Abstract
Authors studied a calculation method on tapered stack, to obtain the natural frequencies and mode shapes of bending vibration, of which cross section varies freely in height, and this paper is the first report of a series on the dynamic response analysis of stack-like structures due to earthquake. They carried out the analysis, regarding the stack as a continuous bending vibration system, not as a concen trative mass system, by numerical computation. To simplify the analysis, they assumed as follows; a) The stack is resisted only by the bending moment and there are no effects of gravity and shearing deformation. b) The stack is rigidly fixed at base. c) The stack has a constant cross section in each devided part. With these assumptions, the equations of natural frequencies and mode shapes of a stack are defined by the following equations; G・H^^-=H^^-/ω^2 where G, H^^- and ω represent the matrix of coeffieients, the column matrices of mode shape and the natural frequency respectively. These results are compared with the results of Stodola's method, Mononobe's method, Naruoka's method and Ishizaki's experiments. All these results (shown in Table 4) show that natural frequencies of stacks will be computed well approximately, for practical purposes, by this method. In this study they used the digital computer FACOM 222, Tokyo Institute of Technology.
