Issue34

C. Baron Saiz et alii, Frattura ed Integrità Strutturale, 34 (2015) 608-621; DOI: 10.3221/IGF-ESIS.34.67 616 R ESULTS Thermal results he plots of the maximum temperatures vs time during the fading test are shown in Fig. 10. For all the configurations, it can be observed that when braking is taking place, not all the heat generated can be efficiently dissipated and, consequently, disks temperatures remarkably increase. During the recovery stage, instead, since no more heat is introduced in the system, due to the effect of the convective mechanisms, the maximum temperatures tend to decrease. Nevertheless, as the recovery time is not long enough to restore initial values, temperatures become higher and higher from the beginning to the end of the test. Analysing the temperatures plots, there is no appreciable difference among the analysed vented discs during the first steps of the fading test. Going forward in the test, instead, temperatures curves gradually diverge among them (fig. 11). Maximum temperature values at the end of the last braking are, respectively, 889 °C for the straight-vanes disc, 841 °C for the curved configuration and 875 °C for the pillar-shaped disc. Figure 10 : Maximum temperature vs time. Figure 11 : Trends of max temperature in the last phases of fading test. Concerning the full disc, after completing the sixth braking, the maximum temperature has reached a value slightly above 1100°C, which is over the safety threshold value [23] for this kind of application. For this reason, numerical results of the full disc have not further considered after the sixth arrest. Nevertheless, this result is useful to quantify the performances difference between the ventilated disks and the full one, so confirming the use of this last kind of rotor for applications in which moderate braking performances are required. As regards the temperature distribution maps, it can be observed that braking surfaces deal with the highest values. The maximum temperature zones are located on the quarters corresponding to the couple of pads. Fig. 12 shows the temperature maps on the external surfaces and the internal vanes of the disks. The maps of temperature distribution on the external surfaces are quite similar among the analysed discs. The efficiency of the vanes in dissipating heat is also appreciable by analysing the temperature distributions on the internal and external surfaces of the discs. In conclusion, with reference to the thermal results, curved vanes represent the best solution because they allow better airflow propagation and, consequently, the maximum temperature reaches a lower value than the straight and the pillar-shaped vanes discs. T