Vibration Analysis Of Free Isotropic
Cracked Plates
Author(s)
M. Alfano & L. Pagnotta
Abstract
Cracks occurring in structural elements of machines cause a local reduction in
the stiffness and consequently lead to a change in the modal parameters, such as
the resonant frequencies. The measurement of the degree of variation in resonant
frequencies can provide a suitable tool for identifying the location and the
extension of damage. For this reason the variation of the natural frequencies in
the cracked elements has been the subject of many investigations. In the present
paper, the dynamic behaviour of free thin isotropic square plates, with a trough
crack emanating from one edge, were investigated by means of an extensive
series of finite element analysis carried out by a commercial code. The variations
of both the natural frequencies and the modal shapes have been pointed out in
terms of a dimensionless frequency factor depending on the length of the crack
and on Poisson’s ratio. Numerical results have been verified by experimental
measurement.
Keywords: FEM, cracked plates, modal analysis.
1 Introduction
Cracks occurring in structural elements of machines cause a local reduction in
the stiffness and consequently lead to a change in the modal parameters (e.g.,
natural frequencies). The degree of change depends on the location, the nature
and the extension of the damage. Frequency measurement can be cheaply carried
out from the measured time response of a dynamically excited structure,
therefore a frequency based approach could be a simple and economic mean to
evaluate the structural damage [1-3]. For this reason the free vibration of cracked
elements has been a subject of many investigations. Several papers deal with the
flexural vibration of clamped and simply supported plates. Byrne [4] has
Keywords
FEM, cracked plates, modal analysis.
Related Book
Other papers in this volume
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