ABSTRACT
The equations of equilibrium for a thin symmetric composite laminate were derived in Section 10.2 based on a summation of forces and moments. Boundary conditions consistent with thin-plate theory were then discussed in Section 10.3. It turns out that exact solutions to these equations and boundary conditions can only be obtained if A A D D N NxyT xyM16 26 16 26 0= = = = = = , that is, exact solutions are only available for specially orthotropic laminates. A few exact solutions for simply supported and symmetric specially orthotropic laminates were presented in Chapter 11. Unfortunately, many stacking sequences widely used in practice are not specially orthotropic. For example, symmetric quasi-isotropic laminates are not specially orthotropic, since D16, D26 ≠ 0 for this stacking sequence. Hence, the solutions presented in Chapter 11 are not rigorously valid for many laminates encountered in practice. Fortunately, approximate numerical solutions are available that are suitable for use with any laminate, including symmetric quasi-isotropic laminates. A brief introduction to these approximate solutions techniques will be presented in this chapter. Readers interested in a more detailed discussion are referred to References 1, 2.
