Table of Content

20 September 2017, Volume 51 Issue 9 Previous Issue    Next Issue

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A TemperatureDependent Hyperelastic Constitutive WANG Lidong1,WEI Ran2,XU Peng2,ZHAO Kexin2,PENG Xiongqi1 2017, 51 (9):  1025-1030.  doi: 10.16183/j.cnki.jsjtu.2017.09.001 Abstract ( 1122 )   Save Uniaxial tensile tests under different temperatures were implemented to obtain the basic mechanical property of diaphragm in hot diaphragm preforming of composites. Based on the hyperelastic theory of continuum mechanics and the principle of virtual work, a constitutive model which considered the influence of the temperature under 90℃ was developed to characterize the large deformation behavior of diaphragm. Material parameters were attained by fitting experimental data. The stability of the model was analyzed and then the constitutive model was implemented in Abaqus through the user material subroutine UHYPER. The developed constitutive model was applied to simulate uniaxial tensile and draping of diaphragm over mold. Numerical results were compared with experimental data as a means of model validation. The results show that the simulation results are in good agreement with the experimental results, which verifies the accuracy of the proposed constitutive model. References | Related Articles | Metrics

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Acoustic Performance Optimization of the Exhaust Muffler for a Car Based on Response Surface Method LI Mingrui1,DENG Guoyong2,MI Yongzhen1,ZHENG Hui1 2017, 51 (9):  1031-1035.  Abstract ( 667 )   Save The noises in the interior and exterior of a vehicle are measured in a stationary test, and the results reveal that noise reduction capability of its exhaust muffler is quite weak in the midfrequency. In order to improve the midfrequency transmission loss (TL) of the muffler, optimization is conducted based on the response surface method (RSM). Firstly, the length of insert tubes, position of perforated plates, perforation rate, etc. are selected as design variables and are sampled by the Latin hypercube method, and the frequencyaveraged TL of each sampled point is calculated by acoustic finite element method. Secondly, an RSM model of the midfrequency TL is developed by the Kriging surrogate technique, and its accuracy is validated by reanalysis. Finally, based on this model, the midfrequency TL is optimized by genetic algorithm. After optimization the midfrequency TL is 41.38dB increasing 14.33dB than the original value 27.05dB, and also the overall noise reduction performance of this muffler is improved significantly. The RSMbased optimization procedure in this paper provides a guideline for the acoustic performance design of the mufflers.   References | Related Articles | Metrics

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Optimal Design of Damping Material Configuration in Vehicle ZHAO Jianxuan,WANG Zengwei,LIU Zhao,ZHU Ping 2017, 51 (9):  1036-1042.  doi: 10.16183/j.cnki.jsjtu.2017.09.003 Abstract ( 1091 )   Save  In order to consider the vehicle interior noise reduction, a finite element method (FEM)  model was established for a simple car. Sound pressure level (SPL) frequency response function was analyzed at low frequency phase. Four main peak frequencies in the range of 20Hz to 200Hz and those body panels contributions were focused. The layout of the damping materials was optimized. With the objective of minimizing the mass of damping material, and variables of the thickness of damping materials, by using Kriging metamodeling technique and particle swarm optimization (PSO), optimization method of damping configuration was proposed based on panel contribution. The mass of damping materials was reduced by 52.0% under the requirement that the SPL of peak frequencies did not increase, and the experiment was done to verify the effectiveness of the method. References | Related Articles | Metrics

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Numerical Model of a Microchannel Parallel Flow Evaporator with New Flow Boiling Heat Transfer Correlation MA Lei,GU Bo,TIAN Zhen,LI Ping 2017, 51 (9):  1043-1049.  doi: 10.16183/j.cnki.jsjtu.2017.09.004 Abstract ( 894 )   Save  In this paper, a numerical model with the recently proposed flow boiling heat transfer correlation was established for microchannel parallel flow evaporator. The numerical model was verified by comparing the experimental data with the open literature, where the refrigerant mass flow rate range was 34.6—245.6kg/h and evaporation pressure was 200—500kPa. The effects of four different flow boiling heat transfer correlations on the numerical model performance were investigated. Results showed that the correlation predicted 99% of experimental data in a ±30% error band. Moreover, the numerical model with the correlation yielded the mean absolute errors of 1.5%, 18.8%, 14.2% and 19.8% in prediction of cooling capacity, refrigerant superheat, air side and refrigerant side pressure drop, respectively. The presented numerical model can be used to evaluate and optimize the performance of  microchannel parallel flow evaporator. References | Related Articles | Metrics

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Influence of Complex Distributed Stress on Structural Power Flow YANG Nian,YI Hong 2017, 51 (9):  1050-1057.  doi: 10.16183/j.cnki.jsjtu.2017.09.005 Abstract ( 895 )   Save  Based on the Kirchhoff plate theory, the orthogonality of specific order modes is used to derive the power flow equation of complex stressed structure, which can help to calculate the power flow of the structure with arbitrary stress distribution. The equation is validated by the numerical examples. Meanwhile, the influences of welding stress on a vibrating plate’s velocity, structural internal force and power flow are obtained. The results show that the influence of stress on power flow is more significant than velocity and internal force field. It should be taken it into account in actual engineering vibration prediction and reduction. References | Related Articles | Metrics

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Vibration Performance Analysis for the Gripper Cylinder of Tunnel Boring Machine with Variable Stiffness LI Lina,YU Haidonga,b,TAO Jianfenga,LIU Chenglianga 2017, 51 (9):  1058-1064.  doi: 10.16183/j.cnki.jsjtu.2017.09.006 Abstract ( 926 )   Save  The vibration of full face hard rock tunnel boring machine (TBM) can cause the damages of the gripper cylinder that may result in breakdown of the whole system. A lumpedmass parameter dynamic model of the gripper cylinder in TBMs is established based on the Lagrange method, and the variable stiffness behavior of the structures in the cylinder and the working conditions are considered in the model. The dynamic performance and load transmission of the gripper cylinder are numerically discussed with the influence of the piston rod extension, the equivalent stiffness of the rock and seals and the copper guide sleeve. The results show that the natural frequency of the gripper cylinder decreases with the extension length of the piston rod. The natural frequency has the positive correlation with the equivalent stiffness of the rock, the seal, the copper guide sleeve and the oil. The equivalent stiffness of the oil and seals are the most important  factor. The characteristics of the vibration load can be achieved in terms of the analysis of the vibration performance of hydraulic cylinder, and may provide the basement of the damage analysis for the hydraulic cylinder. References | Related Articles | Metrics

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Mathematical Model of Orifice Outflow for Magnetorheological Fluid HU Ming,WANG Jiong,FAN Yiqing 2017, 51 (9):  1065-1070.  doi: 10.16183/j.cnki.jsjtu.2017.09.007 Abstract ( 988 )   Save  In order to calculate and adjust the discharge of orifice for magnetorheological fluid, a mathematical model was established through the domain decomposition and analysis of flow field. The local resistance coefficient was revised by numerical simulation. Then, the mathematical model was verified and the influencing factor of discharge was analyzed by the experiment. The results indicate that the discharge of orifice can be calculated accurately by this mathematical model and adjusted effectively by the viscosity of magnetorheological fluid, the length of orifice, the aperture of orifice and the external pressure under certain conditions. References | Related Articles | Metrics

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Effects of Core Thickness and Vacuum Degree on  Sound Insulation Properties of Honeycomb Sandwich XU Hui,LIU Tao,LEI Ye 2017, 51 (9):  1071-1075.  doi: 10.16183/j.cnki.jsjtu.2017.09.008 Abstract ( 944 )   Save  The sound insulation properties of honeycomb sandwich structure with different core thicknesses and cavity vacuum degrees of cavities have been studied in the paper. The theoretical analyses of the honeycomb sandwich in vertical incident wave are performed. The finite element models of honeycomb sandwich and double plates are established by using finite element software. The numerical analysis results show that the sound insulation performance of honeycomb sandwich in different frequency bands can be improved with increasing the vacuum degree and core thickness, especially in the middle and highfrequency bands. The core thickness and vacuum degree chosen by finite element method can achieve the requirements of sound insulation in the process of designing and applying of honeycomb sandwich for sound insulation structures to deal with different noise spectrum requirements. The conclusions drawn in this paper can be used to guide the future design of lowweight thin sound insulation structure. References | Related Articles | Metrics

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Design of Transducer Array Circuit for  Pipeline Tiny Defect Ultrasonic Testing SONG Shoupeng,JIANG Zhou,WANG Zhiyou,NI Yingjie 2017, 51 (9):  1076-1082.  doi: 10.16183/j.cnki.jsjtu.2017.09.009 Abstract ( 844 )   Save   A novel 8channel array emitting and singlechannel receiving circuit is designed to solve the problems of low acoustic emission energy, low tiny flaw detection rate and complex circuit structure for pipeline flaw ultrasonic array detection. A singlechipmicrocomputer is applied to generate 8channel control signals for emission circuit stimulating adjustable time sequence and repetition frequency. Then, the transducers are stimulated by the 8channel highvoltage narrow pulses. A multiplexer is used in receiving circuit for echo signal time sharing multiplex. The designed array circuit is applied to pipeline sample ultrasonic testing. Artificial flatbottom hole with 2mm diameter and 3.6mm height and crack with 10mm length, 0.5mm width and 1.5mm height are inspected by using the designed circuit. In the experiments, wall thickness is also measured with an average relative error of 0.51%. Testing results show that the circuit is stable and reliable. References | Related Articles | Metrics

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RolltoRoll Powder Hot Embossing Process for Fabrication of MicroStructures on Polymer Film ?SHU Yunyi,PENG Linfa,YI Peiyun,LAI Xinmin 2017, 51 (9):  1083-1089.  doi: 10.16183/j.cnki.jsjtu.2017.09.010 Abstract ( 997 )   Save  This study proposed a rolltoroll (R2R) powder hot embossing process for the fabrication of microstructures on polymer film by combining the merits of R2R hot embossing process and powder metallurgy technology. An R2R powder hot embossing system was developed and a series of embossing experiments were conducted. The influences of processing parameters, which included mold temperature, feeding speed and applied force, had been investigated systematically by using the onevariableatatime (OVAT) method. It was found that the completelyfilled micropyramid arrays could be fabricated by R2R powder hot embossing process under the mold temperature of 130—145℃, the feeding speed of 0.2—0.8m/min and the applied force of 250—500N. References | Related Articles | Metrics

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Quench Propagation Characteristics Influenced by NonUniform Properties of YBa2Cu3O7δ  High Temperature Superconducting Tape ?YANG Ping1,SHENG Jie1,WANG Yucheng2,LI Zhuyong1,JIN Zhijian1,HONG Zhiyong1 2017, 51 (9):  1090-1096.  doi: 10.16183/j.cnki.jsjtu.2017.09.011 Abstract ( 946 )   Save The quench propagation characteristics affected by nonuniform properties are investigated by three different types of YBa2Cu3O7δ (YBCO) high temperature superconducting tape which are point defect sample with Cu stabilizers, regional defect sample without Cu stabilizers, and regional defect sample with Cu stabilizers. Voltage probes are attached to the samples to measure the normal zone propagation velocity in liquid nitrogen (77K). The applied current is gradually increased to explore the relationship between the quench characteristics and the degraded critical current. The quench characteristics between point and regional defects are compared. Moreover, comparing the experiments with the numerical results, the influence of the stabilizers is also discussed. The experimental results show that there is no quench under degraded critical current (Id). When the transport current is higher than Id but lower than critical current  (Ic), quench propagations are different between point defect with Cu stabilizers. The point defect sample quenches only in the defect region. References | Related Articles | Metrics

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Operational Optimization of MicroGrid Control:  A Brief Introduction and an Intelligent PlugandPlay Control Strategy JIANG Haixiao1,2,ZHENG Yi 1,LI Shaoyuan1,CAI Xu1 2017, 51 (9):  1097-1103.  doi: 10.16183/j.cnki.jsjtu.2017.09.012 Abstract ( 1053 )   Save   Microgrid is an important method to improve overall energy efficiency, cleaning degree and intelligent degree from demand side. The operational optimal control is the key to the abovementioned issues. This paper summarizes the different control requirements and controlled variables for different types of microgrid (direct current, alternating current and hybrid). The energy management strategies and control algorithms for different microgrids are introduced. Meanwhile, the advantage and disadvantage of different algorithms are summarized. The hotspots and future of microgrids control system are also presented and discussed. Finally an intelligent distributed control and optimization solution is proposed for realizing the “plugandplay” function. References | Related Articles | Metrics

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Research on Operation Condition Monitoring Method of Intellectual Apparatus Based on Data Driven GAO Xiaoting,YANG Dongsheng 2017, 51 (9):  1104-1110.  Abstract ( 694 )   Save  Alternating current (AC) contactor used frequently under full load is taken as a research object, and a method of apparatus operation condition monitoring based on data driven is proposed in this paper. First, historical operation data of AC contactor are collected by test platform and state characteristic parameters are gained. Combined with comprehensive assessment of wavelet transform and principal component analysis, data preprocessing such as denoising and removing outliers is used. Then, aimed at the disadvantage of highdimensionality and redundancy, kernel principal component analysis (KPCA) is adopted to merge multiinformation and kernel parameters are optimized based on test data. Finally, the fused information is input to hidden semiMarkov model (HSMM), and the operation condition monitoring and recognition of intellectual apparatus are realized. The practicability and validity of the method in apparatus condition monitoring is verified by test data from CJX28011 AC contactor. References | Related Articles | Metrics

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A Reconstruction Algorithm for Speech Compressive Sensing Using Structural Features JIA Xiaoli,JIANG Xiaobo,JIANG Sanxin，LIU Peilin 2017, 51 (9):  1111-1116.  doi: 10.16183/j.cnki.jsjtu.2017.09.014 Abstract ( 822 )   Save  It is difficult to reconstruct speech signal after compressive sampling because coefficients of the signal in transforming domain aren’t sparse enough. In this paper the speech signal was recovered from compressed samples in the frequency domain using structural features. Two hidden variables, amplitude and state, are defined for each modified discrete cosine transforming (MDCT) coefficient of the speech signal. The probability density function of the amplitude of the MDCT coefficient is represented using a Gaussian mixture model, and the continuity of the states along the frequency axis is modeled through a first order Markov chain，the continuity of the amplitude along the frequency axis is modeled through GaussMarkov process. The joint posterior distribution of coefficient, amplitude and state is represented by the factor graph, on which the posterior mean of the coefficient is obtained using Turbo message passing method, and then the speech can be reconstructed. After compressive sampling the MDCT coefficients of a speech segment, we reconstructed the signal using our proposed algorithm and other stateoftheart algorithms for comparison. The results showed that our proposed algorithm achieved best reconstruction quality under different frames and compressive ratios. The spectrogram showed that the energy distribution of reconstructed signal using our algorithm was the most similar to the original signal’s energy distribution. It can be seen that better reconstruction accuracy can be obtained using the continuity along frequency axis and Turbo message passing method. References | Related Articles | Metrics

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Research on Interference Suppression in  Generalized Frequency Division Multiplex System WU Hong,LIU Bing,ZHAO Yingxin,WANG Chong,ZHANG Yuting TANG Ran,MA Xiaoxu,XU Xiyan,MU Weiwei,LIU Zhiyang 2017, 51 (9):  1117-1123.  doi: 10.16183/j.cnki.jsjtu.2017.09.015 Abstract ( 1063 )   Save  The disturbances such as: ICI(Inter Carrier Interference), OOBE(Out of Band Emission), etc. in GFDM(Generalized Frequency Division Multiplex) multicarrier modulation communication system may degrade system performance, and timefrequency dualselective fading will worsen this issue. A channel estimation algorithm is introduced to lower the system’s interferences and computational complexity, by optimizing the prototype filter parameters according to disturb signal energy. Precode and equilibrium are also chosen to suppress ICI, OOBE, and interference from other users or antennas. A simulation model by Matlab is set up, BER curves and constellation diagrams have been worked out to evaluate the system performances. The simulation result indicates that GFDM with those corrective actions may get a lower BER level. References | Related Articles | Metrics

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Sparse Decomposition for Frequency Modulation Radar Signal Based on  Advanced Genetic Algorithm and SinChirplet Atom WANG Xing,ZHOU Yipeng,TIAN Yuanrong,CHEN You,ZHOU Dongqing,HE Jiyuan 2017, 51 (9):  1124-1130.  doi: 10.16183/j.cnki.jsjtu.2017.09.016 Abstract ( 1000 )   Save   In order to improve the performance of sparse decomposition for radar signals, a signal sparse decomposition algorithm(SDA) based on a novel SinChirplet atomic dictionary and an advanced genetic algorithm(GA) is proposed. Firstly, a sinusoidal frequency modulating factor is added into Chirplet atom so that the curvature performance of the atom timefrequency curve can be improved. Therefore SinChirplet atom has good matching performance for nonlinear frequency modulation signals. Secondly, based on the matching characteristic of SinChirplet atom, the generation of atom initialization population in GA is improved so that the bestatom searching speed can be raised. The theoretical analysis and the simulation results show that the decomposition efficiency of advanced GA is higher than that of GA and matching pursuit(MP) algorithm. Meanwhile, the matching performance and the decomposition efficiency of SinChirplet atom are better than those of other three traditional timefrequency atoms. References | Related Articles | Metrics

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Broadband Underdetermined Direction of Arrival Estimation Based on  Continuous Sparse Recovery WU Chenxi,ZHANG Min，WANG Keren 2017, 51 (9):  1131-1137.  doi: 10.16183/j.cnki.jsjtu.2017.09.017 Abstract ( 837 )   Save  For the problem of broadband underdetermined direction of arrival (DOA) estimation, a novel DOA estimation algorithm is proposed based on the continuous sparse recovery. Firstly, the dimension of coprime array receiving data is reduced by using direction wavenumber and the covariance matrix is vectorized to improve the degree of freedom. Then, the continuous sparse recovery model of direction wavenumber is established using the spatial sparseness of direction wavenumber, and the estimation of direction wavenumber is achieved with convex optimization and polynomial rooting. Finally, the signal frequencies and direction wavenumbers are pair matched by using Capon method. With this method, offgrid effects caused by discretizing this range onto a grid in traditional sparse recovery can be neglected, it also improves accuracy and resolution of DOA estimation and the number of sources estimated by the proposed algorithm is larger than the number of actual arrays. Theoretical analysis and simulations demonstrate the effectiveness and feasibility of the proposed method. References | Related Articles | Metrics

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TemporalSpatial Sequential Fusion Recognition Method of  Ballistic Missile Target Based on MIMOFNN Model LI Changxi1,2,ZHOU Yan1,LIN Han3,LI Lingzhi1,GUO Ge1 2017, 51 (9):  1138.  doi: 10.16183/j.cnki.jsjtu.2017.09.018 Abstract ( 1028 )   Save  In traditional temporalspatial sequential fusion recognition method of ballistic missile (BM) target, there always exits the problem that the efficiency is low and the antinoise performance is bad. In order to solve these difficulties, this paper proposed a fusion recognition method which is called temporalspatial sequential fusion recognition method of BM target based on multiple input multiple output and fuzzy neural network (MIMOFNN) model. In this model, firstly, we use the idea of multi layer fusion, combine with neural network and fuzzy theory, and put forward the MIMOFNN model with multi sensors of multi features. And then, we reintegrate the results of present moment and next moment to get the fusion results. Meanwhile, we compare with recognition threshold, until the fusion results match the recognition threshold, and the process of fusion ends. Finally, the experiment validates the effectiveness and antinoise performance of this model. References | Related Articles | Metrics

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High Resolution Direction of Arrival Estimation Based on  Covariance Fitting Estimation of Signal Parameters by  Rotational Invariance Technique Algorithm FENG Mingyue，HE Minghao，HAN Jun，YU Chunlai 2017, 51 (9):  1145.  doi: 10.16183/j.cnki.jsjtu.2017.09.019 Abstract ( 1010 )   Save  Spare representation based direction of arrival (DOA) estimation algorithms have the merits of high resolution and good adaptability to coherent signals, while they suffer from the shortages of depending on prior information and offgrid problem. In order to get high DOA estimation resolution and avoid the shortcomings of spare representation algorithms, covariance fitting estimation of signal parameters by rotational invariance technique (ESPRIT) algorithm is proposed in this paper. Firstly, covariance fitting criterion is converted into a semidefinite programming problem solved by convex optimization. As a result, a signal covariance matrix which is closer to theoretical value is obtained. Then, eigen decomposition of the estimated signal covariance matrix is conducted and the number of signals is estimated through the differences between eigenvalues of signal subspace and noise subspace. Finally, rotational invariance technique of signal subspace is used to estimate DOA. Simulation experiments have proved the validity of the method. Compared with traditional ESPRIT algorithm, the proposed algorithm has higher DOA estimation resolution and is slightly affected by coherent signals. It is also superior to spare representation algorithms for independence of prior information and avoidance of the offgrid problem. References | Related Articles | Metrics