Vibration Abatement of a Natural Gas Piping System Using Tuned Mass Dampers

Fluid/structure interaction and the operation of one of the natural gas compressors imparted dynamic forces onto one of the compressed natural gas piping systems of a power plant. The frequency of this dynamic perturbation happened to nearly match the first resonant frequency of the piping system, which in turn resulted in excessive resonant vibration of […]

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Passive Electronic Damping

Passive electronic damping using piezoelectric ceramics is a less temperature-sensitive and more tunable alternative to viscoelastic damping treatments. In this damping technique, the mechanical energy of the structure is converted to electrical energy using piezoelectric material. High mechanical stiffness of piezoceramics enables efficient energy transfer to the piezo damper. The electrical energy, in turn, is […]

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One-Order Tuned Vibration Absorption of a Diesel-Generator

In four stroke engines, including diesel engines driving generators, each cylinder fires every other revolution. This causes the engine vibration to occur at ½ the engine RPM, called the ½ order vibration, and its higher order harmonics namely 1 order, 1½ order, 2 order. In the case of a diesel generator, in addition to the […]

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Passive and Active Pendulum Tuned Mass Dampers

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 […]

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Active Tuned Mass Dampers

The 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 […]

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Self-Tuning of Tuned Dampers/Absorbers

The 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 […]

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Semi-active Air-suspended Tuned Mass Damper

DEICON’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. […]

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Monumental Staircase Vibration Abatement Using a Tuned Mass Damper-2

To lower the vibration level of a monumental staircase, one 500 lb tuned mass damper (TMD) was designed, fabricated, and appended to the structure. The natural frequency of the staircase was measured and used for tuning the TMD. Figure 1 shows the landing of the staircase with two of the measurement locations highlighted. [Monumental aesthetically […]

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Vibration Abatement of a Monumental Staircase Using a Tuned Mass Damper

Following the evaluation of the dynamic attributes of a monumental staircase (in an upscale financial office building), one 500 lb tuned mass damper (TMD) was designed, fabricated, and shipped to the job site. Two views of the nearly completed staircase are shown in Figure 1. [Monumental, aesthetically pleasing staircases are getting incorporated more and more […]

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Vibration Control of an Overlook Using Tuned Mass Dampers

Hunter’s Point South Park is a breath-taking waterfront park located on the edge of the East River, in Western Queens, NY. The focal point of the park is Hunter’s Point South overlook, a beautiful cantilevered platform that offers unobstructed views of the New York skyline. The Overlook’s rather low fundamental frequency (3.5 Hz) combined with […]

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