PSI - Issue 8

4

Author name / Structural Integrity Procedia 00 (2017) 000 – 000

Franco Concli / Procedia Structural Integrity 8 (2018) 14–23

17

Fig. 2. Bending test schematic representation.

Fig. 3 summarizes the test results listed in Tab. 4, which includes also additional test points that are not considered in the staircase.

Fig. 3. Bending fatigue tests results.

Table. 4. Bending fatigue tests results. Test ID MAX Load [kN] MIN Load [kN] Cycles

Test ID MAX Load [kN] MIN Load [kN] Cycles Tests (used to define bending fatigue limit)

Preliminary Tests (not used)

0 0 0 0

-3.0 -3.4 -4.0 -4.2

-30.0 -34.0 -40.0 -42.0

RUNOUT RUNOUT RUNOUT RUNOUT

1 2 3 4 5 6

-4.4 -4.6 -4.4 -4.6 -4.8 -4.6

-44.0 -46.0 -44.0 -46.0 -48.0 -46.0

RUNOUT 1611316 RUNOUT RUNOUT 821414 RUNOUT

To obtain the fatigue limit (X 50 ) with 50% of probability of failure the following equation was used:

6 0.8678 (1) where d is the load step and K is obtained by the table provided by Dixon (1965). The relations between the applied and measured forces and the tooth root stress have been calculated following the approach proposed by the ISO 6336 3 standard (2006). (2) 50 46 0.372 2 46.7 f X X K d kN        F en Y  

2 ( / ) ( / ) F n s n m cos    h e m cos

F

F

n

n