Influence Of Vibration And Sound Pressure On Hydrophone And Improvement Measures

A hydrophone is supposed to have low acceleration responsivity and high sound-pressure responsivity. The author of this thesis studies the characteristics of hydrophone from two aspects which is shown as follows:1. Mechanical vibration effect on the acceleration responsivity of optic-fiber hydrophone. The virtual environmental vibration tests are simulated on the basis of finite element model. Parameters such as type of sensor shelf, assembly height, assembly angel have been studied in the research of hydrophone's natural characteristics and frequency response. The major performance of hydrophone under the condition of environmental vibration test has been evaluated and suggestions on the environmental test have also been provided so as to decrease the responsivity of acceleration.2. Influence of structural parameters on the sound pressure responsivity of optic-fiber hydrophone. The mechanics model of hydrophone subject to the sound pressure has been established. Parameters such as mandrel length, mandrel diameter, the number of fiber layer and materials of both mandrel and fiber layer have been studied in the research of hydrophone's sound pressure responsivity. The major performance has been evaluated and suggestions on the structure optimization have been provide to increase the responsivity of sound pressure according to the simulation results.The thesis consists of 5 chapters. In the first chapter, related hydrophone research background and main idea of the author are introduced. Chapter 2 introduces the finite element modeling of hydrophone and the homogenization process of optic-fiber layer. Chapter 3 shows in details the study of acceleration responsivity under the environmental vibration condition. Chapter 4 gives the results of structural parameters' influence on the sound pressure of hydrophone and Chapter 5 presents the suggestions of vibration test and structure optimization to increase the SNR of hydrophone on the basis of calculation results.The innovation points and progress of the research work can be concluded as follows:The optical feature is properly described in mechanics terminology. And the mechanical vibration and sound pressure detection performance are studied by finite element method.A series of virtual tests have been applied to homogenize fiber layer into orthotropic material, which significantly facilitate the finite element modeling and greatly reduce the calculation amount while the calculation error is effectively under control.All the virtual vibration tests and sound pressure detection are simulated in the general business FEM software. Optimization advices are provided according to the simulation results, which is a useful guide for the design of hydrophone.