Issue 45

C. Huang et alii, Frattura ed Integrità Strutturale, 45 (2018) 108-120; DOI: 10.3221/IGF-ESIS.45.09

2 ( ) 0.0016 0.0118 0.005 f f f b    = + −

(19)

2 ( ) 2.88 5.32 2.18 f f f c    = + −

(20)

9

9

9 2

0 ( ) 1.11 10 5.92 10 f   =  + 

− 

(21)

2.7 10

f

f

The relationship between model parameters of Eqn. (10) and the fiber content characteristic parameter are as follow:

2

2 ( ) 0.615 0.884 0.401 f f f     = + −

(22)

2

1 ( ) 97153.9 675179.3 305297 f f f     = + −

(23)

2

2 ( ) 232.1 559.4 256.2 f f f     = + −

(24)

4

4

4 2

( ) 4.5 10 5.9 10 a  =  − 

+ 

(25)

2.37 10

f

f

f

2 ( ) 0.89 5.74 2.64 f f f b    = + −

(26)

2 ( ) 191.1 1027 391.6 f f f c    = + −

(27)

7

8

7 2

0 ( ) 4.01 10 1.75 10 f   =  + 

− 

(28)

8 10

f

f

By substituting Eqn. (14)-(21) and (22)-(28) into (9) and (10) respectively, the creep equations of present model of FRAC with consideration of fiber content characteristic parameter effect can be obtained: Load phase:

( ) 

( ) 

a

b

     

     

f

f

3

2

+

( ) 

t

t

c

t

t

f

1

t

1

e

3

2

=

+

+

+

(29)

( , t

)

f

0

( ) 

 

( ) 

 

( )

( )

1

f

1

f

2

f

0

f

Unload phase:

( ) 

( ) 

a

b

     

     

f

f

3

2

+

( ) 

t

t

c

t

( − − − t t t  

)

0

0

f

0

0

0

t

(1

e

)

e

3

2

0

=

+

+

( , t

)

(30)

f

0

 

( ) 

 

( )

( )

1

f

2

f

0

f

( ) ( ) f f 

E

2

where,

.

=

 

2

Taking derivative of t in Eqn. (29) and (30), differential constitutive equation of FRAC can be obtained, which is characterized by the present model and considered the influence of fiber content characteristic parameter: Load phase:

117

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