High power electron beams are used for welding critical components in aerospace and nuclear industries due to their inherent advantages. There are high quality requirements in these industries and hence the associated cost of materials and processes is also very high. This makes it very important to ensure that the beam quality is maintained and checked prior to carrying out the welds. The processes in these industries are highly controlled, however, even minor changes in the operating parameters of the electron beams generated by electron guns can make large enough variations in the beam quality that can result in poor welds. Many devices and techniques exist to measure the beam quality, however, these are limited in their operation at high powers
Electron beam intensity cross sections can be investigated using probe devices. TWI has developed a probe called BeamAssure that can be used during production, or in research and development, to provide quality assurance – an essential requirement where electron beam welding is being used for high value, quality critical components such as aero engine assemblies. Recent research has used controlled welding studies, beam categorisation by wavelet transforms, weld quality assessment and statistical correlation to predict the weld quality from measured beam characteristics. It has also been found from users of TWI probing systems that characterisation of the beam profile by measuring above and below the focal position, provides a sensitive method of assessing the beam quality and predicting welding performance. It is anticipated that further research, working closely with users of the BeamAssure probe, will yield methods of beam characterisation that can predict successfully the weld quality and provide diagnostic indications where the beam quality is outside of working windows.
This PhD will focus on the correlation of weld outcomes with measured electron beam characteristics. The BeamAssure tool is able to quantify the shape and power density of the welding beam, but relating this to the resulting weld performance requires in depth study – a large number of beam measurements, weld assessment and analysis of the combined data is required. Extrapolation of the relationship between beam and weld quality for different materials and thicknesses will require significant research and analysis.
This project forms part of a wider research programme in Digital Manufacturing aiming to develop intelligent manufacturing systems.
During this project the Student will develop skills and knowledge in:
• Advanced joining,
• Instrumentation of hardware,
• Data capturing and analysis,
• Process modelling,
• Materials characterisation, testing and analysis.
About Industrial Sponsor
The Lloyd’s Register Foundation funds the advancement of engineer-related education and research and supports work that enhances safety of life at sea, on land and in the air, because life matters. Lloyd’s Register Foundation is partly funded by the profits of their trading arm Lloyd’s Register Group Limited, a global engineering, technical and business services organisation.
NSIRC is a state-of-the-art postgraduate engineering facility established and managed by structural integrity specialist TWI, working closely with, top UK and International Universities and a number of leading industrial partners. NSIRC aims to deliver cutting edge research and highly qualified personnel to its key industrial partners.
About the University
Lancaster University is a strong and dynamic university with a very highly regarded Engineering Department. In the 2014 Research Excellence Framework, 91% of research quality and 100% of impact was assessed as being internationally excellent and world leading. Lancaster’s approach to interdisciplinary collaboration means that it has pre-eminent capacity and capability for the integration of Engineering with expertise in the areas of data science, autonomous and learning systems, intelligent automation, materials science and cyber security. The University is developing an ambitious growth plan for Engineering, including investment in staff, doctoral students, equipment and a new building focussed on research themes including Digital and Advanced Manufacturing. Lancaster is the current Times and Sunday Times University of the Year.
Candidates should have a relevant degree at 2.1 minimum, or an equivalent overseas degree in:
• Engineering (Mechanical, Controls, Manufacturing)
• Materials science
Candidates with suitable work experience and strong capacity in numerical modelling and experimental skills are particularly welcome to apply. Overseas applicants should also submit IELTS results (minimum 6.5), if applicable.
This collaborative project will involve the majority of time spent at TWI in Cambridge, but there is an expectation that the Student will spend a proportion of their time at Lancaster University.
This project is funded by Lloyds Register Foundation and TWI. The studentship will provide a successful Home/EU student with a stipend of £16k/year and will cover the cost of tuition fees. Non-EU students are also welcome to apply, and the studentship will provide a successful non-EU applicant with a maximum of £12k/year towards living costs and tuition fees.