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31 December 2021, Volume 31 Issue 4 Previous Issue    Next Issue
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Technology Theory and Application


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Technology Theory and Application

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Design and Research of External Prestressed Reinforcement of Highway Simply Supported T Beam Based on MIDAS Civil JI Gang-sheng, MA Shi-bin, CHEN Xiao-guang, LIANG Dong 2021, 31(4): 1-7+36.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.001 Abstract ( )   PDF (3526KB) ( )   In view of the serious shortage the baring capacity caused by the long-term disrepair of some important trunk highway bridges , low standard of design load and rapid increase of traffic flow, the construction scheme of external prestressed reinforcement can effectively improve the bearing capacity of the main girder structure, reduce the impact of construction on traffic to the greatest extent, and has good economic effect. In this paper, based on the introduction of the external prestressed structural design of Wusugou Bridge, MIDAS Civil finite element numerical simulation analysis, the load-bearing capacity and normal service limit state of the main beam structure before and after reinforcement are checked. Finally, combined with the actual engineering construction monitoring, the maximum deflection measured after the completion of tension is 15.63mm. It appears at the position of 2# beam in the middle section of the test T beam, and the variation of deflection is basically consistent with the theoretical calculation value and the measured value of the bottom stress of the main beam. The results show that it is feasible and effective to use external prestress to reinforce highway simply supported T beam. Therefore, from the technical feasibility, effect reliability and construction simplicity, this study can provide reference for similar construction projects. References | Related Articles | Metrics

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Research on Vibration Characteristics of Guitar Based on Piezoelectric Impedance Technology ZHANG Jun, ZHAO Lin-yu, LUO De-chang 2021, 31(4): 8-16+49.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.002 Abstract ( )   PDF (4019KB) ( )   How to improve the acoustic characteristics of chord type instrument resonators has been a hot issue in the industry of instrument making. Taking the guitar as an example, this paper presented a verification method of vibration characteristics of guitar based on EMI technology.  A set of finite element models of the resonant box were built. By adjusting its boundary parameters, the main boundary parameters which affect the vibration characteristics were determined by modal analysis. The experimental platform of vibration characteristic impedance and acoustic analysis of the resonance box was built, and the vibration characteristic impedance and acoustic experiments of the resonance box were completed. It is concluded that EMI technology can be used to improve the vibration characteristics of guitar . Finally, the diameter of string was predicted by neural network，it was concluded that the neural network can be applied to the prediction of guitar string diameter. References | Related Articles | Metrics

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Design of Intelligent Guide Robot System Based on Machine Vision WANG Zheng-bo, TANG Yong, CHEN Guo-dong, Lu Shu-xuan, Yao Cheng-zhi 2021, 31(4): 17-22+54.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.003 Abstract ( )   PDF (3172KB) ( )   With the development of intelligence, image processing technology has become more and more widely used in our lives and production, especially in intelligent robots. Aiming at the current research status of blind guide robots at home and abroad, a kind of blind guide robot based on machine vision is designed. This design can detect and recognize the types of surrounding objects and the distance to the robot through monocular distance measurement combined with You Only Look Once Version3 (YOLO V3) algorithm, and inform the blind by phonetic sound. Guide robot completes autonomous combined with various sensors navigation; the blind person walks under the guidance of robots, which greatly compensates for the blind,s visual defects. From the results of the simulation experiment environment, it can be seen that the guide robot realizes the functions of advance, stop, turn and obstacle avoidance, which can also realize the function of indicating the type and distance of the obstacle in front, thereby providing a safe guarantee for the blind to travel. References | Related Articles | Metrics

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Experimental Study on Impact resistance of Fiber Reinforced Concrete Specimens TIAN Wen-ji, LI Chang-hui, NIU Bing-yan, YUE Ze-hao, WANG Yun-zhi 2021, 31(4): 23-27.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.004 Abstract ( )   PDF (2953KB) ( )   Thenormal concrete is easy to crack and its toughness is poor. In this paper, different lengths of synthetic polypropylene fiber and polyacrylonitrile fiber are mixed into normal concrete to improve the brittleness and toughness of concrete. Through the concrete impact test device, the drop weight impact test was carried out on the cube specimens of synthetic polypropylene fiber concrete, polyacrylonitrile fiber concrete and ordinary concrete. In the experiment, 20 mm synthetic polypropylene fiber, 40 mm synthetic polypropylene fiber and monofilament polyacrylonitrile fiber were added into the concrete, respectively. The influence of synthetic fiber on the impact load of concrete was studied by changing the fiber content. The content of each fiber was 1 kg/m3, 3kg/m3,  6kg/m3, 9kg/m3. The experimental results show that the impact resistance of fiber reinforced concrete increases significantly with the increase of fiber content. The impact toughness of fiber reinforced concrete with 40mm length and 9 kg/m3 synthetic polypropylene fiber is the best, which is 306.67% higher than that of normal concrete. References | Related Articles | Metrics

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Theoretical Research on Mechanical Model of Asphalt Pavement Based on Vector Field Action FAN Li-hui, ZHAO Qing-guo, WANG Xin-qiang, MENG Hui-lin, LAN Qing, FAN Xing 2021, 31(4): 28-36.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.005 Abstract ( )   PDF (4293KB) ( )   Taking classical mechanics as the reference system, taking the internal and external effects of force as the breakthrough point, taking vector field and physical equivalence as the basic path, this paper puts forward the research purpose of taking "stability" as the ultimate goal of asphalt pavement, studies and analyzes the four effects that affect the pavement stability, such as the size and shape effect of granular materials, the medium effect and interface effect of asphalt, and the force between granular materials under the load gravity field In this paper, the working mechanism and mechanism of compaction and wheel load on the gravity field of asphalt pavement are explored, and the concepts and models of load gravity field flux and potential energy, physical degree of freedom and stability of asphalt pavement system are proposed and defined, so as to clarify the physical effect and influence mechanism of granular material, asphalt medium and interface microstructure on the stability of asphalt pavement The theoretical system of "field action model" of asphalt pavement mechanics, which is composed of three models, is preliminarily constructed. This will undoubtedly bring a new understanding to the asphalt pavement theory. References | Related Articles | Metrics

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Simulation Research on Truck Offset Behavior on Downhill-Curved Road Section of Two-lane Highway LIU Bing-hua, GUO Zhong-yin, TIAN Ze-yu, Wu Qiong 2021, 31(4): 37-43.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.006 Abstract ( )   PDF (2867KB) ( )   In order to study the offset behavior of trucks on the downhill curved road section, the driving simulation was used to collect the trajectory data of trucks under different slopes, radii and turning conditions, and the shape and distribution law of lateral offset were analyzed. The results show that under the same radius, the same slope and different turning conditions, the main direction and cumulative offset direction of the trucks’ lateral offset are opposite. The maximum offset increases with the decrease of the radius. When the radius and the turning are fixed, the slope has no obvious influence on the mean and volatility of the offset. The maximum offsets obey normal distributions, which can be used as the main basis for safety design. References | Related Articles | Metrics

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Development Status and Application Analysis of Seawater Desalination Industry in Hebei Province YANG Hao-jie, SONG Ze-lin, LIU Tian-tian, Li Yan 2021, 31(4): 44-49.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.007 Abstract ( )   PDF (3032KB) ( )   Under the background of major national strategies such as the coordinated development of Beijing, Tianjin and Hebei, the social economy of Hebei province has ushered in great opportunities and challenges. With the economic development and the continuous increase of population, water shortage has become one of the bottlenecks restricting the economic development of Hebei province. Based on the data of the seawater utilization survey project in Hebei province for 14 consecutive years from 2006 to 2019, this paper analyzes the current situation of seawater desalination industry in Hebei province.Combining with the characteristics of seawater desalination industry in Hebei province, this paper finds out the existing problems of seawater desalination industry, and puts forward suggestions and further development strategies. References | Related Articles | Metrics

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Study on Anti-sliding Stability Analysis and Treatment Method of Rock Mass in Shijiaxia Dam Site LI Gang 2021, 31(4): 50-54.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.008 Abstract ( )   PDF (2688KB) ( )   The anti-sliding stability of the rock and soil mass of the dam foundation and dam abutment plays an important role in the safe operation and engineering investment of the reservoir hub project. Shijiaxia reservoir is a concrete gravity dam. The engineering geological conditions of the dam foundation and dam foundation are complex, and the dissolution cracks and ferritization alteration in the lower part of the right bank are strongly developed, which will have a great impact on the sliding stability of the dam foundation and dam abutment. In this paper, the polar stereographic projection and theoretical calculation methods are used to analyze the anti-sliding stability of various structural planes in the rock mass on both banks, and the consolidation + curtain grouting treatment measures are proposed for the unfavorable parts of anti-sliding, which solves the anti-sliding stability problem of the dam body and bank slope rock mass. References | Related Articles | Metrics

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Design of Intelligent Epidemic Prevention System Based on Face Recognition WANG Ji-chao, ZHANG Li-juan, YOU Tian, SUN Dong-lai, HUI Zhen-qiao 2021, 31(4): 55-59.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.009 Abstract ( )   PDF (2530KB) ( )   In order to improve the protection of epidemic prevention during the epidemic and reduce the risk of spread caused by the movement of people,this paper uses face recognition and infrared temperature measurement technology to design intelligent epidemic prevention system, which first makes mask test and then face recognition, and adds infrared temperature measurement in identification. Upon completion of identity verification and temperature at the same time, the real-time monitoring results will be uploaded to the cloud, which improves epidemic prevention security effectively and reduce the disease spread risk. The experimental results show that the face recognition accuracy of intelligent epidemic prevention system designed in this paper can reach 98.57%, which reaches 98.11% after wearing masks, and the temperature detection is also more accurate. Compared with the simple application of face recognition in the field of identity verification, the added functions of infrared temperature measurement and mask detection meet the special needs of the epidemic period, which can be applied to a wide range of practical scenarios, and can effectively solve the problem of the complex epidemic prevention process and low real-time performance. References | Related Articles | Metrics

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Research on Demand Forecasting of Rarely—used Spare Parts Based on Deep Artificial Neural Network ZHOU Zi-qiang, JIANG Jiu-chao 2021, 31(4): 60-65.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.010 Abstract ( )   PDF (2592KB) ( )   In order to realize the demand forecast of rarely-used spare parts and solve the problem of resource waste caused by the lack of scientific basis when making purchasing plan of rarely-used spare parts, LSTM and Bi-LSTM neural networks are used to study the demand forecast of rarely-used spare parts. This paper establishes the deep neural networks for forecasting the demand of rarely-used spare parts, including LSTM and Bi-LSTM neural networks. Through the case analysis and the comparison of prediction results, it is proved that the two kinds of deep neural networks can effectively forecast the demand of rarely-used spare parts. References | Related Articles | Metrics

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Design of Human Profile Recognizable Surveillance Camera Using Multi-feature Detection ZHOU Li-jie, HAO Rui-lin, CAI Guo-qing, SUN Ying-jian, LIU Hui 2021, 31(4): 66-71+78.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.011 Abstract ( )   PDF (3121KB) ( )   Aiming at the demand problem of highly accurate human profile recognition and rapid tracking, the human profile recognizable surveillance camera is designed based on machine vision. Firstly, the overall work program structure is designed. Secondly, a multi-feature detection method is proposed. Three classifiers are trained, which can classify human profile of the front, side and back. The algorithm of haar feature and adaboost is integrated, which can realize functions of human profile recognition and positioning. The PID algorithm is carried out for the function of human profile tracking with controlling the stepper motor and steering gear. Finally, the Android APP is developed. The test result shows that the method of multi-feature detection can recognize human profile rapidly with frame rate not less than 20Hz. And the recognition accuracy can improve 27.3% in contrast with the method of single feature detection. The tracking time of human profile does not exceed 1.7s. The camera can work smoothly with functions of WiFi control, wireless surveillance monitoring and video downloading. References | Related Articles | Metrics

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A study on Vegetation Coverage Based on NDVI——Taking Cangzhou Grand Canal Cultural Belt as an Example ZHANG Wei, WAN Hong-lin, CHEN Chen, ZHANG Li-jun 2021, 31(4): 72-78.  DOI: 10.16046/j.cnki.issn2096-5680.2021.04.012 Abstract ( )   PDF (2972KB) ( )   Rapid and accurate assessment of urban fractional vegetation cover quality and its change is of important reference to ecological construction and environmental protection. Taking Grand Canal cultural belt in Cangzhou City as an example and choosing Landsat images in 2010 and 2020, based on normalized difference vegetation index the fractional vegetation cover were assessed from 2010 to 2020. The results show that:(1)In 2010 and 2020, the values of FVC  increased from 0.352 to 0.411, showing an trend of increase, especially in the southern area. (2) From 2010 to 2020, 52.6% of the vegetation covered area remained unchanged, 20.2% of the areas decreased, and 27.2% of the areas was increased. Among them, the reduced part mainly concentrated in city center of Cangzhou, Botou, Dongguang, Wuqiao and Qingxian. By analyzing the vegetation coverage change in the past 10 years, it is indicated that the measures to protection, inheritance and utilization of the Grand Canal have achieved initial results,the vegetation coverage of the grand canal cultural belt has been continuously improved. References | Related Articles | Metrics