Modal Analysis of 27 mm Piezo Electric Plate for Small-Scale Underwater Sonar-Based Navigation

Table 2

Summary of the peak response with and without obstacles in the air and water.

Material used	Relative amplitude (dB) in air at		Relative amplitude (dB) in water at		Relative absorption at	Relative absorption at
	30 cm	60 cm	30 cm	60 cm	30 cm	60 cm
No object	−71.29	−81.47	−11.13	−23.56	−60.16	−57.91
Plywood	−88.95	−90.68	−34.11	−32.63	−54.84	−58.05
Asbestos	−83.12	−88.22	−27.40	−30.94	−55.72	−57.28
PVC plastics	−78.95	−81.36	−24.76	−30.21	−54.19	−51.15
Iron sheet	−86.17	−89.12	−20.63	−23.33	−65.54	−65.79