最新刊期
卷 52 ， 期 12 ， 2018
- 摘要：Facing the fact that fault diagnosis in engineering practice is limited by many factors, including the lack of prior knowledge of faulty components, modulation of vibration signals and interference due to various noise, an adaptive filtering algorithm based on mathematical morphology is proposed for rolling bearing fault diagnosis. Following the principle of basic and combined morphological operators, characteristics of each kind of morphological operator and the quantitative effect of varying structure element scale on filtering results are revealed by amplitude-frequency response method of non-linear filter. Besides, the main features of running faulty bearing are obtained while a selection strategy of structure element scale is determined after discussion on the physical model and corresponding vibration signal of typical faulty rolling bearing. The feasibility of this method is validated by numerical simulations. Compared with optimal parameter CMFH method, the proposed adaptive method detects the information more quickly, clearly and accurately from signals of rolling bearing with outer or inner race fault. The FAER index of processed signal and efficiency of signal processing are at least heightened by 29.8% and 50.0%, respectively.关键词：mathematical morphology;adaptive filtering;structure element;rolling bearing;fault diagnosis819|8|41更新时间：2025-05-08
- 摘要：For a spherical roller bearing(SRB), the effect of rollers arrangement form on SRB service performance cannot be evaluated objectively and comprehensively with only considering the effect of radial load in theoretical research. A mathematical model is hence proposed to characterize the rollers arrangement form, self-aligning operating condition, rotor deflection and external loads simultaneously. SRB service performance is simulated and analyzed to obtain the effect of rollers arrangement form on inner-ring vibration in both time and frequency domains, the empirical formula for expressing the characteristic frequency under the self-aligning operating condition, and the rollers load distributions for different arrangement forms. A novel SRB pedestal is designed, which has the capacity to realize the self-aligning operating condition in the laboratory, and two brands of SRB offered by different manufacturers are tested to verify the correctness of the theoretical results. The results show that the staggered arrangement form is recommended under the self-aligning operating condition with huge radial load, while if the amplitude of the axial shock is large, the aligned arrangement form is a better choice. The characteristic frequency is equal to the number of the rollers in a single row times revolution frequency of all the rollers, no matter what kinds of SRB rollers arrangement forms are. Especially, some additional frequencies emerge due to the effect of SRB self-aligning function, which equal the characteristic frequency plus/minus the integer multiples of the rollers-revolution frequency. The bending moment accompanying rotor deflection can be offset by SRB self-aligning function, which leads to unbalanced loading of SRB rollers. It means that SRB self-aligning function is realized at the cost of reducing the carrying capacity.关键词：spherical roller bearings;rollers arrangement form;self-aligning operating condition459|8|0更新时间：2025-05-08
- 摘要：Aiming at the difficulty of the existing variable stiffness technology that the stiffness control structure is complex and the stiffness change rate is low, and it cannot adapt to the deformation structure, a new type of flexible electrostatic adsorption variable stiffness structure is proposed to achieve flexible stiffness of the flexible structure. This structure consists of two upper and lower electrostatic adsorption layers and an interlayer. The electrostatic adsorption layer is composed of a three-layer structure of a substrate, an electrode layer and a sealing film. Instead of the conventional metal electrode, the novel electrode in the electrostatic adsorption layer is made by mixing the carbon grease and silicone rubber. The substrate and the sealing film are also made of soft material. Therefore, the entire electrostatic adsorption layer is a flexible structure, which can stand stretching, compression, bending, torsion and other deformation within certain limits. Thus, the stiffness of different shape structures can be changed. This study reveals the stiffness change effect of the electrostatic adsorption variable stiffness structure via experiments, and explores various factors affecting variable stiffness effect. The results show that the higher the voltage or the smaller the thickness of the film, the more obvious the effect of the structural stiffness. Under the same voltage, the double-layer electrostatic adsorption layer has better effect than the single layer. The thickness of the interlayer does not affect the stiffness change. This approach only needs to adjust the stiffness of the structure by changing the voltage, so it is convenient to operate. The stiffness adjustment range gets very wide and the stiffness change rate is up to 180%.关键词：variable stiffness;flexible electrode;electrostatic adsorption567|7|2更新时间：2025-05-08
- 摘要：A comprehensive control strategy that integrates modal filter controller and zero phase tracking controller is proposed to solve the problem that when numerical control(NC)machine tools work at high speed with high feeding speed and acceleration of each axis, it is difficult to control the tracking error and guarantee machining accuracy. The principle of zero pole cancellation is firstly used to obtain a mode filter controller set in the velocity loop, which cancels the first-and second-order torsional vibration modes of the ball-screw feed system, removes the limitations of the two modes on the servo bandwidth and continuously increase the servo bandwidth. Then, the zero phase tracking controller set before the position loop is obtained and the phase lag of the servo feed system is improved by approximating the inverse of the transfer function of the whole servo feed system. Finally, the control of tracking errors of NC machine tools at high speed and acceleration feeding is realized. Simulation results and a comparison with the traditional PID control strategy show that when the feed speed is 30 m/min and the acceleration is 10 m/s2, the proposed integrated control strategy reduces the tracking error to less than 0.1% of the original one.关键词：numerical control machine tools;high-speed machining;tracking error;modal filter controller;zero phase error tracking controller458|5|7更新时间：2025-05-08
- 摘要：A flexible wearable sensor for monitoring angles of wrist motion is proposed to combine a sensor more easily with the flexible rehabilitation robot. It is based on the principle of optical fiber macro-bending loss that a fiber is embedded in silicone rubber to form a flexible sensing module for measuring the angle of wrist flexion after waving. The sensor has the advantages of being insensitive to temperature, free from electrical interference, low cost, and not interrupting the operation of the flexible driver. Experiments verify that the repeatability error, the hysteresis and the calibration error of the measuring device are 1.42%, 1.39% and 0.53%, respectively. A comparison with a traditional method for measuring joint angle using protractor shows that the proposed sensor reduces measurement error, and can realize real-time angle monitoring and closed-loop control.关键词：wrist motion;fiber macro-bending loss;flexible sensor;silicone module567|5|1更新时间：2025-05-08
- 摘要：A model predictive control strategy is proposed to solve the inevitable DC voltage oscillation, inaccuracy phase information of positive voltage, unclear calculation of the active and reactive power of the bidirectional interfacing converters in three-phase unbalanced condition. Firstly, an instantaneous power vector predictive model is built by using instantaneous voltage and current vector to omit the phase-lock-loop and to avoid the effect of inaccurate voltage phase detection; Secondly, power references are designed for the real and imaginary components of the power vector, respectively, to restrain the double-frequency power caused by the negative sequence component and to eliminate the DC voltage oscillation; Finally, objective functions are designed for the real and the imaginary components of power vector, respectively, to avoid the interaction between them, and a switching frequency limitation part is included in objective functions to make the switching frequency tunable. Simulation and experimental results show that the active power is not influenced by the change of reactive power. A comparison with the traditional PWM method shows that the proposed method reduces the overshoot of active power by about 74%, the power factor is regulated to 1, and the DC voltage oscillation is eliminated.关键词：hybrid AC/DC microgrid;bidirectional converter;model predictive control;three-phase unbalance424|6|0更新时间：2025-05-08
- 摘要：A control strategy with low power consumption for the flotation process of buoys is proposed to focus the problem that power consumption in buoyancy control system of submarines is high and severely restricts the range of submarines. A profile buoy is taken as an example to analyze the working process of submarines, and it is found that the power consumption of floating process is much greater than that of sinking process. Firstly, the relation between the output torque of a motor and the pressure of sea water is deduced. A simulation model of speed closed loop control for BLDCM(Brushless Direct Current Motor)is established by using Matlab/Simulink. The regression equation of start-up power consumption and output torque and the relationship between steady running power and output torque are obtained, respectively, through regression analysis of simulation data. Then, the functional relationship between total power consumption and regulation times is derived by considering the variation of seawater density with depth. Numerical solution of the total power consumption equation reveals that the total power consumption of the buoyancy control system is nonlinear with the number of adjustments. Calculation results show that when the floating process is adjusted 16 times for a 4000 m buoyancy, the total power consumption is the lowest, and saves 78.883 J energy than that of being adjusted only once, that is, 48.3% save in theory.关键词：submersible;buoyancy regulation system;low power consumption;control strategy460|7|2更新时间：2025-05-08
- 摘要：A precise curvature estimation algorithm based on local mesh reconstruction is presented to solve the problem that the existing curvature estimation algorithms for point clouds are difficult to achieve a trade-off between accuracy and robustness of estimation. A set of neighborhood points of the target sample is taken as the local sample. The strategy that combines the two-dimensional Delaunay mesh generation and the three-dimensional Delaunay mesh filtering is used to reconstruct a surface of the local sample and to obtain a local Delaunay mesh which interpolates on sampling points and is topologically equivalent to the original surface. In order to robustly estimate the normal direction of the sample points for calculating the curvature of the sample points, the weights of the normals of the first-order neighborhood patches of the vertex are determined by the shape and size of these patches in the local mesh surface, and the weighted summation of the normals of the first-order neighborhood patches is taken as the estimation result of the normal direction. A pre-estimation of curvature of sample points is obtained based on first-order neighborhood patches of sample points, and then the estimation results are modified according to the geodesic distance between neighborhood points and target point. Experimental results show that the proposed algorithm can effectively reflect the surface characteristics, take the accuracy and robustness of the sample curvature estimation into account, and realize the smooth transition of the sample curvature. Compared with the Voronoi algorithm proposed by Meyer, the proposed algorithm guarantees the calculation accuracy of point cloud with higher sampling accuracy, and improves the accuracy and robustness of point cloud with noise by 1-2 times.关键词：neighborhood of sample point;topological isomorphism;curvature estimation;local reconstruction;geodesic distance490|6|3更新时间：2025-05-08
- 摘要：A fast method(SmartMoss)for efficiently estimating the frequencies of 4-node graph-lets in large-scale networks is proposed to address the challenge of exactly counting the frequencies of 4-node graphlets occurring in large-scale networks. SmartMoss compares the estimation errors of the two state-of-the-art algorithms, 3PS(3-Path Sampling)and C3PS(Center 3-Path Sampling), through random variables variance analysis to obtain their different application ranges, and then selects either 3PS algorithm or C3PS algorithm for 4-node graphlets sampling by calculating the distribution of network weight densities and real-time errors, to achieve quick estimation of the frequencies of 4-node graphlets by combing the estimation results of 3PS and C3PS based on the sampling proportions. Experimental results show that SmartMoss is more than 10 times faster than the state-of-the-art algorithms 3PS and C3PS under the same estimation error. SmartMoss efficiently and accurately estimates the frequencies of 4-node graph-lets for large network graphs, and provides theoretical reference for practical applications such as network community evolution and malicious code detection.关键词：network graph;sampling algorithm;graphlet counting748|6|0更新时间：2025-05-08
- 摘要：A security protocol for in-vehicle FlexRay buses is proposed in allusion to the in-vehicle information security issue caused by the rapid development of intelligent vehicles and networked vehicles. The protocol contains two modules: a node identity authentication module and a network security encryption module. The node identity authentication module uses a key exchange algorithm and a asymmetric encryption algorithm to ensure the identity legality of the connected node, and the network security encryption module uses the symmetric encryption algorithm and a hash algorithm to guarantee the confidentiality, authenticity and freshness of the data transmitted by a bus. Compared with previous protocols, the proposed protocol provides node identity authentication and protects the information security of the on-board bus without affecting the real-time communication of the bus. Experimental results show that the protocol provides all-round information security guarantee for buses from start-up to operation on the basis of real-time communication, and greatly improves the security level of the FlexRay bus information.关键词：in-vehicle information security;FlexRay bus;security protocol;real-time communication358|6|1更新时间：2025-05-08
- 摘要：An energy consumption model for softwares using machine learning is proposed to address the problem that software developers either are usually not aware of the specific energy consumption of their codes, or may measure the energy consumption of the application softwares using some tools but do not understand the factors which affect energy consumption and the relationship among them. The Ridge machine learning algorithm is adopted based on testings of 4 different machine learning algorithms to establish the model for estimating the software energy consumption characterized by software performance events. First, the collected measurement values of energy consumptions and the data of the software performance events of a set of softwares are used as the training samples, and the machine learning algorithm is applied to build up the energy consumption model. Then the average energy consumption of any other software is estimated using this model. On this basis, a real-time program energy consumption model for the running programs is established. Experimental results show that the energy consumption prediction error given by the proposed average energy consumption model is less than 9%. A comparison with the average energy consumption model shows that the real-time program energy consumption model further reduces the prediction error. When the software designers use the proposed model to get the energy consumption of their codes, they are not required to measure or train their own software. Not only can the energy consumption of the software be accurately estimated, but also the causes of energy consumption can be explained, and the energy efficiency of the software can be optimized according to the prediction result.关键词：machine learning;software energy consumption model;performance event;energy efficiency333|7|0更新时间：2025-05-08
- 摘要：A single-core instruction-level optimization method for computational fluid dynamics(CFD)programs is proposed to overcome the shortage of most current CFD programs in utilizing the single-core computing power of a system. The method first analyzes the performance indicators of a program to find potential performance deficiencies, and then optimizes them according to the analysis results. Then the memory structure and memory access sequence are adjusted according to the memory access characteristics of the system and the container to optimize memory access performance and space overhead. The pipeline mechanism of CPU is analyzed, and the control correlation and data correlation of instructions in loops and branches are eliminated to reduce the pipeline interruption rate. Both the characteristics of a compiler processing the high-level language and the runtime stack at the instruction level are analyzed to optimize the instruction structure and to reduce instruction redundancy and duplication. Experimental results show that the performance of the optimized program is greatly improved. Testings on TIANHE-1A supercomputer system show that the execution time of the program reduces by 68.34% and the space consumption reduces by 55.43%. Analyses show that the performance of the program is greatly improved in pipeline interruption rate, cache hit rate and number of machine instructions. It shows that the proposed method has more coverage than other existing optimization methods and better optimization effect, and has a good reference value.关键词：computational fluid dynamics program;instruction-level optimization;memory-access optimization;pipeline optimization348|6|0更新时间：2025-05-08
- 摘要：A scheme of adding high temperature water vapor to the combustion system to achieve low-nitrogen combustion is proposed to reduce NOx production during coal combustion, and its thermodynamic calculation and experimental research are carried out. Firstly, the possibility and limitation of the reactions in the volatile combustion process of coal after adding high temperature water vapor are examined by theoretical calculation based on the standard molar reaction Gibbs free energy change, the standard molar enthalpy and the equilibrium constant. Results of reaction path speculation show that in the high temperature water vapor atmosphere, the reactions of converting N element to N2 occur in the temperature range of coal combustion. Secondly, in reactions with various excess air coefficients, the equilibrium components after adding different concentrations of high temperature water vapor are calculated using the software HSC Chemistry. Results of the thermodynamic calculation show that the reaction of NOx precursor to N2 happens in a wide temperature range: when the temperature ranges from 700 to 800 and excess air coefficient lies between 0.6 and 0.8, the formation of NOx significantly reduces by adding high temperature water vapor; Reduction rate of NOx increases with the concentration of high temperature water vapor increasing. Eventually, the combustion characteristics of pulverized coal in water vapor and air atmosphere are tested in a pulverized coal fixed bed combustion experiment system. It shows that the formation of NOx is inhibited by adding high temperature water vapor and the effect is better that the result of the thermodynamic calculation, and the NOx reduction rate has a nonlinear relation with the water vapor concentration and the temperature. This study may provide an economical and efficient reference solution to low NOx combustion of coal.关键词：coal combustion;low NOx combustion;water vapor359|6|2更新时间：2025-05-08
- 摘要：Aiming at the problem of poor accuracy and portability of normal intake charge calibrating method used in natural gas engine and taking a Weicai WP10NG336 turbocharged single-point injection natural gas engine as the research object, an intake charge model suitable for natural gas engine was studied. Based on the mean model, the equivalent gas flow was used to describe the intake process. The gas flowing through the cylinders was divided into reversing flow exhaust gas, scavenging exhaust gas, backflow residual gas, consistently stayed residual gas and fresh equivalent gas. Synthetic modeling and analyses were conducted on the turbocharger, throttle valve, intake manifold, exhaust manifold and cylinders, and the model was verified in consideration of the influence of intake inertia. Experiments on the WP10NG336 turbocharged natural gas engine were conducted, and results showed that the error range of the intake model proposed in this paper is within 4% and the air charge model is able to accurately estimate the actual air charge under different working conditions while occupying little computing resources.关键词：turbocharged natural gas engine;intake;physical model;intake manifold pressure421|6|1更新时间：2025-05-08
- 摘要：A dual adaptive fading extended Kalman filter(DAFEKF)algorithm is proposed for the problem of low accuracy and convergent speed of state-of-charge(SOC)estimation. The algorithm designs an observer of state-of-charge for the power battery, and the measured current and voltage are taken as input and observation values of the observer, respectively. Then the state of charge of a battery is estimated by the DAFEKF. The DAFEKF bases on the Kalman algorithm, and adds the time-varying fading factor to reduce the influence of past data on current filtering values and to adaptively adjust the covariances of the process noise and measurement noise. SOC results of a lithium battery obtained using the proposed DAFEKF are compared with those obtained using the extended Kalman filter(EKF)and the adaptive extended Kalman filter(AEKF), and the comparison shows that the DAFEKF method provides better accuracy, robustness and convergence, and the SOC error of the proposed method is less than 2%.关键词：lithium-ion batteries;state of charge;adaptive Kalman filter;extended Kalman filter;dual adaptive493|6|9更新时间：2025-05-08
- 摘要：Aiming at the UHV transmission line with single-phase reclosing, a time-domain line parameters calculation method using fault recording data of non-full phase operation during reclosing is proposed. For the non-faulty lines, the positive sequence and zero-sequence parameters are calculated respectively by the equivalent model of linear mode and zero-mode central parameters. With regard to the faulty lines, the positive sequence parameters are calculated using the non-faulty phase-to-phase linear-mode parameter equivalence model. If the secondary arc is not extinguished, the faulty line zero-sequence parameters are calculated using the three-phase coupled line model. If the secondary arc is extinguished, the zero-sequence centralized parameter model is used to calculate the faulty line zero-sequence parameters. The selected calculation model is adopted to establish differential circuit equations, the voltage and current samples at both ends of the line are set as known parameters, and the least squares method is used to calculate the line parameters. Simulation results of ATP-EMTP show that the proposed method can obtain the positive sequence parameters and zero-sequence parameters of non-faulty lines and faulty lines, and a suitable model can improve the accuracy of parameter calculation. Among them, the errors of positive sequence resistance, inductance and capacitance are less than 1%, 0.5% and 0.23% respectively, and the errors of zero-sequence resistance, inductance and capacitance are less than 0.12%, 0.1% and 0.04% respectively.关键词：non-full-phase operation;line parameters;fault recording data;single-phase reclosing;faulty line;non-faulty line352|6|3更新时间：2025-05-08
- 摘要：This approach reveals the inertia and damping characteristics of grid-tied energy storage systems for alleviating the reduction of grid stability caused by distributed energy. Focusing on the dynamic of the DC voltage control time-scale, the dynamic model of the grid-tied energy storage system with improved droop control is established, and the static synchronous generator model is used to analyze the influencing factors of inertial level, damping effect and synchronization ability. It is found that the physical nature of the energy storage system is similar to the droop characteristic of the prime mover. The results show that when the DC/DC converter uses the frequency droop control strategy and the grid-tied inverter uses the voltage and current double closed-loop control strategy, adjusting the PI parameters can equivalently change the inertial and damping characteristics of the system. This study may be helpful to design an effective control of grid-tied energy storage system, which enhances the inertia and damping capacity of power grid and improves the stable operation of distributed power system.关键词：droop control;energy storage system;inertial level381|5|6更新时间：2025-05-08
- 摘要：A novel distributed algorithm for transmit power optimization based on Markov approximation framework is proposed to solve the problem that it is difficult to collaboratively optimize communication and computing resources for computing task offloading of devices in a large-scale mobile edge computing's network architecture. Strategy for minimizing power consumption of user devices is modeled as a combinatorial optimization model based on Shannon's theorem and link transmission characteristics, and then the problem is transformed into an approximation problem for minimum weight configuration by the Log-Sum-Exp approximation rule.Then, the approximation problem is efficiently solved by proposing the Markov state transition rule and the distributed self-adjustment mechanism. Experimental results show that the optimized result of total power consumption of the devices by using the proposed algorithm is 78.5% better than that by using the random method. The proposed algorithm approaches the optimal solution after only 130 iterations in a given scenario, while the complexity of the exhaustive search's optimal solution is up to 410. The proposed algorithm effectively reduces the delay and ensures that the adjustment result of the transmission power quickly converges to the optimal target.关键词：mobile edge computing;computation offloading;Markov approximation608|5|1更新时间：2025-05-08
- 摘要：A single-inductor multi-input-multi-output buck-boost DC-DC converter is designed for multi-source energy harvesting according to wearable devices' demand for miniaturization and adaption to different environments. To achieve high efficiency and stable voltage for the load, inductor-peak-current pulse-frequency modulation technology is proposed to control the converter via combining inductor-peak-current control(IPCC)strategy and the threshold-based variable-frequency(TBVF)strategy. The inductor-peak-current pulse-frequency modulation technology changes the frequency of the energy transformation according to the states of inputs and outputs to implement the maximum power point tracking and to regulate the output voltage. At the same time, it controls the peak current of the inductor to improve the efficiency and to decrease the output voltage ripple. Furthermore, two kinds of low power control strategies are implemented to reduce the power consumption of the control circuits: adopting low voltage control circuit and discontinuously working circuit modules. Finally, the converter circuit and layout are designed and verified in the CSMC 0.18 μm process. Simulation results after layout parasitic extraction show that the efficiency of the converter is above 73.8% under the input voltage from 0.2 V to 3 V with load varying from 0.001 to 3 mW and the power consumption of control circuits is less than 300 nW.关键词：buck-boost converter;single-inductor multi-input-multi-output;inductor-peak-current;pulse-frequency modulation427|5|3更新时间：2025-05-08
- 摘要：Aiming at the spreading difficulty and low energy absorptivity of aluminum alloy during fused coating process, the GTAW arc-preheating device is designed. With the finite difference method, separate action models and a coupling analysis model for the driving forces generated by the arc heat source on the molten pool are established, and the evolution process of the temperature field and flow field in the molten pool is described. It is found that in the case of 200 A current, the influences of the driving forces in descending order are surface tension, arc pressure, Lorenz force, drag force, and buoyancy force, and this result provides the basis for analyzing the evolution of the flow field inside the weld pool when the coupled driving force is applied. Liquid metal from the nozzle rapidly flows into the molten pool at the moment of contact under the influence of surface tension and molecular affinity. Comparison between the numerical and experimental results indicates that the maximum width and height errors of the molten pool reach 1.1% and 0.6%; the maximum width and height errors of heat-affected zone reach 9.3% and 5.4%; the maximum width and height errors of single-layer single-passage parts reach 3.5% and 2.1%.关键词：fused coating;arc preheating;driving force;flow field380|6|1更新时间：2025-05-08
- 摘要：To improve the control accuracy of web tension in gravure printing, it is necessary to construct a more accurate mathematical tension model, where the effects of the drying temperature on web tension in shaft-less drive gravure printing process are considered. The tension model of printing section including temperature is derived following the law of mass conservation, in which the non-uniform distribution of the web temperature caused by the drying system is considered. Then, simulations with MATLAB/Simulink and experiments are carried out, and the effects of the drying temperature on the characteristics of web tension are obtained. The results show that the drying temperature exerts significant influences on transient web tension in printing section rather than on steady responses. In the transient responses, the settling time increases with the rising drying temperature. As the drying temperature is 60-80 ℃, the settling time in transient responses is about 41%-82% more than that without drying system under normal working condition.关键词：shaft-less drive;gravure printing;drying temperature;web tension365|4|1更新时间：2025-05-08
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Detection Method for Series DC Arc Using Time-Frequency Domain Characteristics of Capacitive Current
摘要：High frequency components accompany when series DC arc happens. A series DC arc fault detection method according to parallel capacitive current with time-frequency characteristics is proposed. A DC arc test platform is constructed to measure the current flowing through the internal filter capacitor of the DC source to detect the high frequency current generated by the arc fault. A simulation model is established with PSCAD/EMTDC, and the DC arc can be equivalent to a nonlinear resistance by the Nottingham formula. On the simulation platform, the time-frequency characteristics of the parallel capacitive current during the series arc generation are analyzed. The results show that when the series arc is generated, the parallel capacitive current changes suddenly, and the integral value in the 5-50 kHz band of the capacitive current spectrum increases. The simulation results are verified in the experiment. The parallel capacitance currents for different loop currents and electrode materials are tested. The rate of change of the capacitive current is proportional to the magnitude of the loop current, and it is inversely proportional to the boiling point of the electrode material. The current spectral integration difference is proportional to the loop current and the boiling point of the electrode material.371|5|3更新时间：2025-05-08 - 摘要：How to obtain a broad band gap in low-frequency is a challenging task for the applications of locally resonant phononic crystal(LRPC)in the reduction of vibration in engineering. A novel structure composed of double-sided clinical composite stubs, which are deposited on 2D locally resonant PC plate, is proposed and theoretically studied. Generation mechanism of low frequency broadband phononic crystal band gaps in phononic crystal plate is studied by using the finite element method(FEM). It is found that, the coupling between the local resonance mode and the Lamb wave mode follows the modal superposition principle, and is responsible for the formation of the band gaps. The influence mechanism of bandwidth is further studied, and the core influencing factor, i.e., the local oscillation modal form of local oscillator, is found. When the local oscillation modal form of local oscillator is in whole vibration state, the bandwidth is the widest. Moreover, the local oscillation modal formed resonator is adjusted by introducing the rubber filler and the novel cylinder composite stub, and then the out-of-plane band gap and the in-plane band gap are adjusted to broad bandwidth, respectively. As a result, the bandwidth of the generated band gap is about 600 Hz due to the overlap between the broad in-plane gap and the out-of-plane band gap. The new structure provides an effective way for phononic crystals to obtain broad locally-resonant band gaps in the low-frequency range, and has applications for low-frequency vibration reduction.关键词：phononic crystal;band gap;plate structure;vibration reduction452|5|9更新时间：2025-05-08
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