抄録
Sound is often generated by the vibration of a plate structure. In order to consider the counter measure of noise, it is useful to carry out a numerical simulation of the vibration of the plate. The plate often has a strucutre of non-uniform thickness. An elevated road or railway track is a typical example of such a structure. The extension of Mindlin plate theory has been considered and the implicit time marching method has been adopted, here. The comparison between the results obtained by 3-dimensional theory and Mindlin plate theory was made. The good agreement between two methods was obtained.