Transducer Design Of Helmet-mounted Colorful Imaging Sonars For Frogmen

Underwater acoustic transducer is the core component of sonar equipment. The level of sonar equipment performance is directly depending on its design level. According to the actual demand, the imaging sonar transducer using by the frogman is designed in this dissertation, which is a thickness stretching vibration mode transducer of the rectangle piezoelectric ceramics with the characterizes of small size, light weight, good directive property, high voltage magnitude response.The study of this dissertation is start with the development history of acoustic susceptance and the current situation of foreign research. The second part of this dissertation is pointing out the significance of the research and lading to the concept of transducer and classification methods. And then, this dissertation mainly introduces the transducer of performance parameter, vibration mode, resonance characteristics and dynamics characteristics, and briefly describes two sonar equations.At the same time, this dissertation gives a brief description of the transducer requirements analysis, and confirms the transducer is imaging sonar systems that are used to identify the orientation of the target object, contour, shape and size for drivers’ underwater operations according to the needs analysis.At the same time, the operating frequency and the shape of the transducer are confirmed by the usage, experience and references of similar products at home and abroad. The suitable vibration mode and piezoelectric materials is chose by selected operating frequency and the size of piezoelectric materials and the demand of emission voltage response are confirmed by imaging precision. The purpose of transducer performance simulation that combined with the idea of the finite element software ANSYS is proving that the size of the design meets the requirements. From the simulation results, the transducer achieves the required performance requirements. The purpose of making the transducer specimen samples and testing the performance of the samples is certifying that the actual situation is consistent with the theory. The results of testing show that the actual situation is consistent with the theory and computer simulation. However, there is a difference between actual and theoretical, and the actual operating distance of transducer is smaller than the theoretical distance. The reasons may be included the following:First, the propagation loss is determined in theoretical calculations, but the actual change in is variation; Second, the virtual voltage of transducer drive may slightly smaller than the theoretical, which results the actual sound source level of transducer is smaller than theoretical source level. Therefore, the role of operating distance cannot reach the design value. From the overall performance, the indicators of the transducer meet the basic requirements of design, and further illustrates the way of thinking is correct.