Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Research on the Deformation of Ship and Shafting Based on Model Experiment and Simulation
Liu Yi-yang, Zhao Yao, Yuan Hua
School of Naval Architecture & Ocean Engineering, Huazhong University of Science and Technology
Wuhan, Hubei, China

ABSTRACTThe purpose of this paper is to study the deformation of ship hull andshafting, so as to provide guidance for dealing with abnormal wear ofship bearings. In this paper, a simplified model test of the stern isdesigned by combining test and simulation, and a finite element modelis established. The results show that when the ship is sailing, the positionof the bearing changes due to the deformation of the hull, and the shaft
rotates slightly around the edge of the bearing, which causes the internalpressure distribution of the bearing to change.

KEY WORDS: Shaft system; Model test; Deflection line; Internalpressure distribution of bearing

INTRODUCTION
The ship's shaft system support bearing is an important part of the ship'spropulsion system. The ship's shaft system runs through the stern of thehull and provides thrust for the ship's navigation. And in recent years, as
the ship keeps developing toward large-scale and high-power, the ship's
hull stiffness becomes relatively weaker, while the length of the shaft
system keeps increasing and the relative stiffness difference increases.
Ship works in complex wave environment, once launched, under theinfluence of a series of factors such as temperature, wind and waves,current, water depth hull structure and material, etc., the ship hull will
have a large non-linear deformation with strong randomness. The
deformation of the hull will cause the deformation of the inner bottom
plate, which will lead to the change of the vertical position of the bearing
base. Even a small change will have a large impact on the bearing force
distribution(Li Heng, 2017), and when the relative deformation of thehull and shaft system is too large, the bearing reaction force distribution
is unreasonable and the pressure distribution inside the bearing is not
uniform, which leads to abnormal wear of the bearing. Thordon is apolymer material with good wear resistance, so it is widely used inbearings and seals. Fig. 1 shows a certain type of ship’s Thordon bearing,from which it can be seen that the lower edge of the bearing has shown
obvious wear phenomenon.

Fig. 1 Thordon bearing abnormal wearing
The causes of bearing wear have also been studied worldwide. Murawski
argued that hull stiffness should be considered in the shaft alignment andanalyzed the effects of load conditions and regular waves on hull
deformation at the theoretical level; K.H. Low summarized theconditions that have the greatest impact on the ship's shaft system basedon theoretical analysis and practical measurements; Xiang Kui Ruan
based on a large container ship, an integrated finite element model of thehull with propulsion shaft components was calculated for the hull
deformation at the position of the shaft support under different loading
conditions and compared with the finite element model without
shaft.(Murawski, 2005; Low, 2004; Xiang, 2014). The existing finite
element calculations in the shaft alignment are usually modeled bymeans of elastic beams. However, this approach is too simplified, andthe calculation results are difficult to guarantee. Moreover, the shaftsystem and the hull are a typical complex and nonlinear coupling process,and the influence of the shaft system on the hull cannot be neglected,
therefore, the comprehensive effect of the hull and the shaft systemshould be considered in the shaft system calculation.( Cong Zhang, 2019)

STERN SIMPLIFIED MODEL TEST AND FINITE ELEMENTMODEL CONSTRUCTION
In this paper, we design and manufacture a simplified model of thestern and finite element simulation models and conduct experiments to3110