Machine learning performance comparison for main propulsive shafting systems alignment

Magalhães, Diego L.; Martins, Dionísio Henrique Carvalho de Sá Só; Castro, Brenno Moura; Vaz, Luiz A.; Monteiro, Ulisses A.; Gutiérrez, Ricardo H. R.

doi:10.1016/j.oceaneng.2023.114556

Cited by 4 publications

(2 citation statements)

References 21 publications

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“…The bearing constraints on the shaft system are reflected in both the vertical and lateral dimensions, but the lateral load is significantly less than the vertical load, so the vertical force is typically considered. Therefore, the function of the bearing in the shaft system can be reduced to a single-point force opposing gravity [27]. From the forces of the shaft system, it can be seen that the main loads are in the longitudinal plane, i.e., the OYZ plane, as shown in Figure 1.…”

Section: Hull-bearing-shaft Interaction Analysismentioning

confidence: 99%

Study of the Hull Structural Deformation Calculation Using the Matrix Displacement Method and Its Influence on the Shaft Alignment

Zhou

Zhao

Yuan

et al. 2023

JMSE

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The analysis of the influence of hull deformation on shaft alignment is predominately conducted using the finite element method (FEM), which is time-consuming, labor-intensive, and challenging to use for iterative hull design optimization. In this paper, hull deformation is separated into two parts—global deformation and local deformation, simplified to a single-span beam model and a grillage beam model, respectively—then solved using the matrix displacement method (MDM). Compared to FEM, the proposed method has a small calculation error, proving its correctness, while the calculation time is greatly reduced. The proposed method has been used to calculate the hull deformation of a ship under various conditions and evaluate its influence on shaft alignment. The results indicate that under certain conditions, the bearing reaction forces are constant, whereas the bearing pressure changes as a consequence of the change in shaft-to-bearing angle. The comparison between local rotation and shaft-to-bearing angle reveals that bearings in various positions follow distinct laws. We suggest that the shaft-to-bearing angle be used as an additional parameter in the evaluation of shaft alignment calculations. Moreover, when optimizing bearing pressure, bearings in different positions are affected differently by global and local deformation, and their optimization priorities are distinct.

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Section: Hull-bearing-shaft Interaction Analysismentioning

confidence: 99%

Study of the Hull Structural Deformation Calculation Using the Matrix Displacement Method and Its Influence on the Shaft Alignment

Zhou

Zhao

Yuan

et al. 2023

JMSE

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“…The alignment quality of the propulsion shafting is a critical factor influencing ship propulsion performance [1]. High-quality alignment of shafting is an important guarantee for safe navigation [2,3].…”

Section: Introductionmentioning

confidence: 99%

Displacement Values Calculation Method for Ship Multi-Support Shafting Based on Transfer Learning

Deng,

Li,

Zhu

et al. 2023

JMSE

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Deviations between the design and actual shafting occur due to limitations in ship construction accuracy. Consequently, accurately obtaining the relationship between the actual shafting load and displacement relationship based on the design shafting becomes challenging, leading to inaccurate solutions for bearing displacement values and low alignment efficiency. In this research article, to address the issue of incomplete actual shafting data, a transfer learning-based method is proposed for accurate calculation of bearing displacement values. By combining simulated data from the design shafting with measured data generated during the adjustment process of the actual shafting, higher accuracy can be achieved in calculating bearing displacement values. This research utilizes a certain shafting as an example to carry out the application of the bearing displacement value calculation method. The results show that even under the action of shafting deviation, the actual shafting load and displacement relationship model can become more and more accurate with the shafting adjustment process, and the accuracy of bearing displacement values calculation becomes higher and higher. This method contributes to obtaining precise shafting adjustment schemes, thereby enhancing alignment quality and efficiency of ship shafting.

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Optimizing the bearing vertical offset of a marine propeller shaft system

Bsiso,

Ripin

2024

Proceedings of the Institution of Mechanical Engineers, Part M:

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The Vertical bearing offset is vital for the safe and efficient operation of marine shafting systems. The bearing offset is made relative to the shaft and must be tested for various operational conditions to prevent overheating, whipping, vibration, and wear that can lead to costly repairs and downtime. The offset of each bearing is achieved by minute adjustment of the bearing pedestal performed during dry-docking. However, the hull load variation can cause the preset bearing offsets to be inadequate resulting in potential bearing damage. Classification Society of ABS and DNV specifies the limit of bearing reaction force, shaft slope, and bending moment to ensure safe operation. These values are usually determined using a finite element model or experimentally using costly strain gauges. A more cost-effective solution is using the stiffness matrix of the bearing shaft system to derive the influence coefficients for the bearing reaction forces (BIC), shaft slope (SIC), and bending moment (MIC). This approach is validated with the existing model of a marine shafting system of a 50 DWT oil tanker that consists of one tail and intermediate shaft supported by stern tube bearing (STB), and intermediate bearing (IB) respectively along with six bearings at the engine shaft using the finite element method. Besides, the study applies the Multi-Objective Particle Swarm Optimization (MOPSO) technique to optimize the vertical position of bearings. It uses BIC, Slope SIC, and MIC to construct the objective functions and find a Pareto-optimal solution that satisfies the requirements of ABS and DNV in terms of bearing reaction forces, bending moments, and slope at the main stern tube and intermediate bearing. The optimal bearing offsets show improved shaft bending state for the operating condition under evaluation and reduced the slope at the STB by 34%, indicating its effectiveness in solving optimization problems.

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Machine learning performance comparison for main propulsive shafting systems alignment

Cited by 4 publications

References 21 publications

Study of the Hull Structural Deformation Calculation Using the Matrix Displacement Method and Its Influence on the Shaft Alignment

Study of the Hull Structural Deformation Calculation Using the Matrix Displacement Method and Its Influence on the Shaft Alignment

Displacement Values Calculation Method for Ship Multi-Support Shafting Based on Transfer Learning

Optimizing the bearing vertical offset of a marine propeller shaft system

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