3.1.10.70. FourNodeQuadUP Element

This command constructs a four-node plane-strain quadrilateral element for coupled solid-fluid (u-p) analysis of saturated porous media based on Biot theory. Each node has two solid displacement DOFs and one pore-pressure DOF. Use with -ndm 2 -ndf 3. The registered command name is quadUP.

element quadUP $eleTag $iNode $jNode $kNode $lNode $thick $matTag $bulk $fmass $hPerm $vPerm <$b1 $b2 $t>

Argument	Type	Description
$eleTag	integer	unique element tag
$iNode $jNode $kNode $lNode	integer	four nodes in counter-clockwise order
$thick	float	element thickness
$matTag	integer	tag of a previously defined ND material
$bulk	float	combined undrained bulk modulus relating pore pressure and volumetric strain
$fmass	float	fluid mass density
$hPerm $vPerm	float	permeability in horizontal and vertical directions
$b1 $b2	float	optional body-force components (default 0.0)
$t	float	optional uniform normal traction; positive in tension (default 0.0)

Note

1. Record pore pressure at nodes with a Node Recorder on DOF 3.

2. Valid Element Recorder queries include force, stiffness, and material $matNum ....

Example

1. Tcl Code

element quadUP 1 1 2 3 4 1.0 1 2.2e6 1000.0 1.0e-5 1.0e-5

2. Python Code

element('quadUP', 1, 1, 2, 3, 4, 1.0, 1, 2.2e6, 1000.0, 1.0e-5, 1.0e-5)

Code developed by: Zhaohui Yang, UC San Diego