MODAL CONSTANTS CONSISTENCY: APPLICATION OF A NEW METHOD FOR SOLVING OVERDETERMINED NON-LINEAR EQUATIONS

摘要

Modal identification techniques seek to extract from experimental data the modal parameters that characterize the dynamic behaviour of a structure. Thus, a modal model is derived through the determination of the values (for each mode of vibration) of the natural frequency, damping ratio and complex modal constant. Theoretically, the modal constants obey a set of relationships which are often referred to as the consistency equations. However, experimental data is bound to be polluted by a number of different errors. Therefore, the application of modal identification techniques to experimental data will yield sets of inconsistent modal constants, making it necessary to impose consistency by means of adequate techniques. In this paper, the authors propose a new mathematical tool and its application for the solution of the over-specified sets of non-linear equations resulting from imposing the consistency relationships to the experimentally derived inconsistent modal constants.