US-Jordan Cooperative Research: Nonlinear Energy Exchange Between High-Frequency and Low-Frequency Modes in Composite Structures

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0242109 NayfehDescription: This project supports a cooperative research project between Professor Ali Nayfeh, Department of Engineering Sciences and Mechanics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia and Dr. Khaled Asfar, Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan. They plan to conduct experimental and theoretical investigations to study the mechanism for the transfer of energy for high-frequency to low-frequency modes in composite structures. The mechanism responsible for this energy transfer is unique as it is neither an autoparametric resonance, nor an external combination resonance, nor a parametric combination resonance. Composite structures to be investigated are mainly beams and plates with various boundary conditions. Analytical and experimental work that was done at Virginia Tech revealed such energy exchange in multi-degree-of-freedom systems due to combination and internal resonances and interaction between widely-spaced modes. Such energy exchange may alter the behavior of the system leading to undesirable consequences. Effects of various composite material parameters on the energy exchange will be studied in order to improve the design process of such materials.Scope: The project involves analytical and experimental approaches, and combines the complementary expertise of the US and Jordanian scientists. Dr. Nayfeh has contributed significantly to the understanding of various energy transfer mechanisms. The application to composite structures is of particular interest. The project would enhance the international exchange of ideas and expertise in the general field of nonlinear vibrations, and would strengthen the ties between the PI's research group at VPI and the Jordan University of Science and Technology. The research will add the study of composite materials to a large volume of research that has been performed in the last three decades on nonlinear modal coupling in mechanical structures of homogeneous materials.