structure shell property command

Syntax

structure shell property keyword <range>

Primary keywords:

density    thickness    thermal-expansion    anisotropic-membrane    anisotropic-bending    anisotropic-both    material-x    isotropic    orthotropic-membrane    orthotropic-bending    orthotropic-both

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

shell thickness

thermal-expansion f

thermal expansion coefficient

anisotropic-membrane f1 f2 f3 f4 f5 f6

anisotropic membrane material properties {c’11, c’12, c’13, c’22, c’23, c’33} [F/L2], which define membrane material-stiffness matrices [E’m] and [E’b], respectively, in the material directions x’, y’, z’.

anisotropic-bending f1 f2 f3 f4 f5 f6

anisotropic bending material properties {c’11, c’12, c’13, c’22, c’23, c’33} [F/L2], which define bending material-stiffness matrices [E’m] and [E’b], respectively, in the material directions x’, y’, z’.

anisotropic-both f1 f2 f3 f4 f5 f6

anisotropic membrane and bending material properties {c’11, c’12, c’13, c’22, c’23, c’33} [F/L2], which define membrane and bending material-stiffness matrices [E’m] and [E’b], respectively, in the material directions x’, y’, z’.

material-x v

Specify the vector (Xx, Xy, Xz) whose projection onto the shell 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/L2] and v is Poisson’s ratio

orthotropic-membrane f1 f2 f3 f4

orthotropic membrane material properties {c’11, c’12, c’22, c’33} [F/L2], which define membrane material-stiffness matrices [E’m] and [E’b], respectively, in the material directions x’, y’, z’.

orthotropic-bending f1 f2 f3 f4

orthotropic bending material properties { c’11, c’12, c’22, c’33 } [F/L2], which define bending material-stiffness matrices [ E’m ] and [ E’b ], respectively, in the material directions x’, y’, z’.

orthotropic-both f1 f2 f3 f4

orthotropic membrane and bending material properties {c’11, c’12, c’22, c’33} [F/L2], which define membrane and bending material-stiffness matrices [E’m] and [E’b], respectively, in the material directions x’, y’, z’.

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 shell 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.