Table of Content

25 May 2022, Volume 33 Issue 10

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Hydrodynamic Force Calculation Method of Tracked Equipment Based on Artificial Lateral Line#br#

WU Jiaxiong, SHEN Yanhua , YANG Shudi, FENG Zhipeng

2022, 33(10):  1135-1141.  DOI: 10.3969/j.issn.1004-132X.2022.10.001

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 Aiming at the challenge that the hydrodynamic forces of underwater equipment could not be measured in real time， a method for calculating the hydrodynamic forces of track equipment was proposed based on ALL. Through the ALL system of the track equipment， the pressure values of different incoming flow speeds and angles were extracted， and the distribution law of pressure values was used to perceive the local flow field information of the track equipment. Through the hydrodynamic force restraint experiments of the track equipment combined with the computational fluid dynamics（CFD）simulation method， the functional relationship between the front surface shapes of the track equipment and the viscous coefficient was established. Based on the flow field perception results of the ALL， the hydrodynamic force empirical model of the track equipment was derived. The verification results show that the pressure distribution characteristics of the ALL may effectively identify the incoming flow velocity and angle. The hydrodynamic force empirical model combined with the results of ALL perception may be used to estimate the hydrodynamic force of underwater track equipment in real time， the water resistance calculation error of underwater track equipment model is within the acceptable range of the engineering application. 

Navigation Trajectory Prediction Method of Inland Ships Based on Multi-model Fusion

ZHANG Yang, GAO Shu, HE Wei, CAI Jing

2022, 33(10):  1142-1152.  DOI: 10.3969/j.issn.1004-132X.2022.10.002

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 Inland waterway navigation was an important part of the modern comprehensive transportation systems. The real-time and high-precision ship trajectory prediction method was helpful to effectively avoid water traffic accidents and enhance the ability of automation and intelligent supervision. Aiming at the problems that the accuracy of the existing inland ship trajectory prediction was not high， in order to improve the short-term prediction accuracy of ship trajectory， comprehensively using the recent AIS (automatic identification system) data and historical AIS data of the ships， and based on the relationship among trajectory and speed， course， and the characteristics of inland waterway， the temporal convolutional network model for speed and course prediction， ship trajectory dynamics equation model and adaptive double-hidden layer RBF network were constructed. The ship trajectory prediction method based on multi-model fusion was proposed. Experimental results show that the proposed method has obvious improvement in trajectory prediction accuracy and may meet the real-time requirements. 

Near-field Sea Ice Perception and Course Decision for Ice Navigation

XIE Zongxuan, LI Bo, WANG Shengzheng, LIU Wei

2022, 33(10):  1153-1161，1168.  DOI: 10.3969/j.issn.1004-132X.2022.10.003

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In order to realize real-time mastery and obstacle avoidance of near-field sea ice around the ship during ice navigations， the near-field sea ice perception and course decision method was studied based on the image fusion of marine radar and ice radar. The use of radar fusion images for sea ice concentration calculation could get more accurate and reliable results than the estimations by artificial observation method. The drawing of sea ice risk heat map and contour map was helpful to quickly grasp the current near-field sea ice risk distributions. Considering the concentration of sea ices and the degree of yaw， the proposed course decision method in ice area could obtain the appropriate course angle. After collecting the marine radar and ice radar images of the polar research icebreaker Xuelong 2 during the maiden voyage to Antarctica， the experimental results of dense ice field and sparse ice field show that the proposed near-field sea ice perception and course decision method may obtain the risk distributions of near-field sea ice and give the appropriate course change suggestions to provide effective support for the safety of polar autonomous navigation. 

Research and Applications of Condition Monitoring and Predictive Maintenance of Marine Diesel Engines

CHEN Dongmei, ZHAO Siheng, WEI Chengyin, CHEN Yajie

2022, 33(10):  1162-1168.  DOI: 10.3969/j.issn.1004-132X.2022.10.004

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Based on the four dimensions of thermal-pressure parameters， lubricant oil conditions， vibrations and cylinder pressures， data acquisition and feature extraction were carried out， and a method for diesel engine condition monitoring was proposed based on OCSVM anomaly detection algorithm and Fisher discriminant analysis.  The CUSUMMR was used for parameter trend detection and the D-S evidence theory and weight of evidence method were used for multi-source information fusion. the RUL(remaining useful life) of diesel engine lubricating oil was predicted by LSTM. The Paper solves the problems such as low early warning rate， poor adaptability of the model under diesel engine dynamic conditions. 

A Multi-agent-based Simulation Method for Health State Assessments of Naval Equipment

DING Shanting, WANG Miao, DONG Zhengqiong, NIE Lei,

2022, 33(10):  1169-1177.  DOI: 10.3969/j.issn.1004-132X.2022.10.005

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 Considering that the sea conditions had a significant impact on the safe navigation and mission execution of ships， a multi-agent technology-based equipment health state simulation assessment method was proposed herein. Based on the analysis of naval equipment navigation task， the “task-equipment-maintenance-environment” equipment health state model was established， and the internal rules and communication mechanism of the environmental agents were formulated to realize the health state assessment of naval equipment under different sea conditions， in view of the influences of sea condition factors on equipment performance and maintenance capability. Taking a ships power system as the object， the health states of the cruising mission was evaluated under sea state 0， 5 and 7 level， respectively， and the simulation analysis results show that compared with sea state 0， the health and mission success rate of the power system under sea state 5 and 7 are reduced， and the quantitative evaluation results are consistent with the trend of expert qualitative evaluation results. 

Fault Diagnosis Method of Marine Fans Based on MTAD  and Fuzzy Entropy

JIANG Jiawei, HU Yihuai, FANG Yunhu, ZHANG Chen, RUI Xiaosong, WANG Meng

2022, 33(10):  1178-1188.  DOI: 10.3969/j.issn.1004-132X.2022.10.006

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Ship rotating machinery often operated in a multi-vibration source environment. How to effectively extract features and reduce noise processing of the vibration signals was a hot topic for scholars. The time-domain synchronous averaging method had good effect iveness on the noise suppression of vibration signals. However， the key phase signals required by this method were difficult to obtain， and fault information other than the specific frequency would be lost， and the waveforms of the frequency multiplication signal would be mixed with each other. The above problems limited the applicability of this method. A MTAD method was proposed to overcome the problems of the traditional time-domain averaging method effectively， and combined fuzzy entropy feature selection to perform fault diagnosis on ship wind turbines. The accuracy and calculation speed are better than that of EMD， EEMD and VMD method. The effectiveness of the proposed method is demonstrated through simulation data analysis and fault simulation experiments. 

Digital Verification Method of Ship EEDI

WANG Zhifang, YANG Zixuan, CHEN Qingren

2022, 33(10):  1189-1194.  DOI: 10.3969/j.issn.1004-132X.2022.10.007

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 In order to promote the implementation of the EEDI of inland waterway ships and the improvement of EEDI level， a fast， efficient， and accurate digital forecasting method for EEDI of inland waterway ships needed to be developed. The paper collected a large number of tank test data samples about inland waterway ships and divided them into two parts. One part samples were used to analyze and improve the Ayre method resistance evaluation and calculation method， based on the research， an improved Ayre method was proposed, which was suitable for the resistance curve estimation and effective power calculation of the wide and flat inland waterway ships with twin-engine double-propeller and large square coefficient. The other part samples were used to verify the improved Ayre method， and the results show that the revised Ayre method has a much more lower forecasting errors than that of the original version from 9.4% to 3.4%， and then the ship speed forecasting method was proposed. Through testing and verification of the collected 32 real ship speeds， the results show that the method has high prediction accuracy with an average error of only 2.678%， which is far lower than the 5% error accepted by the shipowner. Finally， EEDI digital verification software was developed to meet the needs of economic and rapid verification of EEDI， and promote the green and efficient development of inland waterway ships. 

Influence Law of Relative Position of Static Pressure Holes on Bearing Capacity for Fluid Pivot Tilting Pad Bearing

HUA Ertian, ZHAO Tiancheng, XIE Rongsheng, XU Yongli, XIANG Chun, XU Gaohuan

2022, 33(10):  1195-1202，1209.  DOI: 10.3969/j.issn.1004-132X.2022.10.008

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In order to improve the oil film stiffness of the supporting bearings in the steam turbine rotor systems， the influence law of the relative position of static pressure hole on the bearing capacity is studied by taking the three-pad fluid pivot journal bearings as the research object. The oil film lubrication model of the fluid pivot tilting pad bearing was established， and the three-dimensional Navier-Stokes equations numerical solution was carried out on CFD， revealing the variation law of bearing pressure distribution， minimum film thickness， eccentricity， stiffness and other performance parameters at different relative positions of static holes. The analysis results show that the stiffness of bearing oil film can be improved by changing the position of the hole under the load of 890 N； when the relative position of the static pressure hole=5°， the hole position is close to the maximum pressure distribution area of oil film the principal stiffness， the minimum film thickness and eccentricity are reduced by 9.8% and 48% respectively， compared with γ=0 °， kyy and kxx are close to 1.4 times and 1.1 times of the original structure， the static pressure hole position is relatively optimal at this time. Based on the analysis results， a new type of fluid pivot tilting pad bearing （γ=5°） is developed. The comprehensive performances of the common sliding bearings and the new type of fluid pivot tilting pad bearings are compared and analyzed by experiments. The results show that the new type of fluid pivot tilting pad bearings has better bearing capacity and vibration reduction performance at high rotating speed. This study has certain reference value for the performance analysis of the fluid pivot tilting pad bearings. According to the distribution law of oil film pressure， the design of bearing static pressure holes may be optimized to improve bearing performance. 

Design of Cross-spring Flexure Hinges

WU Hao, LI Zongxuan, ZHANG Defu, LI Qingya, LI Yunfeng,

2022, 33(10):  1203-1209.  DOI: 10.3969/j.issn.1004-132X.2022.10.009

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To realize the requirements of a certain optical instrument for flexural hinges， a new type of cross-spring flexural hinge was proposed， and the design method was studied by using the Castiglianos second theorem. First， the Castiglianos second theorem was used to derive the flexibility calculation formula of the cross-spring flexural hinges to determine the axial rigidity and rotational rigidity of the hinges. Then， a case design was carried out and the finite element analysis was used for simulation. Finally， an optical test platform was set up and the rotation stiffness of the example was measured. The results show that the analytical solution， the simulation solution and the experimental data are in good agreement， and the relative error is as 8.7%. Using the Castiglianos second theorem as a design tool， the designer may determine the dimensional parameters according to the rigidity and structural requirements of the cross-spring flexural hinges， and the design of the cross-spring flexural hinges provides a new approach method for other hinges. 

Investigation of Fluid Filled Behaviour of Cracks under Rolling Contacts

DONG Longlong, YU Shurong, LI Shuxin, SONG Wei

2022, 33(10):  1210-1218.  DOI: 10.3969/j.issn.1004-132X.2022.10.010

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In order to clarify the crack change processes after the liquid penetrated into the cracks， the two-dimensional liquid-filled model of a rolling contact disk with a crack was established. The cavity was composed of the crack surface and the contact surface of the disk surface. The movement of the disc deformed the crack surface， and the pressure in the cavity increased as the liquid was compressed. In addition， the cavity pressure applied to the crack surface accelerated the crack propagation. Based on the changes of the crack surface contact states， the stress intensity factor curve and the crack propagation direction of the cracks under the conditions of cavity formation， cavity sealing and liquid leakage were analyzed. The results show that the pressure in the cavity is less than the maximum pressure at the crack contact positions. Under the action of liquid pressurization， the crack propagation mode changes from Ⅱ to Ⅰ. As the length and width of the crack increase， the crack propagation mode changes from Ⅱ to Ⅰ. As the crack geometry increases， the liquid pressurization effect is significantly enhanced. As the crack growth， self-sealing and leakage of the dynamical cavity occur in the processes of liquid leakage. 

Imaging Distortion Analysis and Optical Path Optimization of Tooth Surface Interferometry Systems

WANG Zhaohui, YANG Pengcheng , XU Jin, LIANG Pujia, ZHU Xindong

2022, 33(10):  1219-1225.  DOI: 10.3969/j.issn.1004-132X.2022.10.011

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Aiming at the tooth surface image shape distortions caused by object optical path errors， three factors that might lead to tooth surface image shape distortions were analyzed by using accurate ray tracing algorithm， the main error sources of tooth surface image shape distortions were defined， the judgment model of tooth surface image shape distortions was established， and the mapping relationship between tooth surface image shape distortions and gear axis inclination was established. An object optical path optimization method was proposed based on the shape distortions of tooth surface images. Finally， the experimental verification was carried out， and the results show that the error ranges are controlled at about 2%， which prove the rationality and correctness of the proposed method. 

Generalization Method of Dynamic Movement Primitives Based on Weighting of Task Parameters

ZHANG Lei, FANG Zaojun, WANG Juxing, HE Chen, GU Danning,

2022, 33(10):  1226-1233,1243.  DOI: 10.3969/j.issn.1004-132X.2022.10.012

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In order to improve the computational efficiency and generalization performance of robot learning from demonstration， a robot learning from demonstration model was proposed based on generalization of dynamic movement primitives weighted by task parameters. The main steps were as follows：the dynamic movement primitives model was used to extract the characteristic parameters of the multi teaching motion trajectories； Under the new task parameter， the extracted feature parameterswas used to reconstruct the feature motion trajectory； the approximate degree of the teaching task parameters and the new task parameters were usedto weight the feature motion trajectory to generate a new motion track. Experiments on Kukaiiwa robot show that the proposed method may quickly and effectively generalize the new trajectory in the new task scenario. Compared with the existing methods， the proposed method has a great improvement in computational efficiency and generalization performance near the teaching task parameters. 

An Unsupervised Bearing Health Indicator and Early Fault Detection Method

ZHAO Zhihong, LI Lehao, YANG Shaopu, LI Qing

2022, 33(10):  1234-1243.  DOI: 10.3969/j.issn.1004-132X.2022.10.013

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A method of unsupervised bearing health indicator and early fault detection was proposed. A deep separable convolutional auto-encoder model was designed to effectively extract bearing state features， where the outputs of the encoder were used as bearing state features. Then， the Bray-Curtis distance was used to calculate the distance between the degenerated state features and the healthy state features as the bearing state health indicator（BC-HI）. An early fault detection method combined with Savitzky-Golay filter was proposed based on BC-HI. The abnormal threshold was obtained according to the trend of health indicators to judge the occurrence of early faults. In order to verify the effectiveness and generalization ability of the proposed method， the experiments were carried out on datasets of bearing accelerated life tests. The experimental results show that the health indicator proposed may reflect the degradation trend of bearings， and is sensitive to early faults， and has strong generalization ability. Compared with the methods such as isolated forest and support vector machine， the first fault detection time is earlier and the false alarm rate is lower， so it has certain application values. 

High-performance Paper-based Electronic Fabricated by Electric-field-driven Jet Micro 3D Printing#br#

ZHANG Yongxia, ZHANG Guangming, ZHOU Longjian, ZHOU Hefei, XU Quan, LAN Hongbo

2022, 33(10):  1244-1259.  DOI: 10.3969/j.issn.1004-132X.2022.10.014

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A novel method of the electric-field-driven（EFD）jet deposition micro-scale 3D printing for fabricating high resolution circuit on paper-based surface was proposed. The basic principles and process flows of the proposed method were presented. The effects and rules of the main processing parameters（e. g.， the voltage， back pressure， printing speed） on the accuracy and quality of silver wires fabrications were revealed by a serial of experiments. Then， by using optimized parameters and the nano silver paste（75% silver content and 35 Pa·s（at 25 ℃）dynamic viscosity）， the micro/nano-scale structure with high resolution and high aspect ratio was fabricated by multi-layer stacking on three kinds of paper substrates. For example， the line width with 15 layers stacking on RC photo paper may be kept at 10 μm， and the aspect ratio may be increased to 6.33， causing the 94.8% decrease of the resistance. Finally， flexible electromagnetic actuators（FEMAs） and complex conductive patterns were fabricated on different paper substrates to prove the printing ability. The results show that the new method of EFD 3D printing technology combined with high viscosity and low temperature sintering nano silver paste may provide an effective way for high-performance paper-based electronics. 

Study on Microstructure and Mechanics Properties of 2.25Cr-1Mo-0.25V Steel Fabricated by CMT Wire ARC Additive  Manufacturing for Petrochemical Vessels

ZHONG Yang, QIN Xiaobo, ZHENG Zhizhen, LI Jianjun, WANG Cheng

2022, 33(10):  1251-1259.  DOI: 10.3969/j.issn.1004-132X.2022.10.015

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In order to explore the new manufacturing processes of large petrochemical cylinder root edges， a newly self-developed 2.25Cr-1Mo-0.25V flux-cored wire was firstly used to deposit 2.25Cr-1Mo-0.25V straight-walls based on cold metal transfer and wire arc additive manufacturing（CMT-WAAM）， and the best post-weld heat treatment was explored to improve microstructure and mechanics properties. The experimental results show that the internal microstructure of the straight-walls deposited by CMT-WAAM are mainly composed of lathy bainite， granular bainite and some martensites， with obvious differences in the building direction， dramatic floating micro-hardness and much higher tensile strength than that of the base metal， but lower fracture elongation. After applying “hydrogen elimination treatment+stress relief treatment” and “simulated minimum post-weld heat treatment” on the deposited walls， the latter was found to increase the plasticity to a level comparable to the base metal. Microstructure observations reveal that original lathy-bainite and partial martensite may be transformed into the uniformly distributed granular bainite after the “minimum post-weld heat treatment”， and the microstructural anisotropy may be significantly reduced. The experiments prove that the newly developed 2.25Cr-1Mo-0.25V wire may be used to deposit straight-walls under the optimal parameters， the subsequent “minimum post-weld heat treatment” may improve microstructure and mechanics properties to the greatest extent， which finally meet the service specifications of petrochemical vessel root edges. Compared with the casting-forging processes， CMT-WAAM is expected to significantly save production costs and improve manufacturing efficiency.