SSPbrick Element

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This command is used to construct a SSPbrick element object.

element SSPbrick $eleTag $iNode $jNode $kNode $lNode $mNode $nNode $pNode $qNode $matTag <$b1 $b2 $b3>

$eleTag	unique integer tag identifying element object
$iNode $jNode $kNode $lNode $mNode $nNode $pNode $qNode	the eight nodes defining the element, input in counterclockwise order (same node number scheme as for the stdBrick Element)
$matTag	unique integer tag associated with previously-defined nDMaterial object
$b1 $b2 $b3	constant body forces in global x-, y-, and z-directions, respectively (optional, default = 0.0)

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The SSPbrick element is an eight-node hexahedral element using physically stabilized single-point integration (SSP --> Stabilized Single Point). The stabilization incorporates an enhanced assumed strain field, resulting in an element which is free from volumetric and shear locking. The elimination of shear locking results in greater coarse mesh accuracy in bending dominated problems, and the elimination of volumetric locking improves accuracy in nearly-incompressible problems. Analysis times are generally faster than corresponding full integration elements.

NOTES:

1. Valid queries to the SSPbrick element when creating an ElementalRecorder object correspond to those for the nDMaterial object assigned to the element (e.g., 'stress', 'strain'). Material response is recorded at the single integration point located in the center of the element.
2. The SSPbrick element was designed with intentions of duplicating the functionality of the stdBrick Element. If an example is found where the SSPbrick element cannot do something that works for the stdBrick Element, e.g., material updating, please contact the developers listed below so the bug can be fixed.

EXAMPLES:

SSPbrick element definition with element tag 1, nodes 1, 2, 3, 4, 5, 6, 7, and 8, material tag 1, x- and y-directed body forces of zero, and z-directed body force of -10.0

element SSPbrick 1  1 2 3 4 5 6 7 8  1 0.0 0.0 -10.0

Elemental recorders for stress and strain when using the SSPbrick element (note the difference from the stdBrick Element)

recorder Element -eleRange 1 $numElem -time -file stress.out  stress
recorder Element -eleRange 1 $numElem -time -file strain.out  strain

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Code Developed by: Chris McGann, Pedro Arduino, & Peter Mackenzie-Helnwein, at the University of Washington

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