Understanding the development and distribution of residuals stresses (RS) during manufacturing is a key factor in the development of methods to minimise distortions in components during machining.

Residual stress monitoring is also crucial for the overall control and maintenance of high performance components operating in extreme environments due to its influence on lifecycle. Therefore understanding the evolution and interaction of residual stresses during the whole manufacturing chain is of utmost importance; this is why one of the cores areas at the AMRC is the modelling and monitoring of bulk and near surface residual stress. The Residual Stress Measurement Group at the AMRC has developed competence in residual stress measurements (RS) using different technologies, including X-ray Diffraction, Ultrasonic, Contour Technique for RS measurements, as well as, Digital Image Correlation (DIC) Technique for strain measurements.

The Residual Stress Measurement Group has the aim to provide measurement capability on range of materials encountered at AMRC as a ‘wholesale’ RS service, to support ongoing machining projects on-site, and to validate process models in-house.

The group also has taken part in ‘Round Robin’ tests for X-Ray Diffraction (XRD) for RS measurements, involving research centres in Singapore, Germany and UK, designed to demonstrate the robust and stable nature of each centre’s measuring capabilities. The group also has collaboration with Research Centres for residual stress measurements using Neutron diffraction.

Research

The Residual Stress Measurement Group at the AMRC has interest in investigating the factors that influence the generation and distribution of residual stresses in manufacturing processes, including i) development of an understanding of the factors that influence the generation and distribution of RS during heat treatment; ii) effect of process variability on RS; iii) machining-induced stresses; iv) influence of RS on machining distortions; v) interaction of near and bulk RS; vi) validation of process models in-house for RS predictions.

Capabilities

  • Portable X-ray Diffraction System (XRD)
    X-ray diffraction can be used to measure residual stress using the distance between crystallographic planes, i.e., d-spacing, as a strain gage.
  • Ultrasonic Stress Measurement System
    The portable, semi-automatic device for Ultrasonic Measurements of Applied and Residual  Stress  is  designed  for  measurement  of  bulk  and  surface residual  and applied  stresses  in  samples,  parts,  welded  elements  and  structures  non-destructively.
  • Contour Measurement Technique
    Contour measurements are used to measure bulk residual stresses. Contour measurement is performed as following: 1) EDM machine; 2) CMM machine and 3) FE Modelling
  • Digital Correlation Technique
    Digital Image Correlation (DIC) is an optical method that employs tracking & image registration techniques for accurate measurements of changes in images. 

For more information, please contact:
Dr. Sabino Ayvar-Soberanis
s.ayvar@amrc.co.uk