Q4/E4#
- Model.element("Q4/E4", tag, nodes, section[, pressure, rho, b1, b2])
- Parameters:
- tag: integer
unique Element tag
- nodes
tuple, a tuple of four element nodes in counter-clockwise order
- section:
xara.PlaneSection Section object defining element material, thickness, and plane stress/strain conditions.
- pressure
float, surface pressure (optional, default = 0.0)
- rho
float, element mass density (per unit volume) from which a lumped element mass matrix is computed (optional, default=0.0)
- b1: float
constant body forces defined in the domain (optional, default=0.0)
- b2: float
constant body forces defined in the domain (optional, default=0.0)
- element quad $eleTag $iNode $jNode $kNode $lNode $thick $type $matTag <$pressure $rho $b1 $b2>
Argument |
Type |
Description |
|---|---|---|
$eleTag |
integer |
unique Element tag |
$iNode $jNode $kNode $lNode |
integer four nodes defining element boundaries |
input in counter-clockwise order around the element. |
$thick |
float |
element thickness |
$type |
string |
string representing material behavior. The type parameter can be either “PlaneStrain” or “PlaneStress.” |
$matTag |
integer |
tag of nDMaterial |
$pressure |
float |
surface pressure (optional: default = 0.0) |
$rho |
float |
element mass density (per unit volume) from which a lumped element mass matrix is computed (optional: default=0.0) |
$b1 $b2 |
float |
constant body forces defined in the isoparametric domain (optional: default=0.0) |
Theory#
EnhancedQuad element node numbering#
This element implements the Q1/E4 assumed strain interpolation [4]. The formulation is generally credited to Taylor, Beresford, and Wilson (1976) [1]. A variational basis for the formulation is given by Simo and Rifai (1990) [2].
For linear-elastic response, the formulation is equivalent to a Hellinger-Reissner element [3] with interpolation