Ho
2
ME
ALL
CONSTANTS
(E W S g) ARE EQUAL
.
IN
THE
THE
STRESS-STRAIN
ALSO ,
IN
2
,
,
DIRECTIONS ;
THEREFORE
CURVES ARE IDENTICAL
ALL CONSTANTS ARE DIFFERENT
THE
FIBERS
/ AND
>
THOMAS GLissMAN
420
S DIRECTION
DO
NOT
GO
BECAUSE
IN THAT
THE
DIRECTION
2
Ho
ME
[S]
[C]
E, = 138 GPa
Giz
Ec
Viz = Do Vg =. 65
=
9GPa
=
THOMAS GLissMAN
420
609GPa
=
- =
=
v
=
0
.
0196
-
[5]
=
E
Si
Siz
G
Sa ,
Saz
g
G
6
Sob
Ez
,
-E
I
↓
G12-
0
O
-
5
S
=
=
=. 0072
S2
Sob
-
[s]
[S]
.
=
·
[
1449
0072
.
Szi
-
.
0022
·
0022
o
IIII
G
6
O
·
=
0
.
-
.
0
0022
=
-
-
0022
1449
[c]
138 82
.
=>
0 1111
,
~
=
=
S2
.
=
E
=
-=
=
The
Saz
[C]
=
2 72
2 72
E
.
3 05
.
D
.
O
⑧
6 9
.
1
Ho
2
ME
420
THOMAS GLissMAN?
In the single tensile test, the load applied must be in the 1 direction, giving the
longitudinal normal stress (S1). This is also the direction of reinforcement; and
any other stresses in the 2 or 3 directions will be equal to 0. For a transversely
isotopic material, the properties of the material are the same in all 3 directions (1,
2, and 3). However, specially orthotropic materials are directional, so the
subscripts are needed to differentiate between the 3 directions. During testing,
two stresses develop- normal and shear; and due to the shear stresses, the
generated shear and normal strains cause the shear coupling effect which cause
the zeros in the compliance matrix to disappear.
If the single tensile test is performed on a specially orthotropic or transversely
isotropic material, the subscripts are interchangeable in directions 2 and 3 in the
[S] matrix. Due to their interchangeability, G13 = G12, E2 = E3, v12 = v13, and
v23 = v32. This equation:
is used to find G23 (Shear modulus
in the 2 and 3-directions), where E2 is the Young’s modulus in the 2-direction,
v23 is the Poisson’s ratio in the 2 and 3-directions. Therefore, the values for
Young’s modulus in the 2-direction Poisson’s ratio in the 2 and 3-directions
would have to be recorded.