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A method of characterizing the vibration of a plurality of rotating blades (12), such as turbine blades in a gas turbine engine, includes the steps of providing a single strain gauge (16A) on a single one (12A) of the blades and providing either one or two tip timing probes (22A, 22B) on a casing su

A method of characterizing the vibration of a plurality of rotating blades (12), such as turbine blades in a gas turbine engine, includes the steps of providing a single strain gauge (16A) on a single one (12A) of the blades and providing either one or two tip timing probes (22A, 22B) on a casing surrounding the blades. The data from the strain gauge (16A) allows the vibration of the single blade (12A) to be fully characterized while the data from the tip timing probes (22A, 22B) allows the amplitudes or velocities of vibration of all the blades to be determined. The relationship between the data from the tip timing probes for the single blade (12A) and the stress data from the strain gauge may be established. This relationship may then be assumed to apply to all the blades, thus allowing the stresses induced in all the blades by the vibrations to be determined.

대표청구항 ▼

A method of characterizing the vibration of a plurality of rotating blades (12), such as turbine blades in a gas turbine engine, includes the steps of providing a single strain gauge (16A) on a single one (12A) of the blades and providing either one or two tip timing probes (22A, 22B) on a casing su

A method of characterizing the vibration of a plurality of rotating blades (12), such as turbine blades in a gas turbine engine, includes the steps of providing a single strain gauge (16A) on a single one (12A) of the blades and providing either one or two tip timing probes (22A, 22B) on a casing surrounding the blades. The data from the strain gauge (16A) allows the vibration of the single blade (12A) to be fully characterized while the data from the tip timing probes (22A, 22B) allows the amplitudes or velocities of vibration of all the blades to be determined. The relationship between the data from the tip timing probes for the single blade (12A) and the stress data from the strain gauge may be established. This relationship may then be assumed to apply to all the blades, thus allowing the stresses induced in all the blades by the vibrations to be determined. tions is performed. 3. The ultrasonic detection apparatus according to claim 2, further comprising: a transmitting circuit configured to output an electrical signal to said transmitting transducer; a receiving circuit provided in a housing different from one for said transmitting circuit and configured to receive an electrical signal from said receiving transducer; and a received-wave determination device connected to said receiving circuit and configured to determine an earliest ultrasonic wave when predetermined ultrasonic waves are included in a plurality of ultrasonic waves received at a measurement point, said earliest ultrasonic wave having the earliest time of generation among said predetermined ultrasonic waves received wave at said measurement point. 4. The ultrasonic detection apparatus according to claim 2, wherein said transducer-distance varying device comprises: a plurality of transmitting oscillators evenly spaced apart from said receiving transducer and disposed within said transmitting transducer. 5. The ultrasonic detection apparatus according to claim 2, wherein said transducer-distance adjusting device comprises: a plurality of receiving oscillators evenly spaced apart from said transmitting transducer and disposed within said receiving transducer. 6. The ultrasonic detection apparatus according to claim 1, wherein said arithmetic averaging device is configured to perform arithmetic averaging 1,000 times or more per one detection. 7. The ultrasonic detection apparatus according to claim 1, wherein said distance between said transmitting transducer and said receiving transducer is adjustable. 8. An ultrasonic detection apparatus, including a receiving transducer configured to receive a plurality of ultrasonic waves transmitted by a transmitting transducer, comprising: an arithmetic averaging device configured to perform an arithmetic averaging process a plurality of times per one detection, each of said plurality of times performed in response to one of said plurality of ultrasonic waves being received by said receiving transducer, said arithmetic averaging process includes averaging said one of said plurality of ultrasonic waves and at least one prior received ultrasonic wave of the plurality of ultrasonic waves, said one of said plurality of ultrasonic waves being formed by applying a step function voltage to an oscillator, wherein said predetermined frequency is given by ((n±(1/2)×(106×v/ΔL)(Hz), where ΔL is a variation in a distance between said transmitting transducer and said receiving transducer, v is an ultrasonic wave transmission velocity of a material being detected, and n is a natural number. 9. An ultrasonic detection apparatus, including a receiving transducer configured to receive a plurality of ultrasonic waves transmitted by a transmitting transducer, comprising: an arithmetic averaging device configured to perform an arithmetic averaging process a plurality of times per one detection, each of said plurality of times performed in response to one of said plurality of ultrasonic waves being received by said receiving transducer, said arithmetic averaging process includes averaging said one of said plurality of ultrasonic waves and at least one prior received ultrasonic wave of the plurality of ultrasonic waves, said one of said plurality of ultrasonic waves being formed by applying a step function voltage to an oscillator; and an extractor configured to extract an extracted ultrasonic wave from said set of averaged ultrasonic waves, said extracted ultrasonic wave having a predetermined frequency as a center frequency, wherein said predetermined frequency is given by ((n±(1/2)×(106×v/ΔL)(Hz), where ΔL is a variation in a distance between said transmitting transducer and said receiving transducer, v is an ultrasonic wave transmission velocity of a material being detected, and n is a natural number. 10. A method for detecting an ultr