ACOUSTIC FATIGUE AND FAILURE OF METAL SHEETS

Modern supersonic aeroplanes produce a high-intensity noise level up to 155 dB near the jet nozzles, which is enough to cause acoustical fatigue and failure. We used the electro-pneumatic loudspeaker coupled directly to the travelling-wave tube to produce about 165-170 dB of the high-intensity random sound field in the test section. This paper studied experimentally for three types of the metal sheets, i.e. type L_yl2-CZ-δ0.8, type L_yl2-CZ-δ1.0 and type Ʀ1T-0.6. Under such sound field, we observed the whole process) of the crack initation, growth, propagation and failure, and compared the acoustical fatigue of the different structures and obtained experimentally the L_p-_t curves of the 0.8mm and 1.0mm allumiun sheets, and 0.6 mm stainless steel sheet.