Analysis of Bifurcations in Multiharmonic Analysis of Nonlinear Forced Vibrations of Gas Turbine Engine Structures With Friction and Gaps

Abstract

An efficient frequencydomain method has been developed to analyze the forced response of largescale nonlinear gas turbine structures with bifurcations. The method allows detection and localization of the design and operating conditions sets where bifurcations occur, calculation of tangents to the solution trajectory, and continuation of solutions under parameter variation for structures with bifurcations. The method is aimed at calculation of steadystate periodic solution, and multiharmonic representation of the variation of displacements in time is used. The possibility of bifurcations in realistic gasturbine structures with friction contacts and with cubic nonlinearity has been shown.