A factorization algorithm for wave propagation in periodic structures withapplication to torsional waves in an infinite cylinder

In this paper we introduce a fundamentally new concept in the field of wave -propagation in periodic structures. We show that a phenomenal amount of si mplification can be achieved by using symmetry arguments. Problems which or dinarily lead to (2n x 2n) determinantal eigenvalue equations, can effectiv ely be reduced to two (n x n) determinantal equations. We state the final r esult in the form of a factorization theorem and then with the help of a si mple problem, we show the superiority of this new result over the tradition al methods of solution.