Residual stress measurements for aerospace structural integrity
Prof Mike Fitzpatrick (Coventry University)
Aerospace structures are highly-safety critical. With the drive towards lighter structures, the competition between metallic and composites, and the introduction of new manufacturing and processing methods, residual stresses are becoming increasingly important. All the available experimental techniques have advantages and limitations, and selection of the correct process, with appropriate validation, is an important skill for those concerned with the analysis and consequences of residual stresses. There is increasingly a trend towards modelling of residual stress effects, often with incomplete or incorrect material data, and the use of a single measurement technique, selected for convenience rather than because it is the most informative method to use.
Using digital image correlation and high energy dispersive X-rayelastic follow-up
Prof David Smith (University of Bristol) Authors: David Smith, Graeme Horne and Matthew Peel
This talk provides an overview of a detailed experiment that used a combination of digital image correlation (DIC) and high-energy-dispersive X-ray diffraction (HEXRD) to measure initial residual The various DIC and HEXRD measurements then led to an evaluation of the elastic follow-up provided by the structural stiffness of the sample. One of the important consequence of their being elastic follow-up is that there is much more plastic strain accumulated in the sample then is expected if it is assumed that the initial residual stress relax as if subjected to pure displacement controlled loading.
Exploring natural and artificial materials design using micron-scale structure and strain mapping
Prof Alexander Korsunsky (University of Oxford)
The availability of sub-micron focused synchrotron X-ray beams has opened up exciting opportunities for understanding the internal architecture and deformation behaviour of intricately structured natural and artificial materials. In recent years we have looked at a wide range of systems that range from human dental tissues to flax fibres to thermoplastic polyurethanes to carbon fibres and aerospace alloys and composites. The unifying theme in our studies is the interest in strain:
How does it manifest itself at different scales?
How can it be reconstructed in all its complexity of multiple components and spatial variation?
How do we overcome the decade-old problem?
Answers will be provided using examples from recent research.
A brighter light for science
