Development of air-coupled ultrasonic inspection device for spacecraft insulation
Mayuzumi, Takashi1; Nemoto, Norio1; Aoyama, kazuhiro1; Matsubara, Shigeyuki2; Shinoda, Kunihiko2; Miyamoto, Hiroshi2
Context As the technique for detecting the disbonding of fairing insulation, there is a sound inspection by tapping method. This method depends on workmanship, so regard enough for the human error, scanning speed, and recording accuracy. So it is meaningful to establish a new inspection technique, which is handy, sensitive to disbonding and preventive of liquid couplants. Principal Transmitter and receiver proves were arranged for air coupling, and ultrasound emitted into air to specimen. Lamb wave propagates the specimen is detected by receiving probe clearly, the amplitude decreases in the disbanding part. Disbonding can be detected by this inspection technique from the amplitude change. Under the present condition Silicon resin insulation with a thickness of 4mm is applied on honeycomb with aluminum skin. To simulate disbondings with diameters of 3 to 17mm, five sets of four Teflon sheets with a thickness of 0.05mm are inserted into the interface between aluminum skin and insulation at the position. Detectability was shown experimentally that the artificial defect with a diameter of 8mmƒÓ located between aluminum skin and insulation of 4mm in thickness could be detected.