User Area > Advice
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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