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    15 June 2020, Volume 25 Issue 3 Previous Issue    Next Issue

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    Analysis of Transmission Power and Efficiency of Side-Mounted Inductive Power Supply System for Metal Rotary Shafts
    ZHAO Yong, JI Xiaojun, DAI Ming, QI Hongli, GAO Junkai
    2020, 25 (3):  273-280.  doi: 10.1007/s12204-020-2181-4
    Abstract ( 510 )   PDF (1987KB) ( 46 )  
    The online detection of metal shaft parameters, such as torque, power and deformation, is widely applied in engineering projects. The power supply of metal shafts is the key to the detection reliability and practicality. However, traditional slip ring and battery power supply are limited in reliability and service life. In this paper, a side-mounted inductive power supply system for the rotating metal shaft is designed by using a Utype core. The equivalent reluctance and circuit models of the system are analyzed, and the methods of improving the coupling coefficient and transmission efficiency are proposed from theoretical analysis. Through the finite element simulation analysis of the system, the general relationships between the transmission power and efficiency of the system and the number of coil turns, the working frequency and the load are analyzed. The accuracy of theoretical analysis and simulation analysis is verified by the practical power transmission experiments. This paper provides a novel and reliable power supply method for inductive power supply of rotating equipment, and enriches the solutions of rotating power supply.
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    Thermoelastic Dissipation in Diamond Micro Hemispherical Shell Resonators
    FENG Jun, ZHANG Weiping, LIU Zhaoyang, GU Liutao, CHENG Yuxiang
    2020, 25 (3):  281-287.  doi: 10.1007/s12204-020-2182-3
    Abstract ( 352 )   PDF (1656KB) ( 30 )  
    Maximizing quality factor (Q) is essential to improve the performance of micro hemispherical shell resonators (μHSRs) which can be used in microelectromechanical system (MEMS) gyroscopes to measure angular rotation. Several energy dissipation mechanisms limit Q, where thermoelastic dissipation (TED) is the major one and studied in this paper. Fully coupled thermo-mechanical equations for calculating TED are formulated, and then temperature distribution in a deformed μHSR and its quality factor related to TED (QTED) are obtained by solving the equations through a finite-element method (FEM). It has been found that different fabrication process conditions can obtain various geometrical parameters in our previous studies. In order to provide guidelines for the design and fabrication of μHSRs, the effects of their geometry on resonant frequency (f0) and QTED are studied. The change of anchor height and small enough anchor radius have no effect on both f0 and QTED, but the shell size including its radius, thickness and height has significant impact on f0 and QTED. It is found that whether a μHSR has lower f0 and higher QTED or higher f0 and higher QTED can be achieved by changing these geometrical parameters. The results presented in this paper can also be applied to other similar resonators.
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    Semi-Global Consensus Problems of Discrete-Time Multi-Agent Systems in the Presence of Input Constraints
    WANG Jian, SHI Liangren
    2020, 25 (3):  288-298.  doi: 10.1007/s12204-020-2183-2
    Abstract ( 397 )   PDF (1921KB) ( 32 )  
    This paper studies the consensus problems of the discrete-time multi-agent systems (MASs) in the presence of input saturation constraints over directed communication networks. Two kinds of consensus problems, of the leaderless consensus problem with no leader agent and the containment control problem with multiple leader agents, are investigated in this paper. Low gain feedback consensus algorithms based on the improved discretetime parametric algebraic Riccati equation (ARE) are proposed to solve the consensus problems. For the MAS without any leader, the trajectories of all agents converge together when the communication networks contain a directed spanning tree. For the MAS with multiple leaders, the trajectories of all follower agents converge to the convex hull spanned by the leader agents when there is at least one leader agent which is trackable for each follower agent. Simulation examples are provided to verify the theoretical results.
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    Model Predictive Control for Steering System of Water-Jet Propulsion
    GONG Zhenghua, SONG Chenwei, LI Gangqiang, CHEN Jianping, XU Zijing, YUAN Jingqi
    2020, 25 (3):  299-303.  doi: 10.1007/s12204-019-2141-z
    Abstract ( 388 )   PDF (477KB) ( 41 )  
    Water-jet propulsion is a widely applied ship propulsion technology. Its steering control system has an important impact on manoeuvre performance. In this paper, transfer function model is firstly established on the basis of mechanism analysis of water-jet steering system. Then, by considering the variability of model parameters and input constraints in practical operation, a model predictive controller is designed for steering system control. Subsequently, model based disturbance observer is employed in an attempt to reject environmental disturbances. The performance of the proposed model predictive control (MPC) scheme for a particular steering system is compared with that of conventional proportional integral derivative (PID) control strategy. Simulation results demonstrate that the proposed model predictive controller outperforms conventional PID controller, particularly in robustness, response delay and tracking accuracy.
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    Optimized Design for a Combined Die with Two Stress Rings in Cold Forging Considering Thermal-Mechanical Effects
    LI Zibo, ZENG Fan, ZHAO Zhen, HU Chengliang
    2020, 25 (3):  304-314.  doi: 10.1007/s12204-019-2150-y
    Abstract ( 282 )   PDF (2269KB) ( 24 )  
    Stress analysis and optimization of combined die structure with two stress rings were performed. Using thermoelastic deformation, the contact pressure at the interfaces between layers was calculated. Then, theoretical expressions of stress distribution for the combined die were derived. The thermal-mechanical effect under working conditions was considered. To verify the theoretical expressions, simulation work was performed. Optimization of die design was carried out by defining radius ratio and shrink fit coefficient as optimization variables. The objective was to minimize the effective circumferential stress at the inner surface of the die insert, under the constraint that the maximum equivalent stress values of die insert and stress rings did not exceed their respective yield stresses. The Kriging model was used to describe the influence of shrink fit and die dimensions on the objective function and the maximum equivalent stress. Using a genetic algorithm, optimum parameters were found with a minimum circumferential stress of 442.9MPa under a working stress of 1 800MPa. Further analysis of five selected optimal results was carried out, and the specific design parameters of these combined dies are different under the same level of circumferential stress, and the combined die is overdesigned if the thermal effect is ignored.
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    T-S Fuzzy Model-Based Depth Control of Underwater Vehicles
    QIAN Yuan, FENG Zhengping, BI Anyuan, LIU Weiqi
    2020, 25 (3):  315-324.  doi: 10.1007/s12204-020-2165-4
    Abstract ( 391 )   PDF (357KB) ( 21 )  
    A T-S fuzzy model with two rules is established to exactly describe the nonlinear uncertain heave dynamics of underwater vehicles with bounded heave speed. A single linear-matrix-inequality-based (LMI-based) state feedback controller is then synthesized to guarantee the global stability of the depth control system. Simulation results verify the effectiveness of the proposed approach in comparison with linear-quadratic regulator (LQR) method. Nonlinear disturbance observer is appended to the system when the underwater vehicles are affected by the gravity-buoyancy imbalance. The two-stage control method is effective to stabilize an uncertain system with both parameter uncertainties and external disturbances.
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    Fine-Grained Opinion Mining on Chinese Car Reviews with Conditional Random Field
    WANG Yinglin
    2020, 25 (3):  325-332.  doi: 10.1007/s12204-020-2184-1
    Abstract ( 391 )   PDF (231KB) ( 14 )  
    Nowadays, the Internet has penetrated into all aspects of people’s lives. A large number of online customer reviews have been accumulated in several product forums, which are valuable resources to be analyzed. However, these customer reviews are unstructured textual data, in which a lot of ambiguities exist, so analyzing them is a challenging task. At present, the effective deep semantic or fine-grained analysis of customer reviews is rare in the existing literature, and the analysis quality of most studies is also low. Therefore, in this paper a fine-grained opinion mining method is introduced to extract the detailed semantic information of opinions from multiple perspectives and aspects from Chinese automobile reviews. The conditional random field (CRF) model is used in this method, in which semantic roles are divided into two groups. One group relates to the objects being reviewed, which includes the roles of manufacturer, the brand, the type, and the aspects of cars. The other group of semantic roles is about the opinions of the objects, which includes the sentiment description, the aspect value, the conditions of opinions and the sentiment tendency. The overall framework of the method includes three major steps. The first step distinguishes the relevant sentences with the irrelevant sentences in the reviews. At the second step the relevant sentences are further classified into different aspects. At the third step fine-grained semantic roles are extracted from sentences of each aspect. The data used in the training process is manually annotated in fine granularity of semantic roles. The features used in this CRF model include basic word features, part-of-speech (POS) features, position features and dependency syntactic features. Different combinations of these features are investigated. Experimental results are analyzed and future directions are discussed.
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    Test of Friction Parameters in Bulk Metal Forming Based on Forward Extrusion Processes
    CHEN Xia, WEN Tong, LIU Kefan, HONG Yifei
    2020, 25 (3):  333-339.  doi: 10.1007/s12204-020-2162-7
    Abstract ( 237 )   PDF (2988KB) ( 14 )  
    Existing methods for examining the friction parameters in metal forming all have advantages and disadvantages. Based on the theory of plasticity, the current study established quantitative correlations among friction coefficient/factor, yield stress of the workpiece material, load and die geometry in the forward extrusion with a conical die, and then designed a procedure for testing the friction parameters in forming processes using the correlations. A series of extrusion experiments along with the numerical simulations, using AA 7050 specimens under various lubricating conditions, were carried out. The results proved that the method can obtain the friction coefficient/factor with an acceptable precision. Theoretically, since the effects of material properties, forming velocity, temperature and surficial condition, etc., on the deformation can be directly considered in the operation, this method is applicable to a wide range of material types and forming conditions. To avoid the occurrence of “barreling phenomenon” under large load which may lead to failure of the operation, it is recommended that half angle of the conical die ranges from 5 to 10 degrees.
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    Cargo Hold Structure Optimization of Small and Medium-Sized Duplex Stainless Steel Chemical Tankers
    ZHOU Min, GAO Mingze, LI Chuang, WANG Liancheng
    2020, 25 (3):  340-351.  doi: 10.1007/s12204-020-2164-5
    Abstract ( 264 )   PDF (993KB) ( 22 )  
    A mathematical model of optimization for cargo hold structure of small and medium-sized duplex stainless steel (DSS) chemical tankers based on the rule is described. The weight of DSS is defined as the objective function. The explicit formulas of the relevant rules, the explicit geometric relations formed by the structural arrangement and the implicit constraints such as layout, lines, expert experience, workmanship and so on are taken as the constraints. The design variables and the algorithm are determined by analyzing the logical relations among the factors. Besides, the efficiency of the optimum algorithm is improved by utilizing the distribution law of the optimal corrugations. Finally, the comprehensive optimization of the cargo hold DSS is accomplished by C++ programming. The weight of the optimized scheme of the example is 4.93% lower than that of the original scheme. The finite element analysis results show that the optimized scheme is satisfied with the requirements of the rules and has a good structure performance. The optimization method based on the rules and accomplished by the programming is practical for structural preliminary design.
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    Numerical Prediction of the Pumpjet Propulsor Tip Clearance Vortex Cavitation in Uniform Flow
    LI Han, PAN Guang, HUANG Qiaogao, SHI Yao
    2020, 25 (3):  352-364.  doi: 10.1007/s12204-019-2138-7
    Abstract ( 383 )   PDF (8617KB) ( 23 )  
    Previous studies show that the tip clearance loss limits the improvement of pumpjet propulsor (PJP) performance, and the tip clearance flow field is the most complicated part of PJP flow. In this work, the noncavitation and cavitation hydrodynamic performances of PJP with a tip clearance size of 1mm are obtained by using the detached-eddy simulation (DES). At constant oncoming velocity, cavitation first occurs on the duct and then disappears with the decrease of the advance ratio. The rotor blade cavitation occurs at the low advance ratio and comprises tip clearance cavitation, tip leakage cavitation, and blade sheet cavitation. In the rotor region, the typical vortices include tip separation vortex, tip leakage vortex, trailing edge shedding vortex, and blade root horseshoe vortex. Combined with the pressure distribution, both the Q and λ2 criteria give reliable results of vortex identification. The cavitation causes an expansion of tip leakage vortex in the circumferential direction and decreases the intensities of tip separation vortex in the whole tip clearance area and tip leakage vortex in the cavitation area, and enhances the strength of tip leakage vortex in the downstream non-cavitation area.
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    Effect of Relative Humidity on Resuspended Particles Caused by Human Walking
    ZHENG Shuihua, DU Weiyuan, ZHAO Lipan, LI Xiangpeng
    2020, 25 (3):  365-371.  doi: 10.1007/s12204-020-2176-1
    Abstract ( 291 )   PDF (1347KB) ( 21 )  
    The goal of this study is to investigate the effects of relative humidity on particle resuspension. The experimental study on the resuspension of different size particles is performed in the laboratory at 50%, 60%, 70% and 80% relative humidity separately. The material of flooring is shaggy carpet. The experiments are carried out in a closed room with four laser dust instruments and a laser dust particle counter. The results show that when the relative humidity is 60% and 70%, the resuspension of indoor particulate matter is likely to occur. Human walking has a greater impact on larger-size particles. Under the conditions of different humidity, four situations all follow a rule that the larger the particle size is, the more stable the particle state is.
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    Parameter Optimization and Control Characteristics Analysis of TLMD System Based on Phase Deviation
    HU Jingjing, XU Jiayun
    2020, 25 (3):  372-383.  doi: 10.1007/s12204-019-2148-5
    Abstract ( 240 )   PDF (433KB) ( 13 )  
    Combined with the advantages and disadvantages of tuned liquid damper (TLD) and tuned mass damper (TMD), a double tuned liquid mass damper (TLMD) is proposed by replacing the rigid connection of TLD with the spring structure. The motion equation of a single-degree-of-freedom structure with a TLMD attached at its top is found under harmonic excitation. Comparing the energy consumption and amplitude of primary structure with equal mass ratio TMD, it is found that the energy dissipation performance of TLMD is better in the effective phase region. The interaction process between TLMD and structure is analyzed, and the formula of phase deviation between the relative velocity of tank and the displacement of primary structure is deduced. By analyzing the influence of mass ratio, frequency ratio, damping ratio and water depth ratio on the damping effect, the results show that the frequency ratio and liquid depth ratio have great influence on the size and location of deep resonance peak, and the mass ratio and damping ratio have great influence on the width of the effective frequency band. The formula of equivalent damping ratio is proposed based on the principle of energy and it is found that the equivalent damping ratio is related to the phase deviation and change with the frequency ratio of the external excitation.
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    Dynamic Responses of Cellular Metal-Filled Steel Beam-Column Joint Under Impact Loading
    DING Kewei, LIU Jianhua, REN Jianwei, MA Wei
    2020, 25 (3):  384-393.  doi: 10.1007/s12204-020-2160-9
    Abstract ( 347 )   PDF (3265KB) ( 17 )  
    Taking the excellent energy absorption performances of cellular structures into consideration, three beam-column steel joints are proposed to analyze the effect of cellular metallic fillers on impact mechanical responses of beam-column joints. Based on the existing experimental results, the finite element models of the associated joints are established by using finite element method software. The deformation mode, the bearing capacity and energy absorption performance of various joints subjected to impact loadings with the loading velocities from 10 to 100 m/s are analyzed, respectively. The dynamic responses of cellular metal-filled beamcolumn joints are quantitatively analyzed by means of displacements of central region, nominal impacting stress and energy absorption efficiency. The results can be concluded that the filling of cellular filler weakens the stress concentration on joints, alleviates the occurrence of tearing in connection region among column and beam, and reduces the displacement caused by impact loading. Energy absorption efficiency of filled joints subjected to impact loading increases as the impacting velocity increases, and the cellular metallic filler improves their impact resistance of beam-column joints. The energy absorption efficiency of fully filled joints is superior to that of others. This study can provide a reference for steel structural design and post-disaster repair under extreme working conditions.
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    Fatigue Analysis of Liquefied Petroleum Gas Cylinders for Safety Risk Assessment
    ZHOU Feng, LIU Haotian, LA Jiankai
    2020, 25 (3):  394-397.  doi: 10.1007/s12204-019-2143-x
    Abstract ( 282 )   PDF (334KB) ( 31 )  
    With the widespread application of liquefied petroleum gas (LPG), the safety of LPG cylinder has received more and more attention. For the safety of LPG cylinder, we conduct a safety risk assessment of cylinder using the failure mode and effect analysis (FMEA) method. Taking the most influential inflatable fatigue under normal conditions as the research object, we use FE-safe software to analyze the fatigue failure. The risk compliance coefficients of various failure modes are calculated and classified according to the risk level. In this way, the service life of the LPG cylinder weld is determined. The presented method improves the safety risk assessment process of LPG cylinder and provides a good theoretical and practical basis for similar pressure vessel risk assessment.
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    Quasi-Periodic Replacement Policy for a Two-Unit Production System
    GAO Wenke, WANG Yu, YANG Tianshu, JI Hong, CHEN Yin
    2020, 25 (3):  398-406.  doi: 10.1007/s12204-019-2149-4
    Abstract ( 249 )   PDF (285KB) ( 14 )  
    Maintenance optimization of periodic replacement for mono-unit production system is a widely discussed topic. In practice, the replacement for a parallel production system with multi-unit served by one repairman is universal. The replacement action is often implemented in a maintenance window at random, although the replacement period appears as a quasi-periodic event. To optimize these maintenance policies, this study analyzes a bivariate quasi-periodic replacement policy (T,W) for a two-unit parallel production system with a maintenance window and one repairman. One unit of the system is replaced when either a failure occurs or a replacement plan comes in the maintenance window, whichever comes first. If one of the two units is in the replacement, the other may continue operating or waiting until the replacement is completed. An optimal replacement window [T*, T*+ W*] can be obtained by jointly considering the system’s long-running cost rate and the availability using the genetic algorithm. This study also introduces three examples of the production system with different types of units to illustrate the proposed policy.
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