PSI - Issue 72

Mohamed Khodjet Kesba et al. / Procedia Structural Integrity 72 (2025) 164–171

166

( , ) C C z t à t 

0

0

.

pour

z h



 

(3)

0

/2. /2.

1 C C à t C C à t  

pour z h pour z h  



0



2

A





0 exp

.

D D 

RT     

3. Aging Consideration In the absence of a unified theory of mechanical characterization of unidirectional composites, several formulations have been proposed in the literature, we cite the law of mixtures, the method of continuity which is based on the arrangement of fibers (G.Staab et al 1999), the semi-empirical method by Halpin-Tsai (Z.Sereir et al 2006,2005), and additional technical method, based on the establishment of fibers (S.Tsai 1988, Z.Boualem et al 2011, C.Chamis 2000 ). In this work, we used the law of mixtures applied to anisotropic composites with fibers, which was modified by Hahn as described in reference (A.Tounsi et al 2005, H.Hahn et al 1978) . Therefore, the longitudinal Young's modulus for a composite material is:

(4)

( , ) z t

.

( , ) z t

( , ). z t

(1 ).

E

V E

V E m



 

X

f fx

f

The transverse Young's modulus and shear modulus modified for the (T300/5208) is:

1 0.516( / 

)

Vm V f

(5)

.

( , )

E z t Y



0.516( /

)

Vm V f

1



( , )

( , )

E z t

Em z t

fy

1 0.316( / 

)

Vm V f

(6)

.

( , )

G z t XY



0.316( /

)

Vm V f

1



( , )

( , )

G z t

Gm z t

fx

Tsai (S.Tsai 1988) proposed an adimensional temperature T *

T

T



( , ) z t

g

opr

*

(7)

T



( , ) z t

.

T

T



( , ) z t

g

rm

We assume that the humidity shifts the glass transition temperature.

(8)

( , )

. ( , ).

Tg z t

T gc z t g

 

We use T* to calculate empirically the matrix and fiber parameters as a functions of moisture and temperature.

( , )

( , )

( , )

E z t

E z t

G z t



( , ) z t

(9)

fx

fy

fx

fx

f

( *( , )) T z t









.

0

0

0

0

E

E

G



fx

fy

fx

fx