Table of Content

10 August 2019, Volume 30 Issue 15

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Research on Models of Overrunning Clutch-Gear Systems Considering Dynamic Characteristics of Self-locking Components

LIU Yanwei1;ZHU Yunxue1;LIN Ziyue1;ZHAO Kegang2;HUANG Xiexin3

2019, 30(15):  1765-1775. 

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The existing dynamics models of overrunning clutchs regarded the rotational speed differences or angle differences between driving and driven parts as the only standard to recognize the engaging states. Actually, due to the self-locking part inertia, deformation factors, and interspaces between the driving and driven parts, the above mentioned models had some difficulties in accurately describing and studying the dynamic characteristics of overrunning clutchs and the transmission systems. In order to solve these problems, this paper proposed a modified modeling method considering the influences of dynamic characteristics of self-locking components through angle compensation. The modified models were established on MATLAB/Simulink platform under constant driving torque conditions and varying driving torque conditions. To validate the effectiveness and accuracy, the bench experiments were carried out. Then, the comparison between simulation and experimental results show that the overrunning clutch models with angle compensation may help to describe the dynamic characteristics of overrunning clutch-gear systems more accurately.

Study on Distracted Driving Caused by Taxi-hailing Applications

FENG Xiexing1;ZHANG Xinyu2;ZHANG Yinglin1;CAO Libo1,3

2019, 30(15):  1782-1789. 

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The impacts of the reminding and operating modes of taxi-hailing application on drivers' driving behaviors were studied. The virtual driving environment was built on the driving simulator to provide a realistic and controllable test environments, including follow-car, lane change and crisis driving tasks. APP Inventor software was used for making test taxi-hailing application to ensure that the content and timing of taxi orders was controllable. Volunteers from the group with high risk of distraction driving were recruited to carry out tests according to the test procedures. Data were recorded, such as driver's behavior, approach speed, minimum follow-up time and so on. The data were analyzed by analysis of variance(ANOVA) and Post Hoc, and the reliability evaluation model was built to evaluate the degree of driving safety under various conditions. The data of driving performances of 18 volunteers were statistically analyzed. The results show that the exhibition mode has significant influence on the reliability. And the reliability from high to low is: the text exhibition, the audio exhibition, the combined exhibition. The safest exhibition and control mode is text exhibition plus voice control operations.

Wear Model of Disc Hob Cutter Rings Based on Abrasive Wear

LIU Peilei;YANG Shiqiang;BAI Lele;LI Zhuo;LI Dexin

2019, 30(15):  1782-1789. 

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Aiming at the severe wear of the disc hobs during tunneling construction, a modeling method on disc hob cutter rings was proposed. Based on the main wear form of the disc hob-abrasive wear, the rock trajectories and the rock breaking forces were analyzed, and the wear model of the comprehensive plastic removal mechanism and the fracture removal mechanism were established. The particle swarm optimization algorithm was used to remove the two different types. The proportions of the mechanism were optimized. Through the finite element analysis software DEFORM, the hob wear simulation model was established to simulate the actual working conditions and calculate the wear of the disc hobs. The results show that the errors between the calculated values and the actual engineering ones are less than 20%, which indicates that the wear model has good accuracy and may be used for the calculation of tool wear.


Research on Vehicle Rollover Warning Based on Secondary Predictive Lateral Load Transfer Ratio

JIN Zhilin1,2;YAN Zhenghua1

2019, 30(15):  1790-1795. 

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Accurate warning might effectively reduce vehicle rollover accidents. To solve the contradiction between model complexity and warning accuracy of algorithm of vehicle rollover warning, a rollover warning method based on secondary predictive lateral load transfer ratio for vehicles was proposed herein. A linear three-degrees-of-freedom dynamics model of sport utility vehicle(SUV) rollovers was established to calculate the lateral load transfer ratio, the primary predictive lateral load transfer ratio, and the secondary predictive lateral load transfer ratio using the dynamics theory of vehicle rollovers. Then, the theoretical solution of time to rollover of the vehicles was deduced from the secondary predictive lateral load transfer ratio. Furthermore, the characteristics of time to rollover(TTR) were demonstrated by simulations of SUV at high-speed under both tripped and untripped rollover conditions. The results show that the proposed rollover warning method based on the secondary predictive lateral load transfer ratio may accurately calculate TTR. Therefore, the active safety of vehicle rollover prevention may effectively be improved.

Effects of PFI Parameters on Mixture Formation for High-speed Gasoline Engines

SUN Cheng1;ZHANG Yi2;JIANG Wu1;YANG Jing1;MING Yang1

2019, 30(15):  1796-1803,1812. 

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The effects of different injection parameters on the mixture formation of a high-speed PFI gasolines were studied at full speed and full load conditions using the methods of combined with CFD numerical simulations and experiments. The results show that under the conditions of high speed, more nozzles and smaller nozzle diameter may significantly reduce the formation of the attached oil film and increase the equivalent ratio; The effects of fuel injection angle on equivalent ratio are remarkable, and the equivalent ratio of the larger injection angle is significantly lower than the smaller, and after injection angle reduced to a certain extent the equivalent ratio decreases with the decreasing of the injection angle; there is less attached oil film and larger equivalent ratio in semi-open injection mode compared with closed valve injection; Compared with the single injection, the equivalent ratio of split injection has no obvious differences.

Research on Reliability of Sliding Bearings of Nuclear Main Pump Motors Based on Small Samples

YANG Shiping1;TAN Bosi1;XIA Tianyu1;ZHU Jie2;DING Qiangming2

2019, 30(15):  1804-1812. 

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In order to study the reliability of the sliding bearings of nuclear main pump motors, under the conditions that a small number of sub-samples could not carry out a large number of complete machine tests, the working conditions of the sliding bearings of the nuclear main pump motors were analyzed, the failure modes were determined and the fault tree was drawn. The ANSYS software was used to simulate and analyze the bearing forces of important bearing units, and the stresses distribution of the units were solved. According to the stress-strength interferometry methods, the reliability of the units was obtained by Monte-Carlo sampling methods. The reliability of other units was obtained by the data manual methods. Then, the overall reliability of the bearings was obtained. Several samples of the reduced thrust bearing shoe model and the original size cooler of a few prototype bearings were tested to verify that the sliding bearings of nuclear main pump motors meet the engineering reliability requirements.

Study on Multi-disciplinary Design Optimization on Civil Turbofan Engines

LUO Ju;GUO Fushui

2019, 30(15):  1813-1820. 

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In order to take account of the couplings of various disciplines and balance the conflicts of different indicators, a multi-disciplinary design optimization platform was built based on collaborative optimization strategy for the civil high bypass ratio turbofan engines in the conceptual design phases, which included analysis and estimation modules of thermodynamic cycle, size/mass, fuel consumption, NOx emission, noise, component aerodynamics and structure strength. Based on NSGA-Ⅱ (non-dominated sorting genetic algorithm Ⅱ) algorithm, a multi-objective optimization study of engine scheme designs was conducted. Through the researches, the following conclusions are obtained: bypass ratio and turbine inlet temperature have greater effects on the fuel consumption and total weight. Besides, the distribution of the fuel consumption and total mass in Pareto solutions is similar to a conic.

Multi-physics Coupling Analysis and Experiment of Elevator MRB

ZHENG Xiangpan1,3;GUO Yuanfan2;TANG Xiaoteng1;CHEN Shumei3

2019, 30(15):  1821-1827. 

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A MRB with dual-coil structures was designed. The requirements of elevators with large braking torques and good heat dissipation were met by the structures. Based on the mathematical physics method, the multi-physics model of elevator MRB was established in COMSOL Multi-physic finite element software, namely the static magnetic field, flow field and rotor dynamics equation, the mathematical model of coupled to each other. The model was used to research dynamic simulation, the braking torque, braking time, temperature changes and dynamic performance of the magneto-rheological braking device under different current and rotational speed were revealed. Finally, experimental verification was carried out, the simulation results were consistent with the experimental ones.

Research on Reverse Logistics Model and Network for Used Electric Vehicle Batteries

ZHU Lingyun;CHEN Ming

2019, 30(15):  1828-1836. 

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A study on the reverse logistics model and network of the used electric vehicle（EV） batteries which were from Shanghai Automotive Industry Corporation(SAIC) Group's EVs was carried out. The fuzzy comprehensive evaluation method was employed to establish the analytic model and indicator system for the choices of reverse logistics model and network building. The results indicate that the self-operated option is totally the most suitable model for SAIC Group's battery recycling. In terms of specific indicator systems, the self-operated model has outstanding advantages in economy and management factors, and the outsourcing model has obvious superiorities in technology factors. Finally, in accordance with the advantages and characteristics of the models, a self-operated model-based composite recycling network for SAIC Group's battery recycling was established with the analysis of stakeholders and the reverse logistics processes.

Robust Optimization Model and Algorithm for Polymorphic Shop Layouts Considering Layout Entropy

CHEN Yong;CHENG Ziwen;JIANG Congcong;WANG Yaliang;WANG Cheng;LI Shiyun

2019, 30(15):  1837-1848. 

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In order to meet the multi-variety and small-batch markets' demands and dynamic fluctuating customers' demands under mass customization and industrial cluster, and to meet the low cost and high robustness layout requirements of workshops,a multi objective layout optimization model was designed which included unit area layout cost, unit product logistics cost and layout entropy. A clustering parallel multi-objective genetic algorithm was proposed based on Pareto optimization. Fuzzy C-means clustering algorithm was introduced to improve the diversity and uniformity of Pareto solution set distributions. The multiple cell differential evolution re-insertion operation and the migration operation based on “elite strategy” were designed to enhance the global and local search ability of the algorithm, and effectively avoid the phenomenon of precocity. By comparing the typical examples, the validity of the algorithm and model was verified. In addition, the model may provide high practicability in real layout applications since it may reach the aim of low cost, and control the entropy of workshops within an ideal range.

Optimization of Forming Specific Energy of Metal Hot Extrusion Based on DOE and Data Analysis

LI Hongcheng;MA Guoxi;LUO Rong;LUO Zhiyong

2019, 30(15):  1849-1855. 

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In order to reduce the energy consumption of metal extrusion forming stages, a robust optimization model of forming specific energy consumption with the control variables such as initial temperature, length of the aluminum bar, extrusion speed, extrusion temperature, and die angle was proposed by using thermal conductivity and material strength coefficient as disturbance varibales  based on DOE and data analysis model. Furthermore, thermal equilibrium constraints equivalent equation was established in the robust optimization model. Results show that even though the extrusion forming is constrained by thermal equilibrium and controlled by multi-parameters, the proposed robust optimization model also may reduce the energy consumption and simultaneously guarantee the product quality.

A Material Recommendation System for  Enterprise Manufacturing Integrated Systems

WU Wenli1;FAN Xiaopeng2;ZHOU Gengshen1;HUANG Yi1;CAO Yang1;LIN Guichan1

2019, 30(15):  1856-1865. 

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Aiming at providing effect informations efficiently for appropriate users in the integration systems of enterprise manufacturing who was faced excessive search volume, information overload, time-consuming manual filtering, and no approximate query support problems, a product-user recommendation model was proposed and a recommendation system available for integrating was implemented. This recommendation model combined contents based on filtering and collaborative filtering. In the aspect of items, the specific forms of the recommended items were considered, all the characteristics of the BOM including parts, semi-finished products, products were comprehensively analyzed, and new metric methods were proposed based on content similarity, BOM-based similarity and the integration. Different items selected different methods to define the approximate distances which were the foundation of subject clustering or classification according to the specific circumstances. While in the aspect of users, the user interests were quantified and the user approximation formula were defined according to the characteristics of the production systems. Finally, this paper implemented the recommendation platform in the form of a system suite, considering cold start problem by introducing the latest research results. Experiments show that the system may accurately recommend the items that meet their needs for users and it is an important supplement for current manufacturing systems for obtaining information efficiently.

Finite Element Simulation Analyses and Tests on Internal Temperatures of Electrical Connectors under High Temperatures

GAO Cheng;ZHANG Rui;HUANG Jiaoying;ZHAO Dong

2019, 30(15):  1867-1872. 

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Simulation, experimental design and influential factors analysis were carried out, in view of the difficulties to measure the internal temperatures of the electrical connectors and the inaccurate measurement results, taking Y2 type electrical connectors as the research objects. Three-dimensional model was conducted by SolidWorks, thermal-electric coupling finite elements simulation was implemented by ANSYS, and then temperature rise and temperature field distribution were analyzed under different environmental temperatures. A set of internal temperature test systems was designed, actual internal temperatures of electrical connectors were measured and the experimental data show a good agreement with simulation results. The influences of number of cores, current and contact resistance on internal temperatures of electrical connectors were simulated, and the results show that the maximum temperatures increase with the increases of the three factors.

Research Progresses on Cast-rolling Bonding Technology of Laminated Metal Clad Strips

JI Ce1,2;HUANG Huagui1,2;SUN Jingna1,2;LIU Wenwen1,2

2019, 30(15):  1873-1881. 

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The development background and significance of cast-rolling bonding technology for laminated metal clad strip were introduced herein. The development status and research results of solid-liquid cast-rolling bonding processes and liquid-liquid cast-rolling bonding processes in recent years were summarized. The bonding mechanism differences among the traditional solid-solid bonding, solid-liquid bonding and the cast-rolling bonding were compared and analyzed. Combined with research status, the developments of the cast-rolling bonding technology for laminated metal clad materials were forecasted in terms of product specifications, product types, interface performance controls, and whole life cycle theory et al.

Friction Stir Welding Deformation Behaviors of Large Thin-walled Aluminium Alloy Structures with Different Clamping Restraints

TANG Yibo1;SUN Hongbo2;YU Haidong1;ZHENG Bin1;LAI Xinmin1

2019, 30(15):  1881-1889. 

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The stress mapping method was applied to simulate the welding processes of FSW for large thin-walled aluminum alloy structures. The calculation accuracy of this method was verified by experiments as well as the mechanism of welding distortion was studied. Then, the influences of different fixture constraints on the welding distortions of large thin-walled structures with different sizes were investigated. The results show that the stress gradient along the thickness of the welded parts before releasing the clamp is the main reason for the longitudinal warping deformations of thin plates by FSW. For general welded parts, the welding deformations may be reduced effectively with a smaller restraint distance. With the increase of the dimension of the welded parts, the welding deformations increase obviously, and the influences of the clamping positions on the deformations become more apparent.