Non-destructive evaluation of residual stress using the collaborative robot

Lead Research Organisation: University of Strathclyde
Department Name: Electronic and Electrical Engineering

Abstract

In the Centre for Ultrasonic Engineering (CUE) at the University of Strathclyde, the non-destructive evaluation of residual stress in welding and Wire + Arc Additive Manufacturing (WAAM) is considered as part of a larger programme through a 5-year Chancellor's fellowship led by Dr Javadi. Therefore, an advanced robotic system for the in-process residual stress measurement will be developed within the centre's state of the art robotic facility: Sensor Enabled Automation, Robotics & Control Hub (SEARCH). The measurement process will be carried out using (i) a phased array ultrasonic system and (ii) a flexible robotic cell. The innovative idea of robotic residual stress measurement is anticipated to increase the repeatability and the accuracy of the measurement, through reducing human errors and increasing the positioning accuracy of the measurement system, and also saving the measurement time. Traditionally, the majority of residual stress measurement methods are carried out manually with some basic automation, where the whole process still requires supervision by a highly skilled operator (expert in both areas of NDE and residual stress). In this project, a collaborative robot (Cobot) similar to KUKA KMR iiwa, will be used to facilitate the transition from a manual process (residual stress measurement) to an automated process in direct collaboration with the highly skilled operator (this PhD student). Such a smart collaborative robot can help with the residual stress measurement in both (A) offline measurement on the as-built components and (B) high-temperature in-process residual stress measurement. For the offline measurement, it is expected to increase the flexibility of the measurement as the operator should reach the different sections of weld, Heat Affected Zine (HAZ) and parent material of the component for the comprehensive residual stress measurement. This flexibility is also required to deal with the variations in the size and geometry of the components because the complex geometry of WAAM components is challenging to be fully covered during a manual residual stress measurement process. Furthermore, some parts of the process are time consuming in a repetitive procedure, The cobot can be trained by the operator on one of the testing sections and then the same process will be repeated automatically for the whole measurement reaching a more accurate results and saving time/energy. For the high-temperature in-process residual stress measurement, the cobot can also allow the initial testing and experiments on the hot sample to facilitate the transition from the manual measurement to the fully automated in-process inspection. All of these developments will be considered in this project to explore the requirements of a system of cobot residual stress measurement.

Planned Impact

The proposed CDT in NDE will deliver impact (Industrial, Individual and Societal) by progressing research, delivering commercial benefit and training highly employable doctoral-level recruits able to work across industry sectors.

Industry will benefit from this CDT resulting in competitive advantage to the industrial partners where our graduates will be placed and ultimately employed. The global NDE market itself has a value of USD15 billion p.a. [Markets and Markets NDE report January 2017] and is growing at 8% per year. Our partners include 49 companies, such as Airbus, Rolls-Royce, EDF, BAE Systems, SKF and Shell, whose ability to compete relies on NDE research. They will benefit through a doctoral-level workforce that can drive forward industrial challenges such as increased efficiency, safer operation, fewer interruptions to production, reduced wastage, and the ability to support new engineering developments. Our 35 supply chain partners who, for example, manufacture instrumentation or provide testing services and are keen to support the proposed CDT will benefit through graduates with skills that enable them to develop innovative new sensing and imaging techniques and instrumentation. To achieve this impact, all CDT research projects will be co-created with industry with an impact plan built-in to the project. Our EngD students will spend a significant amount of their time working in industry and our PhDs will be encouraged to take up shorter secondments. This exposure of our students to industry will lead to more rapid understanding, for both parties, of the barriers involved in making impact so that plans can be formulated to overcome these.

Individual impact will be significant for the cohorts of students. They will be trained in an extremely relevant knowledge-based field which has a significant demand for new highly skilled doctoral employees. These graduates will rejuvenate an ageing workforce as well as filling the doctoral skills and capability gaps identified by industry during the creation of this CDT. Our industrial partners will be involved in training delivery, e.g. entrepreneurial training to equip our graduates with the skills needed to translate new research into marketed products. Many of the partners are existing collaborators, who have been engaged regularly through the UK Research Centre in NDE (RCNDE), an industry-university collaboration. This has enabled the development of a 5,10 & 20 year vision for research needs across a range of market sectors and the CDT training will focus on these new priorities. Over the duration of the CDT we will actively discuss these priorities with our industry partners to ensure that they are still relevant. This impact will be achieved by a combination co-creation and collaboration on research projects, substantive industrial placements and as well as communication and engagement activities between academic partners and industry. Events aimed at fostering collaboration include an Annual CDT conference, technology transfer workshops, networking events as well as university visits by industrialists and vice versa, forming a close bond between research training and industrial impact. This approach will create lasting impact and ensure that the benefits to students, industry and society are maximised.

Society will benefit from this CDT through the research performed by our CDT graduates that will underpin safety and reliability across a wide range of industries, e.g. aerospace, energy, nuclear, automotive, defence and renewables. As NDE is an underpinning technology it feeds into many of the UK Government's Industrial Strategy Challenge Fund Grand Challenges, for example in energy, robotics, manufacturing and space. It is aligned to the EPSRC prosperity outcomes, e.g. the Productive Nation outcome requires NDE during manufacture to ensure quality and the Resilient Nation requires NDE to ensure reliable infrastructure and energy supplies.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S023275/1 01/10/2019 31/03/2028
2747646 Studentship EP/S023275/1 01/10/2022 30/09/2026 Brandon Mills