Most of sound sources are complex vibroacoustic objects consist of numerous elements. Some coupled vibrating plates of different shapes and sizes can be easily found in urban environments. The main aim of this study is to determine the sound radiation of coupled plates system of practical importance. The investigated vibroacoustic system consist of a thin circular plate coupled with a thick flat baffle with a circular hole. The circular plate has been mounted to the baffle’s hole using screws and two steel rings. The measurement setup was located inside a semi-anechoic chamber to assure the free field conditions. It was necessary to take into account the whole system surface to obtain the radiation efficiency based on the Hashimoto’s method. Such an approach can be troublesome and time-consuming. Therefore, the criterion has been proposed which allows the vibration velocity measurements and calculations to be performed only for the thin plate’s area. An alternative approach has been proposed based on the classical Rayleigh integral formula. Its advantage is a simpler implementation in a computer code. The obtained results have been compared with the theoretical results obtained for the elastically supported circular plate. A good agreement has been obtained at low frequencies.
The paper gives an introduction to nanostructuring techniques used for industrial fabrication of bulk nanocrystalline metals – basic
materials utilized in shaping nanoscale structures. Nanostructured metals, called nanometals, can be produced by severe plastic deformation (SPD). We give an expert coverage of current achievements in all important SPD methods and present future industry developments and research directions including both batch and continuous processes. In the laboratories of both WUT and UOS we have developed industry standard equipment and machinery for nanometals processing. Utilizing the latest examples from our research, we provide a concise introduction to the field of mass production of nanometals for nanotechnology.