The problem of active structural acoustic control in an enclosure using radiation mode is investigated. The response of the coupled enclosure is derived in terms of radiation modes. The potential energy in the enclosu...The problem of active structural acoustic control in an enclosure using radiation mode is investigated. The response of the coupled enclosure is derived in terms of radiation modes. The potential energy in the enclosure can be decomposed into independent parts and the radiation modes contribute to potential energy independently. The control strategy for minimizing first G radiation modes with large radiation efficiency is proposed, and the optimal model of control forces is presented. Finally, a numerical simulation for minimizing sound transmission into a rectangular enclosure using the proposed method is conducted. Simulation results indicate that one control force can control one radiation mode and controlling the first four-order radiation modes with four control forces can achieve significant potential energy reduction at the low frequency range.展开更多
The active control of structural sound radiation in an acoustic enclosure is studied by using distributed point force actuators as the secondary control force, and the control mechanisms for the radiated noise in the ...The active control of structural sound radiation in an acoustic enclosure is studied by using distributed point force actuators as the secondary control force, and the control mechanisms for the radiated noise in the cavity are analyzed. A rectangular enclosure involving two simply supported flexible plates is created for this investigation. The characteristics of the primary and secondary sound field and the structural-acoustic coupled system are analyzed, and the optimal control objective for reducing the sound pressure level （SPL） in the cavity is derived. The response of the SPL in the cavity is analyzed and compared when the secondary point force actuators with different locations and parameters are applied to the two flexible plates. The results indicate that the noise in the cavity can be better controlled when some point force actuators are applied to two flexible plates for cooperative control rather than the point force actuators being only applied to the excited flexible plate.展开更多
Regarding woodworking machines, machine acoustics are of particular significance due to the high noise emission of these machines. Among other things, this can be attributed to the adoption of the European Commission ...Regarding woodworking machines, machine acoustics are of particular significance due to the high noise emission of these machines. Among other things, this can be attributed to the adoption of the European Commission Machinery Directive as a national law, which demands protection against noise emission in the design phase of new machines. In order to accomplish this, it is necessary to examine and locate the causes of emissions on existing machines. In this paper, the sound source is located through sound intensity measurements, using planing machines as an example, which are particularly noise-intensive woodworking machines. In addition, different influencing parameters on noise emission are analyzed, such as manual and automatic feed, rotational speed and the influence of the type of wood of the workpiece.展开更多
基金Supported by the National Natural Science Foundation of China(50375027,50575041)~~
文摘The problem of active structural acoustic control in an enclosure using radiation mode is investigated. The response of the coupled enclosure is derived in terms of radiation modes. The potential energy in the enclosure can be decomposed into independent parts and the radiation modes contribute to potential energy independently. The control strategy for minimizing first G radiation modes with large radiation efficiency is proposed, and the optimal model of control forces is presented. Finally, a numerical simulation for minimizing sound transmission into a rectangular enclosure using the proposed method is conducted. Simulation results indicate that one control force can control one radiation mode and controlling the first four-order radiation modes with four control forces can achieve significant potential energy reduction at the low frequency range.
基金The National Natural Science Foundation of China(No.50975047)
文摘The active control of structural sound radiation in an acoustic enclosure is studied by using distributed point force actuators as the secondary control force, and the control mechanisms for the radiated noise in the cavity are analyzed. A rectangular enclosure involving two simply supported flexible plates is created for this investigation. The characteristics of the primary and secondary sound field and the structural-acoustic coupled system are analyzed, and the optimal control objective for reducing the sound pressure level （SPL） in the cavity is derived. The response of the SPL in the cavity is analyzed and compared when the secondary point force actuators with different locations and parameters are applied to the two flexible plates. The results indicate that the noise in the cavity can be better controlled when some point force actuators are applied to two flexible plates for cooperative control rather than the point force actuators being only applied to the excited flexible plate.
文摘Regarding woodworking machines, machine acoustics are of particular significance due to the high noise emission of these machines. Among other things, this can be attributed to the adoption of the European Commission Machinery Directive as a national law, which demands protection against noise emission in the design phase of new machines. In order to accomplish this, it is necessary to examine and locate the causes of emissions on existing machines. In this paper, the sound source is located through sound intensity measurements, using planing machines as an example, which are particularly noise-intensive woodworking machines. In addition, different influencing parameters on noise emission are analyzed, such as manual and automatic feed, rotational speed and the influence of the type of wood of the workpiece.
