Investigation has been made into various approaches for analyzing the
vibration of plates with stepped thicknesses. First, attention has bee
n paid to updating a classical approach for the analysis of such probl
ems, correcting the boundary conditions cited in an earlier paper and
dealing with the difficulties that can arise when calculating high ord
er modes. Secondly, contribution has been made to improving the classi
cal finite strip method (FSM) by replacing the ''static'' shape functi
on of the strip element model by a. ''dynamic'' function. This leads t
o the development of a dynamic finite strip method which improves solu
tion accuracy without compromising model size and which therefore is m
ore efficient than the classical FSM. When compared with the finite el
ement method (FEM), which is also considered here, the advantages of s
maller model size and higher accuracy of the dynamic FSM are significa
nt. In order to demonstrate the application of the above approaches, t
he modes of simply supported plates with uniform and stepped thickness
es have been analyzed. From this numerical study, it is noted that the
updated classical approach can be used to obtain a solution for any o
rder mode to any specified accuracy and is the most efficient approach
considered in the present study. It is also noted that, compared with
the FEM of similar solution accuracy, the dynamic finite strip method
normally produces a much smaller model size, so that such calculation
s are significantly more efficient than for the FEM. The aim of this w
ork is to establish efficient methods for the analysis of stepped plat
es that might be used in optimization studies where speed of formulati
on and solution are at a premium. There are, of course, a number of ot
her methods that could be used to tackle such problems, but they lie o
utside the scope of this work; see for example the papers of Liew and
co-authors [1,2]. (C) 1997 Academic Press Limited.