Nonlinear combination resonances in cantilever composite plates

Abstract

We experimentally investigated nonlinear combination resonances in two graphite-epoxy cantilever plates having the configurations (90/30/-30/-30/30/90L and (-75/75/75/-75/75/-75)~. As a first step, we compared the natural frequencies and modes shapes obtained from the finite-element and experimental-modal analyses. The largest difference in the obtained frequencies for both plates was 6%. Then, we transversely excited the plates and obtained force-response and frequency-response curves, which were used to characterize the plate dynamics. We acquired time-domain data for specific input conditions using an A/D card and used them to generate time traces, power spectra, pseudo-state portraits, and Poincarg maps. The data were obtained with an accelerometer monitoring the excitation and a laser vibrometer monitoring the plate response. We observed the external combination resonance f~ ~ a)2 -t-037 in the quasi-isotropic plate and the external combination resonance f~ ~ (1/2) (a~2 + cJs) and the internal combination resonance f~ ~ w8 ~ (1/2)(co2 + w13) in the +75 plate, where the wi are the natural frequencies of the plate and fZ is the excitation frequency. The results show that a low-amplitude high-frequency excitation can produce a high-amplitude low-frequency motion.

Modal shape measurement of fiber-reinforced composite plate with high efficiency and precision based on laser linear scanning method

“…3,4 For a long time, the experimental modal analysis theory has been mainly employed to measure the modal shapes of fiber-reinforced composite structures, which is realized by combining the frequency response function measurement method with modal parameter identification method. For example, Oh and Nayfeh 5,6 tested modal shapes of a fiber-reinforced composite thin plate by using hammer and laser vibrometer, and found that the most of the modal shapes can be obtained by this technique. Yet, it was hard to identify some shape results due to the interference of some nonlinear phenomena.…”

Global bifurcations of symmetric cross‐ply composite laminated plates with 1:2 internal resonance

“…In the past two decades, the nonlinear dynamics of composite laminated plates have been paid much attention by many researchers. Oh and Nayfeh used an experimental method to study nonlinear combination resonances in cantilever composite laminated plates to a harmonic transverse excitation. Chen et al.…”

Nonlinear dynamics of angle-ply composite laminated thin plate with third-order shear deformation

“…Turkmen and Mecitoglu [2] conducted both theoretical and experimental studies of the composite laminated plates exposed to normal blast shock waves and presented a correlation with numerical and experimental results of the strain time histories. Under harmonic transverse excitation, Oh and Nayfeh [3] used the experimental method to study nonlinear combination resonances in cantilever composite laminated plates. Recently, Zhang [4] studied the global bifurcation problems and chaotic dynamics of a parametrically excited, simply supported rectangular thin plate.…”