ULTRASONIC METHOD OF DETERMINING INTERNAL MECHANICAL STRESS IN STRUCTURAL MATERIALS Russian patent published in 2012 - IPC G01N29/04 

FIELD: physics.

SUBSTANCE: ultrasonic pulses are passed through the analysed sample; signals which have passed through the sample are picked up based on measuring the difference in velocity and time in the stressed state of the analysed sample, wherein ultrasonic pulses are passed along the analysed sample; regions of the stressed state of the analysed sample are determined; a spherical segment is placed at that point, said segment being made from the same material as the analysed sample; ultrasonic signals are then focused by a system of lenses placed in a liquid, one of which faces the analysed sample and the other to piezoelectric sensors; the lens facing the analysed sample is moved in a direction perpendicular to the principal acoustic axis such that its focal plane moves on the entire surface of the analysed sample; the second lens is moved along the acoustic axis such that its focal plane cross the plane where the sensors are located; the passing signals are picked up by the sensors; time intervals and speed of the ultrasonic signals scattered by inner regions of the analysed sample are measured and mechanical stress is determined from a certain mathematical relationship.

EFFECT: high accuracy of determining speed of sound and more accurate determination of internal mechanical stress in analysed material.

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