满足固有频率相似的海洋平台相似模型设计

基于Bockingham的π定理,推导出海洋平台相似模型设计需要满足的条件,并分析了实现各个相似比的基本条件.分析发现,在海洋平台相似模型设计中,模型与原形的固有频率相似是最难以满足的相似条件,但它对动力相似又至关重要.作者首次引入固有频率比相对误差作为模型相似程度的衡量标准,通过分析各个参数对固有频率比相对误差的影响,最大限度地满足相似比条件,为海洋平台相似模型设计提供了实用方法.应用该方法对南海W12-1海洋采油平台进行模型设计,得到较为满意的相似模型.

Design of the offshore platform model similar to the natural frequency of original shape

The conditions satisfied for the design of the similar offshore platform model are derived based on the Bockingham's pi-theorem.The basic conditions for realizing every similar ratios are analyzed.The analysis shows that it is the most difficult to satisfy the similarity of the natural frequency of model to that of original shape,but the similarity is very important to the dynamic similarity of model to original shape.For this reason,a parameter——the relative error of natural frequency ratio—— is introduced,which is used for measuring the extent of the actual natural frequency ratio approaching to the theoretical natural frequency ratio.All the factors of influencing the relative error are analyzed in order to minimizing it.This method provides a practical technique for the design of the similar models of offshore platforms.An actual model is designed for W12-1 offshore production platform sited in South China Sea using this method and a satisfactory result is obtained.