抄録
This paper clarifies vibration response characteristics of a vertical mechanical structure subjected to horizontal and vertical nonstationary random excitation. The structure is modeled as a cantilever beam with a lump mass at its free end ; taking into account the first vibration mode for numerical computation of vibration response, response multiplication factor maps with respect to dominant frequencies, wH and wv, of both horizontal and vertical extitations are obtained for the structure's damping, , magnitude and randomness of vertical excitation. A very high response appears at wv=2 and wH=1 and its magnitude varies with a slight change in the power spectral density contained in nonstationary vertical excitation waves at wv=2. For wH=1, the conditions of unstable parametric random vibration are obtained for structure damping and magnitude of vertical excitations.
