Nonlinearity Index And Structural Analysis–based System Identification Using Modal Assurance Criterion (MAC)

Abstract

It is well known that all the dynamic system has some level of nonlinearity. This nonlinearity is caused from numerous sources that can be classified differently (e.g. material, geometry and contact). In this work a relative nonlinearity index is defined through vector correlation by expanding the existing methods and through the introduction of finite element analysis (FEA). Steels beams are investigated to determine its non-linear behaviour while considering the % variation in young's modulus 'E' in one case and variations in E along with the presence of a crack in another case. Severity of material assurance criteria (MAC) is also tried to find out by establishing a linear reference set point for both cases. This research acknowledge on the basis of the results of damage indices that the non linearity is maximum deviated towards the crack presence with respect to change in material properties (E).