양단 단순지지 다른 양단 자유단인 변단면을 가진 복합재료 판의 진동해석 = VIBRATION ANALYSIS OF COMPOSITE PLATES WITH VARIABLE CROSS-SECTION AND WITH A PAIR OF OPPOSITE EDGES SIMPLE SUPPORTED AND THE OTHER PAIR OF OPPOSITE EDGES FREE

다국어 초록 (Multilingual Abstract)

The problem of deteriorated highway concrete slabs and other structural elements is very serious all over the world. Before making any decision on repair work, reliable nondestructive evaluation is necessary. One of the dependable methods is to evaluate the in―situ stiffness of the structural member by means of obtaining the natural frequency. By comparing the in―situ stiffness with the one obtained at the design stage, the degree of damage can be estimated rather accurately.
A method of calculating the natural frequency corresponding to the first mode of vibration of beam and tower structures, with irregular cross-section and with arbitrary boundary condition was developed and reported by D. H. Kim in 1974. This method has been developed for two-dimensional problems including the laminated composite plates and was proved to be very effective for the plates with arbitrary boundary conditions and irregular sections.
In this paper, the result of application of this simple method of vibration analysis developed by the senior auther, to the special orthotropic plates with variable cross-section, and with a pair of opposite edges simple supported and the other pair of opposite edges free is presented. This problem represents the simple-supported single span bridge system without effective longitudinal edge beams. The effect of concentrated point mass/masses is also studied.