On Normal Vibrations of a General Class of Nonlinear Dual-Mode Systems

Abstract

Free vibrations in normal modes are examined for a system consisting of two unequal (or equal) masses, interconnected by a nonlinear coupling spring, and each mass connected by nonlinear unequal (or equal) anchor springs to fixed points. All spring forces are odd functions, and proportional to the k’th power, of the spring deflections, where k is a real, positive number. The frequency-amplitude relations for the in and out-of-phase modes are derived without approximation, the stability of these modes is analyzed, and several numerical examples are worked out. A surprising feature of these systems is that they may have a greater number of normal modes than they have degrees of freedom.