上海工程技术大学学报

Discussion on some problems of small face impact bonding effect

WU Qichang, HE Jianping

2021, 35(4): 295-304.

Abstract:
Impact bonding has attracted much attention due to its excellent performance. In order to understand impact bonding effect with small face, the interface morphology by impact welding was investigated, the affecting of interface morphology on mechanical properties of welds was discussed, and it is indicated that the wavy interface is important for a reliable weld. In addition, based on bonding process of impact welding workpiece with large face, the formation mechanism of wavy interface was further analyzed. On this basis, the formation mechanism of wavy interface produced for impact welding workpiece with small face was discussed. It is indicated that an artificially set collision angle is necessary to form a wavy interface. Moreover, it is proposed that the effective method to solve the asymmetric problem occurred in impact welding workpiece with small face is to change the bonding surface of flying plate with conical bonding face.

[Abstract](751) [FullText HTML] (741) [PDF 1214KB](1738)

Progress in research methods of microstructure evolution during welding solidification

JIN Shuode, HE Jianping, PAN Xuehang

2021, 35(4): 305-314.

Abstract:
The final microstructure of welding joint is affected by microstructure evolution during welding solidification, and then it affects mechanical properties of welding joint. Experimental-based analysis methods such as Gleeble thermal simulation experimental method, comparisons of microstructures in different areas for welding joint on microstructure evolution analysis method, microstructure evolution analysis method based on chemical composition changed, in-situ observation of synchrotron radiation were discussed. And then, theoretical-based methods of microstructure evolution during welding solidification such as phase field method, cellular automata method, Monte Carlo method were analyzed, and it obtains that these seven methods which are analyzed microstructure evolution during welding solidification have their own advantages and disadvantages.

[Abstract](759) [FullText HTML] (718) [PDF 997KB](912)

Multi-objective optimization of process parameters of 45 steel laser cladding Ni60 alloy powder

JI Youdi, GONG Hongying, XU Peiquan

2021, 35(4): 315-320.

Abstract:
In order to extend the service life of the parts and reduce the production costs, the laser cladding of the Ni60 molten coating layer on the 45 steel surface can meet the production requirements, avoid the waste of resources and achieve green manufacturing. The weights were determined by analytic hierarchy process and a three-level, three-factor orthogonal test was established to analyze the macro and micro morphologies, friction wear characteristics and micro hardness of the molten coating layer. The results show that the optimized process parameters are laser power of 3 kW, a scanning speed of 12 mm/s and overlap rate of 45%. The suitable process parameters can refine the tissue grain and avoid the generation of cracks and pores. The coating obtained by optimizing the process parameters has better wear resistance, lower friction coefficient, less wear weight loss than the base, the wear mechanism is abrasive wear and the hardness is three times that of the base.

[Abstract](972) [FullText HTML] (467) [PDF 1336KB](712)

Research on sensorless control strategy of PMSM

HE Zheng, MA Xipei, FAN Pingqing, ZHAO Heng, WANG Yansong

2021, 35(4): 321-326.

Abstract:
Aiming at the problems of overshoot, chattering and slow response in the sensorless control system of permanent magnet synchronous motor (PMSM) for electronic water pump, PMSM sensorless control algorithm based on hybrid sliding mode speed controller and Luenberger observer was proposed. In the speed loop, a sliding mode speed controller based on the new reaching law was designed. On the basis of the traditional exponential reaching law, the motion error of the moving point was introduced into the constant velocity term, and the hyperbolic tangent function was adopted to replace the comparison switching function, so as to improve the convergence speed and chattering suppression ability of the sliding mode. The Luenberger observer of the linear control structure combined with the phase-locked loop was applied to the sensorless control system, in order to improve the chattering problem and stability of the estimated speed. The simulation results show that under the no-load starting and external disturbance conditions of the motor, the algorithm can effectively improve the speed tracking effect of PMSM sensorless control system, improve the speed overshoot and chattering problems, and enhance the anti-interference ability of the system.

[Abstract](956) [FullText HTML] (753) [PDF 1466KB](819)

Fractional-order sliding mode control of robotic arms with boundary layer

LIU Shijie, HUANG Zhilai, YANG Mingxing, XU Peimin

2021, 35(4): 327-332.

Abstract:
For the robotic arm system with perturbation, the fractional-order calculus was introduced to construct a fractional-order sliding mode surface based on classical sliding mode control. While a boundary layer had set in the reaching law, and the sign function was replaced with the saturation function to weaken chattering phenomenon of the sliding mode surface to obtain a fractional-order sliding mode control of robotic arms with boundary layer, and its convergence had proved by the direct method of Lyapunov. Example with a two-degree-of-freedom robotic arm system as the controlled object, the simulation result shows that the fractional-order sliding mode control of robotic arms with boundary layer can achieve better convergence and accurate trajectory tracking by adjusting the differential order compared with the classical sliding mode control.

[Abstract](755) [FullText HTML] (633) [PDF 948KB](435)

Study on relaxation rule of over temperature creep stress in superheater tube of ultra-supercritical boiler

LIN Qidie, YAN Zhenrong, WANG Huanan, CHEN Le, WEI Jingtao

2021, 35(4): 333-339.

Abstract:
The superheater tube in the outlet area of the high-temperature superheater box of ultra-supercritical boiler is easy to be exposed to overtemperature environment, resulting in creep stress relaxation and material failure. Based on Norton creep model, the stress relaxation behavior and creep distribution of T91 superheater tube wall during long-term thermal induction were simulated under the operating conditions of flue gas temperature of 750℃, steam temperature of 600℃ and steam pressure of 26 MPa. The simulation results show that stress relaxation phenomenon of the heat pipe firstly occurs on the inner wall and spreads along the radial direction with time accumulation. After 10000 h, the inner wall surface appears stress relaxation and relaxation accelerates. At the same time, high temperature creep behavior also occurs on the tube wall during the stress relaxation process, and the creep behavior firstly appears on the inner wall and spreads along the radial direction, and the creep degree of the inner wall is higher than that of the outer wall. After 10000 h, the thickness of pipe wall begins to decrease. The results show that the overtemperature operation of superheater tube of ultra-supercritical boiler for 10000 h is the time point from creep stress relaxation to creep damage.

[Abstract](2306) [FullText HTML] (610) [PDF 1896KB](767)

Numerical simulation and test analysis of magnetic field in 500 kA aluminum electrolyzer

LI Shangwei, DENG Shengxiang, KUANG Jianghong

2021, 35(4): 340-345.

Abstract:
Using 3D modeling of SolidWorks and 3D simulation software of COMSOL, the numerical simulation of 500 kA aluminum electrolyzer was carried out. A magnetic field test on 500 kA aluminum electrolyzer of a manufacturer is carried, and the test results are in good agreement with the simulation results. The magnetic field distribution of 500 kA aluminum electrolyzer was obtained and optimized, the influences of the column bus bar and groove bus bar on the molten aluminum layer are reduced by increasing the distance between the column bus bar and aluminum electrolyzer as well as the distance between the groove bus bar and aluminum electrolyzer. After the optimization, the magnetic field distribution of the molten aluminum layer tends to be uniform and stable along the Z-axis direction. The simulation and test provide technical support for improving the technical conditions of production process.

[Abstract](764) [FullText HTML] (714) [PDF 1101KB](283)

Research progress on detection technology of large-size aircraft parts

LI Binpeng, MAO Jian

2021, 35(4): 346-353.

Abstract:
Large-size aircraft parts have complex structure and huge external dimension characteristics. In view of the research of large-size measurement technology in the aircraft manufacturing process, five kinds of detection technology methods for large-size parts, like three-coordinate measurement method, LIDAR measurement method, indoor GPS measurement method, laser tracker measurement method and machine vision measurement method were proposed. The applicable fields and respective advantages and short-comings of five detection methods were analyzed. The visual measurement which can achieve real-time measurement has non-contact, high precision and efficiency characteristics. It has a great prospect in the field of aviation measurement. It was pointed out that vision measurement technology is research direction in large-size measurement. A series of issues such as the theoretical models establishment, detection parameters optimization and real-time feedback need to be further studied in the future.

[Abstract](1140) [FullText HTML] (714) [PDF 1011KB](535)

Research status of GIS application in highway engineering field based on knowledge graph

TIAN Xueze

2021, 35(4): 354-361.

Abstract:
In order to gain insight into current status and hotspots of geographic information system (GIS) application research in the field of highway engineering in our country, relevant documents in the CNKI database from 2010 to 2020 were used as data sources, and softwares such as COOC, GIGO, SPSS and UCINET were used comprehensively. The research topics of high-frequency keywords in the field were classified through clustering tree diagram analysis, factor analysis and multi-dimensional scale analysis; the social network analysis method was used to draw the co-occurrence network map and centrality analysis of the key words to reveal its research hotspots and structure intuitively. The results show that the hot keywords of GIS research are route design, slope geological hazard susceptibility evaluation, landslide monitoring, pavement management system and so on. Research topics can be divided into three main categories namely: GIS diversification research and application, road transportation network and geological disaster evaluation, road management information and visualization.

[Abstract](1082) [FullText HTML] (502) [PDF 1001KB](377)

Fuzzy comprehensive evaluation of civil aircraft operational requirement based on AHP-entropy method

CHU Shuanglei, WEI Zhiqiang, REN Qiang, LIU Fei

2021, 35(4): 362-369.

Abstract:
At present, the evaluation index for the demonstration program of civil aircraft operation requirement is not comprehensive and complete, and it is difficult to identify key indicators that affect the quality and competitiveness of civil aircraft products. On the basis of analyzing the operational environment and operational mission of civil aircraft, an index system of operational requirements for civil aircraft was established from six dimensions of aircraft adaptability, aircraft usability, equipment matching, maintenance rationality, aircraft advancement and dispatch reliability. The subjective weight and objective weight of the index were considered by the AHP-entropy method. The weight of each index was obtained, the membership degree of the index was determined by fuzzy set method, and fuzzy comprehensive evaluation matrix was constructed. A model for fuzzy evaluating the operational requirements of civil aircraft was proposed, an example of B737−800 was used to verify the rationality and feasibility of the evaluation model. The result shows that the model can reflect technical indicators of civil aircraft operation requirements and realize comprehensive evaluation of operational needs of civil aircraft.

[Abstract](771) [FullText HTML] (487) [PDF 715KB](259)

Study on preparation and anti-UV properties of TiO₂ film on terylene

CHENG Ya, CHEN Zhuoming, ZHENG Yuansheng, XIN Binjie

2021, 35(4): 370-376.

Abstract:
Titanium dioxide/polyester (TiO₂/PET) ultraviolet (UV) resistant fabric was prepared by deposition of titanium dioxide on the surface of polyester fabric by magnetron sputtering. The effects of magnetron sputtering time and sputtering power on the UV resistance of the fabric during the preparation process were investigated. The UV absorption and shielding mechanism of TiO₂ thin films were analyzed, and the thermal insulation and thermal stability of the fabric were also detected. The results show that TiO₂ film deposited on the surface of PET can improve the UV resistance of the fabric, which is attributed to the good UV absorption capacity of TiO₂ film and the effective shielding ability of UV visible light. In addition, the roughness of TiO₂ film increases and the thickness decreases when the sputtering power is greater than 150 W, so when the sputtering power is 150 W and the sputtering time is 90 min, TiO₂/PET fabric has the strongest UV resistance, and its UV protection coefficient (UPF) is 1211.19. Simultaneously, the deposition of TiO₂ thin film endows the PET fabric with good thermal stability and heat insulation performance.

[Abstract](976) [FullText HTML] (1524) [PDF 2298KB](1176)

Mechanism of a drug pair of Astragalus membranaceus and Lycium barbarum on ulcerative colitis based on network pharmacology

HAO Fangjia, PENG Yuanyuan, ZHAO Linjing

2021, 35(4): 377-382.

Abstract:
The drug pair comprising of Astragalus membranaceus and Lycium barbarum (AL) has the clinical efficacy to prevent ulcerative colitis (UC). However, the mechanism of action is still arcane. The possible mechanism of this drug pair in the treatment of UC was investigated using a network pharmacology platform. The components and putative targets of AL were collected based on integrative pharmacology-based research platform of traditional Chinese medicine, String database, and David database. By analyzing the protein-protein interactive network containing the targets of AL and potential therapeutic targets of UC, GO and KEGG pathway enrichment analyses were performed, and a regulating network of herb-constituent-target-pathway was constructed. The results suggested that AL may play a beneficial role in UC through affecting the expression of targets associated with immune and inflammation such as PTGS2, and regulation of nuclear transcription factor-κВ signaling pathway, TNF signaling pathway, etc. The results of the study provide a reference for the systematic elucidation of the mechanism of AL in the treatment of UC.

[Abstract](797) [FullText HTML] (649) [PDF 850KB](437)

Research status and existing problems of intelligent wearable clothing for the elderly

ZHANG Yifei, KE Baozhu

2021, 35(4): 383-388.

Abstract:
With the increasing demand for functional clothing and the accelerating aging of the population, developments of intelligent wearable clothing for the elderly need to be paid attention to. The researches of intelligent wearable clothing for the elderly were summarized, it was pointed out that it mainly involves four aspects: physiological data monitoring for elderly with chronic diseases, physiotherapy and maintenance of elderly with frequent diseases, safety protection such as fall prevention and warning, and auxiliary entertainment for elderly psychological needs. The existing problems, difficulties and future development trend of intelligent wearable clothing for the elderly were summarized, and existing problems like how to pursue the innovation of intelligent technology while ensuring the wearing experience effect, as well as the difficulties like how to mass produce and reduce the price of intelligent wearable clothing for the elderly were concluded. Then it put forword the future in terms of design, process, manufacturing, and marketing operations.

[Abstract](821) [FullText HTML] (1525) [PDF 2466KB](377)

Establishment of differential equation of in-plane free vibration of curved beams under MOI and shear deformation

ZHANG Zhichao, SONG Yumin

2021, 35(4): 389-394.

Abstract:
The derivation and establishment of vibration differential equation are the key to the structural dynamic analysis. The moment of inertia (MOI) and shear deformation were taken into account, the differential equations of in-plane free vibration about lateral bending and axial deformation of curved beams were derived and established by combining geometric equations and the internal force equilibrium according to the theory of Timoshenko beam. The research results can provide a theoretical basis for dynamic study on the curved beams.

[Abstract](663) [FullText HTML] (390) [PDF 781KB](189)

Objective Bayesian analysis of mixture cure model based on exponential distribution

XIAO Xiang, WU Yiqi, GU Xi

2021, 35(4): 395-400.

Abstract:
A mixture cure model based on exponential distribution was proposed. By using full likelihood function and latent variables, it was easy to calculate Fisher information matrix, drive Jeffreys prior and reference priors, and the appropriateness of posterior distribution was verified. The results show that the objective Bayesian method has a good effect on parameter estimation, especially when the sample size is small.

[Abstract](693) [FullText HTML] (616) [PDF 734KB](186)

2021 Vol. 35, No. 4