Thermoelastic investigations for fatigue life assessment

Abstract

An investigation is presented on the suitability and accuracy of a thermoelastic technique for the analysis of fatigue cracks. The stress intensity factor ranges K I and K II are determined from thermoelastic data recorded from around the tip of a sharp slot in a steel specimen under biaxial load, in order to assess the accuracy of the technique. K I and K II are determined to within 4 % and 9% of a theoretical prediction respectively. The results from a similar test on a fatigue crack under biaxial load are also presented. These show that thermoelastic stress analysis is a rapid and accurate way of analysing mixed-mode fatigue cracks. A discussion is given on the potential of thermoelastic stress analysis of propagating cracks.

A review of using thermoelasticity for structural integrity assessment

“…They also pointed out the importance of the frictional effects between the two crack surfaces. The most complete research program in investigating mixed mode cracks was published by Tomlinson and Marsavina [20]. They grow real mixed mode cracks under successive loading using method developed by Bold et al [21] and then record thermoelastic data under a reduced sinusoidal load range, e.g.…”

Thermoelastic Investigations for Fatigue Life Assessment

“…The success of the interfacing procedure was tested by determining stress intensity factors from opening mode and predominantly mode I mixed-mode edge slots for which the algorithm is known to give accurate results, using SPATE data 16 , and opening mode cracks using DeltaTherm data 2,3 .…”

Noncontact Fatigue Crack Evaluation Using Thermoelastic Images

“…A thermoelastic stress analysis (TSA) has been studied as one of the representative passive techniques [16][17][18]. It builds on the 'thermoelasctic effects' which are temperature changes caused by force-induced volume changes [19].…”