Issue 14

B. L

obato da Silva

et alii, Frattura

ed Integrità Stru

tturale, 14 (201

0) 36-44; DOI:

10.3221/IGF-ESI

S.14.04

H us

igh-cyc ed in h

le notc ydroge

h sensi nator tu

tivity of rbine c

alloy s ompon

teel AST ents

M A74

3 CA6N

M

Br Fed Bra lob

aitner Lob eral Universi sília, Brazil, atoae@gmail. STRACT . T raulic comp that sense, ponents w the consid 2.42. In o od, Stairca it. For such tor were co results obta diction of t YWORDS . N

ato da Silv ty of Brasília, 70940-910. com.br, jorge@ he presenc onents is a specimens as tested. T ered stress rder to dete se method w geometry a mpared thro ined it was he Peterson otch, fatigu e analysis in mponents a ly occur at st due to the f ometric disc formation fa imen, S fe . Th ost definitio lly unaffecte with respect   1 t q K  N

a, Jorge L Mechanical E unb.br, alex e of notche current pro of the AS he specimen concentratio rmine the f as used. T t least 8 spe ugh fatigue possible to and Neube e strength,

uiz de Alm ngineering D 07@unb.br s and othe blem in eng TM A743 s were test n factors, K atigue limit his approac cimens wer notch redu conclude r’s empirical staircase me

eida Ferr epartment, Ca

eira, José mpus Univer

Alexander sitário Darcy

Araújo

Ribeiro,

r stress co ineering. It CA6NM a ed under un t , values, c for such no h is based e tested. In ction factor that the tes models. thod, up an

ncentration causes a re lloy steel u iaxial fatigu alculated wi tch type, a on the assu addition, th , K f , obtain ted materia

s in turbin duction of e sing in sev e loading w th respect t reduction d med target e Peterson a ed from exp l is less sen

d other no mit of mate enator turb tio equal to were 1.55, 2 by Dixon of the fati ’s notch fati ata. Accord tches than

tch rial. ine -1, .04 and gue gue ing the

e blades an ndurance li eral hydrog ith a load ra o net area, ata method distribution nd Neuber erimental d sitive to no

A B hyd In com and and Mo

lim fac to pre

d down met

hod, ASTM

A743 CA6N

M.

K E

I N

TRODUCTIO

T

he fatigu these co invariab

turbine blad re designed ress concent atigue. Ther ontinuities. I ctor that rel is relation c n accepts is d for 10 6 to the cycle nu

es and other to operate b rators. In th efore, the str n that sense ates the fati an be expres the relation 10 8 cycles. In mber [1].

hydraulic no elow its en e cases that t ess concentr , appears th gue strength sed by Eq. 1 showed by E addition, w

tch compon durance limi he loading is ation factor e fatigue not of notch sp , where q is q. 2. Exper hen the fatig

ents is a ver t and becau dynamic, th should be m ch reduction ecimen, S f , the notch s imental inve ue life is les

y important p se fatigue fa e ductile ma odified accor factor, K f . with the fat ensibility fact stigations ind s that 10 6 cy

roblem beca ilures in ser terials behav ding to mat It establishes igue strength or and 0 q  icate that th cles, the K f v

use vice e as erial

bri sen imp unn Ho val dec

ttle materials sitivity to ge ortant trans otched spec wever, the m ue is practica rease quickly 1 f K  

an of

1  . e K f alue

(1)

S S

(2)

f

K



f

fe

K f . Accordin anic models r and Peters

notch fatigu erage stress m y with avera

In tho ( iii )

the last 40 ye se considera Stress field

ars many ex tions, they ca intensity mo

pressions hav n be classifie dels [2]. In

e been deve d in three m this work, w

loped to the odels: ( i ) Av e work onl

e notch redu odels, ( ii ) F ge stress mo

ction factor, racture mech dels: Neube

g to and on’s

36