Application of thermoelastic stress analysis for the experimental evaluation of the effective stress intensity factor

摘要

In recent years, the advent of staring array detectors has made Thermoelastic Stress Analysis (TSA)a technique with considerable potential for fatigue and fracture mechanics applications. The technique is noncontactingand provides full field stress maps from the surface of cyclically loaded components. In addition, thetechnique appears to have a great potential in the evaluation of the effective stress intensity factor range duringfatigue since fracture mechanics parameters are derived directly from the temperature changes in the vicinity ofthe crack tip rather than from remote data. In the current work TSA is presented as a novel methodology formeasuring the effective stress intensity factor from the analysis of thermoelastic images. ?K values inferredusing TSA have been employed to estimate an equivalent opening/closing load at different R-ratios in a crackedaluminium 2024 CT specimen. Results have been compared with those obtained using the strain-offsettechnique showing a good level of agreement.