Table of Content

28 April 2018, Volume 52 Issue 4 Previous Issue    Next Issue

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The Influence Factors of Explosion and Shock Resistance Performance of Auxetic Sandwich Defensive Structures YANG Deqing,ZHANG Xiangwen,WU Binghong 2018, 52 (4):  379-387.  doi: 10.16183/j.cnki.jsjtu.2018.04.001 Abstract ( 1291 )   Save Effects of different design parameters on auxetic cellular sandwich defensive structure, like thickness, size and Poisson’s ratio of the honeycombs are studied. The process of a missile impinging on, and penetrating auxetic cellular sandwich structure and the failure mode of the structure under underwater explosion shock are simulated by nonlinear finite element software. Numerical results indicate that structural passive defense has been unable to deal with high speed projectiles. Compared with traditional defensive structures, the auxetic cellular sandwich defensive structure has better anti-shock performance, which will be enhanced by increasing the layers and Poisson’s ratio of the honeycombs. The structure is more suitable for underwater explosion protection. References | Related Articles | Metrics

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A Robust Optimization Approach for the Routing Problem of Road Network Daily Maintenance LIU Yang,CHEN Lu 2018, 52 (4):  388-394.  doi: 10.16183/j.cnki.jsjtu.2018.04.002 Abstract ( 63 )   Save This paper studies the vehicle routing problem for daily maintenance operations of a road network suffered from the uncertainty of service time. A robust optimization model is formulated to minimize total cost and the optimal problem is solved by the branch-and-cut method. In computational experiments, the performances of the robust solutions are analyzed using Monte Carlo simulation. The experimental analysis demonstrates that the robust optimization approach can yield routes that minimize total cost and are less sensitive to substantial deviations of service times. Decision makers may obtain some managerial insights from robust optimization solution to determine an appropriate routing strategy. References | Related Articles | Metrics

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Parametric Stability for Deep-Sea Marine Riser Under Consideration of Complex Pre-Stress Force Distribution CHEN Luyun1,2,WEI Keilong3 2018, 52 (4):  395-402.  doi: 10.16183/j.cnki.jsjtu.2018.04.003 Abstract ( 39 )   Save Parametric Stability for Deep-Sea Marine Riser Under Consideration of Complex Pre-Stress Force Distribution References | Related Articles | Metrics

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A Dynamic Grids Method for Numerical Simulation of Complicated Flexible Movement Flow Field and Its Application GUO Zeyu1,CHEN Zuogang1,2 2018, 52 (4):  403-409.  doi: 10.16183/j.cnki.jsjtu.2018.04.004 Abstract ( 50 )   Save In order to apply the high-precision structured grids in the flow field with complicated moving and flexible boundaries, a new adaptive control generation dynamic grids method is developed based on two-dimensional body fitted grids. The grids generation method is proposed to generate updated high-precision body fitted structured grids in each time step according to movements of boundaries. A numerical study of fish-like propulsion is carried out by using the new method, and the high computational cost, the grids intersection and quality reduction have effectively been avoided. It makes a full use of advantages of structured grids in accuracy and rate of grids generation and applicability of turbulence models. This new grid generation method is benefitial to the research of flow problems with the moving and flexible boundaries. References | Related Articles | Metrics

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Theoretical Analysis of Superelastic Shape Memory Alloy Helical Structures Subjected to Radial Deformation PU Qilong，ZHOU Xiang 2018, 52 (4):  410-418.  doi: 10.16183/j.cnki.jsjtu.2018.04.005 Abstract ( 56 )   Save Based on the analytical models which describe axial extension on both ends of superelastic shape memory alloy (SMA) helical structures and the simplified constitutive model of SMA materials, in this paper, the equivalent-transformed method is applied to establish the relationship between the shrinkage of helical springs undergoing uniform radial pressure and the axial extension deformation, with the purpose of satisfying the practical application of helical structures made of SMA. The validity is proved through finite element method (FEM) and then this analytical model is generalized to braided stents for inter interventional therapy. The possibility of this application and error analysis are discussed through parametric analysis and comparison between results of analytical model and FEM. This model can be applied to analyze the deformation behavior of radial compression of SMA helical springs in an analytical way, and its computational efficiency is obviously superior to FEM, so that it is more convenient to adjust parameters to achieve the desired deformation in earlier stage of helical structure design. References | Related Articles | Metrics

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Numerical Study of the Vortex Induced Vibrations of a Circular Cylinder with Different Degrees of Surface Roughness GAO Yun1, 2,ZHENG Wenlong1,XIONG Youming1,ZOU Li3 2018, 52 (4):  419-428.  doi: 10.16183/j.cnki.jsjtu.2018.04.006 Abstract ( 26 )   Save The vortex-induced vibration (VIV) characteristics of a circular cylinder with different degrees of surface roughness was studied numerically. The response amplitude, response frequency, vortex force, vortex shedding flow pattern and phase angle between the VIV displacement and the vortex force with different degrees of surface roughness were compared. The numerical results show that the VIV amplitude decreases with increase of surface roughness. For smooth cylinder or the cylinder with small surface roughness, the VIV response could be divided into three branches: initial branch, upper branch and lower branch. Within initial and upper branches, the vortex shedding flow pattern displays 2S mode. However, it produces 2P mode within lower branch. For the cylinder with large surface roughness, the VIV response only could be divided into two branches: initial branch and lower branch. The vortex shedding flow pattern displays 2S mode within initial branch, while it displays 2P mode within lower branch. References | Related Articles | Metrics

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Design of the Film Actuator Based on Bridge-Type Mechanism LIU Jihao,YAN Weixin,LI Peixing,PAN Gen,ZHAO Yanzheng 2018, 52 (4):  429-436.  doi: 10.16183/j.cnki.jsjtu.2018.04.007 Abstract ( 37 )   Save A high frequency film actuator for the micropump is proposed based on the bridge-type mechanism. The bridge-type mechanism contributes to the improvement in the amplification ratio, and the linkage mechanism is employed to eliminate the output drift. The ideal model and the elastic theory are respectively used to establish the kinematic characteristics and the deformation of the film actuator in order to investigate the displacement amplification ratio and the output drift. It is possible for the rotational symmetric configuration to reduce the thermal deformations. By the finite element analysis in ANSYS software and prototype experiments the mechanical design and the displacement amplification ratio are evaluated. The prototype was made by MEMS technology, and had the maximum output displacement of 50 μm and the displacement amplification ratio of 23. If the geometric relation agrees with the developed conditions, the output displacement is only relative to the mean of the input displacements, and no output radial displacement exists because of the difference among the inputs. References | Related Articles | Metrics

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The Effect of Carbon-Carbon Double Bond on the Ignition Delay of Methyl Trans-3-Hexenoate YU Liang，WU Danyang，L Xingcai 2018, 52 (4):  437-446.  doi: 10.16183/j.cnki.jsjtu.2018.04.008 Abstract ( 32 )   Save In order to investigate the ignition characteristic of methyl trans-3-hexenoate under homogeneous charge compression ignition conditions, autoignition experiments of methyl trans-3-hexenoate were carried out through a rapid compression machine at compressed pressures of 1.1, 1.5 and 2.0 MPa with equivalence ratios of 0.5, 1.0 and 1.5. The ignition delay of methyl trans-3-hexenoate was compared with that of methyl hexanoate at compressed pressures of 1.5 and 2.0 MPa with equivalence ratio of 1.0. Besides, simulations were performed with CHEMKIN-PRO software. Sensitivity analysis and reaction pathway analysis were conducted to find out the important elementary reactions that control ignition. The effect of n-butanol on ignition delay was studied by adding n-butanol in methyl trans-3-hexenoate. It was found that as the equivalence ratio decreased, the maximum combustion pressure reduced and the ignition delay of methyl trans-3-hexanoate increased. The addition of n-butanol increased the ignition delay, and larger ignition delay was measured with higher content of n-butanol. It was also found that the ignition delay of methyl trans-3-hexenoate decreased with the increase of the compressed pressure. Compared with methyl hexanoate, methyl trans-3-hexenoate features only one stage ignition and no obvious negative temperature coefficient phenomenon. This was due to the existence of carbon-carbon double bond structure in methyl trans-3-hexenoate. This study measured the ignition delay of methyl trans-3-hexenoate and revealed the effect of carbon-carbon double bond on the autoignition characteristic of methyl trans-3-hexenoate. References | Related Articles | Metrics

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Effects of Potential on 508III-52M-690 Dissimilar Weld Joint WANG Jiamei1，SU Haozhan1,HE Kun2，ZHANG Lefu1 2018, 52 (4):  447-454.  doi: 10.16183/j.cnki.jsjtu.2018.04.009 Abstract ( 40 )   Save Effect of applied potential on stress corrosion cracking (SCC) behavior of 508III-52M-690 dissi-milar weld joint of safe-end was researched with slow strain rate tensile (SSRT) tests and high temperature electrochemistry tests in high temperature (300℃) water containing 50mg/kg chloride. The results revealed that the SCC susceptibility increases dramatically with the applied potential, then the potential above a critical value exists between －500 and －400mV (versus standard hydrogen electrode). The SCC susceptibility is low and no obvious intergranular or transgranular stress corrosion cracks can be found when the applied potential below the critical value which corresponds to deoxygenated water chemistry. It means the fracture is dominated by mechanical properties and closely relates to the hardness distribution of welded joint. The lower the hardness is, the more easily fractures occur. Therefore, all ductile fractures are located at 52Mb (butt welded) with the lowest hardness. While, when electrode potential is higher than the critical potential, all brittle fractures are located at 508III heat affected zone (508III HAZ) with the lowest corrosion resistance, where exhibits significant SCC behavior with large area intergranular and transgranular stress corrosion cracks. Hence, the dissolved oxygen concentration need be controlled strictly to make sure the corrosion potential is below the critical potential. Besides, the 52Mb and 508III HAZ of this dissimilar weld joint are the most venerable sites to crack which need to be paid high attention to during the operation. References | Related Articles | Metrics

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An Improved Moving Least Square Method and Application in Structural Reliability Analysis WEI Yifu1,2,KAWAMURA Yasumi3,WANG Deyu1,2,3 2018, 52 (4):  455-460.  doi: 10.16183/j.cnki.jsjtu.2018.04.010 Abstract ( 43 )   Save A response surface method using moving least square method is applied for structural reliability analysis in this paper. In each iteration, sampling point’s weight is redefined by not only the distance between the point and center point but also the distance between the point and response surface. Meanwhile, current iteration’s influence domain is transformed according to the last response surface obtained from former iterations. Thus, an improved moving least method is proposed and numerical results indicate the improved method has higher accuracy. References | Related Articles | Metrics

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Transient Flow Characteristics in Self-Priming Centrifugal Pump Volute MOU Jieganga,WU Zhenxinga,ZHOU Peijiana,GU Yunqinga,WU Denghaob,REN Yunb MOU Jieganga,WU Zhenxinga,ZHOU Peijiana,GU Yunqinga,WU Denghaob,REN Yunb 2018, 52 (4):  461-468.  doi: 10.16183/j.cnki.jsjtu.2018.04.011 Abstract ( 34 )   Save Because of the existence of reflux hole in the self-priming centrifugal pump volute, its internal transient flow is more complicated than the ordinary centrifugal pump, and it largely determines the running stability. In order to study the transient flow characteristics inside a self-priming centrifugal pump volute, the three-dimensional unsteady flow under various operating conditions of a model pump with and without reflux hole were numerically simulated to investigate the volute pressure fluctuations and transient flow characteristics near the reflux hole. The results showed that the existence of reflux hole makes the volute pressure fluctuation more severe and variable. In the volute cross-sections with the largest pressure fluctuation amplitude, there were relatively strong, symmetrical, different sizes and reverse secondary flow vortexes. The vorticity was great at the exit of reflux hole to volute, and there were vortexes flow structures that change periodically over time in the cross-section of both directions. The maximum pressure pulsation amplitude of volute with reflux hole was larger than that without reflux hole. The increased amplitudes were, respectively, 35.5%, 13.7% and 19.6% under the conditions that flow rates were 0.8, 1.0 and 1.2 times of the design flow rate. References | Related Articles | Metrics

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Source Number Estimation Based on Joint Probability Density Function of the Sample Eigenvectors GUO Tuo1,2,WANG Yingmin1,ZHANG Lichen1 2018, 52 (4):  469-473.  doi: 10.16183/j.cnki.jsjtu.2018.04.012 Abstract ( 29 )   Save Correctly estimating the number of sources is a necessary condition for the majority of high-resolution spatial spectrum estimation algorithm. Source number estimations such as the criteria based on Akaike information theory (AIC), minimum description length (MDL) criterion, and Gerschgorin disk criterion (GDE) may lead to performance degradation, or even cannot correctly work in the low SNR. A novel source number estimation method based on joint probability density function of cosine of the angle between sample eigenvectors is proposed. Firstly, in noise subspace the cosine values between an eigenvector and other eigenvectors are obtained by the sample covariance matrix decomposition. Then the joint probability density function value of these vector angle cosine is determined. At last, two divided adjacent values of the density function is compared with a threshold value for determining the source number. Numerical simulation and tank experimental verification show that the performance of the proposed method is far better than that of the conventional algorithms mentioned above. References | Related Articles | Metrics

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Maneuvering Target Tracking Algorithm Based on Weighted Distance of Probability Data Association CHEN Xiao，LI Ya’an，LI Yuxing，YU Jing 2018, 52 (4):  474-479.  doi: 10.16183/j.cnki.jsjtu.2018.04.013 Abstract ( 25 )   Save In order to improve the accuracy of real-time tracking a maneuvering target in clutter, an improved probabilistic data association was proposed based on the weighted distance and using combined interactive multi-model probabilistic data association algorithm. The algorithm can enhance the probability from the target or decrease the probability from the clutter. The improved algorithm has better tracking performance in the dense clutter environment. The improved probabilistic data association algorithm is used as a filter. Simulation results show that the proposed algorithm can improve maneuvering target tracking performance in dense clutter, can also be more effective and reliable to realize maneuvering target tracking. References | Related Articles | Metrics

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The Weak Target Detection Method Based on the Subspace Bearing Stability SUN Ting1,2,GENG Guohua2,ZHENG Enming3,WANG Ping4 2018, 52 (4):  480-487.  doi: 10.16183/j.cnki.jsjtu.2018.04.014 Abstract ( 31 )   Save In unknown underwater target detection and bearing estimation, the weak targets are covered by strong targets, which cannot be detected and estimated at the same time. A weak target detection method based on the subspace bearing stability is proposed to solve the problem. Firstly, this method makes eigen decomposition for covariance matrix of array element receiving data. Then, it utilizes the characteristic that the beam-forming bearing estimation values of targets subspace are stable and close to the true values, and the beam-forming bearing estimation values of background noise subspace are randomly distributed in ［0°,180°］. Lastly, the method statistically weights the normalized spatial spectra of each subspace by the bearing variance, so it can further restrain the spatial spectrum disturbances of background noise subspace, and can decrease the spatial spectrum difference between strong targets and weak targets subspace. The theoretical analysis, numerical simulation and experimental results show that, at the same frequency band and the same beam, compared with sub-band conventional beam-forming (SBCBF) detection method, our method can well enhance the spatial spectrum amplitude of weak target subspace, and decrease the spatial spectrum difference between strong targets and weak targets subspace, and detect strong targets and weak targets at the same time. References | Related Articles | Metrics

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Spatial Representation and Location Estimation Model Based on Place Cells ZHOU Yang,WU Dewei 2018, 52 (4):  488-494.  doi: 10.16183/j.cnki.jsjtu.2018.04.015 Abstract ( 21 )   Save To develop a new navigation method with bio-inspired spatial representation and autonomous positioning ability, a model of spatial representation and location estimation based on place cells is presented in this paper. In the proposed model, the place cells of self-motion perception are generated through the transformation from grid cells to place cells based on radial basis function (RBF) neural network. Simultaneously, the place cells of visual perception are generated through environment perception and similar measure. Finally, the above two kinds of place cells are fused by information weighting, and the place cells of multi-information perception are generated to represent the explored space. When the vehicle runs in the represented space, it can realize autonomous positioning by processing the firing activity of population place cells based on gravity center estimation principle. Simulation results indicate the proposed model can represent the explored space, and the firing characteristic of the generated place cells is similar to that of biological place cells. Besides, when there is an error in one of the perception modes, the spatial representation of multi-information perception can also give the good location estimation performance. References | Related Articles | Metrics

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Model and Simulation of Carrier Collaboration Transportation Based on Holon LI Junsong1,2,RONG Gang1,FENG Yiping1 2018, 52 (4):  495-504.  doi: 10.16183/j.cnki.jsjtu.2018.04.016 Abstract ( 28 )   Save This paper addresses the carrier collaboration transportation with limited sharing of carrier’s request information. From the perspective of control structure, a holon-based multi-level control structure framework is proposed for exchanging tasks between carriers. From the perspective of modeling, the system model based on this control structure is described by using unified modeling language (UML) and discrete event system specification (DEVS). DEVS analysis shows that the system model is the coupling closure, which can convert a multi-level complex carrier collaboration relationship into a local carrier relationship in an alliance. This can simplify the carrier collaboration research. Finally, a simulation platform for carrier collaboration transportation based on holon is designed and developed. A simulation example shows the validity of the collaboration. References | Related Articles | Metrics