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Orthotropic Material Restrictions

For orthotropic material models, the D matrix must be symmetric and, a number of further relations must also be satisfied in order to obtain a valid material...

Material Properties Orthotropic (e.g., QPM4)

To maintain symmetry

n_yx = n_xy * E_y/E_x

and to obtain a valid material

n_xy < (E_x/E_y)^1/2

This applies to Fourier elements as a special case to simulate a bladed structure.

Material Properties Orthotropic Plane Strain (e.g. QPN4)

To maintain symmetry

E_y * (n_xy*E_z + n_yz*n_xz*E_x) = E_x * (n_xy*E_z + n_xz*n_yz*E_y)

Material Properties Orthotropic Axisymmetric (e.g. QAX4)

To maintain symmetry

n_yx = n_xy * E_y/E_x

n_zx = n_xz * E_z/E_x

n_zy = n_yz * E_z/E_y

and to obtain a valid material

n_xy < (E_x/E_y)½

n_xz < (E_x/E_z)½

n_yz < (E_y/E_z)½

Material Properties Orthotropic Solid (e.g. HX8, QSL8)

To maintain symmetry

n_yx = n_xy * E_y/E_x

n_zx = n_xz * E_z/E_x

n_zy = n_yz * E_z/E_y

and to obtain a valid material

n_xy < (E_x/E_y)½

n_xz < (E_x/E_z)½

n_yz < (E_y/E_z)½

Material Properties Orthotropic Thick (e.g. QSC4)

To maintain symmetry

n_yx = n_xy * E_y/E_x

and to obtain a valid material

n_xy < (E_x/E_y)½

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