Issue 14

B. Lo s it is possibl

bato da Silva et e to verify a s

alii, Frattura ed ignificant dis

Integrità Struttu persion of fa

rale, 14 (2010) tigue life for

17-26; DOI: 10 all stress rati

.3221/IGF-ESIS.

14.02

Bas Eff Th cha the end

ed on the ob ect of the mea e experiment racterize the parallel proj urance limit

tained result n stress al data and i fatigue stren ection metho considering a

os tested.

ts respective gth are summ d [12]. Basic n extrapolati

trend lines, arized in th ally, this met on of the fat

for such ratio e Tab. 12. T hod consists igue curve fo

loading, are he enduranc in achieving r life identifi

shown in F e limit, S` f , c S-N curve fo ed as infinite

ig. 4 and the an be easily o r the steel an fatigue life.

parameters btained thro d estimating

that ugh the

1000

Experim

ental Data R = -1 R = 0 R = 1/3 R = 2/3 Trend Line

Sa (MPa)

100

1E+4

1E

+5

1E+6

1E+7

N (number of c

ycle)

re 4 : S- N curv

Figu

es about the ef

fect of mean s

tress.

Basquin’s co (A) [MP ean Stand 06.9 1 6.8 1 9.8 9 2.3 Table ntal results: perimental d djusts to Bas tion, for ratio n real failure

nstant a] ard error M 02.9 -0 46.8 -0 1.2 -0 7.4 -0 12 : Paramete Goodman’s m ata and the quin’s curve loading of condition.

Basquin’s ex (b) ean Stan .0941 0 .0962 0 .0987 0 .0077 0 rs that charact odel predictions but reveal b 2/3, the mo

ponent

Enduranc (S` f ) [M ean Stand

2 e limit Pa] ard error 8. 0

R M -1 14 0 99 1/3 72 2/3 15

dard error M .0059 .0125 2 .0101 .0039 erize the S-N

383.2 63.9 186.7 136.9 curves

28.0 23.3 6.7

Mo Fig adh arri lev

dels’s adheren . 5 shows th erence. The ves to 300 M els around 34

ce to experime e fatigue ex trend line a Pa. In addi % upper tha

low its ress

based on G ig scatter, a del predicts t

oodman’s m s shown in F he possibilit

odel. The re ig. 6. The c y to apply, o

sults reveal onfidence lim n average, st

1000

1000

5 6 7 8 9

5 6 7 8 9

R = -1 R = 0 R = 1/3 R = 2

/3

4

4

R = -1 R = 0 R = 1/3 R = 2/3

3

3

Sar (MPa)

2

2

Sar Goodman (MPa)

Trend Lin Confiden Trend Lin Confiden

man’s predicti +4 1E+5 1E+ er of cycle (N) e - Goodman Eq. ce Interval - Goodman e - Basquin Eq. ce Interval - Basquin

Eq.

Trend

Line

Eq.

100

100

1E

igure 5 : Good +2 1E+3 1E Numb

6 1E+7

100

1000

Sar Bas

’s scatter diagr quin (MPa)

F

on.

Figure

6 : Goodman

am.

23