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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

nyx = nxy * Ey/Ex

and to obtain a valid material

nxy < (Ex/Ey)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

Ey * (nxy*Ez + nyz*nxz*Ex) = Ex * (nxy*Ez + nxz*nyz*Ey)

Material Properties Orthotropic Axisymmetric (e.g. QAX4)

To maintain symmetry

nyx = nxy * Ey/Ex

nzx = nxz * Ez/Ex

nzy = nyz * Ez/Ey

and to obtain a valid material

nxy < (Ex/Ey)

nxz < (Ex/Ez)

nyz < (Ey/Ez)

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

To maintain symmetry

nyx = nxy * Ey/Ex

nzx = nxz * Ez/Ex

nzy = nyz * Ez/Ey

and to obtain a valid material

nxy < (Ex/Ey)

nxz < (Ex/Ez)

nyz < (Ey/Ez)

Material Properties Orthotropic Thick (e.g. QSC4)

To maintain symmetry

nyx = nxy * Ey/Ex

and to obtain a valid material

nxy < (Ex/Ey)

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