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28 October 2022, Volume 48 Issue 5 Previous Issue    Next Issue

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Materials Science and Engineering

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Numerical simulation of temperature field of flux bands constrained arc welding T-joint FENG Rui, WANG Lei, LU Wan-quan, WANG Guang-yu, QIAO Ji-sen 2022, 48 (5):  1-7.  Abstract ( 350 )   PDF (5833KB) ( 310 )   Save In order to investigate the distribution law of temperature field of flux bands constrained arc (FBCA) welding in T-joint which is the basic welding unit of I-core sandwich panel, a computational approach was developed to predict the temperature field of T-joint by FBCA welding based on ABAQUS nonlinear finite element software. The calculated results were compared with the actual measurement results, and the heat distribution on the respective paths of the face and the core plate were studied. The result showed that the temperature field of T-joint in FBCA welding is symmetrically distributed along the weld center, and the heat distribution is mainly concentrated on the face plate. The combined heat source model can not only precisely simulate the temperature distribution morphology of weld section and the width of heat affected zone compared with the experiment, but also have a good agreement about the thermal cycle of typical points measured by the IR camera, which verifies the rightness of the combined heat source model in calculating the temperature field of T-joint in FBCA welding. References | Related Articles | Metrics

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Effect of PVA coating on the performance of electroless copper plating layer on the surface of Kevlar fiber JIA Jian-gang, SU Cheng, XIA Ting-xi 2022, 48 (5):  8-14.  Abstract ( 299 )   PDF (5297KB) ( 172 )   Save The stability and integrity of the metal coating on the Kevlar fiber surface were improved by the method of polyvinyl alcohol (PVA) coating, thereby improving the anti-peeling ability of the coating. The bend-peel-off test was performed to investigate the anti-peeling ability of the metal layer. The resistance tester and the electronic universal testing machine were used to test the conductivity and tensile strength of the sample. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the surface morphology and chemical valence of the sample. The results showed that the PVA coating can effectively improve the anti-peeling ability of the metal coating. As the PVA concentration increases, the surface resistivity of the copper-plated Kevlar fiber increases, while the flexibility decreases. When the concentration of the PVA solution is 5 g/L, the flexibility, conductivity, and anti-peeling ability of PVA-coated Cu/Kevlar fiber can be maintained at an optimal state. At this concentration, the surface unit resistance of the PVA coated Cu/Kevlar fiber is 0.41 Ω/cm, the monofilament tensile strength is 2.396 GPa, and the fitting degree of the Weibull distribution is 0.988 1. References | Related Articles | Metrics

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Hydrothermal preparation of nano-SnO2 electrode materials and their lithium storage properties FAN Ying-qiang, CHEN Xiu-juan, WANG Lin-lin, WU Jia-kui 2022, 48 (5):  15-20.  Abstract ( 309 )   PDF (3150KB) ( 448 )   Save SnO2 anode material was prepared by a simple hydrothermal method using SnCl2·2H2O, polyethylene glycol 400 (PEG400) and Na3C6H5O7·2H2O as the main raw materials. The composition and microscopic morphology of the prepared negative materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Theelectrochemical properties were also tested using galvanostatic charge/discharge (DC) and cyclic voltammetry (CV) methods. The results showed that the addition of PEG400 can effectively improve the surface morphology of SnO2, reduce its agglomeration phenomenon and significantly improve the electrochemical properties. When the addition content was 10 mL, the synthesized SnO2 has good cycling and multiplicative performance with a first discharge capacity of 2 774 mAh/g andthe discharge capacity of 600 mAh/g after 50 cycles, which was significantly higher than that of SnO2 electrode materialsbefore the modification. References | Related Articles | Metrics

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Preparation of MOF based porous carbon and its application in supercapacitor WANG Pi-tao, WU Li-li, CHEN Xin-guo, ZHANG Jian-qiang, LUO He-ming 2022, 48 (5):  21-29.  Abstract ( 273 )   PDF (5544KB) ( 154 )   Save Metal-organic framework materials (MOFs) have broad application prospects as precursors in electrochemical fields due to their high specific surface area, pore structure, and structural and functional diversity. In this paper, the metal-organic framework material [Zn3(bpdc)3(bpy)]·2DMF·4H2O](ZBB) was synthesized by hydrothermal method, the porous carbon ZBBC-T-A was prepared by carbonization and activation method. The effects of different carbonization temperatures and different carbon base ratios on the microstructure and electrochemical properties of porous carbon were studied. The results showed that the porous carbon ZBBC-800-1∶3 is mainly microporous and mesoporous, and the maximum specific surface area is 2 294.6 m2 ·g-1. Using 6 mol·L-1 KOH as electrolyte, the specific capacitance is 304.8 F·g-1 the current density 1 A·g-1. When the current density increases from1 A·g-1 to 10 A·g-1,the capacitance loss rate is 21.26%. At the current density of 1 A·g-1, the capacitance retention is 95.85% after 5 000 cycles calculated energy density is 8.06 Wh·kg-1. References | Related Articles | Metrics

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Study of optical and electrical properties of MoO3doped organic semiconductor NPB ZHAO Yu-kang, SU Jiang-sen, WU You-zhi, ZHANG Cai-rong 2022, 48 (5):  30-34.  Abstract ( 258 )   PDF (1539KB) ( 319 )   Save Hole only single carrier devices were prepared by introducing transition metal oxide MoO3 into the typical organic hole transport material amine derivative NPB (N,N'-diphenyl-N,N'-bis(1-naphthyl) (1,1'-biphenyl)-4,4'diamine). The results showed that the introduction of MoO3 significantly enhances the conductivity of NPB, at an applied voltage of about 2.0 V, thecurrent density for a 100-nm-thick pure NPB device is only 1.28 mA/cm2, while that for NPB∶MoO3 (50 wt.%) device with the same film thickness is as high as 2 530 mA/cm2. The absorption spectrum of the NPB∶MoO3 film with the same doping ratio showed that there is an additional absorption peak near 500 nm, which is different from that of NPB or MoO3, indicating that a charge transfer complex NPB+-MoO-3 has been formed in the doped system, resulting in additional hole carriers and thus enhancing the conductivity of the doped film. Further fluorescence analysis showed that the introduction of MoO3 has a significant quenching effect on the fluorescence of NPB. The fluorescence intensity of the NPB∶MoO3 (30 wt.%) films is reduced by two orders of magnitude compared to the pure NPB films, while that of the NPB∶MoO3 (50 wt.%) film was essentially reduced to zero. References | Related Articles | Metrics

Mechanical Engineering and Power Engineering

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Coupling optimization analysis of casing profile in suction and exhaust for liquid-ring vacuum pump ZHANG Ren-hui, LIU Gui-hong, WEI Xiao-xiao, MENG Fan-rui 2022, 48 (5):  35-42.  Abstract ( 177 )   PDF (6941KB) ( 79 )   Save The direct free-form surface deformation method was used to parameterize the whole casing profile in the suction and exhaust section of liquid-ring vacuum pump. The multi-parameter regression model of the casing profile for the inlet vacuum and efficiency was established byusing the response surface method. Multi-objective optimization of liquid-ring vacuum pump performance was carried out based on NSGA-Ⅱ algorithm, and the internal flow field and external characteristics of the optimized model and the initial model were compared and analyzed. The results show that the vacuum of the optimal vacuum model obtained by NSGA-Ⅱ multi-objective optimization is increased by 4.5%, and the efficiency of the optimal efficiency model is increased by 1.3%. All the different parts of the casing profile have a significant effect on the inlet vacuum and efficiency of the liquid-ring vacuum pump, but the influence of the casing profile in the suction section on the performance of the liquid-ring vacuum pump is obviously greater than that in the exhaust section. On the basis of traditional design, increasing the radial size of suction casing is helpful to improve the vacuum of the pump inlet. The smaller diffusion ratio of suction area and shrinkage of exhaust area would cause higher hydraulic efficiency in the pump. The casing profile with smaller radial size in the compression zone is beneficial to increase the vent pressure and reduce the back flow of the vent, thus improves the efficiency of the pump. References | Related Articles | Metrics

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Dynamic reliability study on driving transmission of mine dump truck wheel side reducer YIN Yu-xin, WEI Yong-qiao, LIU Yong-ping, YAN Chang-feng, XIE He-ping 2022, 48 (5):  43-51.  Abstract ( 284 )   PDF (2151KB) ( 494 )   Save The wheel reducer driving system is the core component of the wheel hub drive system, which reliability directly affects the operating reliability and working life of the entire drive system. In view of the deficiency that only single tooth surface failure or tooth root failure is considered in the reliability evaluation of the existing wheel reducer transmission system, a dynamic reliability calculation method considering the correlation between the two failures is proposed. Firstly, a stochastic model of the strength degradation of tooth surface and tooth root is established respectively on the premise of considering the strength degradation of gear material. Secondly, based on the stress-strength interference theory and the Monte Carlo method, the dynamic reliability curve of the gear considering the strength degradation is calculated for both types of failures. Thirdly, a mathematical model of the dynamic reliability of a single gear is derived based on Copula function. Finally, the theorem of Sklar is applied to describe the correlation of part failure processes to obtain a mathematical model of the dynamic reliability of the wheel reducer driving system. The results of verification by calculation example show that this method can reveal the relationship between the fatigue life of the system and that of each component under multiple failure modes and factors. This method can provide a theoretical basis for the reliability evaluation and prediction of the wheel reducer driving system. References | Related Articles | Metrics

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Identification of axial dynamic characteristic parameters of ball screw feed system WU Qin, CHEN Guo-zhang 2022, 48 (5):  52-58.  Abstract ( 228 )   PDF (1880KB) ( 245 )   Save Aiming at the problem of identifying the parameters of the axial dynamic characteristics of the ball screw feed system, a new method for identifying the parameters of the rolling joints in the assembled state is proposed. First, the left and right bearing pairs and screw nut pairs are simplified into concentrated spring-damping elements, and the ball screws are simplified into elastic rod. The system's axial stiffness and damping parameter identification equations under the action of simple harmonic excitation force are established. Then, based on the excitation force amplitude, frequency, the distance between each support point and the amplitude of the measuring point, the optimization objective function is established, using the particle swarm genetic hybrid algorithm to identify the axial dynamic characteristic parameters. The research results show that the identification error of the stiffness and damping parameters of the feed system is within 2.56%, which verifies the correctness and effectiveness of the method. References | Related Articles | Metrics

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Rolling bearing fault diagnosis based on wavelet packet energy entropy and GWO-SVM XIE Xiao-zheng, WANG Jin, ZHAO Rong-zhen, LI Jun, LÜ Wei-qian 2022, 48 (5):  59-64.  Abstract ( 241 )   PDF (1814KB) ( 177 )   Save Aiming at the problem of low recognition accuracy of rolling bearings with different fault types and damage degrees, a fault diagnosis method combining wavelet packet energy entropy, gref wolf optimizer (GWO) and support vector machine (SVM) was proposed. Firstly, the rolling bearing vibration signal was decomposed by three-layer wavelet packet, following reconstructing the wavelet packet decomposition coefficients of each frequency band in the third layer, and the energy entropy of components in each frequency band was extracted to form fault feature vectors. Secondly, GWO was used to optimize SVM parameters. Finally, based on the optimized SVM classification model, the feature vectors of different fault types and damage degrees of rolling bearings in the test set were recognized and diagnosed. The experimental results show that the proposed method has more outstanding fault identification ability for both different fault types and different damage degrees of rolling bearings than other methods in experiments and literatures. References | Related Articles | Metrics

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Damage analysis of wind turbine hub under random ultimate load ZHENG Yu-qiao, JIN Hong-hong, ZHAO Feng, LU Bing-xi, LI Hao, HE Zheng-wen 2022, 48 (5):  65-69.  Abstract ( 317 )   PDF (1482KB) ( 355 )   Save In view of the uncertainty and diversity of traditional wind turbine hubs load environment, the damage of wind turbine hubs under ultimate load was studied, then the structure was optimized. Specifically, the ultimate load is exerted to the turbine hub according to the blade coordinate system to obtain the strength of the hub under the ultimate working condition, the stress nephogram of hub was obtained and the strength of the hub under the ultimate working condition was solved. Then, for the variational law of the damage on the hub surface, the S-N curve and the Miner cumulative damage criterion were combined to correct the average stress of the equivalent stress of the hub. Finally, the topology structure of the hub was optimized, the optimized hub was remodeled and the static strength analysis was carried out.The results indicated that the optimizedhub mass was decreased by 9.2%,which met the strength requirements and provided a theoretical basis for subsequent hub structure optimization. References | Related Articles | Metrics

Chemical Industry and Light Industry

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Numerical simulation of stress characteristics of aluminum fin-plate-side bar brazing structure under low temperature MA Hong-qiang, JIA Ji-wei, HOU Cai-qin, WANG Gang 2022, 48 (5):  70-78.  Abstract ( 157 )   PDF (6710KB) ( 76 )   Save Based on the thermal-elastic theory, a thermal and structure stress analysis model of aluminum brazing structure with fin-plate-side bar is established. The coupling method of thermal-structure was used to simulate and analyze the stress distribution of aluminumbrazing structure with fin-plate-side. The results show that the stress concentration of equivalent thermal stress, equivalent structure stress and equivalent stress is generated at the brazed joint of brazing structure, which is mainly caused by the incomplete matching of the material properties of the base metal and the brazed layer at the brazed joint and the discontinuity of the structure at the brazed joint. The distribution of equivalent thermal stress, equivalent structure stress and equivalent stress along typical path are mainly affected by normal stresses. Under the coupling effect of thermal and structure, the equivalent thermal stress has a significant influence on the equivalent stress. Therefore, the selection of thermal boundary is crucial to the simulation results. References | Related Articles | Metrics

Automation Technique and Computer Technology

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A digital LED driving circuit with the primary side feedback control flyback converter LIU Fang, WANG Qun-jie, BAI Qian 2022, 48 (5):  79-84.  Abstract ( 189 )   PDF (2495KB) ( 179 )   Save In order to reduce flickering of the LED, a driving circuit with the primary side feedback control flyback converter is specifically designed on the basis of the digital technology. The principle of soft-start and the controlling flow of constant current output is deduced, the constant current control principle is given, and the internal structure of the digital controller is constructed. The setting of soft-start/constant current switching module can effectively suppress the surge current of the flyback converter and ensure that the flyback converter enters the constant current state smoothly. Based on the principle of constant current control, the demagnetization time sampling module and counter modulation module are designed, which works in coordination with the control signal generation module to automatically switching signal. Finally, the feasibility of the presented scheme is verified by the united simulation technique based on ModelSim and Simulink. The results show that the ratio of demagnetization time to switching period is constant when the flyback converter operates in constant current state, with the output constant current of about 320 mA and the current ripple of 0.38%. Consequently, the drive circuit investigated in this paper can work stably and reliably. References | Related Articles | Metrics

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Optimal control of sensorless low speed operation of PMSM based on high frequency signal injection XIE Ping, BAO Guang-qing, QI Wu-gang, DU He-xuan 2022, 48 (5):  85-91.  Abstract ( 473 )   PDF (2459KB) ( 491 )   Save In the zero low speed operation control of sensorless permanent magnet synchronous machines (PMSM), the high frequency signal injection method is often used to track the position information, which will cause torque fluctuation and time delay. In this paper, a filter free rotor position identification method is proposed by combining sliding mode speed control and high frequency square wave signal injection. By increasing the frequency of square wave signal to the switching frequency of inverter and taking advantage of the characteristic that the fundamental wave signal cycle is far less than the high-frequency injection signal cycle, the signal separation in the traditional high-frequency signal injection is avoided through two current samples in the single high-frequency signal injection cycle. Meanwhile the filter is removed to effectively improve the system convergence speed. The simulation results show that compared with the traditional high-frequency signal injection method, the proposed method can achieve high-precision low-speed operation under sensorless control of PMSM, and has good steady-state characteristics and dynamic performance. References | Related Articles | Metrics

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Convergence analysis of PDα type iterative learning control for a class of fractional-order nonlinear systems ZHANG Ke-jun, PENG Guo-hua, DU Yong-jun 2022, 48 (5):  92-98.  Abstract ( 184 )   PDF (1104KB) ( 122 )   Save For a class of single input and single output (SISO) fractional-order nonlinear continuous systems, by taking advantage of the generalized Young inequality of convolution integral, the sufficient conditions for the convergence of open-loop, closed-loop and open-closed-loop PDα type fractional-order iterative learning control (FOILC) algorithms are presented in the sense of Lp norm with strict theoretical proof of these algorithms followed. It is found that the sufficient conditions for the convergence of the control algorithms depend on the gains of the algorithms and the attributes of the systems themselves. The open-closed-loop PDα-type control algorithm has faster convergence speed than the open-loop control algorithm under appropriate gain matrices. These conclusions are the same as those of fractional-order linear systems. The simulation experiments further verify the feasibility and the correctness of the above theory. References | Related Articles | Metrics

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Uyghur-Chinese neural machine translation method based on back translation and ensemble learning FENG Xiao, YANG Ya-ting, DONG Rui, AZMAT Anwar, MA Bo 2022, 48 (5):  99-106.  Abstract ( 1666 )   PDF (863KB) ( 365 )   Save From the perspective of efficient utilization of existing resources, a method based on back-translation and ensemble learning is proposed to solve the problem of the poor performance of Uyghur-Chinese neural machine translation caused by the lack of parallel corpus. Firstly, Uyghur and Chinese pseudo-parallel corpora are constructed by using back translation and large-scale Chinese monolingual corpora, and the intermediate model is obtained by using pseudo parallel corpora training. Secondly, the bootstrap is used to resample the original parallel corpus for N times, and N sub-datasets with similar distribution but different characteristics are obtained. The intermediate model were fine-tuned based on N sub-data sets, and N sub-models with differences were obtained. Finally, integrate these sub-models. Experiments on the test sets of CWMT2015 and CWMT2017 show that theBLEU(Bilingual Evaluation Understudy) value of this method are 2.37 and 1.63 higher than that of the baseline system, respectively. References | Related Articles | Metrics

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Research on short-term traffic flow forecasting method based on SARIMA-GA-Elman combined model ZHANG Xi-jun, WANG Chen-hui 2022, 48 (5):  107-113.  Abstract ( 260 )   PDF (1605KB) ( 219 )   Save Aiming at the limitations of a single model that can not dig into the complex linear and nonlinear characteristics of traffic flow and the slow convergence of neural network models during training, a combined prediction model based on SARIMA-GA-Elman is proposed. The combined model effectively combines the excellent linear fitting ability of the seasonal autoregressive integrated moving average (SARIMA) model and the powerful nonlinear mapping ability of the Elman recurrent neural network. In the prediction process, the linear component of the time series is firstly predicted based on the SARIMA rolling, and then the prediction error sequence of the SARIMA model is used to establish the Elman-RNN to construct the nonlinear error model. In addition, in the process of training the nonlinear error model, the binary-coded genetic algorithm (GA) is used to optimize the Elman-RNN in order to improve the training efficiency of Elman-RNN. Finally the prediction results of the two models are weighted and combined to obtain the final prediction value. Experimental results show that the combined model has a significant improvement in prediction accuracy and robustness compared to a single model. References | Related Articles | Metrics

Architectural Sciences

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Study on the impact resistance block stone of built-in H-shaped steel debris flow retaining dam WANG Xiu-li, CHENG Rong-rong, ZHU Zhong-cheng, LIANG Hai 2022, 48 (5):  114-119.  Abstract ( 153 )   PDF (6267KB) ( 181 )   Save In order to solve the problem that ordinary gravity debris flow retaining dam is easy to be damaged by large rocks in debris flow disaster, and to make full use of the advantages of good plasticity and impact resistance of H-shaped steel, a new type of debris flow retaining dam with built-in H-shaped steel is proposed. The finite element ABAQUS software is used to carry out the numerical simulation under the impact of the block stone. The dynamic response of the dam is compared with that of the ordinary gravity debris flow retaining dam in terms of the dam bottom reaction force, top displacement, acceleration, energy absorption, etc. The results show that the reaction force of the new type of dam with built-in H-shaped steel is about 1/2 less than that of the ordinary dam, and the top displacement of the new type of dam is 9/13 of that of the ordinary dam. Concrete and H-steel form double retaining effect. After concrete crack, H-steel still has better bearing capacity and deformation capacity. The new type of dam with H-shaped steel improves the anti impact performance of the ordinary gravity debris flow retaining dam and weakens the disaster of debris flow block rock impact. References | Related Articles | Metrics

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Preliminary analysis of robustness of progressive collapse of composite frame with CFST column SHI Yan-li, WANG Xue, WANG Jing-xuan 2022, 48 (5):  120-125.  Abstract ( 164 )   PDF (3090KB) ( 173 )   Save In order to study the vertical progressive collapse vulnerability of CFST frame structures, an 8-story CFST frame with 4×4 span was analyzed. The finite element software ABAQUS and the Pushdown analysis method were used to simulate the original structure and the remaining structure after the removal of each bottom column. Based on the two improved vulnerability analysis methods considering the component importance, the importance coefficients of structural components were calculated separately, and the robustness coefficients of the structure under double-column failure conditions were calculated to analyze the vertical robustness of this kind of structure. The results show that the calculation results of the two methods are similar, and the change trend of the component importance coefficient is the same The increase in external load is negatively correlated with the structural robustness. The corner column is more important than the side column and center column. When corner posts and side posts fail at the same time, the chance of the structure collapsing is greatly increased. The alternate path method can be choosed in low-fragility designation for components with large importance coefficient. References | Related Articles | Metrics

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Analysis of seismic performance of the light-gauge steel and jute fiber bio-based panel composite wall WU Chang, CHEN Xing-hong, LIU Jia-le 2022, 48 (5):  126-133.  Abstract ( 172 )   PDF (4555KB) ( 220 )   Save In order to promote the application of bio-based fiber materials in green prefabricated ecological village houses, jute fiber bio-based panels are used as the cladding materials of the light-gauge steel wall to form prefabricated composite wall. The elastic modulus and static bending strength of jute fiber bio-based panels were measured through physical and chemical properties experiment and SEM experiment, and the microstructure composition of the panel was analyzed. The simplified calculation model of composite wall based on semi-rigid node connection was established by using ANSYS/Structural finite element software, and the influence of different panel thickness on the seismic energy dissipation performance of composite wall was analyzed. The results show that the elastic modulus and static bending strength of the jute fiber bio-based panel are much greater than that of the traditional OSB panel. Increasing the thickness of the jute fiber bio-based panel can enhance the plastic deformation ability of the composite wall, reduce the extent of stiffness degradation, and increase the residual stiffness. The combined wall has better seismic performance and energy dissipation capacity. References | Related Articles | Metrics

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Finite element modeling and seismic response analysis of wind turbine structures WANG Xue-ping, DING Ming-xuan, HUANG-Jie, LI Wan-run, DU Yong-feng 2022, 48 (5):  134-141.  Abstract ( 212 )   PDF (6706KB) ( 285 )   Save In order to study the applicability of the finite element model of wind turbine structure with different degrees of fineness for different analysis purposes, based on the 2 MW three-blade horizontal axis wind turbines, seven finite element models of wind power generation structures with different degrees of fineness were established by using the finite element software ANSYS. The deformation, internal force, stress and stress concentration of wind turbine structure were achieved to evaluate the efficiency of each model. The results show that when calculating the deformation of wind power generation structure, numerical model with low-order elements can get better simulation results due to the fact that the upper engine room and blades have little influence on it. When calculating the shear force and bending moment of the section at the bottom of the tower, the finite element model of the engine room and blades should be considered to achieve more accurate results, so the high-order solid element should be used when selecting the element. The stress of wind turbine tower will be discrete when the coupling effect of the blades, hub and nacelle are not considered, and the shell element can better simulate the stress of wind turbine in this situation. The superstructures such as blade and nacelle have a great influence on the stress concentration of the wind turbine door opening, so it is suggested to use the multi-scale model of shell element for the tower and solid element for the door opening. References | Related Articles | Metrics

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Research and analysis on influencing factors of slope stability with rainfall infiltration field distribution WANG Jiang-ping, XI Hong-bing, LI Bo-sheng, YANG Xiao-yu 2022, 48 (5):  142-147.  Abstract ( 328 )   PDF (4662KB) ( 367 )   Save Aiming at the slope stability problem under rainfall infiltration, the unsaturated soil theory was used to study the numerical calculation of rainfall infiltration process, and four calculation examples were calculated and analyzed for the influence of rainfall intensity and permeability coefficient on slope stability. The main conclusions are as follows: (1) the matric suction of soil is beneficial to the stability of the slope, and the results obtained by ignoring the matric suction will be seriously smaller; (2) the influence of rainfall intensity on the low permeability model is not obvious, but its influence on the high permeability model is greater; (3) The stress concentration occurs at the slope angle and the top of the slope, and the strength of the soil at this position is low. The above research can provide certain technical support for the prevention and control of slope in practical engineering. References | Related Articles | Metrics

Scientific

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The generalized distance eigenvalues of graphs LU Peng-li, ZHONG Yu 2022, 48 (5):  148-152.  Abstract ( 210 )   PDF (905KB) ( 283 )   Save The generalized distance matrix of a connected graph G is defined asDα(G)=αTr(G)+(1－α)D(G), 0≤α≤1, where D(G) and Tr(G) represent the distance matrix and diagonal matrix of the transmissions of G, respectively. In this paper, the generalized distance correlation spectrum is studied, with the bounds of the spectrum radius, the second largest eigenvalue, and the generalized distance spectrum of the self-complementary graph given. References | Related Articles | Metrics

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Leader-following consensus of second-order multi-agent systems via event-triggered impulsive control JIN Wan-li, YU Zhi-yong, JIANG Hai-jun 2022, 48 (5):  153-160.  Abstract ( 234 )   PDF (1666KB) ( 218 )   Save For the second-order multi-agent systems, the leader-following consensus under the event-triggered impulsive control is solved. First, being different from the event-triggered sample-data control strategy, the designed control protocol requires each agent to implement control only when the state error exceeds the specified upper bound, that is, event-triggered impulsive control. Second, by constructing an appropriate event-triggered function, the consensus criterion for second-order multi-agent systems is given by using Lyapunov stability theory, algebraic graph theory, and inequality technology, and the Zeno behavior of multi-agent systems is excluded. Finally, a numerical simulation is illustrated to prove the effectiveness of the proposed control scheme. References | Related Articles | Metrics

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Some properties of semiring homomorphisms SHAO Hai-qin, LIANG Mao-lin, DONG Fang-fang 2022, 48 (5):  161-165.  Abstract ( 160 )   PDF (441KB) ( 277 )   Save The notions of idealistic soft subsemirings and soft equality on two idealistic soft subsemirings are introduced. Semiring homomorphisms is studied by using idealistic soft semirings, full idealistic softsemirings, trivial idealistic soft semirings and idealistic soft subsemirings over a semiring as well as $\widetilde{\sqcap}$、$\widetilde{∪}$ and $\widetilde{∧}$ operations of idealistic soft semirings. Some important properties of semiring homomorphisms, semiring full homomorphism and semiring simple homomorphism are obtained. References | Related Articles | Metrics

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Regularity and observability of Schrödinger equation under the Neumann boundary control BAI Zhong-yu 2022, 48 (5):  166-172.  Abstract ( 129 )   PDF (477KB) ( 117 )   Save The regularity and observability of aSchrödinger equation are studied. Under Neumann boundary control and collocated observation, it is proved that the system is regular in the sense of G.Weiss via the well posed results. The feedthrough operator is found to be zero, and the observability inequality is established. References | Related Articles | Metrics