NONLINEAR DYNAMIC INSTABILITY OF SHALLOW ARCHESBY RUNNING RESPONSE SPECTRUM CHARACTERISTICS

摘要

The dynamic instability of snapping phenomena has been studied by many researchers. Few papers deal withrndynamic buckling under loads with periodic characteristics, and the behavior under periodic excitations is expectedrnto be different from behavior under STEP excitations. We investigate the fundamental mechanisms of the dynamicrninstability when the sinusoidally shaped arch structures are subjected to sinusoidally distributed excitations with pinendsrn. The mechanisms of dynamic indirect snapping of shallow arches are especially investigated under not onlyrnSTEP function excitations but also under sinusoidal harmonic excitations, applied in the up-and-down direction. Therndynamic nonlinear responses are obtained by the numerical integration of the geometrically nonlinear equation ofrnmotion, and examined by Fourier spectral analysis in order to get the frequency-dependent characteristics of therndynamic instability for various load levels.