Page 376 - Mechanics Analysis Composite Materials
P. 376
Chapter 7. Environmental, special loading, land manufacruring effects 361
120
ao
40
0 0"
40
-80
Fig. 7.52. Dependence of residual strains in a glass-epoxy filament wound cylinder on the winding angle
-calculation, o experiment.
data of Morozov and Popkova (1987). As can be seen, the composite cylinder
experiences in the general case not only the change in its length (E,) and diameter
(E,.), but also twist (r,,).
To study the h$angle-ply layer, we should attract the thermoelasticity
constitutive equations, Eqs. (7.23). Neglecting bending and coupling stiffness
coefficients we can write for the case under study
(7.83)
Applying these equations to the angle-ply composite cylinder removed from the
mandrel we should put N, = 0, N,, = 0 because the cylinder is free of loads and take
E: = El, E$ = E2 in Eqs. (7.18), (7.25) and (7.26) that specify NIT and N~T.Then,
Eqs. (7.83) yield the following expressions for strains that appear in the angle-ply
cylinder after it is removed from the mandrel: