Abstract: An ultrasonic wave propagating method capable of propagating plate waves between a probe and a test piece despite variations in the thickness or the surface angle of a test piece, and an ultrasonic propagating device and an ultrasonic testing device using this method. Ultrasonic waves are propagated between a probe (20) for transmitting or receiving ultrasonic waves and a test piece (100) for propagating plate waves. When propagating ultrasonic waves, a probe that can set an ultrasonic wave incident angle from the probe (20) to the test piece (100) and/or an ultrasonic wave receivable angle from the test piece to the probe in a plurality of states is used. A focal point type probe may be used as the above probe (20).

Abstract: An ultrasonic wave is sent from a transmission element to a test element to produce a plate wave in the test element, and the plate wave propagating through the test element is received by a reception element to thereby test the test element on the propagation route of the plate wave. The other probe that is the other reception element or transmission element is disposed between the transmission element and the reception element. A probe holding mechanism that has support legs contacting the surface of the test element and keeps constant an angle of the other probe with respect to the surface of the test element is allowed to support the other probe. And, the other probe is allowed to cross over in non-contact the propagation route of the plate wave extending from the transmission element to the reception element by means of support legs.

Abstract: An ultrasonic test method for detecting a defective portion more precisely in a noncontact reflection way, and ultrasonic test instrument used for the method. An ultrasonic wave is transmitted from a transmitter (20 (21)) provided on one side of an object under test, and the reflected wave is received by a receiver (30 (31)) provided on the same side. The ultrasonic wave is transmitted/received through an air layer between the transmitter and the object (100) under test and between the receiver and the object (100). The relative positions of the transmitter (20), the receiver (30), and the object (100) are so determined that the air propagation time ta of the air path (RA) between the transmitter and the receiver is longer than the propagation time tb of the reflected wave in the reflection path (RB). The propagation of the ultrasonic wave through the solid body between the transmitter and the receiver is blocked.

Abstract: An ultrasonic test method for detecting a defective portion more precisely in a noncontact reflection way, and ultrasonic test instrument used for the method. An ultrasonic wave is transmitted from a transmitter (20 (21)) provided on one side of an object under test, and the reflected wave is received by a receiver (30 (31)) provided on the same side. The ultrasonic wave is transmitted/received through an air layer between the transmitter and the object (100) under test and between the receiver and the object (100). The relative positions of the transmitter (20), the receiver (30), and the object (100) are so determined that the air propagation time ta of the air path (RA) between the transmitter and the receiver is longer than the propagation time tb of the reflected wave in the reflection path (RB). The propagation of the ultrasonic wave through the solid body between the transmitter and the receiver is blocked.

Abstract: A membrane structure includes an airtight pressure-resistant gasbag and a shape maintaining mechanism which maintains the gasbag in a predetermined shape when the gasbag is in a fully inflated state. The gasbag includes a plurality of spindle-shaped gores of an airtight membrane material, adjacent gores joined together at edges, and a plurality of reinforcing ropes attached to joined sections of the edges, the reinforcing ropes extending along the edges, respectively. Each of the gores outwardly protrudes between two adjacent reinforcing ropes extending along the edges of the gore, respectively, without elongation of the airtight membrane material, when the gasbag is in the fully inflated state. Each protruding gore has a radius of curvature in a direction intersecting the two adjacent reinforcing ropes. The radius of curvature is smaller than a radius of the gasbag.