ESTIMATING THE INTRINSIC DISSIPATION USING THE SECOND HARMONIC OF THE TEMPERATURE SIGNAL IN TENSION-COMPRESSION FATIGUE. PART II: EXPERIMENTS

The theoretical approach developed in the companion paper is applied to the temperature signals acquired by using an infrared camera, during step-load fatigue tests carried out on AISI 304L-colddrawn bars. The intrinsic dissipation, calculated according to the analytical model and by means of the Discrete Fourier Transform of the material temperature, is compared with that measured by using a well-established experimental approach based on the measurement of the cooling gradient of the material temperature, after the fatigue test has been suddenly stopped. The results of this study indicate that the intrinsic dissipation calculated according to the two approaches become increasingly closer to one another for progressively higher applied stress amplitudes.