Page 252 - Mechanics Analysis Composite Materials
P. 252
Chapter 5. Mechanics of Inminates 231
X
Y
Fig. 5.9. Middle plane of a laminate.
As can be seen, we have arrived at three independent groups of constitutive
equations for in-plane stressed state of the layer, bending and twisting, and
transverse shear. Stiffness coefficients, Eqs. (5.34), become
For an orthotropic layer, there are no in-plane stretching-shear coupling (B14 =
B24 = 0) and transverse shear coupling (s56= 0). Then, Eqs. (5.35) reduce to
In terms of engineering elastic constants material stiffness coefficients of an
orthotropic layer can be expressed as
(5.38)
