An Attractor-Based Approach to Safety State Assessment of Large Ship Shafting Alignment

Abstract

The invention provides an attractor-based method for evaluating the safety state of shaft alignment of large ships. The method of the invention includes the following steps: collecting vibration signals at different positions of the shafting bearing seat, extracting a period signal with a large value, that is, a main frequency signal, and a non-periodic signal with a small amplitude, that is, a side frequency signal; Combined into characteristic signals, the shafting attractor is constructed by the characteristic signal; according to the structural characteristics and evolution characteristics of the shafting attractor, the safety state of the shafting alignment is judged. The method of the invention uses harmonic wavelet packet transform to finely decompose the frequency band of the vibration signal, decomposes the noise signal and the effective signal into different frequency bands, realizes the separation of the two, and extracts the main frequency signal and the side frequency signal respectively; The two signals are combined into a characteristic signal, and then a shafting attractor is constructed by the characteristic signal; according to the structural characteristics and evolution characteristics of the shafting attractor, the safety state of the shafting alignment is judged.

Description

technical field [0001] The present invention relates to a safety state evaluation method, in particular to an attractor-based method for evaluating the safety state of shafting alignment of large ships. By using the attractor theory to reveal the evolution mechanism of shafting alignment, the safety state of shafting alignment is established The evaluation method realizes the detection and evaluation of the safety status of shafting alignment of large ships. Background technique [0002] In the process of large-scale ships, people should pay more attention to the safety performance of ships while pursuing low-carbon, environmental protection, energy saving, high efficiency and low cost. However, how to improve the sailing performance of ships still faces many technical challenges. Among them, ensuring the reliable operation of the propulsion power system is an important aspect of improving the sailing performance of ships, especially the shafting of ships. [0003] Ship sha...

AI Technical Summary

Problems solved by technology

At present, the shafting alignment method can ensure that the shafting alignment is in a reasonable state when the ship is not sailing, but the shafting of the ship will be affected by many dynamic factors during the actual sailing process, such as hull deformation, propeller alternating bending moment, bearing oil film And other factors

These dynamic factors can adversely affect the state of shafting alignment

The poor alignment of the shafting system will cause rapid wear or even damage of the bearing bush during operation, the rapid wear of the stern shaft sealing element will cause leakage, and the distance difference between the crankshaft arm of the main engine exceeds the allowable range

Eventually, the vibration of the shafting system will increase and the stability will decrease. When the vibration is too large, it will even cause the shafting system to fail.

For the shaft system installed in the alignment, in the actual operation process, the detection and evaluation methods of the alignment state are rarely involved in the research at home and abroad

Images