Page 204 - Plastics Engineering

Mechanical Behaviour of Composites 187

where
- 1
11 - -[E1cos4e+ E2sin48+ (2u12E2 +4A.G12)cos’Osin28]
-A.
- 1
= Q12 = -[u12E2(cos4 6 + sin4 e)
A.
+ (El + E2 - 4A.GI2)cos2 8 sin’ e]
- 1 3
= & = -[cos esine(E1 - u1& - 2hG12)
A.
- cos 8 sin3 O(E2 - - 2A.Gd1
- 1
22 - -[E2 cos4 8 + El sin4 8 + sin’ 8cos’ O(2ulzE2 + 4A.G12)]
-A.
- 1
= a26 = -[cosesin3 O(E1 - u12E2 - 2A.G12)1
A.
- cos3 8 sin @(E2 - - 2A.G12)]
- 1
QM = -[sin2 8cos’ O(E1 + E2 - 2u12E2 - 2A.Gd1
A.
+ A.G12(cos4 8 + sin4 e)]

in which A. = (1 - ~12~21) and u12E2 = u21E1.
By a similar analysis it may be shown that, for applied stresses (rather than
applied strains) in the global directions, the overall compliance matrix [SI has

(3.25)

from which, using the earlier terms from the on-axis lamina stiffness matrix [SI,