Issue 33

M.Kurek et alii, Frattura ed Integrità Strutturale, 33 (2015) 302-308; DOI: 10.3221/IGF-ESIS.33.34

350 450 500

= 0



a

= 0



a

250

log(N f

)=23,8-8log(  a )

150

a , MPa

, 

a



)=21,4-7,7log(  a )

log(N f

50

10 4

10 5

10 6

10 7

N

f , cykle

Figure 1 : Fatigue diagram for oscillatory bending and bilateral torsion for the 6082-T6 aluminum alloy (where  a ,  a are stress amplitudes generated by torsional moment and bending moment, respectively).

σ a

/τ a

Bending

Torsion

N fi

(N fi

)

Material

cycles

A 

m 

A 

m 

PA6 (2017A) GGG40 10HNAP PA4 (6082) 30CrNiMo8 CuZn40Pb2

21.87 32.39 30.88*

-7.03

19.94 35.48 25.28

-6.87

2000000 1000000 2000000 2000000 100000 1000000

1.696

-10.95 - 9.5*

-12.41

1.11

- 8.2 - 7.7

1.874

23.8

-8.0 8.05 5.86

21.4

1.68

27.54 19.99

69.56

24.62 17.17

1.5

45.3

0.92

Table 1 : Coefficients of regression equation for analysed materials. 0 ,45     . For each of the 46 angles calculated parameters B and K in accordance with the formulas (13) and (14). Fig. 2 presents B and K constants depending on the angle β for the PA4 aluminum alloy. , lg 10 eg a cal A m N    .

0

0.55

-5

X: 13 Y: -2.935

0.5

-10

-15

X: 41 Y: 0.4393

0.45

-20

B

K

0.4

-25

-30

0.35

-35

-40

0

5 10 15 20 25 30 35 40 45

0

5 10 15 20 25 30 35 40 45

 , 0

 , 0

(a) (b) Figure 2 : The dependence of the parameter a) B, b) K from the angle β for aluminum alloy 6082 (PA4).

305