bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization Design of AC Filters for HVDC Systems Based on Improved Particle Swarm Optimization Algorithm
Authors: Wang Chengliang , Shi Fan , Wang Honghua , Yang Qingsheng
Published: April 2020

In order to reduce the adverse effect of harmonic currents on AC systems and ensure the effective transmission of power in high voltage direct current (HVDC) transmission lines, AC filters (ACF) must be installed on AC buses. Aiming at the limitations of current design methods for AC filters in HVDC systems, this paper proposes a new optimization design method using improved particle swarm optimization (PSO), which aims at the cost of filter investment and constrains the total harmonic distortion rate of AC bus voltage and the telephone harmonic form factor. The optimization mathematical model of AC filters is established, then an improved PSO algorithm is proposed to achieve the optimal design of AC filters. This algorithm introduces a mutation operator and the constraint processing mechanism to improve the exploration ability of this algorithm. Lastly, the simulation model of the ±500 kV HVDC system is established, and the simulation results show that the AC filters optimized by improved PSO have the lowest investment cost while satisfying the harmonic restriction standard.
Simulation Analysis of the Sugarcane Leaves Cutting Process of the Electric Returning Machine
Authors: Lin Yisen , Wen Fujun , Yu Meng , Tang Yanqin , Hu Kun , Wang Yuxing
Published: April 2020

In order to improve the sugarcane leaves cutting effect of electric sugarcane leaves returning machine, the sugarcane cutting process is modelled and simulated by ANSYS/LSDYNA software. It shown that in the double-support cutting mode, the cutter roller ensures the multi-layer sugarcane leaves were cut at the rotate speed of 800 rpm. During the cutting process of sugarcane leaves, the stress is mainly concentrated at the incision, and the sugarcane leaves on the side of the blade are subjected to greater stress. The smaller the distance between the rotary blade and the fixed blade of the same combination, the easier the sugarcane leaves are cut off. In the cutting test of sugarcane leaves, the cutting rate was 91.47%, which echoed the simulation results, indicating that modelling and simulation have reference value.
A Phenomenon Study on Spreading and Evaporating Process of Droplet on DBD Actuator for Wind Turbine Anti-icing
Authors: Chen Zhao
Published: April 2020

This paper reports on the phenomenon of the unique spreading and evaporation process of water droplets on the surface of a dielectric barrier discharge (DBD) actuator. High-speed photography was used to capture the droplet spreading dynamics, and the temperature field evolution was characterized by infrared imaging. On the DBD actuator, the maximum spreading diameters of the droplets are shown to be increased by ∼95%, and the contact angles decrease from 58º to 13º, indicating that the DBD plasma significantly increases the hydrophilicity of the actuator surfaces. It is also revealed that the evaporation time induced by the DBD plasma is 6.54 times faster than that of an electric heater. It is argued that coupled effects of the hydrophilicity caused by plasma and the heat flux in the streamers bridging the electrodes and the droplets should be the crucial points of plasma evaporation physics of impinging water droplets, which are especially meaningful in anti-icing applications.
Simulation Analysis of Water Vapor Condensation during Tire Capsule Vulcanization
Authors: Lu Shuzhen , Chen Songying , Cao Yang
Published: April 2020

Even the vapor vulcanization technology has developed a lot. The uneven temperature distribution caused by the condensation water inside the capsule still exists. In this paper, a numerical simulation study was conducted on vapor condensation of tyre capsule. Using a simplified two-dimensional model, after the 240s calculation, we analysed the result. The result shows that there was flow inside, and it was mainly induced by the condensation water flowing down the wall after it had been produced on the wall. The height of the condensed water layer is about 4.0mm. The volume of condensed water in three dimensions is about 240ml, which results in uneven temperature distribution. The temperature of the wall area with condensed water is about 3 to 13 lower than other wall areas, and the maximum °C°C temperature difference occurs at the deepest part of the condensate layer.
Research on the Cost Control Model of Power Gird Maintenance Based on Fuzzy Pattern Recognition Theory
Authors: Ma Xingbin , Zhang Suiyu , Li Moxiao
Published: April 2020

The power grid lines and equipment maintenance of power enterprises is a complicated construction process, the cost of which is affected by meteorological and geographical factors, and the influence mode is uncertain. Using fuzzy clustering method and the threshold intervals of the objective function in clusters, this paper builds a predictive control model to control the project cost. This model uses relative fuzzy operator to build fuzzy matrix, construct correlation between factors, and describe the factors’ effect. Extracting the cluster’s eigenfunction, and defining the boundaries of various clusters, we determined the type of the predicted points and the range of the objective function. When the actual cost of the maintenance project is within the range calculated by the cost model, then it is normal. If the actual cost exceeds this range, then further analysis of all the aspects of the cost is needed to find out the reason.
Research on Multi-function Power Transmitter of AC Sampling Based on Modbus Protocol
Authors: Si Haifei , Hu Xingliu , Shi Zhen
Published: April 2020

It is of great significance for the stability and optimal operation of the power grid to find and control the abnormal conditions in the operation of the distribution system in time. According to the current situation of distribution network and the demand of distribution automation in China, aiming at the problems existing in the cost, accuracy, communication and reliability of distribution monitoring terminal, this paper puts forward a design scheme of distribution monitoring terminal with arm as the control core and high-precision power measurement chip as the data collection core, and designs the serial communication between computer and power transmitter. Communication protocol, and completed the production of the prototype.
Research on Fuzzy Control System for Constant Current Soft Start of Motor
Authors: Hu Xingliu , Si Haifei , Ye Quanyi , Tian Xiaoming , Fang Ting
Published: April 2020

The soft starter is widely used in the starting of three-phase cage asynchronous motors. Because of its small starting current and reduced damage to the grid and motor during the traditional start-up of the motor it is applied in industrial, agricultural and transportation. The starting current of the motor is controlled by intelligently controlling the firing angle of the thyristor to achieve soft start of the motor in this paper. Fuzzy control is added to the system to establish a control model, which enhances the error resistance of the entire system and enhances the robustness, thus continuously improving the entire system. Fuzzy control is applied in this system to control the constant current soft start of the motor, which greatly improves the intelligence of the motor. The system can reduce the starting current, improve its dynamic torque, can effectively suppress the influence of pure hysteresis. In a large number of experiments and practical production work, it can be proved that the fuzzy control system of motor based on PLC has very good stability, can effectively suppress the influence of pure lag, and indeed has very good control effect.
Comprehensive Risk Assessment Method of Power Grid Based on Grey Relational Weight Game Theory
Authors: Lu Dan , Xu Changqing , Zhang Linjuan , Wang Lili , Sun Yanying
Published: April 2020

Taking the risk assessment of power system which include new energy grid and AC/DC hybrid structure as the research object, the paper proposes a comprehensive risk assessment method based on game theory and grey relational projection. Firstly, by analyzing the risk factors faced by modern power grids, the risk assessment index system is reconstructed from three aspects, grid structure, operational status and energy supply. Secondly, by creating combination weighting model based on game theory, the subjective weight values and the objective weight values of indexes are integrated to eliminate the weight deviation caused by single weighting method. Thirdly, based on grey relation projection model, the projection values of risk index samples on ideal states are calculated, and the overall risk of samples is represented by its superiority to negative ideal state. The proposed method could identify operation modes with high risk for power grid, which is significant to safe and stable operation of the power grid. Finally, by case analysis, the effectiveness of the proposed method is proved.
Research on Harmonic Treatment of Intermediate Frequency Furnace
Authors: Li Hailong , Chen Lepeng , Tan Xiaodong
Published: April 2020

In order to solve the problem of power quality caused by harmonics in the factory, this paper mainly focuses on the research of the current situation of the harmonics in the medium frequency furnaces of the factory forging workshop, analyzes the harmonic content of each medium frequency furnace, and adopts a new W-APF active power filter for harmonic suppression. The experimental results indicate that the harmonic content of the medium frequency furnace meets the requirements of the national harmonic standard of power quality public power grid after W-APF filtering.
Polyether Ether Ketone (PEEK) Properties and Its Application Status
Authors: Ling Xuanzhe , Jing Xishuang , Zhang Chengyang , Chen Siyu
Published: April 2020

The physical, chemical and mechanical properties of polyether ether ketone (PEEK) materials have been comprehensively analyzed. Based on methods for reinforcing modification of PEEK, this review has investigated the application status of PEEK materials, summarized the current production and research and development status quo of PEEK at home and abroad and suggested that the application of PEEK should be promoted.
The Investigation about Gel Properties of New Composite Materials with Meta-kaolin
Authors: Ren Jiaqian , Li Meng
Published: April 2020

As one of the most promising building materials, the composite materials of metakaolin have a wide range of applications and excellent performance. Owing to the lack of research on the early-high-strength characteristics of MK, this article tries to make some meaningful attempts. In terms of the characteristics of hydration calcium silicate with gelation performance, this paper studied the preparation of metakaolin, the type of hydrothermal synthesis products, and the corresponding hydration dehydration phase and its rehydration characteristics. Through the exploration and research of the metakaolin hydrothermal synthetic process, it has prepared a new type of early-high-strength concrete regulator and opened up a new way for the effective application of kaolin. The preparation process, structure, and properties of MK-based concrete performance regulators were systematically investigated by XRD and SEM analysis. The macroscopic properties of the MK-based concrete performance regulator were discussed through coagulation time, hydration heat, and compressive strength performance.
Basic Research on carbon fiber in Discharge State
Authors: Peng Yang
Published: April 2020

In order to solve the oxidation problem of the inner electrode in the pipeline reactor during decontamination, this paper proposes that carbon fiber was used as the pipeline structure of the inner electrode for plasma decontamination. The research results show that the reactor with carbon fiber as internal electrode can work for a long time and the decontamination effect will be enhanced. The decontamination efficiency of the experimental device by using ethyl acetate can reach 91%, and the experimental device was characterized by discharge state of discharge voltage and frequency in argon atmosphere, thus describing the process of discharge energy enhancement.
Study on Catalytic Synthesis of Low Molecular Weight Polyether Polyol by Composite Alkaline Earth Metal
Authors: Li Shuo , Gu Zhenggui , Wang Kaijun , Cao Xiaoyan , Liu Yacheng , Wang Can
Published: April 2020

Polyether Polyol is one of the main intermediates in the synthesis of polyurethane. This research work investigated the optimization of polyether polyol from propylene oxide using Single Factor Experiments and Response Surface Methodology (RSM) through composite alkaline earth metal catalyst (BaO/MgO/γ-Al2O3). The BaO/MgO/γ-Al2O3 catalyst was prepared with alkaline earth metal oxide immobilized on γ-Al2O3 by co-precipitation method. The preparation conditions of the catalysts is calcination temperature=600 °C, n(Ba):n(Al)=0.1:1, n(Mg):n(Al)=0.3:1. Represented with XRD, SEM, BET, CO2-TPD, etc. Characterization results showed that the catalysts indicated strong basic site, perfect particle surface area, pore volume, pore size and relatively uniform particle size distribution. Batch analyses demonstrated that the polyether molecular weight and the epoxide conversion was highly influenced by different process factors which include reaction temperature, pressure, time and the amount of catalyst. The conversion of propylene oxide and molecular weight to target product reached almost 63.5% and 600, respectively under the conditions of reaction temperature 190 °C, pressure 2 MPa, time 6 h and catalyst dosage 6%.
Preparation of Cu2O Particles and their Photocatalytic Properties
Authors: Liu Zongbin , Yu Xiaojiao , Yang Fan , Nie Junkun , Zhao Ningning , Li Junpeng , Yao Binghua
Published: April 2020

Photocatalytic technology is a potential way for the environmental problems caused by antibiotics contained in water. In this paper, Cu2O particles were prepared by hydrothermal method. The microstructure and morphology of Cu2O were characterized by XRD, SEM. The optical and electrochemical properties of the prepared samples were studied by UV-Vis and photocurrent. The results show that the prepared Cu2O have an octahedral morphology and exposes more (111) crystal planes, with a particle size of 2-5 μm, and has the better optical absorption performance at 500-600 nm. Finally, the photocatalytic performance of the samples was evaluated using Norfloxacin as the target degradation pollutant. The results show that the degradation rate of Norfloxacin over the prepared Cu2O was 79.8%.The •OH and •O2
− play a major role in degradation of Norfloxacin.
Adsorption Characteristics of Lead by Biochar from Mouth Rinse Residue
Authors: Xie Fang , Zhang Haoke , Liu Jiajia , Tian Shuge
Published: April 2020

Biochars were prepared from mouth rinse residue between 200°C and 600°C.The effects of different pH, adsorbent dosage, adsorption time, and initial concentration of solution on Pb2+ adsorption were investigated. The results showed that the Pb2+adsorption amount of the biochar increased with the increasing pH. At 200°Cand 300°C, the optimum pH was 6.0, and the optimum pH was 7.0 between 400°C and 600°C. The optimal adsorbent dosage was 0.02 g. Pb2+ adsorption amount indicated that biochar prepared at lower temperature was better. The Pb2+ adsorption process of biochars could be well fitted by the quasi-second-order kinetic equation. Fitting five kinds of biochar with Langmuir and Freundlich model showed that the biochars fitted the Langmuir model whose maximum adsorption capacities were 188.68, 185.19, 135.14, 109.89 and 86.21 mg/g respectively. Accordingly, biochar can be a effective way to expand the resource utilization of residue.
Breeding of High-yield Alkaline Protease Producing Strain by Atmospheric and Room Temperature Plasma Mutagenesis
Authors: Liu Yongkang , Li Shichang
Published: April 2020

To obtain alkaline protease producing strain with high-yield, the strain Bacillus subtilis was treated by atmospheric and room temperature plasma (ARTP) mutagenesis. The results showed that the strain had a higher positive mutation rate when the mutagenesis time was 50s. Finally, a high-yield mutant strain A59 was obtained after repeated mutagenesis by ARTP and enzyme activity increased by 23.38% from 6835U/mL to 8433U/mL. Then fermentation conditions of mutant strain were optimized by single-factor method and response surface method, and the optimum fermentation conditions were as follows: 3.6% soybean meal, 5.2% corn meal, 0.9115% Na2HPO4, 0.1593% Mg2+, 0.09% Tween-80 and 5% inoculation volume. Under the conditions of the verification experiment, the enzyme activity of the A59 strain reached 14026 U/mL, which was 2.05 times that of the original strain.
Weather Resistance Performance of Backsheets with Various Structures
Authors: Zhuang Hao , Gou Linlin , Bai Xueliang , Zhou Su , Huang Guoping , Li Jingnan
Published: April 2020

Backsheet is the key element to ensure the power generation of PV modules during their whole life cycle. To continually decrease the LCOE, backsheets of new structures are gradually applied. Currently, the evaluation of module product performance is mainly on the module scale, while the assessment of each single material is rare. This paper is aimed at the evaluation of each single backsheet’s reliability when applied in different climatic environments for the widely used new backsheet structures (BS1-BS5). Through comparative research, the backsheet based on thicker PET was found to have a better mechanical performance and BS3 exhibited good resistance performance in hot and humid condition, which could be attributed to the low water vapor transmission rate of the PO film.
Study on Vertical Bearing Characteristics of Bridge Pile Foundation in Karst Area Considering the Size
Authors: Feng Zhongju , Chen Jinhua , He Jingbin , Huang Zhouyi , Dong Yunxiu , Jiang Dingran , Meng Yingying
Published: April 2020

By using finite element software, the influence of different karst cave span on the bearing characteristics of bridge foundation is analyzed. It is found that when other conditions are certain, with the increase of karst cave span, the ultimate bearing capacity presents a decreasing trend, and the lateral friction of pile drops steeply within the range of karst cave and decreases to a greater extent, showing a certain degree of depth effect, and the end resistance proportion also increases. The results show that when the span of the karst cave is more than 9m, the lateral friction resistance within the range of the karst cave of the pile body drops sharply. The research results can further deepen and perfect the design of pile foundation in karst development area and guide the construction, which has certain theoretical significance and engineering application value.
Study on the Influence of Karst Size on the Vertical Bearing Capacity of Pile Foundation
Authors: Feng Zhongju , Guo Suizhu , He Jingbin , Huang Zhouyi , Dong Yunxiu , Jiang Dingran , Xia Chenming
Published: April 2020

Based on the actual project, this paper studies the vertical bearing characteristics of bridge pile foundation in karst area by Marc numerical simulation. The results show that the vertical ultimate bearing capacity of pile foundation has a negative correlation with the size of karst cave. With the increase of span, the bearing capacity of pile foundation and its sub- bearing capacity decrease. When the span of karst cave is 2m × 2m, the ratio of pile side resistance to pile end resistance is 3:1. When the cavern span is increased to 12m × 12m, the ratio of pile side resistance to pile end resistance is 9 : 1. Therefore, it is necessary to fully consider the influence of the size of the karst cave on the bearing characteristics of the pile foundation during the construction, and make corresponding engineering disposal measures according to the influence degree of different influencing factors, so as to improve the design and construction effect of the pile foundation.
CONSTRUCTION Process Analysis of Giant and Complex Steel Structures
Authors: Chen Junjie , Luan Wei , Gong Ke , Ma Jun
Published: April 2020

The main structure of Xi ’an Silk Road International Conference Centre is a giant steel braced frame structure. The façade of the structure is made up of huge suspended skirtlike suspended structure supported by cantilever roof trusses and steel suspensions, which adds up its complexity. In order to accurately control the installation precision and facilitate the installation of curtain wall glass in the later stage, the pre-chamber construction method is adopted in the roof truss installation to compensate the construction deformation of suspended structure. The static analysis is conducted by SAP2000 to propose a reasonable pre-camber value of the roof cantilever truss. The nonlinear simulation of the construction process is carried out. Through comparative analysis, the optimal sequence of the steel structure construction is obtained, which provides the theoretical basis for the construction of giant and complex steel structures.
Finite element analysis on connection performance of prefabricated steel joints with grouting bolt sleeve
Authors: Kaixuan GUO , Lin GAO , Linlin LIU , Gefei LI
Published: April 2020

Under the national strategy of developing vigorously the prefabricated structure, to study the prefabrication and assembly of steel reinforced concrete shear walls, but the connection performance of the precast steel frame is the key to determine whether the prefabricated structure can be carried out. To the steel joint with grouting bolt sleeve, based on the ABAQUS finite element analysis software, the anchorage length, the thickness of sleeve wall and the bolt diameter are used as the analysis parameters, and it is to be analyzed for the influence trend of the model parameters on the joint performance. The results show that the anchorage length, the thickness of sleeve wall and the bolt diameter all have a positive influence on the tensile bearing capacity, in the meantime, the rational combination can optimize the failure state and improve the tensile bearing capacity of the joints.
Finite Element Calculation and Analysis of Stress and Deformation Characteristics of Arch Dam
Authors: Wei Ping , Wei Liuchuang
Published: April 2020

The arch dam is a high-order and ultra-static overall space shell structure on the consolidation and bedrock, and its geometry, boundary conditions and stress state are complex. The three-dimensional finite element solid model of arch dam is established, and the stress and deformation characteristics of the actual dam project are calculated. It is concluded that there is a large tensile stress at the dam at the arch crown section and a large compressive stress at the dam site. The transverse displacement of the body occurs at the abutment of the upstream and downstream faces. The calculation results are in accordance with the stress and deformation characteristics of the arch dam, and the maximum stress and maximum displacement meet the design requirements of the arch dam.
Numerical Analysis of Deformation of Deep Foundation Excavation in Soft Clay Considering Influences of Time-effect
Authors: Lu Yuan , Bian Youyan , Liu Fusheng , Huang Juehao , Chen Jian
Published: April 2020

The traditional foundation pit design generally only considers the transient deformation. However, the excavation deformation characteristics of deep foundation pits in soft soil layers not only consider the small strain characteristics during the excavation, but also consider the time effect. Taking a foundation pit in Wenzhou as the engineering background, based on the HSS model and the SSC model, PLAXIS finite element software was used to simulate the excavation process of the deep foundation pit. The deformation characteristics of retaining structures and deep excavation are compared and analyzed. Calculations prove that: The deformation rules of the foundation pit with the time effect is basically the same as those without the time effect. During the excavation of the foundation pit, the horizontal displacement of the diaphragm wall, the ground settlement and the foundation upheaval calculated based on the SSC model are larger than those calculated based on the HSS model. The calculation results based on the SSC model show that after the completion of the excavation, the deformations of the foundation pit continue to increase with time, showing a rheological effect. The conclusion can provide theoretical guidance for the construction of foundation pit excavation in Wenzhou area to ensure the safe implementation of the construction process.
Saint Venant solutions for elastic cylinders
Authors: Zhang WX , Yang LM
Published: April 2020

Under the Hamilton system, the dual form governing equations of the cylindrical problem are established using displacements and stresses as the basic variables, and the problem is accordingly transformed into finding the eigenvalues and eigensolutions by adopting the method of separation of variables. Furthermore, solutions for zero eigenvalues and non-zero eigenvalues are systematic studied. The study shows that zero eigensolutions are composed of all the overall deformation solutions such as the traditional tension and bending problems, while non-zero eigensolutions include the torsion and bending groups charactered by local deformations.
An analytical method for the creep and stress relaxation of viscoelastic materials
Authors: Zhang WX
Published: April 2020

Based on the properties of symplectic system and the symplectic orthogonal normalization relation between the eigensolutions, the calculation method of viscoelastic boundary condition problem is given, and the computation of stretching and bending problems is carried out. The results show that the creep property of viscoelastic materials.
Inference of Short-Term Maximum Crack Width of RC Flexural Members Based on Interval Estimation Method
Authors: Yao Jitao , Yan Hanbing , Yan Mingdong
Published: April 2020

The design method based on observation and experimental model only considers the design of ultimate limit state in related research, the application range is not wide. This paper takes the short-term maximum crack width of RC flexural members as an example, puts forward the application of this method in the design of serviceability limit state. Dimensionless method was used to collect 4665 pieces of RC flexural member crack width data, and the normality test was performed to obtain the type of probability distribution obeyed by the crack width. Considering the situation without parameter information and known coefficient of variation, a direct estimation formula for short-term maximum crack width of RC flexural members based on interval estimation method is proposed.
Energy saving application of phase change materials in buildings: A comprehensive review
Authors: Yichao Zhang , Ying Wang , Jinghai Zhou , Zhongren Zhang , Tong Li
Published: April 2020

The theoretical basis of the preparation of phase change energy storage materials is analyzed firstly, and then the preparation methods of fatty acid phase change energy storage materials are analyzed in detail. Furthermore, the application of phase change energy storage materials in building energy saving is analyzed. Finally, combined with the above contents, the application prospect and research direction of phase change energy storage materials are briefly described.
Numerical Simulation on Dynamic Response of Prestressed Concrete Slab Subjected to Blast Loading
Authors: Bai Chongxi
Published: April 2020

In order to obtain the dynamic response of prestressed concrete slab subjected to blast loading, the numerical modeling method for the dynamic response analysis of this kind of member subjected to blast loading was introduced, and the numerical model was established based on the ANSYS/LS-DYNA program. By comparing the numerical simulation results of the dynamic response of reinforced concrete slab with the experimental data subjected to blast loading, the accuracy of the numerical model was verified. So the numerical simulation method can be used in dynamic response analysis of prestressed concrete flexural members subjected to blast loading, with a certain precision.
Improving Duct Parameters to Design Auxiliary Ventilation in Mining Roadways Driven
Authors: Dang Phuong Thao , Bui Van Duyen
Published: April 2020

The level of air leakage of air movement through the duct to the face in underground mine is an important factor in ensuring the efficiency of ventilation during mining roadways being driven in mine. Ventilation ducting system leakage can, in many cases, supply an insufficient quantity of air to the workplace.

Based on the experimental data of the duct leakage measurement when mining roadways driven in Ha Lam Coal mine, a relationship of leakage coefficient, aerodynamic parameter and geometric parameter of the duct has been derived; also maximum vent length with certain auxiliary ventilation equipments has been determined.
Exploration and practice of teaching reform of industrial robot course based on application ability training
Authors: Wang Li , Zhang Enguang
Published: April 2020

Intelligent manufacturing is the main direction of the development of modern manufacturing, and robot technology is applied more and more widely, which puts forward higher requirements for the cultivation of robotics talents in Colleges and universities. As a pilot college transforming to an application-oriented college, we have carried out reform and exploration on the teaching content, teaching method and teaching mode of the course of industrial robot. We have adopted flexible and diverse teaching methods and step-by-step practical courses, which have effectively stimulated students’ interest in learning, cultivated students’ innovative practical ability and achieved good practical results.
Finite element analysis of passenger car transverse stabilizer bar based on NX8.0
Authors: Zhang Enguang , Hui Shuai
Published: April 2020

The parametric design and finite element analysis of the lateral stabilizer bar of the new energy bus were carried out by using NX8.0, and the structural strength and stiffness of the stabilizer bar were qualitatively analyzed. The simplified methods for different boundary conditions, solving types and finite element models are compared. All the processes are completed under the same software, which ensures the uniformity and editability of the data. Finally, the subject is introduced into the student s computer-aided engineering analysis training program, so that the students” comprehensive ability is improved.
Mechanical response analysis and optimization of snap on Prefabricated Concrete Pavement Slab
Authors: Chunhua Hu , Xuan Wang
Published: April 2020

In this paper, a kind of assembled cement concrete pavement slab was numerical analysis to investigate the influence of the size of the tongue and groove joint on load transfer capacity between slabs and the maximum stress in the slab. And the load transfer capacity of the slab and the maximum stress in the panel of different sizes are optimized.
Research on development law of horizontal freezing temperature field of complex curtain
Authors: Yu Changyi
Published: April 2020

Artificial freezing method has been widely used in various underground projects, but the development law of freezing temperature field of complex curtain is difficult to be calculated by analytical method. As a general method, numerical method is feasible to simulate the development law of horizontal freezing temperature field of complex curtain. In this paper, the development law of temperature field in the freezing process is analyzed based on the freezing method construction of a subway connecting passage. The feasibility of this method is verified by comparing with the measured data. The results can be used to guide the design and construction of artificial freezing.
Modeling and Analysis of CTCS-1 On-board Subsystem Based on Simulink/Stateflow
Authors: He Yangyang , Liu Zhongtian
Published: April 2020

According to the structure of the CTCS-1 train control system and the complexity of its on-board subsystem functions, a model-based method was used to implement the modeling and simulation of the on-board subsystem that using the combination of Simulink and Stateflow in MATLAB software. Then this paper analyses the emergency braking distance and the actual running curve of the train when the following trains at different speeds exceed the emergency braking trigger speed. The results show that the braking distance generated by the established emergency braking trigger model meets the requirements given by train manufacturers, and has a certain safety margin, which also verifies the correctness of the model. The modeling method is intuitive, efficient, visual, and easy understand that the model can well describe the characteristics of the system. The simulation results can provide certain support for the design, research and implementation of the on-board control subsystem of the CTCS-1 train control system.
BDS triple-frequency carrier phase combination smoothing pseudo-range algorithm
Authors: Meng Fanjun , Li Shujun
Published: April 2020

The carrier phase smoothing pseudo-range algorithm can effectively reduce the influence of multi-path effect and observation noise on pseudo-range positioning and improve the accuracy of pseudo-range positioning. Aiming at the problem that the existing classic Hatch filter smoother is susceptible to the cumulative interference of ionospheric delay in the pseudo-range smoothing process, the ionospheric delay and observed noise of the original double-difference observation are further weakened by constructing the optimal Beidou triple-frequency linear combination. The triple-frequency double-difference carrier phase combination are used to smooth the pseudo-range combination to replace the original observations. Finally, four groups of Beidou triple-frequency measured data with different baseline lengths, including 4m, 14.4km, 61.7km and 131.6km, are used to verify the algorithm. The theoretical derivation and effectiveness of the algorithm are verified by comparing and analyzing the smoothing effect of the algorithm in the following four groups of baseline conditions.
Ways to Correct the Errors in Posture of Multi-beam Sounding Resulted from Water Flow
Authors: Wang Xin , Feng Chengkai , Yu Jiayong , Tian Maoyi , Fu Pingwei
Published: April 2020

Multi-beam bracket deformation is caused by factor like water flow and speed of ship. Such deformation also leads to the axle offset of relative attitude indicator of transducer, which may influence the accuracy of results. As for this phenomenon, the paper proposes a method that calculates water velocity and output speed of ship according to the navigation data, in order to fit the attitude deviation and correct the results of depth measurement. First of all, water velocity and output speed of ship of two adjacent stripes without abnormal sounding results in the testing zone in good sea condition are calculated respectively according to navigation data, and then the errors in posture of these two stripes in different time are worked out respectively based on discrepancy in elevation of the overlapping portions of the stripes; secondly, a modifier formula of water velocity, output speed of ship and errors in posture is formulated; finally, this formula is applied to solving errors in posture and correcting the sounding data of stripes in the testing zone. According to the experimental results, the proposed method can eliminate errors in posture effectively, with the average of discrepancy in elevation reduced from 0.188m (before) to 0.032m (after). The stripe splicing effect is improved and the data accuracy is enhanced enormously.
Application Research of Earth Volume Calculation Based on 3D Laser Point Cloud Data
Authors: Wang Yan , Fan Zixian , You Yingchun
Published: April 2020

the accurate calculation of earth volume is a very important work in engineering construction. The traditional calculation of earth volume requires the use of RTK measurement to collect a large number of data, which makes the workload outside the page very large and seriously affects the efficiency. 3D laser scanning technology is now widely used in many areas. This paper uses a 3D laser scanner to collect data from a school experimental site and calculate the earth volume. Then compare with traditional RTK measurement methods. The results show that the three-dimensional laser scanning technology has a fast speed, high precision and good results. This technical method has achieved good results and is worth promoting.
Characteristics and Prevention Measures of Loess Geological Disasters in Longdong Region
Authors: Yang Yang , Liu Wanfeng , Hu Aiping , Zhang Binwei , Yang Hongping
Published: April 2020

In recent years, loess geological disasters in Longdong region occurred more and more frequently. On the basis of investigation on loess geological disasters in Longdong region and analysis of basic physical characteristics of loess geological disasters, landslide, collapse, debris flow and loess collapsibility are identified as the main geological disasters in Longdong region. The causes of four types of loess geological disasters in Longdong region are studied and corresponding prevention measures are proposed.
Experimental Study On Mechanical Properties Of Polyacrylonitrile-Polypropylene Thick Fiber (PAN-PPTF) Concrete With Different Thickness
Authors: Liang Cao , Yun-fei Zhang , Zhen-shu Li
Published: April 2020

In order to improve mechanical properties of concrete and reduce the use of steel, in this experiment, polyacrylonitrile fiber (PAN) and polypropylene thick fiber (PPTF) were mixed to replace the use of steel fiber, and the thickness of the PAN-PPTF concrete was changed. The results showed that the compressive strength of concrete test blocks decreased with the increase of the thickness of PAN-PPTF concrete, but the split-tensile strength and bending strength of test blocks both increased. When PAN-PPTF concrete was 1/3 of the test block, the compressive strength decreased by 5.62%, but the split-tensile strength increased by 36.08%, and the bending strength increased by 38.48%.
Research on Field vane Shear Strength of Marsh Peat Soil in South America
Authors: Zhang Ruiqi , Chen Yuntao , Zhu Shengli
Published: April 2020

According to high backfilling project in South America, through a large number of laboratory tests data and field vane shear test results, the engineering characteristics of marsh peat soil in this area are analyzed, and the variation of the shear strength of the peat soil along the depth and the sedimentary characteristics are demonstrated. The selection principle of the calculation index of the foundation for the high-filling operation of peat soil foundation is proposed. It has reference significance for similar engineering construction.
Technology for Rapid Consolidation of Shallow Ultra-soft Soil
Authors: Tianyun LIU
Published: April 2020

The shallow ultra-soft soil needs to be consolidated quickly to form the early working layer in more and more land reclamation. Through the innovation and improvement of the conventional vacuum preloading method, the technology for rapid consolidation of the shallow ultra-soft soil is created, which adopts auxiliary measures such as erection of foam floating bridges, construction of water retaining dams, and laying of geotextiles on the mud to realize the manual construction of plastic drain plates, and innovatively applies of the recyclable tri-planer geonet instead of the sand cushion. The technology has been successfully applied to the practical reinforcement engineering of the shallow ultra-soft soil and achieved good effect, which has a good prospect of popularization and application.
Seismic Behavior of a Novel Prefabricated Concrete Sandwich Panel System
Authors: XU Zilong , Xie Qun , YU Xiaowei , Zhang Shoushuo
Published: April 2020

An innovative sandwich wall panels as structural load-bearing elements have been presented. Besides the conventional configuration of sandwich panel, this new panel system has some distinctive characteristics including core column reinforced by spiral stirrup along the panel cross-section with spacing 650mm, foamed concrete as insulation layer, self-compacting concrete used in external layers. Furthermore, to improve the global strength and stiffness of panel, 3D steel wire system which is composed by two vertical steel wire meshes connected by horizontally short steel bar has been uniquely employed in concrete layer. An experimental campaign has been carried out to investigate the seismic behavior of this new panel system. According to the analysis of load-bearing capacity, hysteretic behavior, skeleton curves and stiffness degradation, conclusions could be drawn that the new prefabricated concrete sandwich wall system has comparable performance with traditional concrete solid wall.
Study on deformation characteristics of permafrost roadbed considering the influence of temperature field
Authors: Li Bin , Liu Zhao
Published: April 2020

Taking ha-da railway passenger line as the research object, the temperature field of the subgrade in frozen soil area is simulated by numerical calculation method, and the influencing factors and distribution of the temperature field of the permafrost subgrade are analysed. Finally, the following results are obtained: with the increase of climate warming temperature, the temperature field in the roadbed changes slowly, and the temperature at different depths increases. When the maximum freezing depth appeared after 20 years, the roadbed was in full positive temperature due to the influence of climate warming. The settlement of roadbed after construction under the action of temperature field and force field does not exceed 15mm, which meets the requirements of the code.
Finite element analysis of rutting on full depth asphalt pavement in port area considering temperature field
Authors: Chunhua Hu , Yuhao Chen
Published: April 2020

To investigate the rutting of the full depth asphalt pavement in the port area, finite element software is used to establish a temperature field model. The vertical deformation of the pavement structure is calculated under five axial load level. Numerical analysis results show that for the proposed pavement structure, vertical deformation is more obvious on the upper layer of the pavement. And it is mainly reflected in the positive deformation of the center of the wheel gap and the negative deformation of the tire centre. In the pavement structure, the middle layer contributes the most to rutting, and the methods for reducing rutting can be explored for this layer of material. The magnitude of the axle load has a great influence on the rut, and the road at the P
1 level in the port area is more suitable for full depth asphalt pavement. During the period of 220,000 to 400,000 axle loads, the increase in rut deformation is the largest, and the prevention of rut problems on the road can be carried out at this stage.
Research and analysis on residual shear strength of surrounding rock base on elastic-plastic softening model
Authors: Zhou Heng , Zhang Ying , Liu Bo , Di Shengjie , Huang Peng
Published: April 2020

The excavation of caverns caused the unloading of the surrounding rock, which decrease the strength of the rock mass. In this paper, an ideal elastic-plastic stress-strain softening model is used to analyse the shear strength sensitivity of the surrounding rock during cavern excavation, in order to research the relationship between deformation, stress, plastic zone and the strength parameters. The results show that the values of each shear strength parameter have a significant effect on the distance of the plastic zone, and the sensitivity of the plastic zone distance shows that the influence of peak internal friction angle, residual internal friction angle, residual cohesion and peak cohesion decreased successively.
Study on physical and mechanical properties of flowing mud in the Shenzhen area
Authors: Ai-rong ZHENG
Published: April 2020

Flowing mud is a kind of special soil with fluidity under gravity. It is found that the flowing mud has ultra-high water content, high limit moisture content, and its strength is very low due to the large amount of free water. Therefore, the shear strength evaluation is not appropriate. With the increase of preloading load, the shear strength increases continuously. However, the coefficient of consolidation is small and the consolidation time is long.
The influence of excavation of the dredged foundation of transmission towers on the stability of Yanzi landslide
Authors: Yingbo Zhou , Hang Chen , Qiupeng Zhou , Zhiqiang Duan , Xiaojing Gao , Lisong Gao , Yongqiang Zhou
Published: April 2020

With the construction of the national network project, transmission towers are inevitably erected on the landslide body. Excavation of transmission tower foundation often causes disturbance to the soil of the slope and reduces the stability of the slope. At the same time, the unfavorable stacking of construction spoil is also an unfavorable load to the slope. Under the combination of various unfavorable factors, slope instability accidents are prone to occur, causing losses to the grid operation. In order to reduce the amount of excavation and to minimize the impact of foundation excavation on the landslide, generally, dredged foundation is the selected excavation method of the transmission tower foundation. Therefore, this article takes the Yanzi landslide and 500kV transmission tower as the research object. Firstly, the mechanical parameters of the soil of the Yanzi landslide were analyzed, and then the influence of the excavation of dredged foundation and the spoil pile loading on the stability of the landslide was studied by 2D finite element method. Finally, 3D finite element method was used for verification and supplementation. The results show that the foundation excavation of transmission tower has negligible effect on total landslide stability, but local potential landslides need to be considered.
3D printable ‘just-add-water glass and water’ geopolymer-an experimental research based on extrusion-based 3D printing practices
Authors: Yin Xiaohong , Liu Kaiyuan , Zheng Shuyi , Zhuang Kunde , Wang Xiaodong , Fang Yuan , Ding Zhu
Published: April 2020

The application of 3D printing technique has been bringing construction to a new stage. Development of suitable materials and suitable printing process of printable mixtures are very important issues. The present study aims to understand the strategies for the application of ‘just-add-water glass and water’ geopolymer in extrusion-based 3D printing. The 3D printing practice showed that the satisfactory printing quality, including extrudability, shape retainability, and buildability, can be achieved by adjusting water-to-binder ratio and gap time between layers for the ‘just-add-water glass and water’ geopolymer in fly ash – slag binary system.
Validation of MODIS C6 Aerosol Optical Depth in China
Authors: Zhang Tianqi , Cao Hongye , Song Huaiqing , Shi Haixia
Published: April 2020

The accuracy of MODIS Collection 6 (C6) aerosol optical depth (AOD) products in China is validated by using AERONET (Aerosol Robotic Network) ground observation data. The scatter plots and linear fitting results of each ground site are obtained, and the research area is divided into five parts. Analyzed the retrieval effects of MODIS C6 AOD products in different areas. The results show that: (1) In North China and Southeastern coastal, the difference between MODIS and AERONET AOD is small, and the retrieval accuracy is good. (2) The Northwest and Central and Eastern are uncertain due to the diversity of topography and landforms. (3) The accuracy of the Qinghai-Tibet Plateau is poor and there is a serious overestimation. Compared with the previous MODIS version of AOD products, the accuracy of C6 products in various regions of China has been significantly improved, which can provide data support for aerosol spatial-temporal distribution and atmospheric particulate matter retrieval research.