Abstract: Vibration or acoustic sound control is achieved using an elastic layer of thermal or insulation material in which a plurality of discrete masses are distributed throughout. The elastic layer may be installed as a pre-formed layer, or be blown into position within a structure where vibration or acoustic sound control is required.

Abstract: A passive distributed vibration absorber that utilizes multiple discrete mass elements and a viscoelastic layer and that effectively attenuates vibration in modally dense structures excited by a broadband input noise excitation. and is tunable to multiple natural frequencies in such modally dense vibrating structures including low frequencies.

Abstract: Vibration or acoustic sound control is achieved using an elastic layer of thermal or insulation material in which a plurality of discrete masses are distributed throughout. The elastic layer may be installed as a pre-formed layer, or be blown into position within a structure where vibration or acoustic sound control is required.

Abstract: Vibration or acoustic sound control is achieved using an elastic layer of thermal or insulation material in which a plurality of discrete masses are distributed throughout. The elastic layer may be installed as a pre-formed layer, or be blown into position within a structure where vibration or acoustic sound control is required.

Abstract: A hot melt adhesive hose assembly comprises a heater circuit wrapped around an external surface portion of the hose assembly, a temperature sensor, and an elongated thermal fuse which is likewise wrapped around an external surface portion of the hose assembly such that successive spiral turns of the thermal fuse are effectively interposed between successive spiral turns of the heater circuit. The thermal fuse may be electrically connected in series with the heater circuit so as to effectively terminate electrical power to the heater circuit as a result of the melting of the thermal fuse, or alternatively, the thermal fuse may be electrically connected in series with the temperature sensor, so as to detect abnormal temperature levels at substantially any location throughout the length of the hose assembly.

Abstract: Vibration or acoustic sound control is achieved using an elastic layer of thermal or insulation material in which a plurality of discrete masses are distributed throughout. The elastic layer may be installed as a pre-formed layer, or be blown into position within a structure where vibration or acoustic sound control is required.

Abstract: The active/passive absorber for extended vibration and sound radiation control includes principally two layers. The first layer has a low stiffness per unit area which allows motion in the direction perpendicular to its main plane. The second layer is principally a mass layer. These two combined layers have a frequency of resonance close to one of the main structure. The dynamic behavior of the coupled system makes the active/passive absorber a passive absorber; however, the first layer can be electrically actuated to induce motion in the direction perpendicular to its main plane. This addition property induces and/or changes the motion of the mass layer and therefore improves the dynamic properties of the active/passive absorber system. The active/passive absorber can have multiple mass layers and multiple elastic layers stacked one on top of the other. In addition, the mass layers can be continuous or discretized, and have varying thicknesses and shapes for sections and/or segments in the mass layer.

Abstract: A passive distributed vibration absorber that utilizes multiple discrete mass elements and a viscoelastic layer and that effectively attenuates vibration in modally dense structures excited by a broadband input noise excitation and is tunable to multiple natural frequencies in such modally dense vibrating structures including low frequencies

Abstract: A hot melt adhesive hose assembly comprises a heater circuit wrapped around an external surface portion of the hose assembly, a temperature sensor, and an elongated thermal fuse which is likewise wrapped around an external surface portion of the hose assembly such that successive spiral turns of the thermal fuse are effectively interposed between successive spiral turns of the heater circuit. The thermal fuse may be electrically connected in series with the heater circuit so as to effectively terminate electrical power to the heater circuit as a result of the melting of the thermal fuse, or alternatively, the thermal fuse may be electrically connected in series with the temperature sensor, so as to detect abnormal temperature levels at substantially any location throughout the length of the hose assembly.

Abstract: The active/passive absorber for extended vibration and sound radiation control includes principally two layers. The first layer has a low stiffness per unit area which allows motion in the direction perpendicular to its main plane. The second layer is principally a mass layer. These two combined layers have a frequency of resonance close to one of the main structure. The dynamic behavior of the coupled system makes the active/passive absorber a passive absorber; however, the first layer can be electrically actuated to induce motion in the direction perpendicular to its main plane. This addition property induces and/or changes the motion of the mass layer and therefore improves the dynamic properties of the active/passive absorber system. The acive/passive absorber can have multiple mass layers and multiple elastic layers stacked one on top of the other. In addition, the mass layers can be continuous or discretized, and have varying thicknesses and shapes for sections and/or segments in the mass layer.

Abstract: The active/passive absorber for extended vibration and sound radiation control includes principally two layers. The first layer has a low stiffness per unit area which allows motion in the direction perpendicular to its main plane. The second layer is principally a mass layer. These two combined layers have a frequency of resonance close to one of the main structure. The dynamic behavior of the coupled system makes the active/passive absorber a passive absorbe; however, the first layer can be electrically actuated to induce motion in the direction perpendicular to its main plane. This addition property induces and/or changes the motion of the mass layer and therefore improves the dynamic properties of the active/passive absorber system.

Abstract: The active/passive absorber for extended vibration and sound radiation control includes principally two layers. The first layer has a low stiffness per unit area which allows motion in the direction perpendicular to its main plane. The second layer is principally a mass layer. These two combined layers have a frequency of resonance close to one of the main structure. The dynamic behavior of the coupled system makes the active/passive absorber a passive absorber; however, the first layer can be electrically actuated to induce motion in the direction perpendicular to its main plane. This addition property induces and/or changes the motion of the mass layer and therefore improves the dynamic properties of the active/passive absorber system. The acive/passive absorber can have multiple mass layers and multiple elastic layers stacked one on top of the other. In addition, the mass layers can be continuous or discretized, and have varying thicknesses and shapes for sections and/or segments in the mass layer.

Abstract: An active foam system for noise and vibration control which employs embedded PVDF layers (12) in a urethane foam pad (13). The system can be used to isolate and/or attenuate vibration. It can also be used to cause a reduction in far-field acoustic pressure and to act as a structurally radiated speaker (130).

Abstract: The invention relates to noise or sound control achieved by enclosing the noise source in an active enclosure. Arrays of vibration inputs (for example, shakers, piezoceramics, etc.) are attached to the walls of the active enclosure, or loudspeakers located inside the enclosure can be used to excite the sides of the enclosure. An array of error microphones are located in the radiated acoustic field or PVDF strips are positioned on the wall. A controller senses the levels of sound observed at the error microphones or PVDF film and adjusts the oscillating inputs (in terms of frequency content, phase and magnitude) to the active vibration inputs in order to minimize the radiated sound.

Abstract: Reduction or cancellation of acoustic noise is achieved by providing an amplified, oppositely phased version of the noise by means of an acousto-fluidic amplifier. The amplified acoustic output noise is delivered through an impedance matching horn in destructively interfering relation with the original noise. Depending on the acoustic noise source and its spatial distribution, the acousto-fluidic amplifier may be a single stage amplifier or multiple stages connected in parallel and/or cascade, with output horns spatially distributed to have the maximum cancellation effect. Sensed noise, prior to fluidic amplification, may be processed in a manner to effect feedback or feedforward control of the amplified acoustic output signals.

Abstract: Apparatus is disclosed for attenuating sound radiated from a vibrating surface into a control volume as comprised of a source of a control signal indicative of the amplitude and frequency content of the sound transmitted from the vibrating surface. An actuator(s) or shaker is directly connected to the vibrating surface for further vibrating the vibrating surface to induce a cancelling sound into the control volume for combining with and attenuating the transmitted sound. A sensor(s) is also disposed within the control volume for detecting the resultant sound indicative of the combination of the cancelling and the transmitted sound to provide an error signal indicative thereof.