Modal vibration response measurements for characterization of composite materials and structures

This paper summarizes recent research by the author, his colleagues and graduate students on the use of modal vibration response measurements to characterize, quickly and accurately the mechanical properties of fiber-reinforced composite materials and structures. It is shown that modal testing in either a single mode or multiple modes of vibration can be used to determine elastic moduli and damping factors of composites and their constituents under various environmental conditions. Modal testing by the use of impulsive excitation methods has been shown to have the potential to be a fast and accurate approach not only for the characterization of intrinsic material properties, but for quality control and inspection as well. Such measurements have been used to characterize the global elastic constants of composites, the distribution of reinforcing fibers within composites, time-domain creep response of composites, elevated-temperature behavior of composites and their constituents, interlaminar fracture toughness of composites, and the presence of defects, damage, and degradation in composites and adhesively-bonded composite structures. Recent research in these areas will be reviewed and recommendations for future work will be made.