Modelo para la estimación de una frecuencia natural a partir de la respuesta vibratoria de un sistema sometido a un barrido sinusoidal de alta aceleración

Abstract

A natural frequency from a machine or structure can be determined from the vibratory response due to a variable frequency excitation. There is a rise in vibratory amplitudes at the moment the frequency of excitation is close to natural frequency. If the change rate in the excitation frequency is high in comparison to natural frequency, then the maximum vibration amplitude will occur when the excitation frequency is different to natural frequency. This difference could induce errors in the determination of natural frequencies during startup and shutdown. In this article we assess the difference between natural frequency and maximum amplitude frequency of a simple one degree of freedom system, and a model is proposed to obtain natural frequency from maximum amplitude frequency. It is concluded, by means of experimental results obtained in tests on a cantilever beam, that the value of a natural frequency estimated from the proposed model is a better approximation than that obtained when the natural frequency is estimated as the frequency of excitation when the maximum vibratory response occurs.