Abstract
In this report, a rational reduction method for a large-scale nonlinear system using constrained modes is presented. Generally, analysis methods based on linear modal expansion, which are usually called Galerkin's method, are used in vibration analysis of large-scale nonlinear systems. Then, analysis methods based on this method have good point that regularity and versatility of algorithm are highly sophisticated, but also have bad point that accuracy of analysis deteriorate significantly if adopted modes were not adequate for constituting a reduction model. Still more, practical calculation often becomes impossible because computation time increases explosively with increasing the number of adopting modes to improve the computational accuracy. To overcome these problems, authors proposed a rational reduction method using constrained modes for a large-scale system having locally nonlinear elements. In this report, by applying the harmonic balance method to a reduction model, a method for obtaining periodic steady-state solution is presented.
