University: University of Strathclyde  Supervisor: Dr Theodosia Stratoudaki & Dr Charles MacLeod  Start date: October 2021

The majority of challenges for NDE and high value manufacturing today stem from the increased use of advanced materials and advanced processes that push the performance limits to extremes. Inspection techniques are faced with extreme operating environments (high temperature/radioactive environments), places of restricted access (e.g. the inside of engines or the human body), components of complex geometries, remote deployment, and in-process monitoring of high-value manufacturing (e.g. additive manufacturing). For all these reasons, what is needed is remote ultrasonic inspection: a technique that is non-contact, couplant free, has small footprint and minimal weight and can be delivered through an endoscope. Laser ultrasonics (LU) address these challenges and Laser Induced Phased Arrays (LIPAs) provide superior ultrasonic imaging than conventional LU techniques by successfully addressing the poor signal-to-noise ratio (SNR) usually associated with LU, especially for the non destructive regime.  

The aim of the PhD is to enable automated, remote ultrasonic imaging, based on LIPAs, which will be deployed using robots on real and challenging processes -such as welding and 3D metal printing- environments and components. 

The techniques to be developed will influence life-cycle costs of UK industrial products, enhancing the success of UK manufacturing, especially those depending on safety critical applications, such as aerospace. As a result, the results from this study will ensure safer transport, reduced usage of natural resources and benefit society as a whole. 

Robotically delivered Laser Ultrasonic inspection offers a monumental opportunity to inspect components as they are being built, ultimately leading to automated on-line process monitoring. This project seeks to investigate the potential for combining state-of-the-art developments in 1) Automation and Robotics, 2) Advanced Phased Array Laser Ultrasonics and 3) Complex Fusion Welding and large-scale 3D metal printing. Specifically, this project will investigate and develop a system for laser-deployed inspection using a 6 Degree of Freedom (D.O.F.) manipulator for true 3D surface and volume mapping, for the first time. Automated interpretation of all-optically acquired, ultrasonic data, providing information on the location, size and type of defects, will also be developed. This interpretation will be adaptive and real-time, forming a feedback loop to the data acquisition process.  

Optical-based techniques, which can be delivered through flexible optical fibres, are also best suited for places of restricted access, such as in situ inspection of engines, or the human body. This project is directly applicable to industrial sectors such as additive manufacturing, space, aerospace, nuclear, defence and even human health.  

Robotic delivery of NDT inspection is an area where Strathclyde are international pioneers, using transducer based methods. Laser Ultrasonics will be integrated to the existing robots, addressing the requirements for increased inspection speeds and taking advantage of the flexible trajectory planning of the robotic system to realise LIPAs potential on synthesising arrays without physical constraints. The benefits are firstly expected in the inspection of curved structures and then for on-line process monitoring of welding and additive manufacturing. 

In summary, there is a high degree of novelty in the proposed research plan. In particular, high academic and industrial impact is expected from the idea of remote robotic laser inspection and the development of automated decision making process. 

The core objectives of the PhD study will be: 

  • Demonstration of LIPAs on industrial samples. 
  • Development of automated decision making process for the synthesis of LIPAs.
  • Demonstration of the potential of the technique in a variety of inspection cases encountered in industry. 
  • Investigate on-line deployment of the inspection system within a realistic manufacturing environment. 

Funding: 

This studentship covers fees at the home/EU rate, a stipend of £16877 per annum and the full technical and professional training programme as part of the FIND CDT.