Crack Paths 2009

Figure 3: A part of test spectrum, maximulmoad = 50 k N

Constant peened

Variable peened

1450

Constant un peened

Variable un peened

130

120

110

K N

1900

r,ange

80

Maximum l o a d

670

50

40

10000

100000

1000000

1 E 7

Nf

Figure 4: Loadrange vs. numberof cycles to failure

The shot blasted components showed a markedly better performance compared to the

forged components for both constant and variable loading conditions. If the equivalent

load (the load level which causes the same lifetime as the variable history if applied for

the same number of cycles[7]) is then calculated:

(1)

(2)

Frange = Equivalent load

N =Total number of cycles

ni = Numberof cycles for level i

m=Numberof range pair levels

Frange

i = T h e force range (peak-valley) for level i

k= the reciprocal of the slope of the F vs. N plot

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