu13, nu23).

Hi,

It depends of your material.

For an isotropic material (such as Steel), you have the same E, same G and same nu.

For an anisotropic material (such as composite) you have 3 E modulus (E1, E2, E3), 3 G modulus (G12, G13, E23) and 3 nu (nu12, nu13, nu23).

For orthotropic material therea are 9 elastic constants namely young's modulus,Shear modulus and poissson ratio.All of these constants have different in three directions and it will vary.

Kindly refer this file.

https://ocw.mit.edu/courses/aeronautics-and-astronautics/16-01-unified-engineering-i-ii-iii-iv-fall-2005-spring-2006/materials-structures/zm17_20.pdf

Thanks & Regards

Dr.Yogesh Dewang

For anisotropic materials like composites, the three elastic constants: E, G and μ are different in different directions. So in Cartesian coordinate system, there are nine elastic constants.

The three shear modulii Gxy, Gyz, Gzx are identical for isotropic materials ((Ex: Steel) i.e. same in all directions. In other words E, G and Poisson's Ratio are unique for isotropic materials. They will change with temperature.

For orthotropic material (composite material) , the three elastic modulii are different in different directions.

To ensure that work done on the material be strictly positive as thermodynamics requires, there are some relational restrictions on the constants such that the elasticity or compliance tensors are positive definite.

Please refer to Article Thermodynamic restrictions on the elastic constants of bone

I think it depend on material type

best regard