PSI - Issue 28

Slobodanka Boljanović et al. / Procedia Structural Integrity 28 (2020) 2370 – 2377 Slobodanka B oljanović et al. / Procedia Structural Integrity 00 (2020) 000 – 000

2372

3

b a

M 1.08 0.03 1  

(3)

 0.3 0.44 1.06

M

  

(4)

2

b a

15

b a

b a

  

   

   

  

0.5 0.25

14.8 1

M

  

(5)

3

1.65

b a

  

  

1 1.464

( /

1.0)

Q

a b

 



(6)

where t and b are thickness of the plate and crack length in surface direction, respectively. In the stress-raiser analysis, the interaction between the angle location  and crack length in depth direction together with thickness is herein generated by means of relevant corrective factors, g 1 , g 2 , f   discussed by Newman and Raju (1984), whereas the corrective factor , f w , which takes into account the finite-width effect of the plate, is defined as follows: 

4 3 2 1 0.2 9.4 19.4 27.1          w f

(7)

 w b 

t a

    w b

  

0.5

(8)

where w is the width of the plate. 3. Fatigue life analysis using Huang-Moan crack growth concept

A throughout understanding of surface stress-raiser mechanisms is critical to ensure efficient functioning of large moving structures, by employing fracture mechanics concepts. In this regard, the behavior of a quarter-elliptical corner crack is herein theoretically examined, according to the damage tolerance philosophy, through depth and surface ( a and b ) crack growth directions, respectively, taking into account the following differential equations (Huang and Moan, 2017):   A m A A C M K dN da   ,   B m B B C M K dN db   (9) where da/dN , db/dN and  K A ,  K B are crack growth rates and stress intensity factors for depth and surface directions, respectively, C A , C B , m A , m B represent material parameters experimentally obtained.