3.1.10.88. AC3D8 Element

This command constructs an eight-node hexahedral acoustic fluid element for dam-reservoir and fluid-domain modeling. Each node carries one pressure DOF. The element requires an AcousticMedium ND material. Use with -ndm 3 -ndf 1 for the fluid mesh.

element AC3D8 $eleTag $N1 $N2 $N3 $N4 $N5 $N6 $N7 $N8 $matTag

Argument	Type	Description
$eleTag	integer	unique element tag
$N1 … $N8	integer	eight node tags in standard brick order
$matTag	integer	tag of a previously defined AcousticMedium material

Note

1. Define the acoustic material first: nDMaterial AcousticMedium $matTag $K $rho <$gamma>.

2. For fluid-structure coupling at interfaces see ASI3D8 Element. For acoustic boundaries see AV3D4 Element.

3. Valid Element Recorder queries include force and stiffness.

Example

1. Tcl Code

nDMaterial AcousticMedium 1 2.2e9 1000.0
element AC3D8 1 1 2 3 4 5 6 7 8 1

2. Python Code

nDMaterial('AcousticMedium', 1, 2.2e9, 1000.0)
element('AC3D8', 1, 1, 2, 3, 4, 5, 6, 7, 8, 1)

Code developed by: Quan Gu, Yichao Gao, and Zhijian Qiu, Xiamen University