A link object connects two joints, i and j, separated by length L, such that specialized structural behavior may be modeled. Linear, nonlinear, and frequency-dependent properties may be assigned to each of the six deformational degrees-of-freedom (DOF) which are internal to a link, including axial, shear, torsion, and pure bending. Internal deformation is then calculated from joint j displacement relative to joint i, where i may be grounded to simulate a support point. To utilize nonlinear and frequency-dependent properties, corresponding analysis cases must be defined and run.
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Each F-D relationship is defined within a local coordinate system which is specific to that link. Links may be of zero length, as is the case with links grounded at support points. For dynamic analysis, numerical solution requires that mass m, and mass moments of inertia mr1, mr2, and mr3, be assigned to a link such that response captures translational and rotational inertia. Half of each of these values will be assigned to each joint within a link. Internal deformation and internal forces are then reported as output local to each joint. Additional information is available in the CSI Analysis Reference Manual (The Link/Support Element Basic, page 229) and (The Link/Support Element Advanced, page 253).