Loading...

Table of Content

    01 March 2021, Volume 55 Issue 3 Previous Issue    Next Issue
    Workpiece-Contour-Image Based Wheel Wear Online Detection Methodology
    NIU Mu, XU Liming, ZHAO Da, FAN Fan
    2021, 55 (3):  221-228.  doi: 10.16183/j.cnki.jsjtu.2019.285
    Abstract ( 1030 )   HTML ( 279 )   PDF (2908KB) ( 511 )   Save

    A method for online detection and compensation of grinding wheel wear based on machine vision is proposed in this paper. The principle of workpiece-contour-image (WCI) based online wheel wear detection is presented, and the online compensation of wheel-wear-induced contour error is analyzed, based on which, studies are conducted on the developed complex contour grinding platform. The results reveal that the proposed method can effectively detect the wheel wear in real-time and compensate the contour error caused by wheel wear to improve the machining accuracy. The research provides a new method for online detection of wheel wear and prediction of wheel dressing.

    Figures and Tables | References | Related Articles | Metrics
    Reliability Modeling and Maintenance Optimization of Manufacturing System Based on Stochastic Flow Network and Markov Process
    GAO Yingming, CHEN Zhen, ZHANG Xiufang, PAN Ershun
    2021, 55 (3):  229-235.  doi: 10.16183/j.cnki.jsjtu.2019.345
    Abstract ( 948 )   HTML ( 4 )   PDF (788KB) ( 392 )   Save

    Aimed at the uncertainty of equipment quantity and input, the defective products and its rework in the manufacturing process are investigated. Considering the influence of the number or input of the devices on system reliability, a manufacturing system reliability evaluation model is established based on stochastic flow network. The homogeneous Markov process is used to analyze the state of system degradation and maintenance. Considering the constraint of system reliability, a systematic maintenance model is proposed to minimize maintenance cost. The results of the numerical experiment demonstrate that the proposed model is effective and advanced.

    Figures and Tables | References | Related Articles | Metrics
    Fretting Fatigue of a Kind of Flexible Pin of Double Cantilever Beam
    YANG Shiping, DONG Mengyu, LI Fei
    2021, 55 (3):  236-248.  doi: 10.16183/j.cnki.jsjtu.2019.288
    Abstract ( 850 )   HTML ( 10 )   PDF (24684KB) ( 228 )   Save

    The double cantilever beam flexible pin structure with interference fit is usually adopted by the planetary gear shaft of large gear gearbox, and the interference fit structure at this location is prone to fretting fatigue. The maximum and minimum values of effective interference are theoretically calculated. Besides, the bending load process of flexible pin is simulated by using the finite element software Abaqus. In addition, the influences of bending load, interference and the depth of carburized layer on contact stress, frictional shear traction and slip amplitude are analyzed. Moreover, the influence degrees of various factors on fretting fatigue damage are investigated, and the S-N curve of flexible pin fatigue life is predicted by utilizing the SWT (Smith-Watson-Topper)critical plane theory method. Furthermore, the bending load fatigue loading test is conducted on several groups of specimens, the S-N curve of the flexible pin test is obtained, and the fretting fatigue damage morphology of the component surface is analyzed after the test. The results show that the influence of bending load on fatigue life is greater than that of the interference, and the depth of the carburized layer. The fatigue life of SWT prediction is in good agreement with the test data. Therefore, numerical simulation analysis can be used to help check the fatigue life of the flexible pin in engineering design.

    Figures and Tables | References | Related Articles | Metrics
    Effect of Silicon State on Microstructure and Properties of Al-1%Si Alloy During Severe Plastic Deformation
    TANG Jingzhao, YAN Jiawei, SHEN Yao
    2021, 55 (3):  249-257.  doi: 10.16183/j.cnki.jsjtu.2020.001
    Abstract ( 765 )   HTML ( 3 )   PDF (5520KB) ( 389 )   Save

    Alloy elements can influence the microstructure evolution of aluminum alloys in the state of solid solute atoms or nano-precipitated silicon particles, but it is still a controversial subject which form has a more significant effect on the microstructure of aluminum alloys. Therefore, taking the Al-1%Si alloy as the research object, the ratio of precipitation state and the solid solution state of the silicon atoms was changed before deformation and a multi-pass accumulative roll-bonding method was used to achieve large deformation. In order to compare the influence of solid solute atoms and nano-precipitated silicon particles on the structure and properties of aluminum alloy during deformation, a comparative study was conducted on the evolution of nano-precipitated silicon particles, grain size, and dislocation density in the process of reaching the saturation state of the microstructure and mechanical properties. The results show that the initial samples with less nano-precipitated silicon particles and more solute silicon atoms have a higher saturated dislocation density and a smaller saturated grain size after deformation, corresponding to a higher saturated yield strength. Solid solute silicon atoms dispersed in the Al-1%Si alloy have a better overall effect than nano-precipitated silicon particles of the same volume in preventing the dynamic recovery of dislocations, which is consistent with the theoretical analysis of dislocations. The dislocation recovery ability in the material affects its saturated grain size. The stronger the dislocation recovery capacity, the larger the saturated grain size.

    Figures and Tables | References | Related Articles | Metrics
    Effect of Mold Heating on High-Temperature Friction and Wear Characteristics of Uncoated 22MnB5 Boron Steel
    JIANG Yihan, WU Jiasong, WANG Wurong, WEI Xicheng
    2021, 55 (3):  258-264.  doi: 10.16183/j.cnki.jsjtu.2019.226
    Abstract ( 635 )   HTML ( 1 )   PDF (16288KB) ( 296 )   Save

    A self-developed strip-type high-temperature friction and wear test device was used to simulate the high-temperature friction process of uncoated 22MnB5 boron steel under actual hot stamping conditions. The mold was preheated to simulate the temperature increase of the die in the hot stamping process. The effects of mold temperature on the friction behavior and mechanism of uncoated boron steel were studied by using the friction coefficient test, surface wear morphology observation, and cross-section and matrix structure chart of hot stamping boron steel. The results show that the friction coefficient between the uncoated boron steel and the H13 steel is basically stable at 0.5 when the temperature of the mold is low, and the wear mechanism is mainly classified to abrasive wear and adhesive wear. Besides, when the mold temperature exceeds 100 ℃,the friction coefficient of the uncoated boron steel decreases from 0.474 to 0.414 with an increase of temperature from 150 ℃ to 200 ℃,inferring that the adhesive wear is weakened. The Vickers hardness of the boron steel matrix is approximately close to 430 from room temperature to 100 ℃. Moreover, with the temperature further rising to 150 ℃ and 200 ℃,the hardness decreases to 413.5 and 399.7 respectively, which indicates that the mold temperature has a significant effect on the mechanical behavior of formed parts.

    Figures and Tables | References | Related Articles | Metrics
    Elastic-Plastic Seismic Performance for Jacket Platform Based on Improved Modal Pushover Method
    LIU Hongbing, SUN Liping, AI Shangmao, YAN Fasuo, CHEN Guoming
    2021, 55 (3):  265-275.  doi: 10.16183/j.cnki.jsjtu.2019.204
    Abstract ( 694 )   HTML ( 0 )   PDF (1767KB) ( 282 )   Save

    In connection with the elastic-plastic failure problem of offshore jacket platform subjected to a powerful earthquake, an improved modal pushover method based on performance design is proposed. The elastic-plastic seismic performance and failure modes of the jacket platform are obtained to solve the problem of elastic-plastic performance evaluation of the offshore jacket platform in strong earthquakes. The elastic-plastic seismic responses of the platform in 8-degree seismic fortification and rare intensity are calculated by using different methods, and the differences between these responses are compared. Besides, the influences of combined modes, mode shape vectors, and uncertainties of seismic are discussed. The results show that the high-order vibration modes and mode shape vectors have a great influence on the elastic-plastic seismic performance of the platform. The first 9 or higher order modes and mode shape vectors should be adopted. The seismic-resistant weak links are located at the top of the platform in 8-degree seismic fortification and rare intensity, which should be paid more attention to. The seismic responses of the platform show significant differences and discreteness in different seismic activities, which have the same peak seismic acceleration. The improved modal pushover method is suggested to be used to evaluate the elastic-plastic seismic performance of jacket platform.

    Figures and Tables | References | Related Articles | Metrics
    Research and Test Verification of Dynamic Characteristics of Deck V-Arch Bridge
    XIE Xiaoli, PANG Mulin, QIU Chen, QIN Shisheng
    2021, 55 (3):  276-289.  doi: 10.16183/j.cnki.jsjtu.2019.284
    Abstract ( 876 )   HTML ( 0 )   PDF (11860KB) ( 290 )   Save

    To solve the problem that the natural frequency of deck arch bridges would decrease rapidly when the span increases, a novel arch bridge structure named deck V-arch bridge is proposed. The V-shaped members are added between the main girders and the arch ribs to increase the stiffness of the arch bridge, thereby increasing the natural frequency of the structure. Through the timely conversion of the structural system, the first-phase dead load is carried by the arch ribs, while the second-phase dead load and live load are carried by the variable height truss with main girders as upper chords, arch ribs as lower chords, and V-shaped members as webs, with multi-point elastic constraints. The entire structure has the advantages of arch and truss. In order to verify the correctness of the research and calculation of the dynamic characteristics of the deck V-arch bridge, a test bridge with a span of 10 m is built. The first natural frequency of the vertical bending in the plane of the bridge is tested by utilzing the pulsation test. The stiffness and dynamic characteristics are calculated by utilizing the finite element software. The influence of V-shaped member stiffness on the natural frequency and that of the number of V-shaped members on the temperature stress of the structure are analyzed. The necessity of system transformation is studied. The results show that the difference between test value and calculated value of the first natural frequency of vertical bending in the plane is small. The mode shape is in good agreement with the finite element analysis. With little or no additional material, the natural frequency of the structure is significantly increased, especially the in-plane frequency. The stiffness of the V-shaped members has a reasonable setting range. When the inner angles of the triangle formed by the main girders or the arch ribs are between 45 ℃ and 60 ℃,the number of V-shaped web members is suitable. The structural stiffness of deck arch bridge with V-shaped members is greatly improved, and at the position of L/4 (L is the span of the bridge), the upward deflection generated by the static live load of the train is approximately zero. After the transformation of the structural system, the deck V-arch bridge can fully exert the superiority of the arch force.

    Figures and Tables | References | Related Articles | Metrics
    Physics-Based Simulation of AUV Forced Diving by Self-Propulsion
    WU Lihong, FENG Xisheng, YE Zuolin, LI Yiping
    2021, 55 (3):  290-296.  doi: 10.16183/j.cnki.jsjtu.2019.191
    Abstract ( 677 )   HTML ( 6 )   PDF (4426KB) ( 425 )   Save

    It is necessary to predict accurately the maneuverability of autonomous underwater vehicle (AUV) diving by self-propulsion to improve its safety and stability. A method was presented to predict the vehicle’s forces and flow details in real time during forced diving motion. A full appended model was built, the propeller’s rotating motion was simulated, and coupled with user defined function (UDF), the Reynolds-averaged Navier-Stokes (RANS) equations were solved. This method can improve the accuracy and computation efficiency of the dynamic mesh method by using multi-block mesh with the moving zone method. The numerical method was validated by comparison of the computational and experimental results of AUV’s velocity in AUV self-propulsion test. The numerical results of AUV forced diving by self-propulsion showed that, at the initial time, the AUV had a large acceleration which resulted in a large resistance. When the pitch changed, the vertical force oscillated. The wake of the propeller twisted and the thrust of the propeller varied. In steady diving, the thrust and resistance became steady.

    Figures and Tables | References | Related Articles | Metrics
    Heterogeneous Tramp Ship Scheduling and Speed Optimization with Fuzzy Time Window
    FAN Houming, YU Jiaqi, MA Mengzhi, JIANG Xiaodan, CI Jili, ZHAI Zhiwei
    2021, 55 (3):  297-310.  doi: 10.16183/j.cnki.jsjtu.2019.215
    Abstract ( 690 )   HTML ( 1 )   PDF (1672KB) ( 332 )   Save

    In order to improve the cargo owner’s satisfaction and obtain better economic benefits for shipping companies, the ship deployment along routes and speed optimization of tramp ships are studied, considering the influencing factors of ship scheduling with the configuration and speed of self-owned ships and chartered ships. A goal is developed by minimizing sailing cost, fuel, and waiting cost at ports, penalty cost for late arrival at ports, time cost, and voyage ship chartering cost by applying fuzzy time window to characterize the cargo owner’s satisfaction. The model of scheduling and speed optimization with fuzzy time window for heterogeneous tramp ships is established. A variable neighborhood genetic simulated annealing (VNGSA) algorithm is presented to solve the problem. First, the ship type is matched with the cargo. Then the route is generated according to the time constraint. Finally, the neighborhood search strategy is adopted to improve the solution quality. Computational results indicate that integrated planning for ship scheduling and speed can reduce sailing cost; considering time requirement of cargo owners can increase their satisfaction. This paper can enrich tramp ship routing and speed optimization problems and provide a theoretical tool for shipping companies to make related decisions.

    Figures and Tables | References | Related Articles | Metrics
    Fluid-Structure Interaction Calculation Framework for Non-Rigid Airship Based on Explicit Dynamics
    ZHANG Yu, WANG Xiaoliang
    2021, 55 (3):  311-319.  doi: 10.16183/j.cnki.jsjtu.2019.351
    Abstract ( 855 )   HTML ( 2 )   PDF (3654KB) ( 322 )   Save

    The non-rigid airship is a low-rigidity and inflatable aircraft which has obvious fluid-structure interaction characteristics. In this paper, the unsteady explicit dynamic fluid-structure interaction analysis framework of non-rigid airship is constructed based on the parametric section (PARSEC) method, the radial basis function (RBF), and the Delaunay mapping method. The reliability and accuracy of the numerical method are verified by the cases of plate impact and the aeroelasticity of NACA0014 wing. The calculation framework is also suitable for unsteady bidirectional fluid-structure interaction analysis of thin-envelope aerostats such as high-altitude balloon. Finally, the time domain and frequency domain responses of one non-rigid airship are simulated by the above framework. The research results show that there is an approximately linear relationship between the dominant frequency of vibration and the pressure difference of the airship.

    Figures and Tables | References | Related Articles | Metrics
    Formation Satellite Reconstruction Strategy Based on NSGA-II Algorithm
    SUN Hongqiang, ZHANG Zhanyue, FANG Yuqiang
    2021, 55 (3):  320-330.  doi: 10.16183/j.cnki.jsjtu.2019.376
    Abstract ( 605 )   HTML ( 5 )   PDF (1602KB) ( 307 )   Save

    Aimed at the problem of avoidance strategy of formation satellites when facing the threat of space debris, a non-dominated sorting genetic algorithm (NSGA-II) is improved and used to code satellites. Besides, the improved differential evolution algorithm is used as the orbital generation model, while Pareto dominance is used to select the optimal solution set. By introducing maneuver consumption, collision probability, work efficiency, and other indicators of formation satellites, the avoidance orbits of satellite are screened to ensure that all the indicators of formation satellites are taken into account. Taking the 3-satellite formation of ocean reconnaissance satellite as an example, the phase adjustment, probability calculation, and horizontal dilution of precision (HDOP) calculation models are introduced. The optimal solution of avoiding orbits is obtained by utilzing the multi-objective optimization algorithm. The simulation results show that this method can formulate a more targeted formation satellite avoidance strategy with different objectives.

    Figures and Tables | References | Related Articles | Metrics
    Hourly Energy Consumption Forecasting for Office Buildings Based on Support Vector Machine
    XIAO Ran, WEI Ziqing, ZHAI Xiaoqiang
    2021, 55 (3):  331-336.  doi: 10.16183/j.cnki.jsjtu.2019.310
    Abstract ( 711 )   HTML ( 5 )   PDF (1001KB) ( 350 )   Save

    Aimed at the nonlinearity and uncertainty of building energy consumption, a forecasting approach based on the support vector machine is proposed in this paper for the prediction of hourly energy consumption of an office building. The univariate model test is used to determine the input parameters. Superior model hyper-parameters are found by grid search optimization. The confidence interval of the model fitting error is applied to describe the uncertainty of building energy consumption. A case study is conducted using the data collected from an actual office building to verify the proposed approach. The results show that the overall mean absolute percentage error (MAPE) of the model after grid search optimization is reduced by 31.3%, and a higher model precision is achieved. After combining the prediction with the confidence interval, MAPE is found to be lower than 1.5% in different seasons and the building operation fluctuations are embodied. This approach can be used in the diagnosis and optimization of building operation.

    Figures and Tables | References | Related Articles | Metrics
    Numerical Simulation and Uncertainty Analysis of Wave-Co-Current Interaction with Irregular Waves
    YAO Shun, MA Ning, DING Junjie, GU Xiechong
    2021, 55 (3):  337-346.  doi: 10.16183/j.cnki.jsjtu.2019.375
    Abstract ( 687 )   HTML ( 2 )   PDF (2881KB) ( 343 )   Save

    Uniform current effects on the characteristic of irregular waves along with its uncertainty are presented considering wave-current interaction in the actual ocean environment. First, relative tests of interaction of irregular wave and uniform current are conducted in the circulating water channel at Shanghai Jiao Tong University. Then, the wave elevations are measured to validate the numerical results obtained from the numerical simulation of wave-current interaction based on Reynolds-Averaged Navier-Stokes (RANS) equations. Finally, significant wave height and average period of irregular wave are selected to conduct the uncertainty analysis including both grid-convergence and time-step-size convergence studies. The results show that wave height probability distribution agrees well with Rayleigh distribution in the co-current and no-current cases. The spectral peak of irregular wave moves to the low frequency in the co-current conditions. Besides, significant wave height of irregular wave is more sensitive to grid size, while the average period is more affected by time step size. Moreover, uniform co-current can reduce the degree of dependence of significant wave height on time step size, while the influence on the average period is on the contrary.

    Figures and Tables | References | Related Articles | Metrics