ABSTRACT
The mathematical formulation of wave propagation in solids involves the use of the concepts and principles of 3-dimensional stress and strain analysis. Hence, we start by outlining these principles.
Consider a continuous 3-dimensional body subjected to an arbitrary system of forces. The state of stress at a point O in the body can be studied by considering an innitesimal parallelepiped erected at this point. It is assumed that the resultant forces acting on any two parallel faces are the same, i.e., a uniform state or eld of stress exists.
