Method and system for evaluating sonar self-noise at ship design stage

A system for evaluating sonar self-noise at a ship design stage to ensure a design of ship sonar system is low noise, comprising:

• a geometric model building module, configured to sort out modeling parameters according to preset ship blueprint data, and build a scale geometric model according to the modeling parameters;
• a simulation model building module, configured to establish a statistical energy evaluation model based on a statistical energy basic principle, and build a ship structure full-scale geometric simulation model and an acoustic cavity subsystem by using the scale geometric model;
• a parameter acquisition module, configured to acquire loss factors and sonar transducer space outfitting acoustic absorption coefficient material parameters, wherein the loss factors comprise a structural loss factor and an acoustic cavity internal loss factor;
• an excitation load acquisition module, configured to acquire a mechanical excitation load, a hydrodynamic excitation load, and a propeller excitation load;
• a self-noise calculation module, configured to input the loss factors and the sonar transducer space outfitting acoustic absorption coefficient material parameters into the statistical energy evaluation model, and apply the mechanical excitation load to a face plate of foundation of the ship structure full-scale geometric simulation model, apply the hydrodynamic excitation load to the surface of a ship hull, and apply the propeller excitation load to a stern shaft to perform calculation of the sonar self-noise of the ship to obtain the total spectral density level of the sonar self-noise;
• and
• an evaluation module, configured to evaluate spectral density level calculation results at 100 Hz, 1 kHz, and 10 kHz frequency points by preset index requirements, if the preset index requirements are not met, iteratively optimizing the parameter acquisition module to the evaluation module before evaluation, and otherwise, carrying out the next stage of operation, wherein a risk level of sonar self-noise indexes at the ship design stage is evaluated based on the preset index requirements;
• wherein the risk is low when preset index requirements are met;
• wherein the calculation of the sonar self-noise of the ship specifically comprises:
• setting frequency response analysis to ⅓ octave frequency, setting a calculation frequency band to 100 Hz to 10 kHz, and performing the calculation of the sonar self-noise of the ship;
• converting calculated acoustic pressure level results of each acoustic cavity obtained by division in the sonar transducer space into spectral density levels;
• and
• performing energy superposition on multiple spectral density level results to obtain the total spectral density level of the sonar self-noise.