Issue 50

V. Iasnii et alii, Frattura ed Integrità Strutturale, 50 (2019) 310-318; DOI: 10.3221/IGF-ESIS.50.26 314 The constant values (Tab. 1) of the Eqn. (9) were determined by the approximation of the experimental data using the least squares method. Analysis of the experimental dependencies in Fig. 3 shows that Odqvist's parameter χ f , before failure of material, increase with the decrease in temperature from 20 to 0°C. Moreover, the Odqvist's parameter at both temperatures 0°C and 20°C significantly increase with the increase in loading cycles. It implies from the analysis of experimental dependencies, presented on Fig. 3, that the value of Odqvist's parameter before the fatigue failure of material χ f is increasing with the decrease of temperature from 20°С to 0°C. Also, with the increase of number of loading cycles the ratio of Odqvist's parameter at 0°С and 20 °С increases significantly. Figure 2 : Dependence of the strain range on the number of loading cycles in ice water at 0°С and at 20°С in the air. Figure 3 : Dependence of the Odqvist’s parameter on the number of loading cycles in ice water at 0°С and at 20°С in the air. With the increasing of cycles to failure the dissipated energy per cycle decreases (Fig. 4). Experimental data in this case are well described by the logarithmic dependence W dis f W W N        (10)