147 Rational Reduction Method for a Large-scale Nonlinear System using Modal Analysis : 1st report, Construction Method of a Reduction Model

Abstract

A rational reduction method using real constrained mode is developed in order to analyze accurately a nonlinear vibration and stability generated in a large-scale system with locally strong nonlinearity. In the present method, the state variables of linear nodes are transformed into the modal coordinates, and the modes with significant effect on the computation accuracy of the solution are extracted. On the other hand, the remaining modes with small effect are appropriately approximated and are eliminated. The very accurate low-dimensional model is constructed by these procedures. The effectiveness of the present method is verified from the computational results for the straight-line nonlinear structure as a fundamental example.