上海工程技术大学学报

Fracture analysis of ductile fracture of AA6063 aluminum alloy

LI Hanlin, HE Tao, HUO Yuanming, GAO Jianye, LI Shiqian, JIA Dongsheng

2021, 35(3): 197-200.

Abstract:
In order to explore the ductile fracture mechanism of AA6063 aluminum alloy, a series of ductile fracture tests were carried out, and the ductile fracture morphology of AA6063 aluminum alloy specimens under different stress triaxiality was observed. The results show that the higher the stress triaxiality, the faster the nucleation, growth, and convergence of the holes, and the larger and deeper the holes. The mode of dominant ductile fracture of specimens under different stress triaxiality is also different. The fracture of notched cylindrical tensile specimens is dominated by dimple fracture, and the fracture of grooved plate tensile specimens is co-dominant by dimple fracture and shear fracture. The cylindrical torsion test fracture is mainly dominated by shear fracture and there are some dimple fracture characteristics on the surface of the specimens.

[Abstract](457) [FullText HTML] (1013) [PDF 938KB](444)

Application of glass and glass-ceramics in solid oxide fuel cell

WANG Kun, SU Yu

2021, 35(3): 201-207.

Abstract:
The application requirements of glass and glass-ceramics as solid oxide fuel cell (SOFC) sealing materials were described. An attempt was made to classify the glass and glass-ceramics used in SOFC, and the sealing glasses for SOFC based on different systems (silicate sealing, borosilicate sealing, aluminosilicate sealing and boroalumino-silicate sealing) were introduced. The development trend of glass and glass-ceramics in SOFC was prospected.

[Abstract](540) [FullText HTML] (276) [PDF 961KB](295)

Effect of quenching and partitioning process on texture and properties of high strength Q&P steel

LI Boyan, SU Yu, ZUO Zhicheng, LI Jun

2021, 35(3): 208-214.

Abstract:
The microstructure, texture, mechanical properties and tensile fracture characteristics of quenching and partitioning (Q&P) steel were studied at different quenching temperatures (220, 260, 300 ℃) and quenching times (60 , 120 , 180 s) in one-step Q&P process. The results show that the maximum volume fraction of residual austenite（RA）obtained in one-step Q&P was 7.12%. With the increase of quenching temperature, the width of lath martensite increased. With the increase of quenching temperature and partition time, the maximum strength of the texture decreased, so did the tensile strength, while the yield strength and elongation showed opposite trends.

[Abstract](383) [FullText HTML] (273) [PDF 1360KB](185)

Research status of dissimilar welding-brazing of aluminum to copper

XU Wenhu, YANG Jin, XIAO Ming, PENG Mingjian, ZHAO Yixuan, LIU Hongbing, LU Hanlong

2021, 35(3): 215-228.

Abstract:
Due to the great difference in physical and chemical properties between aluminum alloy and copper dissimilar metals, the strong oxidation property of aluminum alloy and other factors, it has become a difficult point in the welding field of dissimilar metals joining. The research status of aluminum/copper dissimilar metal welding-brazing in recent years and weldability of aluminum and copper dissimilar metal were reviewed, common problems of the aluminum/copper dissimilar metal welding-brazing were discussed. Appropriate welding process with adjustment of alloy elements is the key to solve the problem of aluminum/steel dissimilar metal welding and brazing, and the research and development in this field are prospected and reviewed.

[Abstract](505) [FullText HTML] (436) [PDF 2282KB](196)

Dynamic modeling and analysis of diesel engine valve mechanism

ZHOU Yufeng, ZHANG Haibo, ZHANG Hengyun

2021, 35(3): 229-236.

Abstract:
Finite element analysis of engine valve mechanism is very necessary in modern mechanical design as an important support for basic experiment. Aiming at the optimal design of the performance for in-line four-cylinder diesel valve mechanism, the key thermodynamic and dynamic parameters of diesel engine were calculated and determined systematically. Firstly, the dynamic model of valve mechanism was established by using multi-body dynamic method, the finite element analysis results of static stress were calculated, and the module parameters in the dynamics model of parts were obtained. Then, Sharp 3D software was used to analyze the dynamics of the valve mechanism, and the camshaft strength of the valve mechanism was analyzed and optimized based on the analysis parameters. Finally, the main parts of the mechanism were analyzed through the finite element analysis function. The results show that the analysis results of the dynamics model of the valve mechanism are reliable, which are beneficial to the improvement and optimization of the dynamics design and performance parameters for the diesel engine valve mechanism.

[Abstract](351) [FullText HTML] (242) [PDF 1207KB](125)

Research on target tracking based on improved optical flow method

LIU Xiangqian, YAN Juan, YANG Huibin, JIA Xiwei

2021, 35(3): 237-242.

Abstract:
In view of the low operating efficiency of the optical flow method in tracking motion video sequences and the problem that the video sequence can only be processed in real time, designing a method based on optimized particle filter and optical flow method. Firstly, the algorithm strategy uses the method to find its target point, applys adaptive positioning to obtain the target central situations, and then processes the obtained video sequence with optical flow, then predicts the centroid movement information through particle filtering. Finally, in terms of the algorithm with the optical flow strategy, ViBe and YOLO algorithm, and track various video sequences and all kinds of objects in different situations. Test and simulation datas prove that the optimization strategy can not only effectively enhance the efficiency 13.7 percent and precision of target tracking 5.2 percent, but also demonstrate better anti-interference performance.

[Abstract](458) [FullText HTML] (489) [PDF 1429KB](333)

Customer interruption cost estimation model based on bidirectional search algorithm

HU Jincai, ZHANG Jing, WANG Dalong, LYU Wei, OUYANG Wenan

2021, 35(3): 243-247.

Abstract:
Accurate and fast estimation of customer interruption cost plays an important role in distribution network optimization and planning. A customer interruption cost estimation model based on bidirectional search algorithm was proposed, the bidirectional search algorithm was combined with the customer interruption cost estimation model through programming. Firstly, the fault rate of the circuit breaker was taken into account in the bidirectional search algorithm, so as to be closer to the real situation; then the average failure rate and average duration of failure of each load point were calculated, the average failure rate and average duration of failure were substituted into the customer interruption cost model, the customer outage loss of each load point was obtained ; finally, the total customer interruption cost was obtained by adding the customer outage losses at all load points. Taking feeder F4 in IEEE-RBTS BUS 6 as an example, the effectiveness of the model was verified.

[Abstract](253) [FullText HTML] (257) [PDF 680KB](89)

Study on reliability of metro vehicle doors based on exponential distribution and RAMS

ZONG Zhixiang

2021, 35(3): 248-252.

Abstract:
For the purpose of preventing and reducing metro door failures, an exponential distribution function was used to analyze the door failure time intervals based on statistical data of three-year door failures on Shanghai metro line 13. Combined with the reliability theory in RAMS, the reliability of doors in three years was analyzed, and a method to determine the preventive maintenance cycle of doors with the comprehensive reliability of train doors as the goal was put forward. The results show that the three-year door failure time interval obeys exponential distribution function and door failure rate determines the reliability of the door. The smaller the door failure rate, the higher the reliability of the door and the longer the working time of the door; otherwise the shorter the working time of the door. It was suggested that in addition to the daily necessary maintenance of train doors, dynamic preventive maintenance cycle can be obtained according to the annual door failure data, so that the preventive maintenance cycle can be set in a specific year, thus improving the reliability of train doors. The method can provide a reference for improving the reliability of the door.

[Abstract](329) [FullText HTML] (263) [PDF 884KB](113)

Ethanol conversion over La₂O₂CO₃/ZnO catalysts prepared by two methods: Effect of macroporous structure and basic sites

YU Hongyan, SHIN Eunwoo, MEN Yong

2021, 35(3): 253-258.

Abstract:
In this work, we prepared the La₂O₂CO₃/ZnO catalysts by two different methods-co-precipitation and ethylene glycol combustion method, whose catalytic performance of the dehydrogenation of ethanol to acetaldehyde as well as materials’ properties related to the catalytic behavior through FE−SEM, HR−TEM, FT−IR, XRD, N₂ adsorption/ desorption technique were investigated. The catalyst synthesis method had greatly influenced the morphology and performance, with materials prepared through solution combustion method better in terms of ethanol conversion resulted from the macroporous structure. Characterization results based on CO₂−TPD revealed that catalyst synthesized through co-precipitation or solution combustion method allowed correlation of acetaldehyde selectivity with basicity.

[Abstract](263) [FullText HTML] (268) [PDF 1852KB](134)

Review on influencing factors of green clothing purchasing behavior

LIU Xin, FANG Yuan, LI Pei

2021, 35(3): 259-265.

Abstract:
In order to understand the formation mechanism of consumers’ green clothing purchasing behavior, relevant domestic and foreign researches on green clothing purchasing behavior were sorted out. The definition of green clothing purchasing behavior was reviewed, and influencing factors of green clothing purchasing behavior were summarized, After that, the formation mechanism of green clothing purchase behavior was explored based on the theory of planned behavior and motivation-opportunity-ability. Then Future research direction and development trend were put forward from the perspectives of psychology, individual, environment and product in the end. Subsequently, the existing theoretical extension research model can be integrated to conduct in-depth research on consumers' green clothing purchase behavior, explore the value of green clothing consumption, and also provide reference for related research.

[Abstract](344) [FullText HTML] (278) [PDF 715KB](250)

Objective Bayesian analysis of zero-and-one-inflated geometric distribution

XIAO Xiang, GU Xi

2021, 35(3): 266-271.

Abstract:
Count datas with excess zeros and ones arise frequently in various fields such as medical health, finance and securities. In order to fit these datas better, a zero-and-one-inflated geometric distribution model was proposed and the objective Bayesian analysis was carried out. Based on parameter transformation, the Jeffreys prior and the reference prior were derived for this model. For different sample size and different true values of the parameters, simulations were adopted to assess the performance under the different objective priors through the sampling algorithm.

[Abstract](334) [FullText HTML] (321) [PDF 659KB](268)

Dynamics characteristics of circular restricted three-body problem

LIU Wenfang, HU Shiyang, LIU Fuyao

2021, 35(3): 272-280.

Abstract:
The forbidden zone has a significantly important influence on the motion of the third body in the circular restricted three-body problem. Based on zero-velocity curves, the relationship between the forbidden zone of celestial bodies and dynamical parameters was discussed. It was obtained that the forbidden zones are related to the Jacobian constant, and can affect motion areas of celestial bodies and dynamical types of orbits. The maximum Lyapunov exponents were used to find chaotic orbits, and the distributions of chaotic orbits with respect to the initial positions of the celestial bodies for different dynamical parameters were given. These distributions indicate that when the third celestial body is released from the midpoint of the two main celestial bodies, chaos easily occurs. However, there is no chaos when the mass parameter is small sufficiently.

[Abstract](453) [FullText HTML] (303) [PDF 1223KB](170)

Application of randomized low-rank approximation algorithm in recommendation system

CHEN Xi, DENG Jiechen, XI Shihong, LIU Xiaochen, ZHANG Xiangjun, FENG Yuehua

2021, 35(3): 281-284.

Abstract:
In view of the problem that with increasing large amount of datas in a recommendation system, the computing efficiency of its corresponding matrix completion algorithms need to be improved. Based on randomized algorithm strategy and efficient data access requirements, a new algorithm for solving matrix completion problem was proposed, and the Matlab software was employed to realize the algorithm. The numerical experiment result shows that the new algorithm can speed up the computing efficiency of original one by about 30%.

[Abstract](252) [FullText HTML] (220) [PDF 690KB](91)

E-commerce infringement monitoring system based on big data and machine learning algorithm engine

LI Jiaqi, DONG Xiangxu, LI Yunxia

2021, 35(3): 285-289.

Abstract:
Based on big data and machine learning algorithm engine, a design scheme of intellectual property dynamic monitoring network system for e-commerce platform was put forward. Focusing on the design of big data remote acquisition system, real-time data monitoring and analyzing platform as well as the core algorithm engine model. The remote acquisition system of network big data includes the remote server platform and big data distributed acquisition program. The system uses Web information crawler to accurately collect all relevant datas of major businesses, network platforms and so on. The data monitoring and analyzing platform converts the relevant algorithms such as deep learning, word embedding and common representation of information into programs to analyze and process the intellectual property information involved by the collected data to digitize goods. Based on the traditional public opinion analysis and natural language processing technology, its core algorithm engine builds commodity features and the user opinion mining model, so as to realize the functions of search, analysis, preservation and prediction of intellectual property data of e-commerce products. The system can effectively reduce the cost of infringement and anti-counterfeiting, thus to establish a reliable channel for brand merchants to protect their rights and intellectual property rights.

[Abstract](351) [FullText HTML] (259) [PDF 2038KB](333)

An empirical research on regional development of higher vocational education based on factor analysis

ZHANG Ruijuan, YI Li, LU Jiahua

2021, 35(3): 290-294.

Abstract:
Focusing on “expansion and quality improvement” of higher vocational education, factor analysis method and provincial cross-section data were used to conduct empirical research on the regional development of China’s higher vocational education from three dimensions of school scale, school quality and funding input. At the national level, Jiangsu, Guangdong and Shandong are the leading provinces. At the regional level, the east and central are generally superior to the west. However, subdivision results show that the western needs to consolidate basic elements, as while as the eastern and central should further improve education performance. Based on the industrial characteristics of different regions and the institutional advantages of China, some suggestions were put forward from three aspects of government policy and financing, integration of industry and education and regional coordination.

[Abstract](298) [FullText HTML] (372) [PDF 973KB](154)

2021 Vol. 35, No. 3