Matuda Marcelo Y, Pérez Nicolás, Buiochi Flávio, Adamowski Julio C, Tsuzuki Marcos S G
Department of Mechatronics and Mechanical Systems, Engineering - Escola Politécnica da Universidade de São Paulo, Brazil.
Facultad de Ingenieria - Universidad de la Republica, Uruguay.
Ultrasonics. 2024 Aug;142:107387. doi: 10.1016/j.ultras.2024.107387. Epub 2024 Jun 28.
The ultrasonic pulse-echo technique is widely employed to measure the wall thickness reduction due to corrosion in pipelines. Ultrasonic monitoring is noninvasive and can be performed online to evaluate the structural health of pipelines. Although ultrasound is a robust technique, it presents two main difficulties arising from the temperature variation in the medium being monitored: the mechanical assembly must have high stability and the ultrasonic propagation velocity must take into account the temperature variation. In this paper, a detailed strategy is presented to compensate for changes in the propagation velocity whenever the temperature changes. The method is considered self-compensated because the calibration data is obtained from the ultrasonic signals captured using the pipe under evaluation. The analysis of systematic errors in the temperature compensation is presented, first considering that a reference initial pipe thickness is given, and second when a reference sound velocity is given. The technique was evaluated under laboratory conditions using a closed loop with accelerated corrosion through the use of continuous flow saline water containing sand. In this test, the ultrasonic results were compared with the traditional coupon method used to determine corrosion loss. The results show that the self-compensated method was able to compensate for temperature fluctuations, and the total thickness loss measured by the ultrasound technique was close to the value measured by the coupons. Finally, the measurement system was tested in a production pipeline exposed to sunlight. The results show that the self-compensated method can reduce the oscillations in the thickness loss readings, caused by temperature swings, but large temperature variations cannot be completely compensated for. This experiment also shows the effects of low mechanical stability, which caused completely invalid results.
超声脉冲回波技术被广泛用于测量管道因腐蚀导致的壁厚减小。超声监测是非侵入性的，并且可以在线进行，以评估管道的结构健康状况。尽管超声是一种可靠的技术，但由于被监测介质中的温度变化，它存在两个主要困难：机械组件必须具有高稳定性，并且超声传播速度必须考虑温度变化。本文提出了一种详细的策略，用于在温度变化时补偿传播速度的变化。该方法被认为是自补偿的，因为校准数据是从使用被评估管道捕获的超声信号中获得的。本文对温度补偿中的系统误差进行了分析，首先假设给出了参考初始管道壁厚，其次假设给出了参考声速。该技术在实验室条件下进行了评估，通过使用含有沙子的连续流动盐水进行加速腐蚀的闭环试验。在该试验中，将超声结果与用于确定腐蚀损失的传统试片法进行了比较。结果表明，自补偿方法能够补偿温度波动，并且超声技术测量的总厚度损失接近试片测量的值。最后，该测量系统在暴露于阳光下的生产管道中进行了测试。结果表明，自补偿方法可以减少由温度波动引起的厚度损失读数的振荡，但大的温度变化无法完全补偿。该实验还显示了低机械稳定性的影响，这导致结果完全无效。
