PSI - Issue 18

V.N. Shlyannikov et al. / Procedia Structural Integrity 18 (2019) 322–329 Author name / Structural Integrity Procedia 00 (2019) 000–000

326

5

of the key for the full-sized compressor disk and imitation models I and II under uniaxial and biaxial loading conditions. The stress component distributions for the first imitation model agree well with the stress patterns on the surface of the key slot in the compressor disk. The second imitation model preserves the similarity of stress distributions with the compressor disk for long distances from the key slot surface. It is clear that the imitation model I is more suitable for the experimental determination of durability at the stage of the formation of a macro defects. The imitation model II makes it possible to study the crack growth rate and inclined crack path prediction under mixed mode biaxial loading.

b)

c)

d)

a)

e)

f)

g)

Fig. 3. Stress distributions (b-d) along slot fillet and (e-g) key thickness for compressor disk, imitation model I and II.

5. Experimental results The next part of the present study is concerned with manufacturing of imitation models and loading fixtures as well as further testing under uniaxial and biaxial loading conditions. The imitation models I and II were produced from titanium alloy VT3-1. The key slot geometry of the disk and blade dovetail type attachment was fully reproduced for both models strictly according to manufacturer drawings. Figures 4a and 4b represent the configuration of both imitation models. The advantage of the first model is the possibility of its placement in a heating furnace when conducting tests at elevated temperatures. The fatigue test of imitation model I was carried out with a frequency of 10 Hz, at room temperature and with stress ratio R = 0.1, by means of a uniaxial testing machine (Fig. 5a,b). The testing machine is equipped with an axial load cell having 100 kN capacity. Imitation model I was tested applying an only uniaxial load level P y =40 kN, and the failure criterion was the total failure/rupture of the test specimen. The fatigue test of imitation model II was carried out with a frequency of 5 Hz, at room temperature and with stress ratio R = 0.1, by means of a biaxial testing machine (Fig. 5c,d). The testing machine is equipped with four an axial load cell having 50 kN capacity. The test of imitation model II was performed applying in - phase