PSI - Issue 7

Hisao Matsunaga et al. / Procedia Structural Integrity 7 (2017) 460–467 Hisao Matsunaga / Structural Integrity Procedia 00 (2017) 000–000

464

5

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Maximum contact pressure, q max [GPa] 6206 51305

* Depth of hole-edge ranges from 0.05 mm to 0.175 mm.

d [mm]

d

0.05 0.08 0.1

Komata et al. ○

● ◆

Depth

◇

×

＋ ▲

10 8

10 9

10 6

10 7

Number of cycles to failure, N f

Fig. 3: Relationship between the maximum contact pressure, q max , and fatigue life, N f .

0 100 200 300 400 500 600 700 800 900 1000 Shear stress amplitude, τ a [MPa]

* Depth of hole-edge ranges from 0.05 mm to 0.175 mm.

d [mm]

d

0.05 0.08 0.1

Komata et al. ○

● ◆

Depth

6206

◇

×

51305

＋ ▲

10 8

10 9

10 6

10 7

Number of cycles to failure, N f

Fig. 4: Relationship between shear stress amplitude, τ a , and fatigue life, N f .

cracks in an infinite body under uniform shear, ∆ K II0 , via a correlation factor, f drill . This correlation is expressed as follows:

4

d a

  

   + 2

(

) ( ) − ⋅ 2 ν

(1)

π

'

1.56

0.82

∆ = − II, drill K

⋅ + d

∆ ⋅ τ

π

where, ∆ τ is the nominal shear stress range, acting at the depth of the hole-edge, h' . Figure 5 illustrates the relationship between ∆ K II, drill and N f . It is noted that ∆ K II, drill was calculated for the initial defect, i.e. the length of