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Table of Content

    28 April 2022, Volume 56 Issue 4 Previous Issue    Next Issue
    New Type Power System and the Integrated Energy
    Comparative Analysis of Technical Standards for Offshore Wind Power via VSC-HVDC
    YU Hao, ZHANG Zhemeng, PENG Sui, ZHANG Zhiqiang, REN Wanxin, LI Canbing
    2022, 56 (4):  403-412.  doi: 10.16183/j.cnki.jsjtu.2021.465
    Abstract ( 1870 )   HTML ( 1064 )   PDF (1110KB) ( 876 )   Save

    This paper introduces the current situation of domestic and foreign offshore wind power grid-connected via voltage source converter based high voltage direct current(VSC-HVDC) transmission standards, and selects representative standards of offshore wind power grid-connected via VSC-HVDC. It also compares the domestic and foreign offshore wind power grid in terms of power control, fault ride-through, power quality, stability, etc., and analyzes the development trend of offshore wind power grid-connected via VSC-HVDC standards. In order to promote the development of offshore wind power industry, it provides reasonable suggestions for the formulation and revision of Chinese offshore wind power grid-connected via VSC-HVDC standards.

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    State of Health Estimation of Lithium-ion Battery Using a CS-SVR Model Based on Evidence Reasoning Rule
    XU Hongdong, GAO Haibo, XU Xiaobin, LIN Zhiguo, SHENG Chenxing
    2022, 56 (4):  413-421.  doi: 10.16183/j.cnki.jsjtu.2021.345
    Abstract ( 1528 )   HTML ( 545 )   PDF (1150KB) ( 606 )   Save

    The state of health (SOH) estimation accuracy of lithium-ion battery affects the safety and service life of batteries. Aimed at the problem in SOH estimation of lithium-ion battery, a cuckoo search support vector regression (CS-SVR) model based on the evidence reasoning (ER) rule was proposed for SOH estimation. The lithium-ion battery data from NASA Ames Center was used to perform the SOH estimation test. In this method, the average voltage and average temperature of battery discharge cycles were taken as model input, and a fusion belief degree matrix of input data was obtained by the ER rule. The SOH estimation result of the battery was obtained by inputting a fusion belief degree matrix into the SVR model optimized by the CS algorithm. The results show that the CS-SVR algorithm based on the ER rule has a better estimation performance than the five existing models.

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    Naval Architecture, Ocean and Civil Engineering
    In-Plane Yield Criterion of Steel-Concrete-Steel Unit Panel
    HUANG Chengjun, ZHU Tianyi, SONG Xiaobing
    2022, 56 (4):  422-430.  doi: 10.16183/j.cnki.jsjtu.2020.347
    Abstract ( 1617 )   HTML ( 136 )   PDF (2007KB) ( 604 )   Save

    A yield criterion for the steel-concrete-steel (SCS) unit panel subjected to in-plane membrane forces is proposed, which is expressed in the in-plane (principal) stress space and follows the Tresca yielding principle for steel plates. This yield criterion for the SCS unit panel is based on the Navier’s three principles (equilibrium conditions, strain compatibility, and the constitutive laws of materials). A calculation method for determining the yield load of the SCS unit in combination with the test data is proposed, and the method is applied to the bidirectional tensile and compression test of the SCS unit. By using this method, nine SCS tested panels with different steel ratios and different tension compression ratios are analyzed, and the yield criterion of the SCS unit is compared with the test results. In addition, seven SCS shear specimens tested by Ozaki are used for further verification. The results derived from the yield criterion of the SCS panel elements are found in good agreement with the test results.

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    Horizontal Dynamic Response of Pile Based on Layered Generalized Gibson Foundation
    QIU Jiekai, DING Zhaowei, SONG Chunyu, CHEN Longzhu
    2022, 56 (4):  431-442.  doi: 10.16183/j.cnki.jsjtu.2020.382
    Abstract ( 1845 )   HTML ( 147 )   PDF (1931KB) ( 414 )   Save

    In order to directly solve the horizontal dynamic response of a single pile under the condition that the shear modulus of the soil around the pile varies linearly with the depth, a method for solving the horizontal dynamic response of piles in nonhomogenous foundation is proposed based on the layered generalized Gibson foundation and the Adomian decomposition method. Compared with the initial parameter method and the transfer matrix method, the proposed method does not need to discretize the nonhomogeneous foundation. Compared with the numerical method, it has the advantages of low computational cost, high accuracy, and fast convergence speed. The correctness and rationality of this method are verified by comparing it with the calculation results of the layered method, the analytical method of homogeneous foundation, and the numerical method. The influence of boundary conditions on the pile bottom, soil parameters, and pile slenderness on the horizontal dynamic response of the pile is investigated. The result show that in nonhomogeneous foundation, the pile-soil elastic modulus ratio is an important factor affecting the horizontal dynamic response of pile. As the shear modulus of soil increases, the amplitude of horizontal displacement of the pile decreases, and the distribution tends to be gentle. In addition, compared with other parameters, Poisson’s ratio and damping ratio of soil have less influence on the horizontal dynamic response of pile.

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    Analysis of 1-D Consolidation of Double-Layered Saturated Porous-Fissured Clay Foundation
    HU Yayuan, WANG Aqiang
    2022, 56 (4):  443-453.  doi: 10.16183/j.cnki.jsjtu.2021.019
    Abstract ( 1855 )   HTML ( 122 )   PDF (2021KB) ( 382 )   Save

    In order to study the one-dimensional (1-D) consolidation behavior of double-layered saturated porous-fissured clay foundation, the governing consolidation equations of saturated porous-fissured media were developed based on the mixture theory under the condition of one-dimensional complete confinement. The finite element program for 1-D consolidation of saturated porous-fissured clay was compiled by Fortran language, and the results of single-layered foundation research were used to verify the correctness of this model and program. The influences of compression modulus, permeability coefficient, and soil thickness on the consolidation behavior of double-layered saturated porous-fissured clay foundation were analyzed by using the finite element program. The results show that the consolidation rate of the foundation can be significantly accelerated by increasing the compression modulus and permeability coefficient of the softer topsoil, and the dissipation laws of excess pore water pressure and excess fissure water pressure were different. The dissipation of excess pore water pressure at the base of the foundation would lag behind that of excess fissure water pressure, and the lag would increase with the increase of the permeability coefficient of topsoil. For double-layered saturated porous-fissured clay foundation, improving the softer porous-fissured clay properties of the upper layer can better improve the consolidation behavior of the foundation.

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    Accumulative Plastic Deformation of Saturated Soft Clay Under Variable Frequency Cyclic Loading for Subway
    LI Zeyao, ZHOU Jie, TIAN Wanjun, PEI Wansheng
    2022, 56 (4):  454-463.  doi: 10.16183/j.cnki.jsjtu.2021.036
    Abstract ( 1496 )   HTML ( 130 )   PDF (1469KB) ( 497 )   Save

    The acceleration and deceleration movement of the metro near the metro station have a certain impact on the foundation soil. After the soil has been sloped and sampled, a dynamic three-axis undrained dynamic test is conducted to study the influence of the distance of the metro station, acceleration, dynamic stress amplitude, and consolidation confining pressure on the cumulative plastic deformation of saturated soft clay. The results show that the cumulative plastic strain curve of soft clay at variable frequency cyclic loading in and out of the station can be roughly divided into three stages: explosive growth, rapid growth, and gradual stability. The increase in the distance from the metro station, the increase in the amplitude of the dynamic stress, and the decrease in the consolidation confining pressure can reduce the number of entry and exit times required for the soil to enter the gradual stabilization phase, increase the vertical deformation of the soil, and reduce the shear deformation. As the acceleration value in and out of the station increases, the vertical deformation of the soil decreases but the shear deformation increases. For the actual project, the initial stage of metro operation, the settlement deformation of the soil in the inbound section, the horizontal displacement of the soil in the outbound section, the horizontal displacement under the larger acceleration condition, the settlement under the smaller acceleration condition, the high dynamic stress amplitude, and the soil area with a low consolidation stress are the focus of engineering geological disaster prevention.

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    Behavior of Pull-Out and Movement Mechanisms of High-Performance Plain Weave Fabric Yarns
    CHEN Jianwen, WU Shanxiang, ZHANG Ruonan, CHEN Wujun, FAN Jin, WANG Mingyang
    2022, 56 (4):  464-473.  doi: 10.16183/j.cnki.jsjtu.2020.419
    Abstract ( 2300 )   HTML ( 161 )   PDF (8452KB) ( 405 )   Save

    In order to study the movement mechanisms of plain weave fabric yarns, the numerical simulation of behavior of yarn pull-out and movement under various loading conditions was carried out on a typical plain-woven fabric. The effects of friction coefficients, model size, and pre-stress levels on yarn movement responses were analyzed in detail, and the coupling relation among pull-out length, pull-out fractured strength, and model parameter conditions, including friction coefficients and pre-stress levels were shown. The results indicate that positive correlations exist between peak pull-out loads and those main model parameters of plain weave fabrics, including the friction coefficients, model size, and pre-stress levels. As the pre-stress level rises from 200 MPa to 700 MPa, the peak pull-out load increases by 34.49%, and the existence of yarn crimps could lead to improvement of the pull-out loads. The pull-out fractured strength of yarns gradually increases with the growths of pre-stress levels and friction coefficients in the plain weave fabrics. Specifically, the pull-out fractured strength of yarns increases by 16.48% as the friction coefficient grow from 0.1 to 0.2. In addition, the pull-out fractured length of yarns of the plain-woven fabrics is highly dependent on the actual stress state, and the homogenization of the stress state is an important factor that influences the pull-out fractured length.

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    Deflections of Adjacent Underground Tunnel Induced by Excavation Based on Kerr Foundation Model
    FENG Guohui, XU Xing, HOU Shilei, FAN Rundong, YANG Kaifang, GUAN Lingxiao, XU Changjie
    2022, 56 (4):  474-485.  doi: 10.16183/j.cnki.jsjtu.2021.067
    Abstract ( 1855 )   HTML ( 145 )   PDF (2027KB) ( 502 )   Save

    The soil unloading effect caused by the adjacent excavation will influence both the uplift and the deformation of the adjacent existing tunnel, and even interfere with the normal operation of the tunnel. A simplified calculation method for the longitudinal deformation of the underlying tunnel caused by foundation pit excavation is proposed. The tunnel is simplified into an infinitely long Euler-Bernoulli beam resting on a three-parameter Kerr foundation model. The difference method is combined with the boundary conditions at both ends of the tunnel to obtain the longitudinal deformation difference decomposition of the tunnel. The accuracy of the proposed method is proved by comparing it with the finite element simulation method and some cases study. Compared with the tunnel simplified as the Euler-Bernoulli beam which is placed upon the existing Pasternak foundation model, the Kerr foundation model has more advantages. As the elastic modulus of soil mass and the depth of tunnel axis increase, the longitudinal deflection and the inner force of the tunnel will decrease. The inner force of the tunnel will increase with the increment of the stiffness of the tunnel.

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    Transportation Engineering
    Influence of Structural Pseudo-Static Components on Seismic Responses of Low-Medium Speed Maglev Vehicle-Bridge System
    HUANG Fenghua, CHENG Bin, TENG Nianguan
    2022, 56 (4):  486-497.  doi: 10.16183/j.cnki.jsjtu.2020.381
    Abstract ( 1889 )   HTML ( 192 )   PDF (2108KB) ( 366 )   Save

    Unlike the traditional seismic analysis on bridge engineering which mainly concerns the relative motion, the seismic analysis of vehicle-bridge system focuses more on the absolute motion of the vehicle system, where the pseudo-static components need to be considered. In order to study the effect of structural pseudo-static components on the seismic responses of low-medium speed maglev vehicle-bridge system, the discussion relying on a typical low-medium speed maglev line was implemented. Considering the vehicle-bridge coupling relationship based on the proportional integral derivative (PID) active suspension control, two dynamic models for the low-medium speed maglev vehicle-bridge system subjected to earthquake were relatively established in the relative coordinate and the absolute coordinate, and the seismic forces were correspondingly solved by employing the relative motion method and the direct solution method. A case study was subsequently conducted, where the effect of structural pseudo-static components on dynamic responses of the vehicle-bridge system, including the maglev gap, the vehicle system and the bridge was further analyzed. The results show that the influence of pseudo-static components on the dynamic responses of the vehicle system is quite significant. Ignoring the pseudo-static components could seriously undervalue the dynamic responses of the vehicle system, of which the difference could be as high as 447%. Compared to the vehicle system, the influence of pseudo-static components on the vertical and transversal displacement responses of the bridge is fairly limited. Therefore, it is suggested that the absolute displacement method which takes the pseudo-static components into account should be adopted to deal with the seismic excitation in the maglev vehicle-bridge system.

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    Feasibility of Wave Measurement by Using a Sailing Buoy and the Artificial Neural Network Technique
    QIN Yichao, HUANG Limin, WANG Xiao, MA Xuewen, DUAN Wenyang, HAO Wei
    2022, 56 (4):  498-505.  doi: 10.16183/j.cnki.jsjtu.2021.094
    Abstract ( 2013 )   HTML ( 216 )   PDF (7435KB) ( 533 )   Save

    Ocean waves have adverse effects on the operation and safety of ships. Real-time and accurate onboard wave monitoring is essential for green smart ships and navigational safety. It is an important method to use ship motion to perform inversion of the information of encountering waves, which has many advantages such as low cost and high spatio-temporal resolution, and has attracted wide attention. An inversion model based on artificial neural network (ANN) is proposed to deal with the shortcomings of existing ship motion inversion ocean wave models. Taking the motion time history of the ship as the input and the wave elevation time history as the output, the artificial neural network is used to extract the motion features of the ship, and the linear function is input to perform wave surface time history inversion. To verify the feasibility and the accuracy of the inversion model, a ship model tank test is conducted. The results show that the proposed wave measurement method based on the artificial neural network can well achieve regular wave and irregular wave elevation time history inversion. Most of the statistical errors of regular wave inversion are less than 10% and the error of irregular wave inversion is about 10%. The method proposed provides an effective and feasible means for inversion of wave time information in ship motion.

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    Numerical Simulation Strategy Optimization Analysis of Submarine Resistance and Flow Field
    LI Peng, WANG Chao, SUN Huawei, GUO Chunyu
    2022, 56 (4):  506-515.  doi: 10.16183/j.cnki.jsjtu.2020.327
    Abstract ( 2135 )   HTML ( 188 )   PDF (13748KB) ( 835 )   Save

    In order to explore the influence of different turbulence models on the resistance and flow field of an advancing submarine, based on the STAR-CCM+platform, and taking Sub-off as the geometric model, this paper adopts the finite volume method, combing 10 turbulence models to conduct numerical research on hydrodynamic and flow field characteristics of Sub-off. First, the LES-Smagorinsky turbulence model is used for the convergence of grids and time steps. Then, the appropriate grid and time step are selected to calculate 10 kinds of turbulence models in specific cases. Finally, the selected turbulence model is used to analyze the hydrodynamic characteristics and flow fields of Sub-off. The results show that there are great differences among the 10 turbulence models in the prediction of submarine hydrodynamic performance and flow field characteristics. LES-Smagorinsky can not only predict the hydrodynamic performance and the average flow field of submarine, but also accurately predict secondary variables of flow fields.

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    Rogue Wave Prediction Based on Four Combined Long Short-Term Memory Neural Network Models
    ZHAO Yong, SU Dan
    2022, 56 (4):  516-522.  doi: 10.16183/j.cnki.jsjtu.2021.088
    Abstract ( 1205 )   HTML ( 98 )   PDF (1523KB) ( 475 )   Save

    In order to improve the prediction accuracy of rogue waves of the long short-term memory (LSTM) neural network, prediction methods of LSTM with convolution neural networks (CNN), empirical mode decomposition (EMD), auto-aggressive integrated moving averagel (ARIMA) model, and Kalman filtering (KF) were studied. Based on the experimental data of the rogue waves of two single-peak and one three combined peaks, prediction models were established and predicted by data normalization, model parameter optimization and error evaluation. The results show that the prediction accuracy of the four combined models is significantly improved in all the three studied conditions, and the combination with the convolutional neural network has the highest prediction accuracy. The combined models provide a feasible scheme for improving the prediction accuracy of freak waves.

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    Numerical Simulation and Experimental Research of Sheet Hemming Forming Based on Adhesive Filling
    TANG Genglin, LI Jianjun, LI Yuanhui, ZHANG Longyao, ZHU Wenfeng
    2022, 56 (4):  523-531.  doi: 10.16183/j.cnki.jsjtu.2020.429
    Abstract ( 2025 )   HTML ( 139 )   PDF (11461KB) ( 742 )   Save

    The filling rate of adhesive is defined based on the geometric dimensions of the hemming model, and the numerical simulation model of the hemming process with adhesive is established by using the finite element method-smoothed particle hydrodynamics (FEM-SPH) method. By comparing and verifying with the hemming experiment with adhesive, the quantitative study of the influences of the hemming adhesive diameter, the edge distance, and the hemming thickness on the filling rate is realized. The research results show that the flow state and the final filling state of the adhesive layer obtained in the experiment are similar to the numerical simulation results, and the filling rate of the adhesive layer obtained in the experiment is highly consistent with the numerical simulation result, which verifies the feasibility and accuracy of the numerical simulation model. Further analysis shows that the influences of the hemming adhesive diameter, the edge distance, and the hemming thickness on the filling rate decrease in order, and the relationship formulas between the filling rate and process parameters, such as the hemming adhesive diameter, the edge distance, and the hemming thickness, are obtained by fitting, which provides a basis for the optimization design of the hemming process with adhesive of the automobile body sheet.

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    Modeling and Experiment on Roll-Hemming Forming Process of Aluminum Alloy Sheet with Adhesive
    LI Yuanhui, LI Jianjun, WANG Shunchao, ZHANG Longyao, ZHU Wenfeng
    2022, 56 (4):  532-542.  doi: 10.16183/j.cnki.jsjtu.2021.198
    Abstract ( 2014 )   HTML ( 170 )   PDF (17229KB) ( 453 )   Save

    In the roll-hemming forming process of door cover, the non-metallic flanging adhesive and the interaction between light metal and flanging adhesive will affect the manufacturing accuracy and performance of the door cover, and increase the difficulty of roll-hemming forming and quality control of automobile body sheet with adhesive. Therefore, a numerical analysis model for roll-hemming forming of aluminum alloy sheet with adhesive was proposed based on the finite element method and the smooth particle hydrodynamic (FEM-SPH) method. First, SPH was used to simulate the extrusion flow process of the flanging adhesive, and a roll-hemming simulation model of sheet metal with adhesive was established in combination with FEM. Then, an experimental platform for two-pass roll-hemming forming of aluminum alloy sheet with adhesive was built, and the roll-hemming loss and surface wave coefficient were taken as the roll-hemming forming quality index to analysis and verify the validity of the numerical model. After that, the quality change between the first pass and the last pass and the key process parameters affecting quality were studied based on the orthogonal test method. Finally, the fitting relationship between roll-hemming forming quality and process parameters was established. The results show that the roll-hemming loss and the surface wave coefficient of the last pass are reduced compared with the first pass. The process parameters that affect the surface wave coefficient in descending order are flanging height, fillet radius, TCP-RTP value, and roller diameter. The process parameters that affect the roll-hemming loss in descending order are TCP-RTP value, fillet radius, flanging height, and roller diameter. The fitting relationship can support the prediction of roll-hemming forming quality of aluminum alloy sheet with adhesive.

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