Generation of low-frequency vibration using a cantilever beam for calibration of accelerometers

At low frequencies (below 10 Hz), performance of a conventional shaker is limited by small acceleration amplitudes and a high level of total harmonic distortion. The present article describes a low-frequency vibration generator that overcomes these limitations. The vibration generator consists of a cantilever beam excited by a conventional shaker. The cantilever beam is tuned to resonate at the desired excitation frequency, which leads to a relatively large vibratory motion at the beam tip with very small harmonic distortion. Analysis of the system is performed by means of model equations describing both the flexural and longitudinal components of vibration. A comprehensive measurement of the generator's performance confirms that it can serve as an economically attractive alternative to existing low-frequency vibration generators used in vibration measurement and calibration.