Volume 41,Issue 1,2018 Table of Contents

SUN Xiaoqiang , LIU Yaolu , HU Ning

2018, 41(1):1-8. DOI: 10.11835/j.issn.1000-582X.2018.01.001

[Abstract](1169) [HTML](362) [PDF 1.17 M](1091)

Abstract:
With proposing identical particle and virtual particle hypothesis, the control condition of two-dimensional velocity is derived,and the propagation of linear waves is described at the atomic scale with using interatomic potential functions.Furthermore, the generation mechanism of the second-order nonlinear waves is studied by considering the effects of lattice anharmonicity and dislocation. The study shows that the lattice distortion caused by lattice anharmonicity and dislocation induces high-order virtual particles, which are the key factor in generating the high-order nonlinear waves, and early-stage nonlinearities or micro-damages, e.g., dislocation, lead to the increase of the high-order virtual particles, which induces obvious high-order nonlinear waves. Therefore, the early-stage micro-damages can be identified by detecting the high-order nonlinear waves.

2 Structural damage identification based on acceleration inner product vector and gray cloud

WANG Yushan , TIAN Liang , GUO Huiyong

2018, 41(1):9-16. DOI: 10.11835/j.issn.1000-582X.2018.01.002

[Abstract](1045) [HTML](330) [PDF 1.66 M](1271)

Abstract:
In order to solve the uncertain damage problem caused by measurement noise, a damage identification method based on acceleration inner product vector and gray cloud model is presented. First, basic theory and formulas of cloud model and cloud generators are introduced. Then, the acceleration response under random excitation load is calculated, inner product vector is deduced from cross correlation functions and second-order difference method, and an inner product vector damage index is proposed. Finally, the grey cloud rules of inner product vector and damage intervals are built. Considering the uncertainties casused by stochastic measurement noise, a damage identification method based on gray cloud model is presented by using weighted summation and averaging in various modes. Simulation results show that the identification results of the proposed method are better than those of the inner product vector damage index, and the damage identification method based on inner product vector and gray cloud can solve the uncertain damage problem caused by measurement noise.

3 Seismic performance of variable cross-sectional concrete filled steel tubular laced columns with flat lacing tubes

OU Zhijing , CHEN Shengfu , YUAN Huihui , WU Qingxiong

2018, 41(1):17-29. DOI: 10.11835/j.issn.1000-582X.2018.01.003

[Abstract](1210) [HTML](457) [PDF 4.56 M](1073)

Abstract:
A finite element analysis model of variable cross-sectional concrete-filled steel tubular(CFST)laced column with flat lacing tubes is built with universal program of OpenSEES, and the calculating results of specimen obtained by OpenSEES agree well with the quasi-static test results.The seismic performance of four-element variable cross-sectional CFST laced columns with flat lacing tubes is researched with calculation parameter of column slope, including the rules on energy dissipation capacity, skeleton curve, structure ductility, and stiffness degradation of elements, and these calculation results are compared with the research results of uniform cross-sectional CFST laced columns. And the influence of axial compression ratio, column height (slenderness ratio), vertical spacing of flat lacing tubes, steel ratio of longitudinal element, diameter ratio of lacing tubes to longitudinal tubes, yield strength of steel, concrete strength and other structural parameters on seismic performance of variable cross-sectional CFST laced columns with flat lacing tubes are investigated. It's hoped that the results can provide reference for the improvement of CFST calcalation theory and engineering application of variable cross-sectional CFST laced column piers.

4 Calculation of bearing capacity of reinforced concrete bending members considering correlation between bending and shearing

ZHANG Wangxi , LIU Jingjin , CHEN Bao , DENG Xi

2018, 41(1):30-41. DOI: 10.11835/j.issn.1000-582X.2018.01.004

[Abstract](1054) [HTML](836) [PDF 3.84 M](1733)

Abstract:
There is correlation between flexural capacity and shearing capacity in RC(reinforced concrete) bending members. Chinese code GBJ10-89, GB50010, JTJ023-85 and JTG D62-2004, as well as American code ACI318 basically follow the same guidelines. They do not consider the bearing capacity correlation between bending and shearing sufficiently. The amount of longitudinal reinforcement and stirrup of a RC bending member is respectively calculated according to its normal section bearing capacity and oblique section bearing capacity. Only for independent beams under concentrated load, the influence of bending moment on shearing bearing capacity are considered through the shear-span ratio. Based on the analysis of the implicit correlation of bending and shearing from GB50010 and ACI318 strength criteria in stress level, and the effect of shear-span ratio in bearing capacity code formula, a modified formula considering the correlation of bending and shearing is put forward. By introducing several typical examples, the amount of reinforcement with different parameters is calculated with the modified formula and the code formula, respectively, and the reliability indexes of the two formulas are compared. Moreover, according to the target reliability index requirements of Chinese code GB50068-2001, the necessity of considering the correlation of bending and shearing in RC bending member is discussed.

5 Experiments on aeolian vibration of large span overhead transmission lines

WANG Feng , WANG Yu , ZHOU Rui , CHEN Chi

2018, 41(1):42-50. DOI: 10.11835/j.issn.1000-582X.2018.01.005

[Abstract](1053) [HTML](633) [PDF 4.06 M](1455)

Abstract:
An aeolian vibration model of transmission lines is designed and manufactured to grasp the vibration characteristics of large span overhead transmission lines. The vibration responses of a bare conductor and a conductor with a stockbridge damper are researched under different tension. The energy dissipation effect of the stockbridge damper and its installation position are analyzed and the results are compared with those of theoretical analysis. Then a calculating formula of damper installation position is proposed. The results show that the operation tension has a great impact on the aeolian vibration of large span conductors, and the controlling effect of the conductors' damping on aeolian vibration is very limited. The vibration amplitude of the conductor with a stock bridge damper is smaller than that of the bare conductor. However, with the increase of tension, the anti-vibration band of the damper gets narrowed and its anti-vibration effect reduces. The installation position of the damper has a great influence on the vibration of the conductor, and the vibration wave length at each excitation frequency should be considered when we determine the damper's installation position. The best anti-vibration band of FR-4 type stock bridge damper is from 15 to 25 Hz. For high frequency and low frequency vibration, its controlling effect is limited.

6 A new congestion control car-following model with consideration of multi-vehicles' steady-state desired speed effect

ZHOU Tong , ZHENG Linjiang , LIU Weining , TANG Yi , ZHOU Zhaomin

2018, 41(1):51-60. DOI: 10.11835/j.issn.1000-582X.2018.01.006

[Abstract](1034) [HTML](602) [PDF 2.76 M](1038)

Abstract:
In the background that congestion control is one of key problems in intelligent transportation system, based on the pioneer work of Konishi et al., we propose a new congestion control car-following model by considering the multi-vehicles' steady-state desired speed effect. By using the system control theory, the stability criterion is derived. To check the validity of the present theoretical scheme, the numerical simulation is carried out for the new model, and the simulation results show that comparing with the previous research results, multi-vehicles' steady-state desired speed effect can enhance the stability of traffic flow, and reduce the effect range of traffic congestion. Therefore, the new model can suppress the traffic jam more effectively and make the traffic flow operate more smoothly and orderly.

7 Yaw moment control of electric vehicles based on model predictive theory using Laguerre functions

WU Mingyang , JI Jie

2018, 41(1):61-69. DOI: 10.11835/j.issn.1000-582X.2018.01.007

[Abstract](1183) [HTML](400) [PDF 2.74 M](1274)

Abstract:
To improve the lateral stability of electric vehicles driven by rear wheel hub motor, a hierarchically coordinated vehicle dynamics control approach is presented. The high-level controller is based on the theory of model predictive control using Laguerre functions and it is designed to determine generalized moment by tracking the desired yaw angular velocity which is limited by the constraint of additional yaw moment. The low-level controller takes the rear wheels' work-load rate as the objective function and distributes the additioral yaw moment to the two rear wheels by solving quadratic programming. And the constraint problems caused by the road adhesion and actuators are considered in the quadratic optimization. The control method is verified by Carsim and Matlab/Simulink under the conditions of a single step steering input and double-lane change, respectively. Simulation results show that under the condition of high adhesion road, the control method can reduce the reaction time and overshoot, and improve the quality of the transient response of vehicles; under the condition of low adhesion road, it makes cars track the desired yaw angular velocity and avoid cornering instability.

8 Based on neighbor node intimacy for the information flow control model and application in online social network

SANG Jun , FAN Fang , XIA Xiaofeng , HOU Xiang

2018, 41(1):70-77. DOI: 10.11835/j.issn.1000-582X.2018.01.008

[Abstract](1209) [HTML](543) [PDF 1.49 M](1542)

Abstract:
The rapid development of Web2.0 technology promotes the online social network which is becoming the most popular platform for people to spread information. The huge amount of data released by users brings huge commercial value and privacy information disclosure. To solve the problem that the privacy information flow cannot be controlled in online social network, an information flow control model based on neighbor node intimacy is proposed. By computing the sensitivity of resources that users allow their friends to access, the model measures the intimacy relationship of neighbor nodes. And the number of common neighbors between users and their friends can be used to improve the model. In addition, information is divided into different intimacy security levels by referring to the ideas of the level of multilevel security (MLS). By setting reasonable scope of intimacy to convey information, social network managers may control the privacy information flow within a certain scope. The simulation experiments with parameter adjusting demonstrate the validity and practicability of the proposed model.

9 Two-level tuning for fuzzy PID control and its application to curing oven

SHEN Ping , DUAN Xiaogang

2018, 41(1):78-87. DOI: 10.11835/j.issn.1000-582X.2018.01.009

[Abstract](940) [HTML](597) [PDF 2.61 M](1037)

Abstract:
A two-level tuning method for fuzzy PID(proportion integration differentiation) controller is proposed. It includes scale factor tuning and member function tuning. An analytical model of fuzzy PID controller is derived first, which consists of a linear item and a nonlinear compensation item. The nonlinear compensation item is considered as a process disturbance, fuzzy PID control is tuned with the linear item and the SOPDT(second-order plus dead-time) model of plant based on the gain margin. Then triangle member functions are tuned by PSO (particle swarm optimization) algorithm. Simulations show that the proposed method is effective. Finally, the method is applied to the temperature control process of curing oven to improve the temperature control effect.

10 Fault diagnosis of three-way catalytic converter using improved fuzzy C-means clustering

LI Penghua , LIU Jingjing , FENG Huizong , MI Yi

2018, 41(1):88-98. DOI: 10.11835/j.issn.1000-582X.2018.01.010

[Abstract](984) [HTML](536) [PDF 4.61 M](1043)

Abstract:
The model precision of three-way catalytic converter is restricted by its complex physical and chemical reaction, which limits the accuracy of fault diagnosis based on its reaction model. To solve this problem, we propose a fault diagnosis method using improved fuzzy C-means (FCM) clustering. The method includes fault feature extraction and optimization using fractional Fourier transform(FRFT), dimensionality reduction of fractal feature using kernel entropy component analysis(KECA) and FCM fault feature clustering based on improved similarity measure. Firstly, we obtain the detailed features of different fault conditions from time domain to frequency domain using FRFT, then select the optimal FRFT order by particle swarm optimization (PSO) algorithm and these high-dimensional FRFT features with optimal order are transformed into fractal feature vectors through the fractal operator. Next, these fractal feature vectors dimensionality is reduced with KECA. At last, the reduced feature vectors are submitted to the improved FCM for fault clustering analysis. Numerical experiment results show that compared with the FCM method of Euclidean distance or cosine distance, the proposed method could obtain better fault identification result.

11 Fault diagnosis of motor bearings based on SVM and PSO

LI Yuanyuan , YUAN Mei , WANG Yao , CHENG Anyu

2018, 41(1):99-107. DOI: 10.11835/j.issn.1000-582X.2018.01.011

[Abstract](1072) [HTML](588) [PDF 2.38 M](1151)

Abstract:
A fault diagnosis method for motor bearings based on support vector machine (SVM) and particle swarm optimization (PSO) is proposed. The characteristic of the vibration signal is characterized by the time-domain and the wavelet packet energy characteristics, which makes the characteristic of the vibration signal has good reliability and sensitivity and improves the accuracy of fault diagnosis. The PSO algorithm is used to optimize the parameters of the penalty parameter and the radial basis kernel function of SVM, and compared with other parameter-optimization algorithms. Experimental results show that the proposed bearing fault diagnosis method has a very good effect not only on the recognition of motor bearing outer race fault, inner race fault and ball fault, but also on the severity differentiation of every kind of fault. It has strong practicability.

12 The performance comparison of linear predictive vocoders on Linux platform

TIAN Yuan

2018, 41(1):108-114. DOI: 10.11835/j.issn.1000-582X.2018.01.012

[Abstract](961) [HTML](833) [PDF 4.35 M](951)

Abstract:
Linear predictive coders are a kind of significant vocoders. The speech coders using three linear predictive vocoding algorithms are described, i.e. CELP (code excited linear prediction), LD-CELP (low delay-CELP) and MELP (mixed-excitation linear predictive) working at 4.8 kb/s, 16 kb/s and 2.4 kb/s, respectively. The C programs for the three vocoders are complied and executed on the Linux platform and the results are subjectively tested with taking MOS as criterion. Waveform analysis mainly uses Praat and Adobe Audition software. The results show that the performances of MELP and CELP are of comparable quality, while the performance of LD-CELP is much higher, albeit at the expense of higher bit rates.

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