.. include:: sub.txt ===== VS3D4 ===== This command is used to construct a four-node 3D viscous-spring boundary quad element object based on a bilinear isoparametric formulation. .. function:: element('VS3D4', eleTag,*eleNodes,E, G, rho, R, alphaN, alphaT) :noindex: =================================== =========================================================================== ``eleTag`` |int| unique element object tag ``eleNodes`` |listi| 4 end nodes ``E`` |float| Young's Modulus of element material ``G`` |float| Shear Modulus of element material ``rho`` |float| Mass Density of element material ``R`` |float| distance from the scattered wave source to the boundary ``alphaN`` |float| correction parameter in the normal direction ``alphaT`` |float| correction parameter in the tangential direction =================================== =========================================================================== .. note:: Reference: Liu J, Du Y, Du X, et al. 3D viscous-spring artificial boundary in time domain. Earthquake Engineering and Engineering Vibration, 2006, 5(1):93-102 .. seealso:: `Notes `_