Estudo sobre a qualidade da resposta dinâmica do Método de Superposição dos Modos de Lanczos

Abstract

In this work a study about a dynamic response quality for Lanczos Mode Superposition Method for structures submitted to large range of excitation periods is carried out. The unbalanced equation of motion, or residual, was evaluated from global parameters to address the response quality of a modal superposition method with load-dependent basis generated by Lanczos-type algorithms. The Lanczos mode Superposition Method efficiency to find the dynamic equilibrium was verified for a large range of excitation periods including those above the natural period of structure until the lowest modal periods reached in the analysis. Several cut-off criteria, for the generation of load-dependent vectors for the coordinate transformation, were tested with the use of load participation factor and an effective mass. Also, several algorithms to the generation of differents processes of basis orthogonalization were tested. As conclusion, were presented the behavior, limitations and cautions, resultants of this study, of the Lanczos Mode Superposition Method, for the several periods analysed, principally the lowest. Comments about the use of error parameters to the definition of dynamic response quality are also addressed.