Crack Paths 2009

M1

1fi,1"'fn,i O g1.1"'gn,i _r1Sin0l a1

m _ I f L m ' H - f0mgml , m " ' g n , m _ r m s i n 6 m a n

6

v1 _ 0 Mal-"hm i luml

b0

0

r1 Sin 61

n,l

v

Oh1,1"'h

rim-4,,1 rmcosb‘m

b

n,l

where a, and b, are used to compensate for the rigid body motion and R compensates for

the rigid body rotation.

Experimentalresults anddiscussion

Experiments were undertaken on both sharp notches and fatigue cracks emanating from

notches in specimens manufactured from 7010 T7651 aluminium alloy. Pure mode I

loading condition was created ahead of a 4 m mnotch in a 5 m mthick D C Bspecimen with

the dimensions shownin Figure 1.

DEIAIL A

SCALE5; 1

Figure 1: D C Bspecimen dimensions in m m

The specimen was machined from a plate of 7010 T7651 aluminium alloy and spark

eroded to introduce the notch into the specimen. The required speckles for DIC were

produced on the surface of specimen using a fine spray of matt black paint. A 100kN

M A N hDydraulic test machine was used to load the specimen. A load range of 0.5kN to

1.5kN was applied to the specimen. A 14 bit, 1600x1200 C C Dcamera and a Nikon lens

with a resolution of 18.75 microns per pixel was used to record the images. DaVis software

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