An active boom noise control solution is developed to add acoustic damping to the low-frequency standing waves inside the cabin of a large SUV to quiet its tonal persistent boom noise.
Read MoreAir mounts, with their attractive attribute of being able to provide the most softness of all mounts of comparable size, have been gaining popularity and widespread use. The drawback of soft mounting is occasional excessive motion of the mounted machine in response to abrupt, impulse-like disturbances (such as starting up or shutting down an engine). […]
Read MorePendulum 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 MoreLarge vehicles, such as SUVs (Sport Utility Vehicle) and minivans, exhibit body boom phenomena during multiple source excitation events including rough road/impact and powertrain induced events. The main cause of the boom is the low-frequency acoustic/vibro-acoustic modes of the cavity being excited via the high acoustic transfer functions at multiple paths, due to an inherently […]
Read MoreReactive absorbers, such as Helmholtz resonators (HR) or quarter-wave tubes, are commonly used as the most effective solution for abating the low-frequency tonal noise in many applications including the quieting of air intake induction system noise in internal combustion engines. The problem with these low-frequency absorbers is their large size. In addition, reactive absorbers can […]
Read MoreDEICON’s patented, feedback-controlled, electronic acoustic absorber is highly effective in reducing the boominess of sound at frequencies corresponding to offending (coloring) standing waves of an enclosed space. The controller which can be realized by a tunable, analog circuit or a high-speed micro-controller can be tuned to one or multiple low frequencies either to dampen the […]
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 […]
Read MoreHydraulic presses are used in much forming processing including stamping, forging, and injection molding. The quality of the parts produced by these presses depends on how good the motion of the ram is controlled. As such, it is desirable to have tight control on the ram motion in these presses. An alternative in controlling such […]
Read MoreInjection molding is the most common manufacturing process for the production of high volume commercial parts. However, injection molding is characterized by extremely complex process dynamics and material properties, which make it difficult to understand and predict product quality and can lead to unacceptable quality defects. one of the promising solutions to this problem is […]
Read MoreA novel, feed-forward vibration isolation scheme is developed that addresses the shortcomings of adaptive feedforward vibration isolation algorithms. This scheme which is based on the use of Kalman estimators (KE) does not require real-time adaptation and yet maintains its effectiveness when the attributes (such as the frequencies) of the disturbance changes. More importantly, it does […]
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