.. include:: sub.txt === HDR === This command is used to construct an HDR bearing element object in three-dimension. The 3D continuum geometry of an high damping rubber bearing is modeled as a 2-node, 12 DOF discrete element. This is the third element in the series of elements developed for analysis of base-isolated structures under extreme loading (others being ElastomericX and LeadRubberX). The major difference between HDR element with ElastomericX is the hysteresis model in shear. The HDR element uses a model proposed by Grant et al. (2004) to capture the shear behavior of a high damping rubber bearing. The time-dependent values of mechanical properties (e.g., vertical stiffness, buckling load capacity) can also be recorded using the "parameters" recorder. .. function:: element('HDR', eleTag,*eleNodes,Gr, Kbulk, D1, D2, ts, tr, n, a1, a2, a3, b1, b2, b3, c1, c2, c3, c4, <, y1, y2, y3>,,,,,,) :noindex: For 3D problem ========================================================================================= =========================================================================== ``eleTag`` |int| unique element object tag ``eleNodes`` |listi| a list of two element nodes ``Gr`` |float| shear modulus of elastomeric bearing ``Kbulk`` |float| bulk modulus of rubber ``D1`` |float| internal diameter ``D2`` |float| outer diameter (excluding cover thickness) ``ts`` |float| single steel shim layer thickness ``tr`` |float| single rubber layer thickness ``n`` |int| number of rubber layers ``a1`` ``a2`` ``a3`` ``b1`` ``b2`` ``b3`` ``c1`` ``c2`` ``c3`` ``c4`` |float| parameters of the Grant model ``x1`` ``x2`` ``x3`` |float| vector components in global coordinates defining local x-axis (optional) ``y1`` ``y2`` ``y3`` |float| vector components in global coordinates defining local y-axis (optional) ``kc`` |float| cavitation parameter (optional, default = 10.0) ``PhiM`` |float| damage parameter (optional, default = 0.5) ``ac`` |float| strength reduction parameter (optional, default = 1.0) ``sDratio`` |float| shear distance from iNode as a fraction of the element length (optional, default = 0.5) ``m`` |float| element mass (optional, default = 0.0) ``tc`` |float| cover thickness (optional, default = 0.0) ========================================================================================= =========================================================================== .. seealso:: `Notes `_