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 function struct.shell.beta. It can be visualized with the Structural Geometry plot item by choosing the corresponding System attribute.