고유 진동수를 이용한 크랙의 형상 분석법

Abstract

In this paper, natural frequency and damping ratio were obtained by time series modeling of the acceleration signal using the impact hammer test in Euler-Bernoulli beam according to crack depth and crack position by least square method. Also, its result is compared and investigated with FEM analysis of CATIA. The two methods consist well in natural mode characteristics comparatively. The acquired acceleration by experiments was modeled using time series methods and the natural frequency and damping ratio were calculated that are matching with measured ones. Using this data and its polynomial model with two independent variables, the behavior of an average natural mode is investigated and analyzed with an experimental time series modeling of recursive least square algorithm. And it can be used for the prediction of natural frequency in the condition of different crack depth and position regardless of the coordinate of Euler-Bernoulli beam.