Author(s)

M. Trajković, O. T. Bruhns, A. Meyers & M. Mijalković

Abstract

A subspace identification method is proposed as inverse dynamic analysis on examination of real structure behaviour with actual loads and noise-contaminated input/output data. The change of dynamic parameters (stiffness, damping) may be related to the structural history (erosion, friction, fatigue, damage, cracks) and cause the decrease of reliability and serviceability or result in structural collapse. When structural damage is small or hidden inside the structure, its detection cannot be done visually. Vibration monitoring is proposed as a useful and non-destructive dynamic parameter evaluation tool. Some tests on real, impulse loaded models have been conducted and data are procured. It is assayed how damage occurrence or decrease of structural system integrity will lead to the change of the dynamic characteristics. Special software is developed for experiment monitoring, determination of relevant mechanical characteristics and damage localization. Experimental results are used in the software both as an complete data set (number of the acceleration sensors equal to the dof) and as an incomplete data set (number is less than dof). In the latter case missing data are iteratively computed. Benefits and drawbacks of the subspace iteration method are emphasized. However, some unsolved topics are left for investigation. Keywords: subspace identification method, dynamic properties, structural damage, vibration monitoring, linear system. 1 Introduction Erosion, friction, fatigue, internal damages and cracks cause gradual degradation of structural performances during a long term service: the stiffness of the system

Keywords

subspace identification method, dynamic properties, structural damage, vibration monitoring, linear system.