A TMD has three basic elements: mass, stiffness, and energy dissipation (damping), so there are three forms of tuning required in the design of a TMD. The stiffness and mass of the TMD are selected to provide a TMD resonance frequency very close to the structure's resonance frequency. The TMD damping level is selected to optimize the energy dissipation over the effective bandwidth of the TMD. The TMD mass is selected to provide the desired level of vibration mitigation. It is reasonable to expect the TMDs to provide about a 70% reduction in the vibration. If any one of the parameters (mass, stiffness, or damping) is changed, the other two must be adjusted to maintain the tuning (performance).