The armoured vehicle is the main military equipment for the future armoured mechanised troops and will take the very important operational missions in the future war. In order to give full play to the operational effectiveness of the military hardware for the armoured vehicle, the passengers of the armoured vehicle must keep energetic and sensitive in a longer combat period, and it is necessary to create a more comfortable living and operating space for the passengers of the armoured vehicle.
Currently, the noise pollution is generally serious inside the armoured vehicle. The measurement results show that the maximum noise level in the Chinese track-laying vehicle can reach 120dB, and the noise level increases with the increase of vehicle driving speed. The solution of interior noise reduction for the armoured vehicle has great significance to protect the fighters, improve the fighting capacity and give full play to the operational effectiveness.
On the basis of modal analysis technology and related technology, the theoretical modal analysis result based on ANSYS modal analysis software and the experimental modal analysis result based on DASP (Data Acquirement and Signal Processing) software for certain armored car are compared, and the obtained modal parameter error analysis and the influence factor analysis showed the consistency of the two analysis results.
Secondly, the internal sound field of the armoured car is analysed and researched by using the sound and vibration analysis software SYSNOISE. The result shows that the engine vibration is the main noise source for the passenger cabin of the armoured car. The characteristic frequency for the vibration insulation and noise reduction properties in the armored car is obtained by analyzing the vibration and noise signals in the car by the frequency analysis method and the coherence analysis method; by the design of relative improvement measures such as the design of muffler and sound absorbing structure, in theory, the internal noise in the armored car body is reduced, and the man-machine environment in the armored car is improved.
Continuous noise when the tank runs and impulse noise when shelling: the noise when the tank operates is classified into continuous noise (also called steady-state noise when the fluctuation is low) in running and impulse noise when the cannon fires. The noise magnitude is associated with the road condition, the running speed, etc., and the shot noise is related to the cannon type, the bomb type and so on. When the tank is started in situ, the total sound level is 100-109 dB, A sound level is 93-99 dB, and the noise intensity is increased with the increase of engine speed.
See Table 1 and Table 2 for the intensity, distribution and duration of the operation noise and the shelling noise.The continuous noise is 107-112 dB (A) when the tank runs; the impulse noise in the tank is 167-172 dB (P) when the tank shells. The frequency of the operation noise is mainly the low frequency.
See Figure 1 for the spectrum analysis results.
The duration of impulse noise B is wider in the tank and is narrower outside the tank when the tank shoots, as shown in Table 2 and Figure 2.
After the tank runs or shells, the driver and the conductor have the temporary threshold shift of hearing (Table 3) and recover after 24 hours. The noises are extremely harmful to the hearing, health, calling and operation of the passenger.