深海立管固有振动特性的进一步分析

摘要

深海立管固有振动特性是参激振动、涡激振动等复杂振动分析的基础，而立管振动是变系数四阶偏微分方程，不易直接求解。为准确获得立管的固有频率和振型，根据定常轴力下立管固有振动特性的经典理论，考虑深水立管长细比大、自重影响及顶端受浮体升沉影响等特点，分析立管固有振动特性的变化，针对不同的分析模型，提出不同的固有振动特性计算公式，并提出简化计算方法，以满足工程应用和进一步研究的需要。%The investigation on the natural vibration characteristics of deep-water riser is of significant importance for understanding the mechanism of parametric vibration and vortex-induced vibration, and vi-bration of the riser, described by a fourth-order partial differential equation, is difficult to solve analytical-ly. This paper presents natural vibration analysis of deep-water riser with a simplified analytical method based on classical vibration theory. The effects of gravity, bending stiffness and floating platform heave on the natural vibration are investigated and discussed. The results indicate that the simplified analytical method is easily programmed on portable computers and can meet the demand of engineering application and re-search of complex vibration.