Some Applications of the Method of Normal Fundamental Functions to   Oscillation Problems
  We report on the possibilities of using the method of normal fundamental systems for solving some problems of oscillation theory. Large elastic dynamical systems with continuous and discrete parameters are considered, which have many different engineering applications. Intensive oscillations in such systems are possible, but not desirable. Therefore, it is very important to obtain conditions for which oscillations take or not-take place. Mathematically, one needs to search for the solutions of partial differential equations satisfying both boundary and conjugation conditions. In this paper we overview the methodology of normal fundamental systems for the study of such oscillation problems, which provide an efficient and reliable computational method. The obtained results permit to analyze the influence of different system parameters on oscillations as well as to compute the optimal feedback parameters for the active vibration control of the systems. 
Olena V. Mul, Delfim F. M. Torres