The applications of Navier's, Levy's, finite difference, finite element, and energy methods to variously shaped and loaded anisotropic plates are demonstrated in this chapter. These include orthotropic, laminated composite, and sandwich plates. Properties of several commonly employed orthotropic materials are discussed, as are applications to a variety of orthotropic plates. Examples include corrugated and rolled metal sheets, fillers in sandwich plate construction, plywood, fiber-reinforced composites, reinforced concrete, and gridwork. The latter consists of two systems of equally spaced parallel ribs (beams), mutually perpendicular and attached rigidly at the point of intersection.
The orthotropic single or composite material plates illustrated in numerous figures in this chapter are widely used, such as in many space applications, buildings, pressure vessels, and engine components. As already discussed, a material having two or more distinct constituents is considered a composite. Usually, components of such material consist of high-strength reinforcement material (e.g., steel, glass, fiber) embedded in a surrounding material (e.g., resin, concrete, nylon) called a matrix. Thus, a composite material has a relatively large strength-to-weight ratio, as well as other desirable characteristics. Classical structural materials are increasingly being substituted by composite materials.