Analysis of Nonlinear Vibrations Using DIC and the Smoothed Harmonics Method

This chapter focuses on the development of a novel methodology to extend the application of low frame rate stereo-camera systems to the study of the dynamic behavior of components when nonlinear phenomena are considered. The approach overcomes the low frame rate limitation of cameras in cases of steady-state periodic oscillations by making use of a new down-sampling technique, the Smoothed Harmonics Method (SHM). The SHM allows an accurate reconstruction of a down-sampled signal and thus has many possible applications. In this chapter it was applied together with a full-field measurement using DIC. In particular, the methodology was used to analyze the motion of a beam with nonlinear stiffness due to intermittent contact and loaded with harmonic excitation.