基于灰色系统理论的推进轴系负荷预测分析

Prediction analysis on propulsion shafting load based on grey system theory

[目的]推进轴系是船舶的重要组成部分,而轴承负荷直接影响着推进轴系的运行状态和使用寿命。为此,采用灰色系统理论预测船体变形下的轴承负荷。[方法]首先,根据某57000 DWT油轮船体变形引起各轴承相对变位的经验公式,计算轴承相对变位,并将其输入有限元仿真模型,输出各轴承负荷值。在此基础上,引入灰色系统理论中的灰色关联度分析法研究船体变形对各轴承负荷的影响程度,分析各轴承负荷因船体变形引起的相对变化。之后对考虑轴承变位工况下的轴承负荷建立GM(1,1)预测模型,进行船体变形-各轴承负荷的拟合与预测。[结果]结果表明:灰色关联度分析能够有效反映船体变形后对各轴承负荷的影响;船体变形-各轴承负荷GM(1,1)预测模型精度高,预测误差小于6.0%,各模型检验指标能够在一定程度上表征轴承负荷的预测精度。[结论]灰色系统理论在推进轴系负荷研究中是有效且实用的,可以准确预测轴承变位下的轴承负荷,对于实际航行状态下的轴承负荷研究具有一定参考价值。

[Objective]The propulsion shafting system is an important part of a ship,and the bearing load directly affects its operating state and service life.In this paper,bearing load under hull deformation is studied using grey system theory.[Method]First,according to the empirical formula of the relative displacement of each bearing caused by the deformation of the hull of a 57000 DWT oil tanker,the relative displacement of each bearing is calculated and input into a finite element model,and the load value of each bearing is output.On this basis,grey relationship analysis of grey system theory is introduced to study the influence degree of stern bearing displacement on the load of each bearing,and the relative change of the load of each bearing caused by the displacement of the stern bearings is analyzed.A GM(1,1)prediction model is then established for the bearing load considering the bearing displacement conditions,and the hull deformation-fitting and prediction of each bearing load are made.[Results]The results show that grey relationship analysis can effectively reflect the influence of hull deformation on bearing load.The GM(1,1)prediction model has high accuracy and prediction errors less than 6.0%,and the model test indexes can represent the accuracy of the prediction.[Conclusion]Grey system theory is effective and practical in research on propulsion shaft load.It can accurately predict bearing load under bearing displacement,giving it certain reference value for research on bearing load under actual sailing conditions.