Issue 14

B. Lo

bato da Silva et

alii, Frattura ed

Integrità Struttu

rale, 14 (2010)

36-44; DOI: 10

.3221/IGF-ESIS.

14.04

154 158 162 166 170 174 178 182 186 190

Stress level (MPa)

Failure Su

spension

0 1

2 3

testing results 4 5 6 Specimen numb

7 8 9

10 11

er

Figure 3 : Pl

ot of Staircase

for notch rad

ius of 3 mm.

En Sta spe the sec

durance limit f rting from th cimens were result was r ond stage is

or notch radi e obtained re used and the efined and m 214.6 1.2  M

us of 5 mm sults previou endurance l ore five spe Pa.

sly the Stairc imit determin cimens were

ase method f ed was 220. tested as it

or notch rad 3 3.6  MPa. F can be seen

ius was execu ig. 4 shows in Fig. 5. Th

ted at two st the testing re e fatigue lim

ages. Firstly, sults. Follow it taken acco

five ing, unt

174 179 185 190 196 201 207 212 218 223

Stress level (MPa) Fa

ilure Suspens

ion

2 3

ng results for tion at avera ation decreas 4 5 6 Specimen numb

7 8

9 10

0 1

er

Fi ined in secon e Staircase m sponsible for nd notch fatigu btained resu rance limit w

gure 4 : Plot of d stage pres ethod. The s this fact. e reduction st lts starting f hen notch ra

Staircase testi ented a reduc tandard devi

notch radius o ge endurance ed three tim

f 5 mm (stage limit becaus es in relation

1). e the refinem to first stag

Th inc of No Ac dec

e results obta rement of th step size is re tch strength a cording to o rease in endu

ent in the st e. The decrea

ress sed

rength, K f , b rom experim dius decreas

ehavior ental data an e for ASTM

d shown in A743 CA6NM

Tab. 7 and alloy steel.

Fig. 6 we c

an to observ

e a

212 214 216 218 219 221 223 225 227 228

Failure Sus

pension

Stress level(MPa)

2 3

4 5 6 Specimen numb

7 8

9 10

0 1

er

Fi

gure 5 : Plot of

Staircase testi

ng results for

notch radius o

f 5 mm (stage

2).

41