Balance Laws

Abstract

In our foregoing discussion of the changes in shape and size of deformable bodies, no reference was made to the mechanical interactions between either various parts of the bodies, or parts of the bodies and the surrounding environment. For all practical purposes such mechanical interactions can be represented by suitably defined macroscopic forces. As we shall see shortly, the familiar description of the concept of force from Newtonian Mechanics will require some re-evaluation before we can provide a satisfactory mechanical framework for deformable continua. As a prelude to our discussion in the later sections of this chapter, we review below some of the key concepts from the mechanics of rigid bodies.