Pendulum tuned mass dampers (PTMDs) are commonly used in adding damping to tall structures, including high-rise buildings, control and communication towers, stacks, etc. These multi-directional TMDs, which are made up of mass blocks suspended by steel cables or rods, can readily be tuned to the very low natural frequencies associated with the primary modes of […]
Read MoreThe extent of vibration energy that a passive TMD dissipates as well as its effective frequency range (bandwidth) increase with an increase in the mass ratio of the TMD. In addition, the amount of internal damping built into the make-up of a passive TMD increases with the size of that TMD. The TMDs used in […]
Read MoreThe use of a tuned damper or a dynamic absorber in time-varying systems can only be effective if they are adjustable (semi-active) and continuously returned to the current resonant frequency of the system. Such dampers require a tuning algorithm that can automatically adjust the adjustable parameter of the tuned damper/absorber, e.g., the stiffness of the […]
Read MoreDEICON’s patented, semi-actively controlled, ‘air suspended tuned mass damper’ (TMD) uses one/multiple air spring(s) as both the restoring (resilient) and the energy dissipating (damping) elements. Feedback control is used to adjust the stiffness and damping of the air spring(s). The schematic of a tuned mass damper installed on a structure is shown in Figure 1. […]
Read MoreProof mass actuators (PMAs) are used to add tuned damping and tuned dynamic absorption to test structure as well as the rear sub-frame of an all-wheel-drive vehicle. The choice of active vibration control strategy, with a PMAs as the actuator, depends on whether the PMA’s natural frequency is placed below or within the frequency(ies) of […]
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