Crack Paths 2012

35800rot/min

12

10

8

6

4

q u

2

0

30

50

70

90

110

130

150

170

quantityof cycles

temp. 1300C temp. 1000C

Fig. 10.Quantity of damaged elements versus number of thermal cycles.

As mentioned above, below temperature of 10000C and the rotator speed of 35800

rot/min the damage caused by thermo – mechanical fatigue did not occur. Thus, the

situation was examined when the blade was heated cyclicly to temperature 9000C and

then its rotator speed was raised. The fatigue began occuring only after the speed of

42970 rot/min was achieved which considerably exceedes the nominal value. Fig. 11

presents correlation between relative quantity of elements with damage and number of

thermal cycles.

Temeprature900C

10

8

6

4

2

q u

0

40

60

80

100 120 140 160 180 200 220

quantity of cycles

42970rot/min

43500rot/min

Fig. 11. Quantity of damaged elements versus number of thermal cycles.

The development of damage in dependence of number of thermal cycles for blade

without T B Cbarrier

Fig. 12 shows the bottom piece of blade for different quantities of cyclic thermo –

mechanical loadings.

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