Correction Factor for Measured Natural Frequencies in Beams

Abstract

In experimental evaluation of the natural frequencies of beams with different boundary conditions, using signal analyzer and accelerometer, the ratio of the mass of the accelerometer to the total mass of the beam, and the location of the accelerometer along the length of the beam are two important factors that have a considerable effect on the experimental results. Neglecting these factors will sometimes produce errors of up to 50% or more depending on the boundary conditions, mode of vibration, location, and relative mass of the accelerometer to the total mass of the beam. In this technical note, a new correction factor has been introduced to improve the experimental results by eliminating the effect of the accelerometer mass. The corrected experimental values are in good agreement with the theoretical results and they are demonstrated in two examples.