マンガン団塊の採鉱に伴う揚鉱管の係数励振

概要

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A long pipe string hung from the ship in a mining system in the deep ocean may be parametrically excited when the ship undergoes a heaving motion. The vibration of the pipe string does not grow exponentially as in a linear case, but is limited by the nonlinear drag force of the sea water. In this paper, a theoretical analysis is presented to study this limit cycle response of a two-stepped pipe string with a buffer attached to its bottom end. The effect of the longitudinal oscillation of the pipe string is included. Furthermore, the equation of motion is formulated by considering the effect of the constant relative velocity between the sea current and the ship. It is found that the system is excited either only parametrically or both parametrically and directly, depending on whether the relative velocity is equal to zero or not. The steady-state oscillations are determined by the method of harmonic balance, and the stability of the solutions obtained is also investigated.
一般社団法人日本機械学会の論文
1990-10-25