Infrared imaging during low-cycle fatigue of HR-120 alloy

Effects of frequency on fatigue behavior of type 316 low-carbon, nitrogen-added stainless steel in air and mercury for the spallation neutron source

“…The shorter fatigue lives in mercury at 10 than at 0.2 Hz were only found at the higher stress levels (Ն230 MPa) induced by the temperature effect (130 °C at 10 Hz vs 20°C at 0.2 Hz) ( Figure 7). However, at lower stress levels (Ͻ230 MPa), the temperature increase is generally lower, [47][48][49][50][51][52] and, thus, there were comparable temperatures at 10 and at 0.2 Hz, which resulted in similar fatigue lives at lower stresses (Figure 7).…”

An Innovative Technique for Evaluating the Integrity and Durability of Wind Turbine Blade Composites - Final Project Report

“…When torque was applied, the vicinity of the notch root region was subject to a tri-axial tensile stress state. In general, under IR imaging material at peak (or principal) tri-axial tensile stress (or at a localized material stretched state) region will show a relatively lower temperature compared to nearby lower tensile stress regions [Wang, H. 2002]. The temperature profile shown in Figure 15b exhibits this behavior where a relatively small temperature drop was observed in the vicinity of the notch region.…”

Temperature evolution and life prediction in fatigue of superalloys

“…However, there was a noticeable difference in the predicted and experimental results for the fatigue test of HR-120 with a total strain range of 2.3 pct. The reason for this discrepancy was that the main crack in the specimen formed outside the region monitored by the extensometer [13] and, thus, caused the abnormal temperature evolution, as compared to other fatigue tests at different total strain ranges. After the steady state is reached, t Ͼ t s (t s is the time at which the mean temperature reaches a steady state), the third term on the right-hand side of Eq.…”

“…It was noted for the HAYNES HR-120 alloy fatigue test at the total strain range of 2.3 pct, the main crack initiated outside the region monitored by the extensometer, and the temperature continuously increased until the fracture took place. [13] In Figure 5, the equilibrium temperature increases, ⌬T, which is the temperature difference between the equilibrium state and the initial state, were plotted against the final failure cycles, N f , on a logarithmic scale. A linear relationship was observed and can be expressed by the power law [4] where a and b are constants determined by curve fitting.…”