Sonar transducer

The detailed work of Bernd (ref. 15-17) and other investigators has also shown that the tensile strength of water is set by the gas nuclei (i.e., microbubbles) present in the water. (Accordingly, the earlier-mentioned definition of the tensile strength of a liquid can be restated as the minimum tensile stress at which the gas nuclei in the liquid start to explode . This property is also often referred to as the cavitation susceptibility (ref. 57).) Using specially constructed sonar transducers, the behavior of gas nuclei was followed by Bernd by measuring tensile strength. Surface... 

Sonar transducers and laser mounts. Alloys of Tb, Dy, and Fe exhibit magnetostrictive properties (i.e.) change shape under applied magnetic field. These alloys are used in sonar transducers and laser mounts. 

Polyvinyl resins Protein plastics Pyroxylin Rosins, synthetic Rosin modified resins Silicone fluid solution (fluid for sonar transducers)... 

A 100 element 360° scanning sonar transducer utilizing PVDF has been developed by Marconi to provide a 360° view of the acoustic scene on a radar type display. Hydrophones for submarine recotmaisance are of great interest to the military. A comparison between PVDF and a ceramic material PZT-4 commonly used in sources of pressure is shown in Table 5.12. The so-called g-d product, which is considered to be the standard of suitabihty for hydrophone apphcations, is 2.5 times greater for PVDF as... 

The lifetime for many sonar transducers is required to be ten to fifteen years. The device is constantly under environmental stresses due to saltwater attack, temperature and pressure cycling, plus mechanical stresses. Therefore, it has been very difficult so far to develop an adhesive system that can meet these requirements. 

R.Y. Ting, "Elastomer-to-Metal Adhesion in Sonar Transducer," to be published in Polymer News, 1984. 

One type of sonar transducer, primarily used in the surveillance community, is a low-frequency active source. The tonpilz design is commonly used for such projectors at frequencies down to about 2 kHz (a tonpilz at this frequency is almost 0.75-m long). For frequencies below 2 kHz, other types of transducer technology are employed, including mechanical transformers such as flexing shells, moving coil (loud speaker) devices, hydraulic sources, and even impulse sources such as spark gap and air. Explosives are a common source for surveillance, and when used with towed arrays make a very sophisticated system. 

Fig. 6.40. Tripode sonar transducer measured sound level versus frequency...

Claeyssen, F. Progress in magnetostrictive sonar transducers. Proc. UDT93, Reed Exhib. UK (1993), pp. 246-250... 

Jones, D.F. Recent transduction developments in Canada and US. Sonar Transducers Conf, Proc. Inst, of Acoustics, Univ. of Bath, UK, Vol. 17, Pt 3 (1995), pp. 100-106... 

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