Southwest Research Institute

Electric Power Research Institute Incorporated

John J Hanley

Hegeon Kwun

Keith Alan Bartels

David G Alcazar

Gary J Hendrix

Anmol S Birring

An apparatus and method for the non-contact measurement of tensile loading (or tension) in ferromagnetic materials, particularly wire ropes, cables, and strands. The magnetostrictive effect is used to measure wave propagation properties within such materials to determine load forces imposed on the tested material based upon a signature obtained for like materials under like conditions. The apparatus and method contemplate an active measurement application, wherein a transmitting sensor generates an mechanical pulse within a material through the magnetostrictive effect, and a receiving sensor detects reflected mechanical waves within the material by the inverse magnetostrictive effect. Unlike other sensing methods, utilizing the magnetostrictive effect in this way has the advantage of generating and detecting mechanical waves in the tested material without direct physical or acoustical contact. The apparatus and method of the present invention also anticipates the use of a long-term monitoring system that records acquired tensile load measurements for detection of possible structural anomalies and immediate activation of an alarm, or storage and retrieval/analysis at a later time.

Method and apparatus for conducting in-situ nondestructive tensile load

A method for detecting hydrogen attack by ultrasound wave velocity measurements in which ultrasound waves (e.g. longitudinal, shear, or creeping) are transmitted from one transducer to another transducer along a fixed path through a steel body such as pipe. The velocity of the ultrasound wave is determined with an accuracy of 0.1 percent from the fixed path length and the time for a wave to travel from one transducer to the other transducer. A decrease in velocity by more than two percent indicates hydrogen attack. In one embodiment, either refracted longitudinal or refracted shear waves are transmitted, and the velocities thereof are determined. In another embodiment, a creeping wave is transmitted from one transducer to the other transducer with the creeping wave including a surface wave and a subsurface wave. Travel time of the subsurface wave is measured and used with the known fixed path length in determining velocity. In the third embodiment ultrasonic waves are transmitted into the material and the backscattered ultrasound is measured. An increase in backscattered ultrasound is related to hydrogen attack.

Method and means for detection of hydrogen attack by ultrasonic wave

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San Antonio, TX, United States of America

John J Hanley