University of Manchester 

Supervisors: Dr Wuliang Yin, Dr Michael O’Toole & Professor Anthony Peyton


Acoustic or ultrasonic methods, and magnetic or eddy-currents, are the work horses of the non-destructive testing industry. They have both proven to be powerful and practical methods for the internal inspection of materials, and especially the presence of inhomogeneities or discontinuities formed by cracks, flaws, delaminations, etc. Ultrasonic methods are the most widely used, and have the advantages of portability, good penetration depth, high resolution and being non-ionising. However, this technique cannot detect very small defects, which are significantly less than a fraction of a wavelength. Magnetic or eddy-current methods on the other hand are highly sensitive to surface breaking defects but have a limited depth of penetration. 

The hypothesise of this project is that a combined dual-modal approach – using both ultrasonic and magnetic methods – will enhance the utility and capability over the methods working individually, and that their interaction will prove a rich additional source of data to understand the properties of ferrous steels.  

Aims and Objectives 

To work towards combining these two modalities we must first understand the behaviours of their interaction. This project involves a close study of the modes of ultrasonic propagation in a ferritic material as it undergoes a process of magnetisation. Magnetisation changes the internal stress fields causing changes and non-linearity in the ultrasonic behaviour, which we hypothesise will enable sub wavelength defects to become visible.   

The project will involve the theoretical, numerical, and simulated analysis using a multi-physics approach to build models of electromagnetic and acoustic phenomena within a permeable non-linear media, validated by experiments. This includes the development and commissioning of bespoke instrumentation using a combination of standard laboratory systems, and task specific front-end transducers and electronics (inductions coils, etc), for the measurement of ferritic metals. 

We have access to arrange of possible sample sets, from project-specific manufactured controls and phantoms, to material provided by commercial partners working in the UK Research Centre in NDE (RCNDE) network. 

The specific objectives of the project are: 

  1. To investigate and understand the mechanisms of acoustic-magnetic interactions in ferrous steels with microstructural defects. 
  2. To develop new multi-modal non-destructive testing methodology utilizing acoustic-magnetic interactions. 
  3. Develop new models and mechanisms of analysis to understand measured data and generate hypotheses about the characteristics of the microstructure. 
  4. Design of experiments and commissioning of test rigs and bespoke sensor apparatus for measurement on known samples from past and current projects, and manufactured controls. 

Supervision and Student Development 

The research will be primarily supervised by Dr. Mike O’Toole who is a new academic in the Electromagnetic Sensing Group in the Department of Electrical Engineering and Electronics enabling him to leverage his knowledge of electromagnetics and sensing for successful directing of this Ph.D. project. The student will gain access to a wide range of equipment/facilities within the research team and will be supported by Dr Wuliang Yin and Prof Tony Peyton. The proposed subject, focused on NDT of steel microstructure, could be relevant to the immediate demand of some of the industries who are a member of NDEvR and readily encompass safety and performance-critical components.  

In addition to benefiting from the wide range of NDE courses offered by FIND-CDT, the candidate will be also provided with off-campus training courses in modelling, simulation tool, and programming as well as MATLAB and LabVIEW programming courses to acquire the essential coding and system integration skills.  

The student will also benefit from association with the UK Research Centre in NDE (RCNDE) network, which provides further industry links and wider academic pool of collaborators and research opportunities (workshops, training, supplemental funding, etc). 


The project will contribute to the national need of improving materials and energy efficiency and manufacturing competitiveness. The ability to predict material properties through better inspection is key to producing high specification and high value steels and also crucial to the efficiency of the manufacturing process, which brings environmental and societal benefit in terms of contributing to lower energy consumption and reductions in CO2 emissions. 

Steel is the source material for many industries and performance improvements have huge implications in automotive, construction, energy sectors etc., with significant consequential benefits. The new sensing instruments would be capable of supporting research work into engineering new advanced steels required in new energy infrastructure and electric automobiles.