Nonlinear vibration and radiation from a panel with transition to chaos induced by acoustic wavesThe dynamic response of an aircraft panel forced at resonance and off-resonance by plane acoustic waves at normal incidence is investigated experimentally and numerically. Linear, nonlinear (period doubling) and chaotic responses are obtained by increasing the sound pressure level of the excitation. The response time history is sensitive to the input level and to the frequency of excitation. The change in response behavior is due to a change in input conditions, triggered either naturally or by modulation of the bandwidth of the incident waves. Off-resonance, bifurcation is diffused and difficult to maintain, thus the panel response drifts into a linear behavior. The acoustic pressure emanated by the panel is either linear or nonlinear as is the vibration response. The nonlinear effects accumulate during the propagation with distance. Results are also obtained on the control of the panel response using damping tape on aluminum panel and using a graphite epoxy panel having the same size and weight. Good agreement is obtained between the experimental and numerical results.
Maestrello, Lucio (NASA Langley Research Center Hampton, VA, United States)
Frendi, Abdelkader (Analytical Services and Materials, Inc. Hampton, VA, United States)
Brown, Donald E. (Lockheed Engineering and Sciences Co. Hampton, VA, United States)