A device for broadband excitation of underwater cylindrical shell

Abstract

The invention discloses a broadband excitation device for an underwater cylindrical shell, which comprises an electric pick, an excitation rod, a bracket, four shock absorbers, a fan, a base, a gasket and a "U"-shaped frame, and the electric pick passes through the "U" The "shaped frame is fixed on the upper end of the bracket, and the side of the electric pick is connected to the bracket; the bracket includes four bottom corners, each bottom corner is installed on the top of a shock absorber, and the bottoms of the four shock absorbers are installed on the base; One end of the exciting rod is installed in the output mechanism of the electric pick, the gasket is installed on the base, and the fan is installed on one side of the bracket. The working bandwidth of the device of the invention depends only on the natural frequency of the cylindrical shell, without limitation of the working bandwidth, and has the characteristics of small additional mass effect, large excitation force and high electric energy conversion efficiency.

Description

technical field [0001] The invention belongs to the field of mechanical vibration, and in particular relates to a broadband excitation device for an underwater cylindrical shell. Background technique [0002] At present, electromagnetic exciters are generally used for vibration excitation of large underwater cylindrical shells, and the radiation noise spectrum characteristics of cylindrical shells under forced excitation are investigated for a period of time, but there are still the following deficiencies in the process of use: The vibrator is a resonant vibrator with a limited operating bandwidth. In order to meet the test signal-to-noise ratio requirements, it is often used at a single frequency. The radiation noise characteristics of the cylindrical shell can only be investigated one by one, and then the normalized force excitation is calculated. The broadband characteristic of the radiation noise of the cylindrical shell takes a long time; the second is that the electrom...

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Problems solved by technology

[0002] At present, electromagnetic exciters are generally used for vibration excitation of large underwater cylindrical shells, and the radiation noise spectrum characteristics of cylindrical shells under forced excitation are investigated for a period of time, but there are still the following deficiencies in the process of use: The vibrator is a resonant vibrator with a limited operating bandwidth. In order to meet the test signal-to-noise ratio requirements, it is often used at a single frequency. The radiation noise characteristics of the cylindrical shell can only be investigated one by one, and then the normalized force excitation is calculated. The broadband characteristic of the radiation noise of the cylindrical shell takes a long time; the second is that the electromagnetic exciter consists of many equipments when it is used, and the operation process is cumbersome. It needs a power amplifier whose signal source and output impedance match the input impedance of the electromagnetic exciter. The efficiency of the power amplifier is not high, and the power loss is large, resulting in low power conversion efficiency; the third is that the electromagnetic exciter belongs to the inertial exciter. If it is to achieve vigorous excitation, the mass and volume of the electromagnetic exciter required are large , engineering installation is limited, and the large additional mass effect caused by the electromagnetic exciter is one of the main reasons for the difference between the experimental test results and the theoretical calculation results; the fourth is that the electromagnetic exciter is only an independent device, When exciting the underwater cylindrical shell, it is necessary to design the mounting bracket, the exciting rod, etc. At the same time, the connection method between the exciting rod and the cylindrical shell and the allowable stress of the exciting rod must also be considered.

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