Crack Paths 2012

E X P E R I M E NRTEASLU L T S

For a given loading range, the presence of a NaClsolution reduced the numberof cycles

for crack initiation, by a factor of 3 in the aluminium alloy and 1.3 in steel, as shownin

Table 1. Crack growth was also substantially accelerated by the NaCl solution in the

aluminium alloy, but the acceleration was rather limited in steel.

Crackpaths

Figure 2 shows examples of crack longitudinal and transverse profiles, z(x) and z(y),

plus twist angle profiles in 7075 aluminium alloy and S355 steel, at different stages.

a ) “

---x = 1.6mm --x : 6.4mm

I

d )

k

--x = 11.2mm -—x = 15,2mm

7"“

* x= 1 9 . 2 m m - x = 2 3 , 7 r n m

35in’)

ACID

--x = 2 8 . 4 m m

-

'-

E

E

3

a

-1OD n

N

b l

a

s ,0,

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m _

'5

-=

--x= 2 . 7 m m— x= 5 . 5 m m

. E

“on - x= 8.3mm —-x = 11.5mm

.1500

— — x= 1 7 . 1 m—m—x = 2 2 , 4 m m

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e) 5

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+ x = 1 , 6 m -m- x = 6 . 4 m m

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as

.

.

.

25

-——x = 11.2mmnot =15.2rnm

I

4 o

15

--~x : 19,1mm —-x = 235-‘mm

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-m

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‘ I

;

5

~

' _.'

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i E -:u

E 5 0 r,

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a

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,...L.._,_,_

an

-25

as (I

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+ x 8=. 3 m m+ x= 1 1 , 5 m m

as

‘

4o

45

width = ‘((M1)

“is

--x = 17,1mm +>< = 22.4mm

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3.2 m mfrom side 1

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=_ D

a:

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w 3000

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‘.5 2000

9-1000

2'

E

2 1000

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- 4.9 m m[mmside 2

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2.6 m m[mmside 1

0

,

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25

3[

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distance from the crack notch I x(mm)

distance " 0 mthe "01th roof: Xl‘l‘l'fll

Fig 2: Topographic reconstructions. a) z(y) b) twist angle and c) z(x), specimen ccp5a

.d) z(y) e) twist angle f) z(x) , specimen ccp2s.

78