structure geogrid property
command
Syntax
- structure geogrid property keyword ... <range>
Primary keywords:
density thickness thermal-expansion anisotropic-membrane anisotropic-bending material-x isotropic orthotropic-membrane orthotropic-bending coupling-cohesion coupling-friction coupling-stiffness slide slide-tolerance
Assigns a property to elements in the range. The element can have isotropic, orthotropic, or anisotropic elastic material properties. The following properties are available:
- density f
density (needed if dynamic mode or gravity is active)
- thickness f
geogrid thickness
- thermal-expansion f
thermal expansion coefficient
- anisotropic-membrane f1 f2 f3 f4 f5 f6
anisotropic membrane material properties {\(c^{\prime}_{11}, c^{\prime}_{12}, c^{\prime}_{13}, c^{\prime}_{22}, c^{\prime}_{23}, c^{\prime}_{33}\)} \([F/L^2]\), which define membrane material-stiffness matrices \([Eʹ_m]\) and \([Eʹ_b]\), respectively, in the material directions \(x'\), \(y'\), \(z'\).
- anisotropic-bending f1 f2 f3 f4 f5 f6
anisotropic bending material properties {\(c^{\prime}_{11}, c^{\prime}_{12}, c^{\prime}_{13}, c^{\prime}_{22}, c^{\prime}_{23}, c^{\prime}_{33}\)} \([F/L^2]\), which define bending material-stiffness matrices \([Eʹ_m]\) and \([Eʹ_b]\), respectively, in the material directions \(x'\), \(y'\), \(z'\).
- material-x v
specify the vector v whose projection onto the geogrid surface defines the \(x'\)-axis of the material coordinate system. The material directions correspond with the principal directions of orthotropy (for more information, see below).
- isotropic f1 f2
isotropic material properties: \(E\) and \(v\) where \(E\) is Young’s modulus \([F/L^2]\) and \(v\) is Poisson’s ratio
- orthotropic-membrane f1 f2 f3 f4
orthotropic membrane material properties {\(c^{\prime}_{11}, c^{\prime}_{12}, c^{\prime}_{22}, c^{\prime}_{33}\)} \([F/L^2]\), which define membrane material-stiffness matrices \([Eʹ_m]\) and \([Eʹ_b]\), respectively, in the material directions \(x'\), \(y'\), \(z'\).
- orthotropic-bending f1 f2 f3 f4
orthotropic bending material properties {\(c^{\prime}_{11}, c^{\prime}_{12}, c^{\prime}_{22}, c^{\prime}_{33}\)} \([F/L^2]\), which define bending material-stiffness matrices \([Eʹ_m]\) and \([Eʹ_b]\), respectively, in the material directions \(x'\), \(y'\), \(z'\).
- coupling-cohesion f
coupling spring cohesion (stress units)
- coupling-friction f
coupling spring friction angle (degrees)
- coupling-stiffness f
coupling spring stiffness per unit area
- slide b
large-strain sliding flag
- slide-tolerance f
large-strain sliding tolerance
Further information on the material-x keyword
The material coordinate system, \(xʹ\), \(yʹ\), \(zʹ\), defines the orthotropic and anisotropic properties and satisfies the following conditions: 1) \(xʹ\) is the projection of the given vector onto the surface; 2) \(zʹ\) is normal to the surface and aligned with the \(z\)-axis of the shell-type element coordinate system; and 3) \(yʹ\) = \(zʹ\) × \(xʹ\). The material coordinate system moves with the shell surface during large-strain updates, which means that the relative orientations of this system and the element local system do not change (the angle \(β\) in this figure does not change). If the material-x vector is not specified, then the \(xʹ\)-axis will be aligned with the \(x\)-axis of the structural element local coordinate system.
The material coordinate system can be queried with the command
structure geogrid list property material-x
and the FISH functionstruct.shell.beta
. It can be visualized with the Structural Geometry plot item by choosing the corresponding System attribute.
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