Identification of normal modes of a set of strongly nonlinear springs

Abstract. The dynamics of connecting elements should be identified to evaluate their effects on the assemblies where they are employed. In general, a linear analysis is sufficient determine dynamics. However, in some cases, responses depend amplitude and frequency excitation, thus nonlinear analyses must carried out. Following modal approach, Nonlinear Normal Modes (NNMs) can used. aim this work identify NNMs set properly designed considered as strongly springs. These have been manufactured tested measure NNMs. time series oscillation points recorded using laser vibrometer for different frequencies excitation. Then, Virtual Point Transformation (VPT) used reduce obtained data two physical through which spring connected other subsystems. procedure repeated each NNM basis element expressed function level