Chinese Journal of Ship Research is supervised by China Shipbuilding Industry Corporation (CSIC) and sponsored by China Ship Development and Design Center (CSDDC). The journal is a notable academic journal in the field of naval architecture, shipbuilding and marine engineering in China. It aims to push forward theoretical innovation and advanced technologies. Its scope covers the latest technological breakthroughs, trends, concepts, and discoveries related to the marine industry, naval architects and marine engineering.
The journal is included in CSCD.
Honorary Chairmen AI Ting-yuan, SHAO Kaiwen, WANG Jianguo
Chairman WU Xiaoguang
Vice Chairmen CAI Daming, LIN Zhongqin, MIAO Yu, SHAO Xinyu, WANG Zili, XIA Guihua, XU Qing, ZHANG Qingjie
Invited members DING Rongjun(member of CAE), GONG Xianyi(member o
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Objectives] Due to such factors as docking and sunshine-induced temperature difference, overall and partial response and deformation will occur during the construction and maintenance of surface vessels. On the one hand, it will affect the construction accuracy and safety of the hull, and on the other hand, it will affect the calibration of the relevant maintenance system. [
Methods] In this paper, based on the finite-element method, research on the structural response and deformation analysis method of a docked ship is carried out while taking into account the influence of temperature difference caused by sunshine. [
Results] A finite-element model is created for the entire hull of a docked surface ship according to the principles of docking-block arrangement. According to the measured temperature data, the structural response and deformation prediction of the docked ship under the sunshine-induced temperature difference is carried out. The calculation results reveal the reason behind the phenomenon of “lotus-leaf-shaped deformation” in docked vessels. [
Conclusions] The results of this study are of valuable reference values for the calibration of shipborne weapon systems and aviation support systems in a docked state.
[Objectives] A periodic absorber can absorb incident electromagnetic waves and effectively reduce the reflectivity of a target. To this end, a novel microwave absorber based on an active frequency selective surface (AFSS) is proposed in this paper. The absorption frequency bandwidth can be dynamically adjusted by adding one PIN diode to a unit cell. [Methods] First, the tunable reflection performance of the proposed absorber is studied by means of a full-wave electromagnetic simulator CST in order to investigate the reflectivity of the absorber diode, as the equivalent resistance of the PIN diode changes with different forward currents. The propagation and reflection properties of electromagnetic waves in a multi-layer structure are then analyzed based on the multi-reflection interference theory so as to quantitatively illustrate the magnitude and phase conditions with regard to the near unity absorption. Finally, an experiment is conducted on a fabricated absorber to verify its role in an anechoic chamber. [Results] The results indicate that the reflectivity of the absorber can be effectively controlled within the range of 2.5–9.1 GHz after the PIN diode is added. [Conclusions] The results of this paper have the application value in the electromagnetic stealth technology of weapon equipment.
[Objectives] Underwater vehicles with an X-form stern arrangement can be designed to handle plane control jams, which are characterized by their safety over vehicles with a cruciform arrangement. Due to particularity of the X-form stern arrangement and its control, its hydrodynamic characteristics are different from those of a cruciform stern arrangement. [Methods] Numerical simulations of the cruciform stern arrangement are carried out on SUBOFF and validated first with the model test results and then in combination with the determined meshing method. The hydrodynamic characteristics of the X-form stern arrangement are then studied and compared with those of a cruciform stern arrangement with the same rudder area. Finally, the simulations of both the cruciform and X-form stern arrangements with propellers modeled by body force are carried out. [Results] The results show that the horizontal and vertical stability coefficients of the X-form stern arrangement are almost the same and decline compared with those of the cruciform stern arrangement respectively. The force characteristics of the X-form stern arrangement are nonlinear with its angle, and the derivatives of the rudder decline by about 27%. The pump effect improves the stability coefficients and enhances the derivatives of the control surface by about 15%–18%. [Conclusions] The results of this study can provide a guiding reference for the design of underwater vehicles.
[Objectives] When polar ships sailing in polar regions, extremely complex ice resistance poses not only structural threats to ships but new challenges for ship maneuverability, especially when a ship is turning in level ice. In contrast, recent studies have mainly focused on ship–ice interaction with less consideration of effects of fluid on ice loading. [Methods] With the nonlinear finite-element method and based on proper ice material and a reasonable coupling failure mode, this paper studies the complex, strong and nonlinear interaction between ice and ships during turning. In addition, the fluid–structure interaction method is used to consider the influence of fluid on ship–ice interaction. [Results] The validity and reliability of the simulation are determined via the numerical results and empirical formulae. The longitudinal, widthwise and vertical ice resistance to the ship is compared with or without fluid conditions. It is found that ice load has a noticeable increase in three degrees of freedom when the effects of fluid are considered. [Conclusions] Considering the influence of fluid on ice resistance to ship’s ice-breaking movement can effectively ensure the safety of the ship and accurately predict the ice resistance during the turning.
[Objectives] To solve the steering control problem of X-rudder submarines under different available rudder surfaces, the rudder control allocator of an X-rudder submarine is designed. [Methods] A cascade control structure including a main controller and a control allocator is adopted in the design of the steering control system. The main controller adopts an existing mature algorithm, and a constrained control-allocation algorithm is designed by converting the rudder-angle control-allocation problem with rudder-angle and rudder-speed limits to solve the weighted least square problem. The control-allocation algorithm is verified through simulation of turning at certain depth and diving in three operation cases (quadruple rudder, triple rudder, and double rudder). [Results] Under the given rudder conditions, with the decrease in the steering surface, the difference in the submarine's diving performance is not significant; turning performance is reduced slightly; heeling and rudder angle oscillation tends to be serious. [Conclusions] The simulation results show that the control allocation algorithm is reasonable and suitable for different rudder configurations.
[Objectives] In order to make the dynamic positioning of azimuth thrusters respond to external environmental force in time, avoid the large-scale rotation of the thrusters, and achieve high-precision dynamic fixed-point positioning control, we carried out the research on optimal workspaces of azimuth thrusters. [Methods] Taking the dynamic positioning self-driven model with two azimuth thrusters and a lateral thruster as the research object, we analyzed the problem of the current thrust-allocation singularity optimization index and considered the thrust limits of the thrusters. The method of traversing the thrust and azimuth angles of the thrusters to establish an axial maximum capability matrix is applied. According to the mean and variance of external environmental force, the minimum axial capability requirements are calculated; the optimal workspaces of the thrusters in different external environments are determined in combination with the prohibition angle, and a new thrust-allocation logic framework is proposed. The fixed-point positioning experiments of a dynamic-positioning ship model based on the traditional singularity index and the optimal workspace are carried out. [Results] The experimental results show that the proposed method can overcome the shortcomings of the previous singularity index and achieve the control accuracy of 0.1 m in radii and that of 0.5° in heading angles under the thruster azimuth within a range of 50°. [Conclusions] This method can replace the singularity index; it also satisfies the requirements of the ship-model dynamic positioning experiment and has certain practical engineering values.
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Objectives] Aiming at the influence of load fluctuation on the fuel-cell life and power quality of a fuel-cell hybrid ship, this paper proposes an energy management strategy based on real-time wavelet transform. [
Methods] By the frequency division processing of a power-demand signal, each power source undertakes the corresponding frequency part of the power demand according to its own electrical characteristics. Taking a fuel-cell hybrid ferry as the target ship, this paper sets up a hybrid power system model in Simulink to verify the proposed algorithm. [
Results] The experimental results show that this method can be applied to fuel cells. [
Conclusions] The proposed algorithm can prolong fuel cell/battery life and improve the power quality of a hybrid ship.
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Objectives] Ship safety is one of the most important performance indicators, and cabin optimization is closely related to improving damaged-ship safety. Studying the relationship between damaged-ship safety and cabin optimization is a complicated multi-factor problem. [
Methods] Based on SOLAS 2009, the probability of damaged stability is evaluated and the danger zones are quantified. The analytic hierarchy process (AHP) method is adopted, and the subdivision index, type and quantity of danger zones are taken as the evaluation indexes for calculating the influence weight of each index on damaged-ship safety; this is carried out in order to improve the safety of damaged ships and evaluate the optimal scheme of cabins. [
Results] Adjusting the widths of side cabins, lengths of cabins and double bottom heights of cabins in danger zones can improve the stability and safety of damaged ships. [
Conclusions] The experimental results show that the study of danger zones can improve the safety of damaged ships; moreover, based on multiple criteria, the AHP is feasible for evaluating the safety of ships after sustaining damage to the cabins.
[Objectives] For the structure of the lashing bridge of an ultra-large container ship, the complicated design and severe load environments lead to the higher requirements for reliability. Aiming at the problems of the poor efficiency and low accuracy of reliability analysis for large ship structures, this paper proposes an improved gradient boosting decision tree–Monte Carlo (GBDT-MC) method. [Methods] First, an approximation model of the improved gradient boosting decision tree (GBDT) is established through the Python library; a few sample points are generated through experiment design and the sample points near the failure surface are screened. The SMOTE algorithm is then used to synthesize new sample points and participate in finite element calculation, which is also combined with the original sample points to form a training set. The trained approximation model is used to predict the sample point information generated by the Monte Carlo (MC) method, thereby completing the structural reliability analysis. Finally, the feasibility and accuracy of the improved GBDT-MC method are verified by two examples and the method is applied to the reliability analysis of the structure of the lashing bridge of an ultra-large container ship. [Results] The calculation results show that the failure-probability error under the effect of static lashing force is 3.5% and the calculation time of the improved GBDT-MC method is 2.55 h, but the MC method requires 416.7 h. Therefore, within the allowable range of calculation errors, the improved GBDT-MC method can greatly reduce the calculation time of reliability analysis. [Conclusions] This improved GBDT-MC method significantly enhances calculation accuracy and shortens the calculation time, which can provide support for the optimization of structures with large reliability indexes.
[Objectives] To guide a large-scale high-speed unmanned underwater vehicle (UUV) along the desired path smoothly in 3D space while taking the task requirements of its control performance and hydrodynamics into consideration, a fuzzy line-of-sight (LOS) guidance law with robustness is proposed. [Methods] Based on decoupling control, an integral separated PID algorithm is designed for velocity, heading, depth, and pitch. The dynamic characteristics are then modified by introducing filters for commands and state feedback. Finally, the control performance at varying speeds is tested through lake trials. [Results] The experimental results show that at 6, 9, and 13 kn, the vehicle can follow the desired path and depth within a reasonable margin of error, which vindicates the proposed control system. [Conclusions] The achievements lay a theoretical foundation for the motion-control algorithm design of next-generation unmanned underwater test vehicles.
