NDTnet 1998 Aug, Vol.3 No.8

Abstract

The results of an experimental research activity aimed at the system setup of the Stress' Pattern Analysis by Measuring Thermal Emission which is used to measure the sum of the principal stresses of the free surface are presented here. The Spate system detects the infrared flux emitted from points on an observable surface resulting from the minute temperature changes in a cyclically stressed structure or component.

The thermoelastic law, assumed valid only within the elastic range of isotropic and homogeneus materials, relates to the peak to peak temperature changes and peak to peak amplitude of the periodic change in the sum of principal stresses.The experimental activity has been carried out on a cylindrical vessel whose capacity is 50 litres and made from steel 3 mm. thick.
The vessel was connected to an oil hydraulics apparatus providing a cyclical pressure change and able to be adjusted in amplitude and frequency.
The tests have been able to dispaly the stresses distribution on the vessel surface (shell and heads) as well as characterizing most rilevant zones for structural controls (weldings and so on).Furthermore, FEM Analysis has also been performed and a very good correlation achieved with the experimental results.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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