University of Bristol

Supervisors: Professor Alexander (Sasha) Velichko and Professor Anthony Croxford 

This project will focus on exploiting ultrasound multiple scattering phenomenon to quantitatively characterise microstructural properties of metallic materials (grain size and shape or size and the anisotropic crystal orientation of micro-textured regions). There are several major advantages compared to the traditional measurements using a single transducer. Firstly, the approach is based entirely on post-processing of the transmitter receiver backscattering array data and does not require any changes in array hardware or specific requirements on the specimen’s geometry. Secondly, it is possible to extract data for each local area of the material, which leads to the possibility of microstructural characterisation of each local material region. Thirdly, the method can also be used for detection and localisation of weak local material inhomogeneities, which are undetectable using conventional imaging (for example, microtextured regions, creep damage). 

The project consists of several tasks, briefly outlined below. 

  • Development of the fast semi-analytical model of array data for coarse grain materials, which includes multiple scattering of ultrasonic waves. 
  • Development of efficient algorithms to extract multiple scattering parameters from the array data.  
  • Sensitivity study of different multiple scattering parameters to material microstructure. 
  • Development of efficient scheme to solve the inverse problem of estimating microstructural properties from extracted multiple scattering characteristics.  
  • Experimental validation. 
  • Development of software demonstrator.