Modal testing involves the measurement and analysis of input forces and corresponding response vibrations when a structural system is dynamically excited with either an electromagnetic shaker or a hammer. A low-level dynamic force (usually less than 50 lbs) is applied at one location (driving point) on the structure. The location of the driving point and the measurement points are carefully chosen to identify all modes of vibration of the structure in the desired frequency range. The transfer functions between the driving force and dynamic responses are computed during the measurements. The measured data are saved to the hard disk for subsequent analysis.
