基于运行模态分析的船舶推进轴系状态监测

论文提出一种基于运行模态分析(OMA)的新的船舶推进轴系状态监测方法。论文以船舶推进轴系试验台为试验对象,获取轴系运行时不同加载工况下的扭振信号,利用基于数据的随机子空间法(DD-SSI)识别扭振的固有频率,并与已知的试验模态分析(EMA)识别的轴系静态时同一加载工况下的结果进行对比,验证运行模态分析识别结果的准确性,并研究不同加载工况下轴系扭振固有频率随加载工况的变化规律。试验结果表明,运行模态分析能够准确识别轴系的扭振固有频率,且扭振固有频率的增量与加载量呈正相关,因而运行模态分析可以用作一种新的船舶推进轴系状态监测方法。

A New Method for the Ship Propulsion Shafting Status Monitoring Based on Operational Modal Analysis

The paper proposes a new method for the ship propulsion shafting status monitoring based on operational modal analysis(OMA). In this paper, the torsional signals are acquired from a ship propulsion shafting test bed in operation under different load conditions and analyzed with the data-driven stochastic subspace identification(DD-SSI) method to obtain torsional natural frequencies which are then compared with those extracted from the data acquired at the same load conditions when the shaft is static with experimental modal analysis(EMA) in order to verify the accuracy of the OMA results, and the change of the torsional natural frequency with different load conditions is also investigated. Test results show that OMA can identify the shaft torsional natural frequencies precisely, and the relation between the increment of the torsional natural frequency and that of the load amount is positively correlated, and thus OMA can be used as a new method for the ship propulsion shafting status monitoring.