Compact thermosonic NDE system

紧凑型热超声NDE系统

• 批准号: EP/E04641X/1
• 负责人: Darryl Almond
• 金额: $ 19.24万
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE04641X%2F1
• 关键词: Compact; thermosonic; NDE; system

Thermosonics is a novel non-destructive evaluation (NDE) technique that employs an infrared camera to image defects, typically cracks or delaminations, by detecting the heating caused by friction at the surfaces of defects when a part under inspection is vibrated. Typically, a pulse of high power ultrasound in the 20-100 kHz range is applied at one point on the test-piece to generate a high frequency vibration field in the structure. The method is considerably quicker than conventional ultrasonic or eddy current inspection techniques that require point by point scanning. The method is also particularly well suited to the detection of closed cracks that can cause problems with other techniques. Whilst impressive results have been achieved in a number of laboratories worldwide, the system, particularly the excitation, needs engineering. The reliability of the system needs to be improved - there is concern that defects in some locations are missed; this is almost certainly a function of the vibration field that is generated by the exciter. The amplitude of vibration required needs to be defined and assurance that this will not propagate the defects is required. To date a high power ultrasound horn, of the type produced commercially to weld plastics has been used to excite vibrations. The high power horn has the major disadvantage that it is bulky and is very difficult to couple reproducibly to the structure. This proposal follows an earlier research programme in which the applicants have established a quantitative understanding of the excitation requirements for a successful thermosonic inspection. This programme has shown that for a number of industrially important applications, successful thermosonic inspections can be completed using significantly lower amplitude vibrations than those associated with high power ultrasonic welding horns. An objective of this proposal is to design and produce ultrasonic exciters that are engineered for specific demonstrator applications. These demonstrators will be selected from applications that have been found to be particularly suitable (ie requiring low excitation power) for thermosonic inspection in consultation with the industrial partners who are supporting the project. The lower power requirement and tailored design should make the exciter significantly smaller and lighter than the bulky ultrasonic welding horns in current use. The other part of a thermosonic system is an infrared camera that was, until recently, also a bulky heavy component. However, very small microbolomer array infrared cameras are now available for use in NDE systems. The intention is to produce a compact portable, possibly hand held, thermosonic inspection system incorporating a small microbolometer array camera and a custom engineered vibration exciter. A full vibration analysis of the demonstrator parts will be completed to determine the optimum mode to excitation to ensure the reliability of the inspection. The system will also include a means of monitoring the vibrations to enable the user to check that adequate vibration amplitude is produced in a part to reliably complete a test. The inspection system will be field tested on a selection of demonstrator parts. The overall aim of the project is to take thermosonics, a very promising new NDE technique, out of the laboratory and to introduce it successfully into industry.In addition to producing a prototype testing system, the project will advance scientific understanding of the performance of ultrasonic exciters, and in particular the influence of the coupling between the exciter and the structure. Novel means of non-contacting measurement of the vibration field produced by the exciter will be investigated and these are likely to have other scientific and industrial applications.

热超声是一种新型的无损评价（NDE）技术，其采用红外相机通过检测当被检测的部件振动时由缺陷表面处的摩擦引起的加热来对缺陷（通常为裂纹或分层）进行成像。典型地，在20 - 100 kHz范围内的高功率超声脉冲被施加在试件上的一个点处，以在结构中产生高频振动场。该方法比需要逐点扫描的传统超声波或涡流检测技术快得多。该方法还特别适合于检测可能导致其他技术问题的闭合裂纹。虽然在世界范围内的许多实验室中已经取得了令人印象深刻的结果，但该系统，特别是激励，需要工程设计。系统的可靠性需要提高--担心某些位置的缺陷会被遗漏;这几乎肯定是激振器产生的振动场的函数。需要定义所需的振动幅度，并确保不会传播缺陷。迄今为止，商业上生产的焊接塑料的类型的高功率超声变幅杆已被用于激励振动。高功率喇叭的主要缺点是体积大，并且很难可重复地耦合到结构上。该建议遵循早期的研究计划，其中申请人已经建立了成功的热超声检查的激励要求的定量理解。该计划表明，对于许多工业上重要的应用，成功的热超声检查可以使用比高功率超声波焊头相关的振幅低得多的振动来完成。本提案的一个目的是设计和生产超声波激励器，专为特定的演示应用而设计。这些演示器将从与支持该项目的工业合作伙伴协商后发现特别适合（即需要低激励功率）热超声检测的应用中选择。较低的功率要求和定制的设计应使激励器比目前使用的笨重的超声波焊头小得多，也轻得多。热超声系统的另一部分是红外摄像机，直到最近，它也是一个笨重的组件。然而，非常小的微测辐射热仪阵列红外相机现在可用于无损检测系统。其目的是生产一种紧凑的便携式，可能是手持，热超声检测系统，包括一个小的微测辐射热计阵列相机和一个定制的工程激振器。将完成验证机部件的全面振动分析，以确定最佳激励模式，确保检查的可靠性。该系统还将包括一个监测振动的装置，使用户能够检查在一个部件中产生的足够的振动幅度，以可靠地完成测试。该检测系统将在选定的演示部件上进行现场测试。该项目的总体目标是将热超声这一非常有前途的无损检测新技术从实验室中带出，并将其成功地引入工业中。除了生产原型测试系统外，该项目还将促进对超声激励器性能的科学理解，特别是激励器与结构之间的耦合的影响。将研究非接触式测量激振器产生的振动场的新方法，这些方法可能具有其他科学和工业应用。