Compliant elements are bushings, spring-dampers, and beams. For each, the relevant information such as stiffness, damping, preload, attachment markers, etc. needs to be defined. Stiffness and damping value numbers should correctly represent the actual system and must be physically meaningful. Otherwise, the system may inadvertently turn out to be numerically stiff even though the physical system may not be.
Compliant elements can be defined with respect to grid points or with respect to markers.
CMBEAM, CMBEAMM bulk data entries define beam elements.
CMBUSH, CMBUSHM bulk data entries define bushing elements. A bushing element has linear stiffness and damping properties.
CMSPDP, CMSPDPM bulk data entries define spring-damper elements.