SUBSPACE IDENTIFICATION USING N4SID METHODS APPLIED TO MODEL CONCRETE CHIMNEY

Abstract

This article describes a new structural identification tool to define the structure of the modal characteristics have been proposed. N4SID abbreviation means “Numerical algorithms for Subspace State Space System Identification”.  In the SI (System Identification) of structure dynamics area area, N4SID has been used very frequently recently. The aim of N4SID is the determining of a mathematical model of a real or model structure.Thus, a model is formed about the reactions of the structures to different inputs. The model structure is created as an input and placed on the shaking table for output. After the acceleration responses are collected from the existing sensors, the data obtained through the Matlab SI (System Identification) toolbox are processed. Finally, Matrices A, B, C, D, K are obtained. For this purpose, analytical and laboratory studies to illustrate the effectiveness of N4SID evaluated. Concrete chimney sample was used as a model. Results demonstrated that fit to estimation data was 99,72 % and it can be concluded that N4SID system identification method is very efficient and accurate in identifying mathematical model of Model Concrete Chimney.