上海工程技术大学学报

Experimental research on stamping forming numerical simulation of motor cover plate based on DYNAFORM

JIA Xingpeng, GONG Hongying, YOU Jin, LIU Shangbao, WANG Bin

2021, 35(2): 99-106.

Abstract:
The finite element analysis software DYNAFORM was used to stamp forming numerical simulation for a shallow depth and large size motor cover plate. The impacts of main process parameters and drawbead on the drawing quality were studied and the causes of defects were analyzed. Then orthogonal experiment and comprehensive scoring method were used to optimize the process parameters in order to reduce crack, wrinkle and insufficient stretch defects appearing in the process of sheet metal forming. It was found that the drawing quality could be effectively improved through the reasonable arrangement of drawbead and the optimization of process parameters. The optimal process parameter combination was obtained as follows: drawbead resistance coefficient 50%, binder force 600 kN, friction coefficient 0.16, stamping speed 5000 mm/s, die gap 1.1t. The simulation test verified the accuracy and effectiveness of the process parameter combination.

[Abstract](423) [FullText HTML] (364) [PDF 1588KB](601)

Influence of weld width on fatigue strength of butt joint

LIU Zhenxiong, XU Gang, CAO Wentao, MA Chunwei

2021, 35(2): 107-112, 143.

Abstract:
Finite element analysis based on the establishment of a 3D solid model of the butt joint of Q235A steel was conducted, and the influence of weld width on the fatigue strength of the butt joint was simulated. Eight geometric models of different weld widths were established by ABAQUS CAE software. The meshing of the model was carried out and the structural stress was calculated. The stress of butt joint was analyzed based on mesh insensitive structural stress method. The Fe-safe model of ABAQUS software was used to predict the fatigue life. The simulation results show that the fatigue properties of butt joint weld firstly increase with the increase of weld width, and then gradually decrease with the increase of weld width.

[Abstract](379) [FullText HTML] (268) [PDF 1193KB](265)

Warpage optimization of automobile connector based on response surface method

HU Zuoxiu, LIU Shumei, MAO Xinran, ZHANG Chun

2021, 35(2): 113-117.

Abstract:
In order to reduce the warp deformation problem in injection molding process of car plug-in, a car plug-in was used as the research object, the mold temperature, solute temperature and pressure-keeping pressure were selected as the response surface influence factors, the warping deformation value of the plastic part was used as the response target, experiment scheme was designed by using the response surface method Box-Behnken. Taking advantage of Design-Expert software, the test results were analyzed, the second-order response surface model between the response surface sound factor and the response value was established, and the best combination of process parameters obtained as follow: mold temperature of 50℃, melt temperature of 280℃, pressure of 60 MPa. The experimental verification results show that the warped deformation value of injection molding parts produced by the process combination decreases by 21.26%, which can meet the expected requirements.

[Abstract](373) [FullText HTML] (335) [PDF 825KB](235)

Preparation and research on antibacterial activity of inclusion compound of basil volatile oil

MAO Jianzhi, LIU Xiaohui

2021, 35(2): 118-122.

Abstract:
After the volatile oil was extracted by steam distillation, hydroxypropyl-β-cyclodextrin was used to refine the inclusion compound, and the oil content was determined by ultraviolet spectrophotometer. Characterization was accomplished by microscope, thin-layer chromatography (TLC) and infrared spectroscopy (IR). The results show that the yield of inclusion compound is 52.23%, the inclusion rate is 2.82%, and the oil content is 1.02%. The inhibition zone and minimum inhibitory concentration (MIC) of the inclusion complex against Escherichia coli, Staphylococcus aureus and Candida albicans were determined by disk method and two-fold dilution method. The results show that the inhibition zone are 1.74, 0.82 and 1.12 cm respectively, and the minimum inhibitory concentration are 3.79, 8.58 and 3.79 mg/mL respectively.

[Abstract](301) [FullText HTML] (304) [PDF 861KB](234)

Study on synthesis of m-dinitrobenzene based on continuous flow reaction

LI Bo, ZHU Xiaolei, SUN Cong, GU Wei, HAN Lulu, DI Meng, MAO Yongjun, WANG Han

2021, 35(2): 123-128.

Abstract:
The process of nitrobenzene nitration was explored by using microchannel reactor. By adjusting concentration of sulfuric acid, molar ratio of nitric acid to sulfuric acid, molar ratio of nitric acid to nitrobenzene, reaction temperature and residence time, the optimal reaction conditions were obtained as follows: the concentration of sulfuric acid was 92%, molar ratio of nitric acid to sulfuric acid was 1∶5.3, molar ratio of nitrobenzene to nitric acid was 1∶1.15, reaction temperature was 85 ℃, and residence time was 70 s. The experimental result shows that average conversion of nitrobenzene is 99.2%, average yield of m-dinitrobenzene is 85.5%, average yield of p-dinitrobenzene is 3.5%, and average yield of o-dinitrobenzene is 10.2%. When nitrobenzene is nitrated in micro reactor, the waste acid can be recycled by adding concentrated sulfuric acid and fuming nitric acid, which will make it more green, safe and environmentally friendly.

[Abstract](357) [FullText HTML] (380) [PDF 1037KB](358)

First-principles study on adsorption of toxic gases by two-dimensional AlC nanosheets

LI Xiaoyi, MEI Tiantian, WANG Chang, WU Jianbao

2021, 35(2): 129-136.

Abstract:
Based on density functional theory, the adsorption performances of toxic gases (SO₂, NO_2,NO, CO, H₂S, NH₃, HCN) on two-dimensional AlC nanosheets were studied, and the electronic properties and work functions of various adsorption systems were further calculated. The calculated results show that the metallic properties of the AlC monolayer does not change after gas adsorption , and the variation range of adsorption energy was [−3.11, −0.09] eV. All gases except CO and HCN can be stably adsorbed on the AlC monolayer by chemical adsorption. Charge analysis shows that after adsorption, NO₂, NO and SO₂ can obtain 0.473|e|, 0.317|e| and 0.249|e| from the AlC monolayer, respectively. The charge density difference diagram also shows that there are strong interaction of electrons from the AlC monolayer with the three toxic gases of NO₂, NO and SO₂, and the work function of the system increase significantly after NO₂, NO and SO₂areadsorbed. Based on the energy, electronic properties and work function response of the AlC monolayer after adsorbing toxic gases, the AlC monolayer will be expected to become a detection material or sensing material for toxic gases such as SO₂, NO₂, and NO.

[Abstract](342) [FullText HTML] (353) [PDF 1158KB](292)

Research progress on influence of unilateral natural ventilation on environment of urban street canyon

FENG Haoming, LIN Yaolin, YANG Fang

2021, 35(2): 137-143.

Abstract:
Natural ventilation widely exists in cities. To understand the current situation and existing problems of indoor environment quality of urban natural ventilation buildings is the basis of improving the indoor environment quality of urban buildings. Firstly, through literature review, the driving factors of unilateral natural ventilation in urban street canyons were studied. Then, the relative researches of unilateral natural ventilation were summaried from the aspects of building geometric characteristics, ventilation capacity, pollution rate, particulate matter concentration and street canyon facilities, and finally some suggestions for future research were puts forward. The results show that reasonable aspect ratio, better urban layout and careful design of street canyon facilities can take usage of unilateral natural ventilation with maximize effeciency and improve the indoor environment quality of urban street canyon.

[Abstract](268) [FullText HTML] (375) [PDF 669KB](270)

Analysis on influence of rail maintenance on rail smoothness of high-speed railway

LI Ming

2021, 35(2): 144-149.

Abstract:
Rail maintenance is the core operation content of high-speed railway track structure repair, and its influence on line smoothness is directly related to the effective formulation of maintenance operation plans. Based on the track inspection data before and after maintaining of ballastless track of a 300 km/h high-speed railway, the time domain and frequency domain of vertical profile and track alignment irregularities and the coherent function with the vehicle vibration acceleration were analyzed, in the wavelength range of 1~42 m and 1~120 m, the influence of rail maintenance on track irregularity was figured out. The results show that the rail maintenance operation can only significantly improve track alignment irregularity track quality index (TQI) of 1~120 m. In the frequency domain distribution of track irregularity, rail maintenance has no significant effect on the composition of track irregularity wavelength, but improves the short-wave irregularity. Rail maintenance has certain effect on improving vertical vibration of train.

[Abstract](447) [FullText HTML] (365) [PDF 1160KB](375)

Design and analysis of electromagnetic driver control system based on micro nano positioning

SHI Qijing, ZHU Zina, LI Peixing, WU Di

2021, 35(2): 150-157.

Abstract:
Aiming at the problem of low control precision of large stroke electromagnetic drive micro-nano positioning technology, an optimized PID control scheme was proposed. According to the working principle of the electromagnetic drive device, the Simulink model of control system was established and built in Matlab software. Comparing with traditional PID control, the improvement effects of feedforward PID and fuzzy PID algorithm were studied. It is concluded that feedforward PID has better dynamic and static control performance, and fuzzy PID has better robustness.

[Abstract](348) [FullText HTML] (292) [PDF 1494KB](301)

Configuration design and workspace solution of six degrees of freedom walking machining robot

ZHU Wenbin, LIU Yong, ZHAI Changmin

2021, 35(2): 158-162.

Abstract:
A 6-SPU walking machining robot was proposed. According to the principle of compact structure, large stiffness and easy installation, the branch chain and overall configuration of robot mechanism were designed. Based on the screw theory, it was obtained that the robot had 6 degrees of freedom, and the inverse solution of robot position was obtained by the attitude transformation matrix. The workspace of the robot was obtained by geometric method, and the correctness of the workspace was verified by Montecarlo method.

[Abstract](337) [FullText HTML] (351) [PDF 1077KB](188)

Research on mechanism and capability of new type of wall-climbing robot overconming obstacles

LU Hongli, MAO Jian, YAN Juan, LI Peixing

2021, 35(2): 163-170.

Abstract:
The wall-climbing cleaning robot is a cleaning machine and assigned to replace human to work in the dangerous high-rise building environment, so its reliability and stability are particularly important. On the basis of analyzing the disadvantages of traditional wall-climbing cleaning robot, aiming at the obstacles of glass window frame, a four-rotor swinging arm wall-climbing cleaning robot was designed. Based on crawler chassis structure, rotary wing was designed to generate thrust to provide the adsorptive force required for wall walking, and the corresponding robot swinging arm deformation mechanism was designed to increase the obstacle surmounting ability of the robot on the wall. The kinematic mechanism of the robot over the obstacle was analyzed, and the kinematic model of the robot wall-climbing was established. Under the RecurDyn Track LM module, kinematic simulation was carried out for the obstacle crossing process of the robot, and the curve of driving torque and rotor thrust changing with time was obtained. By analyzing the curve of Y-axis center position and acceleration change, the robot can maintain good stability in the process of obstacle surmounting, demonstrating the ability of the new four-rotor swinging arm wall-climbing robot to surmount obstacles and the stability in the process of obstacle surmounting.

[Abstract](447) [FullText HTML] (401) [PDF 2952KB](190)

Analysis of non-Darcy forced convection heat transfer in a porous circular duct under LTNE condition

YUE Feilong, LI Peichao

2021, 35(2): 171-177.

Abstract:
The heat transfer performance of non-Darcy forced convection in a fluid-saturated porous tube under local thermal non-equilibrium was numerically simulated. Firstly, the Brinkman flow model and the local thermal non-equilibrium (LTNE) model were employed to establish the mathematical model of the studied problem to predict the forced convective heat transfer. Then, the mathematical model was numerically solved using COMSOL Multiphysics simulation software. And the fluid velocity field, the solid temperature field, the fluid temperature field, and the Nusselt number were obtained. Moreover, the dependences of the Nusselt number ($Nu$) on some key parameters were analyzed in detail. It was found that the Nusselt number increases first and then tends to approach an asymptotic value with the increase of the Darcy number ($Da$) and the Biot number ($Bi$). The Nusselt number monotonously increases with increasing the Péclet number ($Pe$). On the contrary, the Nusselt number decreases first and then tends to be an asymptotic value owing to the increase of the ratio of effective thermal conductivity of fluid to effective thermal conductivity of solid (the thermal conductivity ratio $\kappa $) and ratio of effective dynamic viscosity of fluid to actual dynamic viscosity (the viscosity ratio M). The model and numerical results obtained can not only be used to improve the heat transfer capacity of porous medium pipes in engineering, but also provide references for related experiments and analytical studies.

[Abstract](254) [FullText HTML] (659) [PDF 1374KB](142)

Research on location of fire station in chemical industry park based on risk assessment

CHEN Jianfei, QI Yuqing, CHEN Haoyu, CAO Yang, CHENG Yaoyao

2021, 35(2): 178-184.

Abstract:
The location planning of fire station in chemical industry park is inevitably affected by potential risks. In order to optimize the layout of fire stations and increase the proportion of the impact of risk assessment on fire station location scheme, a set of risk assessment index system was established based on the difference of potential accident risks of various enterprises in the chemical industry park. The risk assessment of enterprises was carried out by grey relational analysis and fuzzy comprehensive evaluation method. On this basis, the concept of effective distance was introduced, and the actual distance and risk assessment value were combined and applied to the site selection optimization. The number and location of fire stations in the park were planned and designed by building set coverage method, which solves the problems of low coverage rate, repeated fire station area and long response time in traditional fire station location. The risk assessment of each enterprise and the location of fire station were carried out in the background of Nanjing Chemical Industry Park, and three risk levels were divided and the optimal fire station address was selected finally.

[Abstract](263) [FullText HTML] (268) [PDF 5425KB](135)

Spreading pattern of government social media in public health emergencies

HUANG Yilei, XIA Zhijie, YAO Gan

2021, 35(2): 185-191.

Abstract:
Based on the real spreading data of government social media during public health emergency, the spreading pattern of government social media were analyzed from propagation topology model and user behavior temporal pattern. The results show that during public health emergency, broadcast model dominates the spreading of government social media, but there is no significant correlation between the propagation effect and the diffusion network topology; the content emotion of government social media can affect the spreading network topology structure, while the audience emotion caused by it has no effect on the topology model; the change of repost amount in social media roughly conforms to the power-law distribution; the effect on the user repost behavior caused by emotion factors in government social media is not significant.

[Abstract](315) [FullText HTML] (293) [PDF 1192KB](127)

Analysis of influencing factors of the functional network of technological entrepreneurship and innovation of makerspace

SHI Minghong, MAO Haixia, WANG Qianfeng

2021, 35(2): 192-196.

Abstract:
Makerspace provides enterprises with basic services, capital, technical support, business information, professional training and other services cooperating with government, university, scientific research institute, industrial park, financial institution, intermediary institution and so on. Finally, makerspace can realize the transformation of scientific and technological achievements, cultivate scientific and technological start-ups, and promote regional industrial development and regional economic development. Its functional effects are mainly manifested in entrepreneurial incubation effects, technological innovation effects, industrial cultivation and socio-economic effects. The paper will also study the internal and external influencing factors from the external environment and the internal linkage of innovation and service entities basing on the functional positioning and performance of the effects.

[Abstract](250) [FullText HTML] (313) [PDF 610KB](296)

2021 Vol. 35, No. 2