13th International Conference on Fracture June 16-21, 2013, Beijing, China Figure 1: Specimens position (left) under fatigue machine and thermal insulation box (right). Experiments under cyclic loading were conducted with a INSTRON 8801 axial servo-hydraulic load frame at room temperature. Each high cycle fatigue test was load-controlled. The temperature field of the observed Ωsp and Ωdumwere measured using a 350Hz sampling and an integration time of 1200µsinfrared camera (CEDIP Jade MW) with a resolution of 160×120 pixels. The camera, which sensor is cooled down by a Rotary Stirling engine, was started about 4h before the tests in order to ensure its thermal stability. Moreever, the origin manufacturer calibration was used to ensure the precise dissipated energy measurement in this study. Fig.2 shows the dissipated energy Ei d1 obtained with and without the insulation calibration. 0 2 4 6 8 10 0 8 16 24 32 40 48 Time(s) Ei d 1 (J.m−3.cycle−1) ×103 No insulation calibration Insulation calibration Figure 2: Evolution of dissipated energy difference with and without the insulation calibration. During each test, the thermal fields of the observed areas Ωsp andΩdumwere stored for 20s (7000 images), which divided in two sequences (Fig.3): 3
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