Application Cases

Experiment Name: Driving Piezoelectric Underwater Sound Source for Frequency Response Function Testing of Underwater Shells

Research Direction: Underwater Sound Radiation

Experimental Content: During the operation of an underwater vehicle, the underwater sound radiation generated by the operation of mechanical equipment inside its shell can significantly affect the vehicle's acoustic stealth performance. Frequency response functions (FRFs) can be used to accurately assess the sound radiation contribution of mechanical equipment at different locations inside the shell. However, due to the vibro-acoustic coupling effects between equipment and the limited internal space, which complicates experimental setup, direct measurement of FRFs is often difficult to perform. This study aims to test the FRFs of an underwater vehicle shell using the acoustic reciprocity method and to evaluate the sound radiation contribution of equipment at different internal positions. The experiment was conducted in an anechoic water tank using a cylindrical shell structure with end plates to simulate the actual vehicle shell, overcoming the obstacles of direct measurement caused by narrow internal space, difficult equipment placement, and vibro-acoustic coupling effects.

Testing Equipment: Signal source, ATA-2082 high-voltage amplifier, underwater sound source, hydrophone, acceleration sensor, signal acquisition unit, etc.

Experimental Procedure:

Figure 1: Experimental System Layout

Figure 2: Experimental Model of the Underwater Shell

First, a white noise signal generated by the signal source is amplified by the power amplifier to drive the underwater sound source, generating sound waves in the water. Multiple hydrophones are placed near the sound source to measure the sound pressure signals in real time and calculate the volume velocity of the sound source. The sound pressure field excites the shell to vibrate, and acceleration sensors inside the shell simultaneously acquire the vibration response signals. The data acquired by the hydrophones and acceleration sensors are collected by the signal acquisition unit and transmitted to a computer for storage and processing. Based on the volume velocity of the sound source and the shell vibration response data, the FRFs are calculated, and the sound radiation contribution of equipment at different internal positions of the shell is analyzed, achieving indirect measurement and assessment based on the acoustic reciprocity principle.

Experimental Results:

Figure 3: Underwater Sound Pressure and Shell Vibration Response

Figure 4: Comparison of FRFs Obtained by Reciprocity Method and Direct Testing

The ATA-2082 high-voltage amplifier effectively drives the piezoelectric underwater sound source, producing distinct underwater sound pressure and shell vibration responses, with levels exceeding the background noise by more than 20 dB, ensuring the validity of the data. The one-third octave band FRFs obtained by the reciprocity method exhibited similar amplitudes and consistent trends compared to the direct test results, verifying the effectiveness of the reciprocity method for testing the FRFs of underwater vehicle shells.

Recommended Product: ATA-2082 High-Voltage Amplifier

Figure: Specifications of the ATA-2082 High-Voltage Amplifier