PSI - Issue 72

Victor Rizov / Procedia Structural Integrity 72 (2025) 120–127

123

Here

z h    .

2 h

(6)

1

2

The axial force, N i , and the moment, M i , in Eqs. (2) and (3) are generated by F 1 . The latter is estimated by Eq. (7).

(7)

F m g e  1 .

Here m e is the motor mass, g is the gravity acceleration. Equation (8) describes variation of the modulus of elasticity along the thickness.

z

1



2 h

(8)

,

c E E e 

where

z h    .

2 h

(9)

1

2

Here, E c is the value of E at z 1 =0, β is a parameter. The static SERR,

st G , induced by the weight of the motor is estimated by Eq. (10).

2

C



F

F

1

1

G

(10)



,

st

2

b 

a



C F



(11)

,

1

F

1

where a is the crack length (Fig. 1). Equation (12) is used to estimate the dynamic SERR, G dn , induced by F 2 f .

(12)

,

dn F f dn G k G 2 

where f F G 2 is determined by Eq. (10) through replacing of F1 with F2f (the same replacement is done also in Eqs. (1), (2) and (3)). The theoretical base for determining of kdn is detailed in (Malenov (1993)). Thus, kdn is given by

1

dn k



,

(13)

2   

  



1





P

where

30 n 

 

(14)

,