Stress and strain measurements by image correlation and Thermoelasticity
In this paper image correlation and thermoelaticity are proposed as joint measurement techniques to perform a “full field” characterization of materials and mechanical components. The very interesting possibilities offered by using both these non contact measurements techniques is the ability to obtain, by measuring both stress and strain, distributions of mechanical parameters on the surface of a dynamically loaded mechanical component, made, in general, of any material. This kind of results can be very useful for non homogeneous, composite or complex materials, or for complex shapes or loading conditions of the mechanical component under analysis, nowadays largely used for machine and structure realizations. In the work a proper coating, useful to perform measurements by both the techniques, is developed and tested. The coating act as a stressstrain distributed gauges.
Introduction to thermoelastic stress analysis
The theory of thermoelastic stress analysis is reviewed and the assumptions in developing the theory are assessed. The equipment for thermoelastic stress analysis is based on infrared detection systems. The commercially available systems are described and appraised. Techniques for calibrating the output from the detectors are also provided.
Magnetic properties of Lu2Fe17 crystals
Abstract We present the results of crystal structure and magnetization studies of three single crystals grown from melts of different nominal compositions in the vicinity of the Lu2Fe17 stoichiometry. The ferromagnetic state of the crystals is strongly dependent on the real sample composition and the local atomic ordering. A drastic difference is observed in the behaviour of the ferro–antiferromagnetic transition, even in crystals for which almost identical composition and crystal parameters were determined by microprobe and X-ray analysis.