Advanced techniques in ultrasonic nondestructive evaluation

必须仔细检查关键工程部件，以最大限度地减少灾难性故障的危险。这在故障可能导致重大经济损失、环境破坏或人身伤害的领域尤其重要，例如航空、核电、石油和天然气管道、石化加工等行业。潜在危险的缺陷在部件表面可能看不到，因此可以使用X射线或超声波检测等技术来探测部件表面下的缺陷。该研究项目致力于开发新型超声波传感器，以及处理产生缺陷图像的超声回波信号的数学算法。最终目标是获得工程部件中缺陷的大小、形状和类型的更清晰、更清晰的“图”(S)，以便能够准确地评估其导致部件故障的可能性。这项工作的传感器开发部分旨在生产能够在恶劣环境中长时间工作的超声波换能器，特别是高温或升高的伽马辐射场。这种传感器的一个主要应用是将它们永久安装在石化或发电厂中可能容易腐蚀或裂纹萌生的任何部件上。在工厂运行期间，探头可以在高达700摄氏度的温度下持续监测这些关键工厂组件的完整性，并定期将信息发送回中央计算机系统进行分析和存储。工厂的安全性将得到提高，意外的工厂故障将会减少。改进后的探头硬件将通过开发先进的信号处理算法来补充，这些算法可以“锐化”缺陷的模糊图像，或者分离来自一对紧密间隔的亚表面缺陷的两个模糊回波。这种信号增强策略具有丰富的潜在应用，例如，地球物理学、电信、天文学、产科、神经学和微型机器人。一些建议的技术将包含在多种类型的信号中的信息与关于缺陷回波的预期一般形式的知识结合在一起，这是一种“数据融合”方案。结合所有关键因素，可以更准确地估计几个关键缺陷参数，如缺陷大小或形状。这项工作的直接受益者将是加拿大的工业，它将能够减少工厂运营期间的意外故障数量。这将有助于保护环境，减少伤害，并保持低生产成本。

Critical engineering components must be carefully inspected to minimize the danger of a catastrophic failure. This is particularly important in fields where a failure could lead to major financial loss, environmental damage, or personal injuries, e.g., industries such as aviation, nuclear power generation, oil & gas pipelines, petrochemical processing. Potentially dangerous flaws may not be visible at the surface of a component so techniques such as x-ray or ultrasonic wave inspection can be used to probe for flaws that are beneath the component's surface. This research program is focused on the development of new types of ultrasonic sensors, and mathematical algorithms to process the ultrasonic echo signals that yield flaw images. The final objective is then to obtain a much sharper, clearer "map" of the size, shape, and type of flaw(s) in an engineering component such that an accurate assessment can be made of its potential for causing a component failure. The sensor development component of this work is targeted at producing ultrasonic transducers that can operate for extended periods in harsh environments, in particular high temperature or elevated gamma radiation fields. One major application of such sensors would be for their permanent installation on any components in a petrochemical or electrical power generation plant that might be prone to corrosion or crack initiation. The probes could continually monitor the integrity of these key plant components at temperatures up to 700 C while the plant is in operation, and periodically send the information back to a centralized computer system for analysis and storage. Plant safety would be enhanced, and unexpected plant failures would be reduced. The improved probe hardware is to be complemented by development of advanced signal processing algorithms that can "sharpen" a blurry image of a flaw, or separate two blurry echoes originating from a pair of closely-spaced sub-surface flaws. There is a wealth of potential applications for such signal enhancement strategies, e.g., geophysics, telecommunications, astronomy, obstetrics, neurology, and micro-robotics. Some of the proposed techniques combine information contained in multiple types of signals with knowledge about the expected general form of a flaw echo, in a "data fusion" scheme. Combining all the key factors enables a more accurate estimate of a few key flaw parameters, such as flaw size or shape. The direct beneficiaries of this work will be Canadian industry, which will be able to reduce the number of unexpected failures during plant operations. This will help protect the environment, reduce injuries, and keep production costs low.