擾乱を伴う従動力を受ける円形アーチの準周期運動とカオス現象

The deformation, and dynamic behavior mechanism of submerged shell-like lattice structures with membrane are in principle of a non-conservative nature, because the working load is the follower type as hydrostatic pressure that works vertically to its deformed surface at all times. Also, disturbance forces of various types, existing in a marine environment, lead the structure to exhibit dynamic instabilities at a much earlier stage than that could be predicted by a static stability criterion. The dynamic behavior of a circular arch, as basic structural element of shell-like lattice, should be clarified to be the complicated phenomenon undergoing large deflections with small disturbances. This paper deals with a characteristic analysis on oscillatory and chaotic behavior of a circular arch subjected to follower forces with small disturbances. For that purpose, the governing equations for finite deformation and dynamic behavior of the circular arch are defined in a mono-clinically particle coordinates description. Then, the stability region chart of the disturbed equilibrium in an excitation field is calculated numerically. Moreover, the oscillatory and chaotic behaviors of a circular arch are investigated by executing the time histories of motion, power spectrum, phase plane portraits, Poincare section. By the results of these studies, the dynamic behavior of a circular arch is researched to clarify the scenario from quasi-oscillatory motion to non-periodic motion.