Measurement of stress and strain by a thermocamera

In this paper thermoelaticity and correlation of thermal images are proposed as joint measurement techniques to perform a "full field" measurement of stress and strain on the surface of mechanical components dynamically loaded. Thermoelasticity allow to measure the sum of the principal stress on the surface of a dynamically loaded mechanical component, therefore some researcher proposed the use of data processing methods and combined measurement techniques (using also photoelasticity for example) in order to mesure also the single stress components. Here a new measurement and testing technique, based on the recording of thermal images of a random emissivity pattern and of local thermal fluctuation is proposed to obtain both stress and strain on the specimen surface. Tests has been performed using simple specimen in classical configuration on laboratory testing machines. Results and possibility of this new measurement technique are discussed.