Damping, a property of the material and the structure, influences dynamic response. A certain type of damping is available for each type of load case. Within all load cases of a certain type, damping is applied consistently, though additional damping may be added to individual load cases.

• Modal damping is used for response-spectrum and modal time-history analyses. Material modal damping, also known as composite modal damping, is weighted according to element and modal stiffness. For each material, users specify a material modal damping ratio r, in which 0 < r < 1, which relates to the damping ratio of each mode.

• Viscous proportional damping is used for direct-integration time-history analysis. This property is proportional to mass and stiffness.

• Hysteretic proportional damping, also mass- and stiffness-proportional, is used for steady-state and power-spectral-density analyses. 

• Damping devices may also be modeled as a structural subsystem, as described in the Tuned-mass damper tutorial.

See Also

• SAP2000 verification examples 6-005, 6-006, and 6-007 – examples which incorporate dampers and associated behaviors
• Additional information on each of these damping types may be found in the CSI Analysis Reference Manual (Chapter VI: Material Properties, Material Damping)