Table of Content

25 March 2020, Volume 48 Issue 3

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Electronics, Communication & Automation Technology

User Image Aesthetic Representation Based on Personalized Generation Template Aggregation



WANG Weining, MA Xuedong, SU Junjie, et al

2020, 48(3):  1-9.  doi:10.12141/j.issn.1000-565X.190442

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The general image aesthetic research can not represent the user’s personalized aesthetic preferences becaused it does not consider the aesthetic differences among users. In order to represent the user’s personalized aesthetic preferences more effectively, a user aesthetic representation construction method based on personalized generation template aggregation using the Counting Grid model was proposed in this research. It constructs a more compact user image aesthetic representation vector, which can better describe the user characteristics. Experimental results show that the way of user aesthetic representation constructed by the proposed method can obtain higher recognition rate in user identification, and can also obtain more realistic recommendation results in user recommendation.

Forecast Components-RVM Fault Detection Modeling for Wastewater Treatment



CHENG Hongchao, WU Jing, LIU Yiqi, et al

2020, 48(3):  10-17.  doi:10.12141/j.issn.1000-565X.190530

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As a complex nonlinear large-scale system, wastewater treatment plant (WWTP) faces problems such as bad working environment, complex control objectives. These problems often lead to fault of the system, so it is urgent to develop the efficient monitoring technology. This study proposed a new fault detection technology, namely, the forecast component-relevance vector machine, which combines the relevance vector machine with the forecastable component analysis. Firstly, the forecastable component algorithm is used to extract features information from the collected data of WWTPs, in order to remove duplicate features and redundant information. Then the relevance vector machine model is trained by offline data. In order to verify the superiority of the proposed method, the forecast component-relevance vector machine and another three methods (RVM, PCA-RVM, ICA-RVM) are used to monitor the wastewater treatment Benchmark Simulation Model 1 (BSM1) platform provided by the International Water Association. Experiments show that the fault detection accuracy of the forecast component-relevance vector machine is higher than the other three methods.

Simulation of Ultrasonic Human Body Communication Technology Based on DS-UsWB



LIU Jiaojiao WANG Qianqian MA Biyun

2020, 48(3):  18-23,31.  doi:10.12141/j.issn.1000-565X.190178

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The existing ultrasonic wideband ( UsWB) technology, when used in intra-body communications (IBCs), shows some shortcomings such as low rate and poor ability to resist multinode interference. Therefore, a direct-sequence ultrasonic wideband (DS-UsWB) technology was put forward. This technology can effectively resist the multinode interference. DS-UsWB adopts DS and ultra wide band (UWB) technology to simulate ultrasonic IBCs. That means to model the intra-body channel in k-Wave and simulate intra-body multinode communications with the impulse response of the channel model. The signal parameters, which are used to overcome the multi-path effect, are determined by analyzing the time delay characteristics of the channel impulse response. Both the analysis of system performance and simulation results verify that, compared with UsWB technology, DS-UsWB can effectively resist the multinode and multi-path interference, and achieve higher data rate and lower bit error rate.

MIMO UWB Antenna Based on Differential Evolution Algorithm



LIU Han KANG Guoqin LI Kai

2020, 48(3):  24-31.  doi:10.12141/j.issn.1000-565X.190476

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In order to enlarge the channel capacity and improve quality of wireless communication systems, a multiple input multiple output ultra-wideband (MIMO UWB) antenna with high isolation was designed by jointly optimizing S11 and S12 with differential evolution algorithm (DEA) and method of moments (MOM). Compared with the simulation software method, this method can greatly reduce the amount of work and improve efficiency. According to the comparison of the measured results and the simulated results, the proposed compact antenna can be widely applied in short distance wireless communication systems with good performance, and it can effectively improve the the channel capacity. Additionally, the measured results are consistent with the simulated results, demonstrating correctness and effectiveness of the method.

New Four-Dimensional Chaotic System with Multiple Types of Coexistence of Attractor



XIAN Yongju, MO Yunhui, XU Changbiao, et al

2020, 48(3):  32-43.  doi:10.12141/j.issn.1000-565X.190294

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Aiming at obtaining multiple types of coexisting attractors, a new four-dimensional dissipative chaotic system with multi-stability was constructed. The system’s dynamic behavior was analyzed through the numerical simulations of phase diagrams, Lyapunov exponents, bifurcation diagram, etc. An analog circuit of the system was designed and simulated by the Multisim software. And a digital FPGA (Field Programmable Gate Array) circuit of the system was also designed. The simulation results of the two kinds of circuit were consistent with each other, which verified the system’s chaotic behavior and its implementability. The system has some important characteristics, such as for different values of system parameters, there are ten types of coexistence of attractors in the system. The involved coexisting attractors are point attractors, different periodic attractors, quasi-periodic attractors, and different chaotic attractors. The system’s characteristics have strong sensitivity to parameters, which means there are frequent switches between the periodic state and the chaotic state with the varied parameters. The topologies of the system’s attractors are dominated by the parameters, which means there are one-scroll attractors, two-scroll attractors, and four-scroll attractors in the system corresponding to different values of the parameters.

Analysis on the Axial Load Behavior of a New Type of Transferring Joint with Concrete Filled Steel Tubular Inclined Columns



HUANG Shaoteng, HUANG Yansheng, MO Tingwei, et al

2020, 48(3):  44-54.  doi:10.12141/j.issn.1000-565X.190235

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A new type of transferring joint with concrete filled steel tubular inclined columns was proposed in this study. The joint is composed of core concrete, longitudinal and horizontal steel plates, external steel plates and built-in profiled steel. The monotonic loading test of a specimen with geometric ratio of 1：6 was carried out. Then the failure mode of the joint zone was studied through numerical simulation, and the parameter analysis on the thickness of the steel plates in the joint zone was conducted. The experimental results show that the failure of the specimen occurs in the inclined columns, so it can meet the design concept of “strong joint and weak component”. The numerical simulation results further reveal the force transfer mechanism of the joint zone. The calculation results show that the failure mode of the joint zone is that the steel plates basically reach yield and the concrete at the bottom of the joint zone reaches the ultimate compressive strain. The ultimate bearing capacity and yielding load of the joint zone are 2． 10 times and 1． 19 times of those of the numerical model in which the inclined columns fail at first, respectively. The thickness variation of the external steel plates, which can transfer axial internal force and confine the concrete, has the greatest influence on the ultimate bearing capacity of the joint zone.

Seismic Performance of CFT Column-to-Beam Joints with Detached Vertical Stiffeners



HUANG Haibin, WANG Yanchao, LIU Yazhou, et al

2020, 48(3):  55-66.  doi:10.12141/j.issn.1000-565X.180414

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In order to study the seismic performance of CFT column-to-beam joints with detached vertical stiffeners, 7 joint specimens were tested under constant axial compression at the top of the column and cyclic loads at the end of the beam. Through the analysis of test data, the load-displacement curve, skeleton curve, strain curve, strength and stiffness degradation laws, ductility and other results of each specimen were obtained. Three ultimate failure modes of the joints were found in the tests, namely, tensile failure of the beam flange near the short edge of vertical stiffeners, shear failure of welds between the beam flange and vertical stiffeners, and tensile failure of the steel tube wall connected with vertical stiffeners. Then a plastic mechanism model of the joints under tension failure mode of the steel tube wall connected with vertical stiffeners was put forward based on the yield-line theory. And the yield load calculation formula under this mode was derived according to the principle of virtual work. The calculated results are in consistent with the test results. Combining the derived formula with calculation formulas of three typical failure modes, the ultimate failure mode of the joints can be accurately predicted.

Architecture & Civil Engineering

Comparative Study of the Vulnerability of Canonical Structures in Different Intensity Regions



LI Siqi YU Tianlai ZHANG Ming

2020, 48(3):  67-75,90.  doi:10.12141/j.issn.1000-565X.190320

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In order to study the earthquake vulnerability difference of canonical structures in different intensity regions, the seismic damage data of 7099 buildings in Dujiangyan, including masonry structure, reinforced concrete frame structure and bottom frame-seismic wall masonry structure after Wenchuan earthquake, were analyzed. Considering the number of floors, coupling effect of chronological and seismic fortification factors, the probability matrices of actual seismic damage and the comparative analysis model curves of various structural types were developed. The actual seismic vulnerability matrices and its non-linear continuous regression model were constructed in different intensity zones, and the vulnerability curves of transcendence probability of actual seismic damage and seismic damage grade were drawn respectively. A vulnerability matrix model of mean seismic damage index (MSDI) was put forward, and it was verified by the actual seismic damage matrix of canonical structures. Based on the validation results, the vulnerability matrix and multi-dimensional curve model of the city based on this parameter were established.

Time-Frequency Analysis of Blasting Seismic Signal Based on CEEMDAN



SUN Miao, WU Li, YUAN Qing, et al

2020, 48(3):  76-82.  doi:10.12141/j.issn.1000-565X.190179

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Blasting monitoring signals are mostly noisy signals, and nosie can cause serious mode confusion in empirical mode decomposition (EMD) results. The improved EEMD algorithm can restrain mode confusion to some extent, but the effect is not obvious. Therefore, the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) was used to process noisy signals. Firstly, the decomposition results of simulation signals with EMD, EEMD and CEEMDAN were compared, and the permutation entropy values of IMF obtained by EMD, EEMD and CEEMDAN were calculated. Then the decomposition results of EMD, EEMD and CEEMDAN were Hilbert-transformed, and their spectral resolutions were compared. Finally, CEEMDAN was applied to the timefrequency analysis of underwater borehole blasting seismic waves. The results show that CEEMDAN can suppress the mode confusion, and its time-frequency spectrum has high resolution in both time and frequency domain.

Mechanical Engineering

Bolting Jumbo Boom Positioning Based on Compliance Error Detection



XIA Yimin, MA Jiesong, ZHANG Yazhou, et al

2020, 48(3):  83-90.  doi:10.12141/j.issn.1000-565X.190251

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The manual positioning of bolting Jumbo has the disadvantages of low efficiency and low accuracy. In order to improve the positioning accuracy and realize the automatic construction, starting from the positioning error compensation of the boom, a deformation measurement method based on machine vision was proposed to obtain the compliance error of the boom based on the DH kinematics model. The parameter error of the boom was obtained by total station instrument. The kinematic model of the positioning error compensation was established. The Newton Raphson method and the gradient projection method were used to establish the iterative method to find the arm position of the joint value by two inverse solutions. The research results show that the measurement error of the compliance error detection method is kept at about 0． 010 m. When the boom is positioned based on the error compensation model, the measured end positioning error is less than 0． 050 m, which meets the actual positioning requirements of the project. The boom positioning method proposed in this study has been successfully applied to the boom positioning system of bolting Jumbo, and it shows a good application effect in practical engineering.

Study on Chip Formation Mechanism of Deep Hole Gun Drilling of 15-5 PH Stainless Steel



LI Liang, YANG Yinfei, XUE Hu, et al

2020, 48(3):  91-99,107.  doi:10.12141/j.issn.1000-565X.190414

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Chip shape is an important factor affecting the processing quality of the deep hole gun drilling, because the hole is too small and deep. The relationship between chip forming mechanism and process parameters has long been a difficult problem in deep hole gun drilling research. Taking 15-5PH stainless steel as the research object, the research explored the process and influencing factors of spiral chip forming by analyzing the chip flow process. The fracture mechanism of 15-5PH stainless steel gun drilling chips was studied with scanning electron microscope. The chip deformation rule under different process parameters was studied through experiments with varied cutting speed, feed, and oil pressure. The relationship between chip deformation and oil pressure was clarified by analysing fluid pressure and turbulent momentum on the cutting edge of gun drilling under different oil pressure with ANSYS-FLUENT. The study shows that the fracture mechanism of chips processed by 15-5PH stainless steel gun drill belongs to “quasi-cleavage fracture” and the chip morphology is closely related to the technical parameters of the gun drill. The research results can provide guidance and references for the selection of processing parameters and coolant oil pressure of deep hole gun drilling of 15-5PH stainless steel.

Stability Control for Distributed Drive Electric Vehicle Under Steering Condition



GUO Lie, GE Pingshu, XU Linna, et al

2020, 48(3):  100-107.  doi:10.12141/j.issn.1000-565X.190319

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A neural network PID method based steering stability controller was proposed by using particle swarm optimization. It aims to improve the steering stability of distributed drive electric vehicle and solve the problems of slow convergence and easy to fall into local optimal solution based on neural network control algorithm. This method can realize the yaw rate control and slip rate control of each wheel by yaw moment and slip rate adjustment torque. Based on this, an optimal torque distribution algorithm under steering condition was studied. The modified torque was obtained by correcting the driving torque with the fuzzy control algorithm. Then the modified torque was optimally distributed together with the yaw moment and slip rate adjustment torque of the stability controller as a quadratic programming problem to obtain the optimal driving torque of each wheel. Finally, the performance comparison tests under typical working conditions such as double lane shifting condition and serpentine condition were carried out based on the joint simulation platform. The results show that this algorithm can maintain the stability of the vehicle while maintaining good vehicle dynamics. The stability controller can reduce the slip phenomenon by 36． 4% under slalom condition, and the optimal torque distribution algorithm can improve the stability by 31． 2% under the double lane change condition.

Materials Science & Technology

Performance of Short Glass Fiber Reinforced Composite and It's Application in Vehicle Body



CAI Liya, ZHAO Kegang, LI Jianfeng, et al

2020, 48(3):  108-115,135.  doi:10.12141/j.issn.1000-565X.190285

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A toughener and glass fiber (GF) modified polyethylene terephthalate (PET) material was used to study the vehicle body design. Considering the material’s high impact toughness, high specific strength, high specific stiffness and the characteristics of the injection molding process, the non-loaded body adopts a block design and is connected to the body by structural glue, which can minimize the weight of the vehicle body and realizes the weight reduction of the whole vehicle. The experiment shows that the modulus and strength difference of the 15% short glass fiber reinforced PET can reach 40% ~50% because of glass fiber orientation, thus makes it difficult to obtain accurate simulation results for guiding the design. In this research, the microscopic and basic mechanical properties of the glass fiber reinforced PET composites were studied. The high precision spline simulation was established with engineering software such as Moldflow, Digimat and Abaqus. The material parameters were corrected and the results were used for stiffness and modal simulation of the whole injection molded vehicle. The simulation results were compared with the test results, and the quasi-static simulation accuracy of the injection molded product was improved to over 85%.

Microstructure and Corrosion Behavior of 2219 Aluminum Alloy Forging's Joint by TIG Welding



XU Daofen, CHEN Kanghua, XING Jun, et al

2020, 48(3):  116-125.  doi:10.12141/j.issn.1000-565X.190402

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2219 aluminum alloy weldment was prepared by the method of TIG welding. The microstructure evolution and corrosion behavior of 2219 aluminum alloy weldment joint was investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), immersion test and electrochemical corrosion experiment. The results show that the microstructure in the welded zone is dendrites, fine and homogeneous with equiaxed grains. When the corrosion happens, the corrosion potential moves to positive direction and the corrosion resistance increases. The co-existence of residual crystallization phase and continuous grain boundary precipitates in the base metal area, results in the corrosion of the copper poor area around the residual crystalline phase and the grain boundary. Meanwhile, the continuous intergranular phases play a role as channel for electron transfer in the corrosion process, which could accelerate the anodic dissolution rate. All above mentioned factors leaded to the worst corrosion resistance of base metal area. The grain boundary precipitates have discontinuous distribution in the over-aging zone, promoting corrosion potential of grain boundary to shift to a more positive value, which is beneficial to the improvement of corrosion resistance. Lots of Cu-containing supersaturated solid solution and disappearance of precipitate free zones make the corrosion resistance of the quenching zone is superior to that of the over-aging zone. The corrosion resistance of TIG welding joint is different due to the combined action of residual crystalline phases, αAl -matrix, precipitates and grain boundary, which are in the order of welded zone > quenching zone > over-aging zone > base metal.

Analysis on Mechanical Properties and Fractal Characteristics of Micropore Structure of Geopolymer Mortar



YANG Shiyu, ZHAO Renda, JIN Hesong, et al

2020, 48(3):  126-135.  doi:10.12141/j.issn.1000-565X.190495

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In order to investigate the strength development rules and the improvement mechanism of granulated blast-furnace slag (BFS) modified fly ash based geopolymer mortar at different temperatures, the mechanical properties of fly ash based geopolymer with different BFS content at various temperatures were measured, and the microscopic morphology and microscopic pore structure characteristics were analyzed. The results show that the compressive strength and flexural strength of fly ash based geopolymer are small when curing at room temperature, and the mechanical properties of fly ash based geopolymer can be improved by mixing BFS or elevating curing temperature. However, high temperature curing probably lead to a slow development of later compressive strength. When not mixed with BFS, the flow degree of the geopolymer is 232mm, and the condensation time exceeds 8 h. With the increase of BFS content, the flow degree and condensation time of the geopolymer decrease gradually. Both elevating curing temperature and mixing BFS can significantly reduce the porosity of fly ash based geopolymer. When just cured at room temperature, the geopolymer mortar contains a large amount of macroscopic pores, and there is substantially no gelling pores. Through high temperature curing, the proportion of capillary pores becomes the largest in the fly ash based geopolymer mortar, and the modified geopolymer is mostly composed of gel pores and transition pores. It can be seen from the microtopography of the specimens that geopolymer becomes more dense after mixed with the BFS; the fractal model based on thermodynamic relation can perfectly describe the pore structure profile of the geopolymer within the measurement range of mercury intrusion porosimetry, followed by the pore axis model; the fractal dimension of pore structure of the specimens is greater than 2． 0. Adding BFS to the fly ash based geopolymer can improve the pore structure, while lifting curing temperature makes the pore structure of the geopolymer complex.

Freezing-Thawing Damage Mechanism and Evolution Model of Concrete Mixed with CWCPM



XUE Cuizhen SHEN Aiqin QIAO Hongxia

2020, 48(3):  136-144.  doi:10.12141/j.issn.1000-565X.190272

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The pile-up of significant amount of construction waste and the deterioration of the durability of cement concrete under freezing-thawing cycling are two major challenges in civil engineering. In order to improve the reuse rate of the construction waste and to have better understanding of the deterioration mechanism of concrete mixed with construction waste (brick powder) composite powder materials (CWCPM) under freezing-thawing condition, laboratory experiment and theoretical analysis were carried out. The effect of different factors on the macroscopic performance deterioration of concrete was investigated and the freezing-thawing damage evolution model of concrete mixed with CWCPM was established by multifactor analysis. The microscopic structure and appearance and pore structure of the concrete were also analyzed, and the deterioration mechanism was revealed. The results show that the degree of freezing-thawing damage increased with the increase of water cement ratio, the number of freezingthawing cycles and the concentration of the salt solution. The anti-frost performance of the concrete was improved by the CWCPM. Compared with the control specimen, the amount of stripping per unit area and the compressive strength of the concrete specimen with 30% CWCPM decreased by 27． 1% and increased by 6． 2% respectively, after 50 cycles of freezing-thawing. The freezing-thawing damage evolution model based on macroscopic test results can predict the frost resistance of concrete accurately. In essence, the deterioration of the concrete under freezingthawing condition is a physical process during which its microscopic structure gradually become loose and its pore structure become worse.