Crack Paths 2006

5000

1. step

2. step

]

3. step

initial 0,c0ra0c5k m m

12345050505000

m

[N m

a c t o r K

iyt f

e s s i n t e n s

with residual stresses out residual str ses

S 4500 t r

0

0.008 0.01 0.013 0.016 0.019 0.022 0.025 0.028 0.031 0.034 0.037

Cracklength [ m m ]

Figure 6. MaximumSIF for crack propagation from the existing micro pit

Experimental testing

Experimental testing of the spur gear pair has been performed on a FZG- pitting test

machine according to the DIN51354 standard. The tested gears have been subjected to

the same operating conditions and loading parameters as used in the numerical

computations. Figure 7 shows the comparison between numerically and experimentally

determined pits on the gear flanks.

micro-pit

crack growth from the existing micro-pit

initial crack

0.005mm

0.02 m m

Figure 7. Experimentally (left) and numerically (right) determined pit shapes

C O N C L U S I O N S

The paper presents a computational model for the simulation of surface initiated fatigue

crack growth on gear teeth flanks. A simple contact model is used for simulating fatigue

crack growth under conditions of rolling and sliding contact. The contact model is

subjected to moving normal (normal contact pressure) and tangential (frictional forces)

contact forces, which also take into account the influence of EHD-lubrication