Monitoring elastic strain and damage by neutron and synchrotron beams

Large-scale neutron and synchrotron X-ray facilities have been providing im portant information for physicists and chemists for many decades. Increasin gly, materials engineers are finding that they can also provide them with i mportant information non-destructively. Highly penetrating neutron and X-ra y synchrotron beams provide the materials engineer with a means of obtainin g information about the state of stress and damage deep within materials. I n this paper the principles underlying the elastic strain measurement and d amage characterisation techniques are introduced. The capabilities of the m ethods are illustrated through a number of practical applications including ; mapping damage and stress transfer fibre by fibre in continuous fibre rei nforced composites during loading, measurement of residual stresses in weld ing, the use of measurements to refine finite element models, and creep cav itation cracking in power plant steels.