Chapter 5 - Mechanics of Laminates

Abstract

This chapter focuses on the mechanics of laminates. A basic composite structure consists of a system of layers bonded as one. The layers can be made of diverse isotropic or anisotropic materials, and have different structures, thicknesses, and mechanical properties. In contrast to typical layers whose basic properties are determined experimentally, the laminate characteristics are usually calculated using the information concerning the number of layers, their stacking sequence, geometric and mechanical properties, which must be known. A finite number of layers can be combined to form so many different laminates that the concept of studying those using experimental methods does not seem realistic. Whereas the most complicated typical layer is described with nine stiffness coefficients Amn (mn = 11, 22, 12, 14, 24, 44, 55, 56, 66), some of which can be calculated, the laminate is characterized by 21 coefficients and demonstrates coupling effects that are difficult to simulate in experiments. Thus, the topic of this chapter is to provide equations allowing us to predict the behavior of a laminate as a system of layers with given properties. The only constraint that is forced on the laminate as an element of a composite structure concerns its total thickness, which is implicit to be much smaller than the other dimensions of the structure.