Passive, tuned acoustic absorbers, such as Helmholtz resonators (HR) and quarter-wave tubes, are commonly used solutions for abating the low-frequency tonal noise in air induction systems. Since absorption at multiple frequencies is required, multiple absorbers tuned to different frequencies are commonly used. Typically, the large size and multiple numbers of these devices under the hood […]
Read MoreGearboxes are typically sources of vibration, either because they are in the transmission path from the engine to the structure so they transmit vibration coming from the engine or they transmit their own vibration at the gear mesh frequency and its corresponding side-bands. The latter can be heard as a whining noise coming from the […]
Read MoreWide column spans along with the use of high strength material make modern floor systems flexible and oscillatory. Walking (as well as other human activities) can induce high levels of vibration in such floors. When the traditional floor vibration control solutions, such as adding architectural features, mass, and/or stiffness to the floor are either not […]
Read MoreIn order to design and specify vibration abatement solutions (via tuned damping) for a multi-bay floor system, a reasonably accurate knowledge of the dynamic attributes of that floor system is required. These can be evaluated numerically (using finite element analysis) and verified experimentally by vibration measurement. Finite element modal analysis allows for the prediction of […]
Read MoreFollowing the occupants’ (office workers’) complaints about the floor vibration at a certain area in an office building, vibration measurements were conducted by an acoustics consulting firm, the results of which indicated that the floor system was lightly damped and that the vibration associated with occupant activities (mainly walking) was exacerbated by resonant amplification of […]
Read MoreCantilevered structures, such as balconies, when subject to human activity such as walking and jumping, can be susceptible to levels of vibration that may be deemed annoying by some users. If the structure is an irregular shape, the affected areas can often be fairly localized, with the rest of the space performing appropriately. Traditional approaches […]
Read MoreWalking, amongst other Human activities, is the most common cause of floor vibration that can lead to nuisance in building occupants. Walking-induced floor vibration can cause discomfort in people working or living in the building. Adding architectural features, mass and/or stiffness are commonly viewed as possible solutions to floor vibration problem. Such solutions are costly […]
Read MoreDEICON recently received the ‘Notice of Allowance’ and ‘Notice of Allowability’ from the U.S. Patent and Trademark Office allowing the claims listed in DEICON’s air suspended ‘adjustable tuned mass damper’ patent application. In these tuned mass dampers, only air springs are used as the suspension elements. Active control enables the air springs to provide both […]
Read MoreDEICON was called upon to develop a tuned damping solution to mitigate floor vibrations across a variety of rooms inside an educational facility. The make-up of the impacted floors was concrete on metal deck, supported by open-web bar joists. The floors came in various sizes and shapes (rectangular, trapezoidal, and irregular), with the first resonant […]
Read MoreThe combustion instability (thermoacoustic instability) of a gas-fired combustor with a low-frequency instability occurring at 100 Hz, was successfully mitigated using DEICON’s passive acoustic radiation based tuned absorber (damping system). Contrary to the more traditional tuned acoustic absorbers (perforated liners, quarter wave tubes, etc.) that are objectionably large at such low frequencies, DEICON’s passive acoustic […]
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