﻿ 海洋平台主机舱振动建模仿真分析及试验研究
 舰船科学技术  2024, Vol. 46 Issue (5): 74-79    DOI: 10.3404/j.issn.1672-7649.2024.05.014 PDF

Simulation modeling and experimental analysis on vibration of offshore platform engine cabin
LI Hui, YIN Xue-wen, WU Wen-wei, LIU Yuan-hui
China Ship Scientific Research Center, National Key Laboratory on Ship Vibration and Noise, Taihu Laboratory of Deepsea Technological Science, Wuxi 214082, China
Abstract: In order to meet the need for improving vibration and noise isolation performances, a FEM model was established for the complex system composed of platform cabin, machines and isolators to analyze the vibration transmission from the machine to the isolators and to the foundation of the whole cabin structure. Discussions were presented for influences of five different models with different boundary conditions and isolator stiffnesses. Excitation experiments for the platform engine cabin with two different working conditions, ie., 40% power and sailing, were performed. The vibration responses from the excitation points to the vibration points were obtained. The finite element calculation results were compared with the experimental results. The two results were relatively close with each other which indicated that for the low frequency band, it’s improper to simulate the dynamic characteristics with one cabin model. The FEM model of the engine cabin can meet the need for engineering applications and can also provide some useful reference for isolation optimization design of the offshore platform.
Key words: vibration of engine cabin     simulation modeling     vibration transmission     experimental comparison
0 引　言

1 研究对象

 图 1 平台主机布置图 Fig. 1 The diagram of the offshore platform

 图 2 1#主机舱内部布置图 Fig. 2 The diagram of the first engine cabin
2 实船试验

 图 3 1#主机振动测点示意图 Fig. 3 The diagram of the vibration experiment points
3 仿真分析

1）模型A（见图4）。单个1#主机舱三维有限元计算模型。按照主机舱实际结构进行简化，其各层甲板、舱壁采用板元来模拟，其上的纵桁和强横梁用梁元模拟，在主机舱四周进行约束处理，因为主机舱靠近平台尾部，一边悬空，所以将此边的边界条件设为自由，其余三边简支。

 图 4 模型A Fig. 4 The model A

2）模型B（见图5）。包括单个1#主机舱以及部分相邻舱室的三维有限元计算模型。向周边各延伸3个肋位到强构件，在边界进行简支约束处理。

 图 5 模型B（不考虑立柱的影响） Fig. 5 The model B(without column)

3）模型C。包括单个1#主机舱以及部分相邻舱室的三维有限元计算模型。和模型B相同，但是考虑单个立柱对主甲板的支撑作用，在立柱作用舱室的底部进行简支约束，并在其余相邻边界进行简支约束处理。

4）模型D（见图6）。包括全部3个主机舱的三维有限元计算模型。考虑其余2个主机舱对1#主机舱振动特性的影响，三边简支，一边自由。

 图 6 模型D Fig. 6 The model D

5）模型E（见图7）。包括全部3个主机舱以及部分相邻舱室的三维有限元计算模型（模型E）。即将模型D向平台首部及左右各延伸一个舱段到强构件，并考虑平台下部立柱对整个主甲板的支撑作用，在立柱作用舱室的底部进行简支约束，在边界进行简支约束处理。

 图 7 模型E Fig. 7 The model E

 图 8 A2点振动位移响应曲线 Fig. 8 Vibration responses of point A2

 图 10 不同隔振器刚度下A2点垂向加速度响应曲线 Fig. 10 Vertical acceleration responses of point A2with different isolator siffnesses

 图 9 A3～A7均值振动响应曲线 Fig. 9 Average vibration responses from point A3 to A7

 图 11 A2点垂向加速度响应对比曲线 Fig. 11 Vertical acceleration responses of point A2compared with experimental results

4 计算结果对比

4.1 40%DP工况

 图 12 A3、A7点垂向加速度响应对比曲线 Fig. 12 Vertical acceleration responses of point A3 and A7compared with experimental results
4.2 航行状态工况

 图 13 航行状态A2、A3、A7点垂向加速度响应对比曲线 Fig. 13 Vertical acceleration responses of point A2, A3 and A7 compared with experimental results in navigation condition
5 结　语

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