PROCEDURE MEASURING AXIAL MECHANICAL STRESSES IN PIPE-LINES Russian patent published in 2002 - IPC

FIELD: nondestructive test of physical characteristics of structural materials, determination of mechanical stresses in various pipe-lines. SUBSTANCE: ultrasonic pulses of elastic lateral waves polarized along and perpendicular to axis of pipe are excited in examined zone of pipe-line, time of delay of these pulses is found, ultrasonic pulses f longitudinal wave are excited in same zone and time of their delay is found, ratios of delay of pulses of elastic lateral wave polarized along and perpendicular to axis of pipe to delay of pulses of longitudinal wave in material of pipe-line are determined, then ring stress is found, pressure is changed in pipe-line where examined zone is located, ring stress is found. Then ultrasonic pulses of elastic lateral waves polarized along and perpendicular to axis of pipe are excited, time of delay of these pulses is found, ultrasonic pulses of longitudinal wave are excited in same zone and time of their delay is found, ratios of time of delay of pulses of elastic lateral waves polarized along and perpendicular to axis of pipe to time of delay of pulses of longitudinal wave in material of pipe-line is determined. After it mathematically determined system of three equations with three unknowns is obtained. This system of equations is solved analytically or numerically and axial mechanical stress in pipe-line is found. EFFECT: increased measurement authenticity of axial mechanical stresses in pipe-lines. 3 dwg