Issue 14

C.M

. Sharanaprabh

u et alii, Frattu

ra ed Integrità S

trutturale, 14 (2

010) 27-35; DO

I: 10.3221/IGF-E

SIS.14.03

A N

ALYTICAL E

STIMATION

OF CRACK

INITIATIO

N ANGLE

F

or a sin Cartesian

gular elastic co-ordinate

field of an i s ( x , y ) shown

nfinite plate in Fig.1 are

with a crack given as [4].

, the stress

near the cra

ck tip expressed in term

s of

Figure 1 :

Crack tip stres

ses expressed

in Cartesian co

-ordinates.

1

3 sin 2

3

s 1 sin 2    



K    

sin 2 2    

cos cos 2 

  

  

K

co

xx  



(1)

I

II

2

2

r

2

1

3 n sin 2 2 

3

os 1 si 2    

  



cos cos 2 

   

  

K

K

c

sin

yy  



(2)

II

2

2

r

2

II

1

3 cos 2

3

2 2   2 K 2 I r

K  

cos 1 2    

sin sin 2 

    

  

K

in cos

s

xy  



(3)

I

II

2

r

2

   

K  

 

(

)

cos

sin













(4)

Plane Strain



zz

xx

yy

II

2

2

0 zz   e stress inten

(5)

Pla sity factor fo

ne stress r CTS specim

Th

en of interes

t is given by

[11].

   

     

b

0 .2 6

 2 .6 5





0 .0 w

b

p

b

c o s 1





K



(6)

I

b w

2   

w t

  

 

b w b

b

   

   

1 0

.5 5

8

 

w

b

  

   

b

0 .23  

 1 .40



2 .0 w

b

p

b

s in 1





K



(7)

II

b w

2   

w t

  

 

b

b w b

  

   

   

1 0

.67

8

 

w

b

28