Advanced techniques in ultrasonic nondestructive evaluation

必须仔细检查关键的工程部件，以尽量减少发生灾难性故障的危险。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、核能发电、石油和天然气管道、石化加工等行业。潜在的危险缺陷可能在组件表面不可见，因此可以使用x射线或超声波检查等技术来探测组件表面以下的缺陷。本研究计划的重点是开发新型超声波传感器，以及处理产生缺陷图像的超声波回波信号的数学算法。最后的目标是在一个工程部件中获得一个更清晰、更清晰的尺寸、形状和缺陷类型的“地图”，这样就可以对导致部件故障的潜在因素做出准确的评估。这项工作的传感器开发部分的目标是生产可以在恶劣环境下长时间工作的超声波换能器，特别是高温或高伽马辐射场。这种传感器的一个主要应用是将其永久安装在石油化工或发电厂的任何部件上，这些部件可能容易腐蚀或产生裂纹。在工厂运行时，探针可以在高达700摄氏度的温度下持续监测这些关键工厂部件的完整性，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，意外的工厂故障将减少。改进后的探头硬件将与先进的信号处理算法相辅相成，该算法可以“锐化”缺陷的模糊图像，或者分离来自一对紧密间隔的次表面缺陷的两个模糊回波。这种信号增强策略有很多潜在的应用，例如，地球物理学、电信、天文学、产科、神经学和微型机器人。在“数据融合”方案中，一些提出的技术将包含在多种类型信号中的信息与有关缺陷回波的预期一般形式的知识结合起来。结合所有的关键因素，可以更准确地估计一些关键的缺陷参数，如缺陷的大小或形状。这项工作的直接受益者将是加拿大工业，它将能够减少工厂运行期间意外故障的数量。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.