Współrzędne normalne w analizie rezonansów głównych nieliniowych układów drgających o wielu stopniach swobody

The considerations concern steady-state vibrations of dissipative multiple-degree-of-freedom nonlinear systems. Theoretical investigations are based on a single term harmonic solution and the W. Ritz method. The purpose of the paper is the analysis of accuracy and applicability of two approximate procedures leading to uncoupling of the equations of motion: 1) a procedure consisting in introducing normal coordinates of linearized system and neglecting the coupling terms; 2) a procedure based on the concept of nonlinear normal coordinates.