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    31 December 2016, Volume 21 Issue 6 Previous Issue    Next Issue

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    Research on vane end face of cam-rotor vane servo motor based on disturbing torque
    Yuan F.; Wang X.; Tao J.; Miao Z.
    2016, 21 (6):  641-647.  doi: 10.1007/s12204-016-1776-2
    Abstract ( 14 )   PDF (1359KB) ( 27 )  
    Cam-rotor vane motor (CRVM) is one of the new continuous hydraulic servo motors with the characteristics of no pulsation of instantaneous flow rate and output torque, small volume and rotating inertia. It is one of the appropriate actuators for hydraulic servo system which has good dynamic and steady-state performance requirements. The ideal output torque of CRVM is pulseless, but the actual output torque of CRVM is pulsating. This is caused by the disturbing torque of contact components, especially the friction between vane and cam-rotor. In order to get better performance of CRVM, which means more stable output torque and smaller disturbing torque, we discuss four kinds of vane end faces (VEFs). Analytic formulae of the normal contact force and the disturbing torque caused by the vane are derived from systematical force analysis. The normal contact force and the disturbing torque vary through a period under different VEF, and the reduced oil pressure is simulated in this paper. The simulation shows that the VEF with the proper round and reduced oil pressure can significantly decrease the disturbing torque and get better servo performance. The experiment results verify the correctness of the theoretical analysis and simulation. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Effect of interference fits on the fatigue lives of bolted composite joints
    Lü X.; Zhao J.; Hu L.; Wang H.
    2016, 21 (6):  648-654.  doi: 10.1007/s12204-016-1777-1
    Abstract ( 12 )   PDF (1505KB) ( 27 )  
    The effect of interference fits on the fatigue lives of bolted composite joints is investigated by conducting mechanical tests. Static and fatigue tests are carried out on specimens made of carbon-bismaleimide composites joined together as double-lap single-bolt joints. The bolts having interference fits ranging of 0 (neat fit), 0.5%, 0.75% and 1% are performed. The results demonstrate the relationship between fatigue life and different values of interference fits. After the fatigue tests, non-destructive evaluation (NDE) and scanning electron microscope (SEM) are used to observe the damage of the surrender and surface of the hole. The test results show that the interference fitted specimens have improved fatigue life compared to the neat fitted specimen. The NDE and SEM results reveal that the damage degree of interference fitted specimen is weaker than that for the neat fitted one. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Scaling Behavior of bulk freight rate volatility before and after noise reduction
    Dai S.; Chen F.; Zeng Y.; Zeng X.
    2016, 21 (6):  655-661.  doi: 10.1007/s12204-016-1778-0
    Abstract ( 17 )   PDF (395KB) ( 27 )  
    Analysis of freight rate volatility characteristics is a hot topic after year 2008 due to the effect of financial crisis in marine transportation. In this paper, we analyze the bulk freight rate index by detrended fluctuation analysis (DFA) method and discover the scaling behavior. Switching points (SPs), as the indicators of scaling behavior, can be eliminated after Vondr´ak noise reduction technique. Therefore, we conclude that highfrequency noise is the cause of SP. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Study of tunnel thruster performance and flow by quasi-steady Reynolds-averaged Navier-Stokes simulation
    Yu C.; Yang C.
    2016, 21 (6):  662-671.  doi: 10.1007/s12204-016-1779-z
    Abstract ( 17 )   PDF (2313KB) ( 27 )  
    A numerical approach based on the solution of the Reynolds-averaged Navier-Stokes (RANS) equations using the shear-stress transport (SST) turbulence model has been employed to investigate the hydrodynamic performance and flow of tunnel thrusters. The flow passages between adjacent blades are discretized with prismatic cells so that the boundary layer flow is resolved down to the viscous sub-layer. The hydrodynamic performances predicted by the quasi-steady approach agree well with the experimental data for three impellers covering a range of blade area and pitch. Through analysis of the flow field, the reason why the hub of impeller also contributes to thrust which can amount to 40%—60% of the impeller thrust, and the mechanism of the impeller inducing an axial force on the hull are elucidated. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Nonlinear buckling analysis of pre-stressed ring-stiffened circular cylindrical shells under external pressure
    Ning W.; Xu Y.; Liao Y.
    2016, 21 (6):  672-678.  doi: 10.1007/s12204-016-1780-6
    Abstract ( 16 )   PDF (604KB) ( 27 )  
    This paper is concerned with the nonlinear buckling behavior of pre-stressed ring-stiffened thin circular cylindrical shells under external pressure. According to the geometrical nonlinearity, governing equations are derived by incorporating initial stresses based on Donnell-type shell theory. The “smeared stiffeners” approach is used for ring stiffeners. The numerical analyses are conducted by Gelerkin’s method to obtain critical buckling loads of shells. This study shows effects of initial stresses on stability of shells. Moreover, effects of initial stresses on buckling modes of shells are discussed. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Construction of rate-compatible (RC) low-density parity-check (LDPC) convolutional codes based on RC-LDPC block codes
    Mu L.; Han G.; Liu Z.
    2016, 21 (6):  679-683.  doi: 10.1007/s12204-016-1781-5
    Abstract ( 13 )   PDF (485KB) ( 27 )  
    In this paper, a family of rate-compatible (RC) low-density parity-check (LDPC) convolutional codes can be obtained from RC-LDPC block codes by graph extension method. The resulted RC-LDPC convolutional codes, which are derived by permuting the matrices of the corresponding RC-LDPC block codes, are systematic and have maximum encoding memory. Simulation results show that the proposed RC-LDPC convolutional codes with belief propagation (BP) decoding collectively offer a steady improvement on performance compared with the block counterparts over the binary-input additive white Gaussian noise channels (BI-AWGNCs). © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Impact arresting process mechanical modeling and sliding model buffer control based on magneto-rheological fluid
    Fu L.; Li B.; Chen X.; Hu W.; Xi J.
    2016, 21 (6):  684-691.  doi: 10.1007/s12204-016-1782-4
    Abstract ( 19 )   PDF (500KB) ( 27 )  
    The research on the form and control method of impact load arresting buffer has been an active topic in the field of buffer arresting system (BAS). It becomes significant on reducing the weight of arresting system, improving the hindered efficiency, and guaranteeing the security of BAS. The hydraulic hindered device of impact load is currently used in BAS. There are some problems. For example, the system needs large power sources. However, once the power of active hydraulic control system is turned off, there arise unpredictable security risks. An arresting form of semi-active control based on magneto-rheological damper (MRD) is proposed, and the mechanical model of the BAS is established. Meanwhile, the state equation of impact load BAS is established according to the characteristics of impact load buffer arresting, and its sliding model buffer control is achieved. Due to the chattering characteristic of the output signal of sliding mode controller, the method to prevent chattering is designed based on short-term energy and zero-crossing rate detection. For the model and chattering suppression of sliding model buffer control algorithms, simulation results show that the proposed state equation and the arresting model are reasonable, and the design of semi-active control algorithm is effective. On the condition of the buffer control system requirement and the accuracy, the proposed algorithms effectively control the chattering of sliding mode control algorithms, and improve the security of the BAS. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Automatic semantic analysis of software requirements through machine learning and ontology approach
    Wang Y.
    2016, 21 (6):  692-701.  doi: 10.1007/s12204-016-1783-3
    Abstract ( 17 )   PDF (640KB) ( 27 )  
    Nowadays, software requirements are still mainly analyzed manually, which has many drawbacks (such as a large amount of labor consumption, inefficiency, and even inaccuracy of the results). The problems are even worse in domain analysis scenarios because a large number of requirements from many users need to be analyzed. In this sense, automatic analysis of software requirements can bring benefits to software companies. For this purpose, we proposed an approach to automatically analyze software requirement specifications (SRSs) and extract the semantic information. In this approach, a machine learning and ontology based semantic role labeling (SRL) method was used. First of all, some common verbs were calculated from SRS documents in the E-commerce domain, and then semantic frames were designed for those verbs. Based on the frames, sentences from SRSs were selected and labeled manually, and the labeled sentences were used as training examples in the machine learning stage. Besides the training examples labeled with semantic roles, external ontology knowledge was used to relieve the data sparsity problem and obtain reliable results. Based on the SemCor and WordNet corpus, the senses of nouns and verbs were identified in a sequential manner through the K-nearest neighbor approach. Then the senses of the verbs were used to identify the frame types. After that, we trained the SRL labeling classifier with the maximum entropy method, in which we added some new features based on word sense, such as the hypernyms and hyponyms of the word senses in the ontology. Experimental results show that this new approach for automatic functional requirements analysis is effective. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Lean system design for engineer-to-order manufacturing
    Zhou J.; Zhang Q.; Wang X.; Xiao H.
    2016, 21 (6):  702-712.  doi: 10.1007/s12204-016-1784-2
    Abstract ( 10 )   PDF (1725KB) ( 30 )  
    A five-step method framework is proposed by combing improved value stream mapping with simulation and design of experiment (DOE) to design the lean system for engineer-to-order (ETO) manufacturing, and lean practice implementation path is decided. Meanwhile, a real company case like HAVC is taken to display the application of the framework. The results indicate that compared to supermarket Kanban, constant work in process (Conwip) has the broader applicability in ETO manufacturing and the critical business process, like purchasing of key parts, and has more significant effects on value stream performance. Therefore, it should have priority in lean practice implementation. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Soil microstructure evolution and macro deformation mechanism for controlling construction disturbance in Shanghai soft soil
    Jia J.; Xie X.; Yang K.
    2016, 21 (6):  713-718.  doi: 10.1007/s12204-016-1785-1
    Abstract ( 20 )   PDF (1568KB) ( 27 )  
    Abundant practical evidences have indicated that the soil progressively loses its structural configuration under construction disturbance and this can result in long-term macro deformation. The fundamental understanding of soil microstructure evolution subject to construction disturbance is necessary for controlling disturbance in excavation projects and minimizing ground settlement. The microstructure of Shanghai soft soil is investigated in this study. The laboratory isotropic compression tests are respectively performed on the virgin soil and the reconstructed Shanghai soft soil to investigate the macro deformation of soil under disturbance. Discrete element method model is used to study the micro particle level responses of soil under disturbance. The laboratory tests and numerical simulations provide theoretical basis for construction disturbance mitigation to ensure safety and stability of excavation projects. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Optimization of isolation structure under wind load excitation and experimental study of the wind resistant bearing
    Wu Y.; Huang J.; Yan G.; Yan X.; Lü J.
    2016, 21 (6):  719-728.  doi: 10.1007/s12204-016-1786-0
    Abstract ( 17 )   PDF (1235KB) ( 28 )  
    The method of collaborative work between steel plate anti-wind bearing (AWB) and rubber isolation bearing is proposed to study the vibration reduction effect of isolation structure under stronger wind load, and the function mechanism is explained. Based on a practical project, three kinds of schemes with different isolation layers are put forward, the finite element software ETABS is used for time history analysis, and comparison is made on the seismic response of different isolated structure and aseismic structure. Comparison result shows that the isolation layer with rubber bearing and AWB can work reasonably, but further optimization on the designed parameters is needed. Moreover, the design value of horizontal bearing capacity of lead rubber bearing (LRB) is appropriate to be close to the seismic isolation layer under wind load excitation. Finally, numerical simulation and comparative analysis of shear test of the AWB are conducted. With a very small yield displacement and yield strength over 80% of the set of horizontal bearing capacity, the AWB is validated to satisfy the working conditions which provide the horizontal bearing capacity under normal operating conditions and designed earthquake. The AWB yields and malfunctions, when the maximum displacement is less than the displacement of the isolation layer. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Quantitative phase analysis of the calcium silicate slag as the residue of extracting alumina from high-alumina fly ash
    Huang D.; Zong Y.; Liu X.; Peng D.; Yang Z.
    2016, 21 (6):  729-736.  doi: 10.1007/s12204-016-1787-z
    Abstract ( 19 )   PDF (710KB) ( 29 )  
    Calcium silicate slag is the residue of process of pre-desilication alkali lime sintering applied in the high-alumina fly ash to extract the alumina. The quantitative phase analysis (QPA) of the calcium silicate slag has been performed by the Rietveld method based on the powder X-ray diffraction (XRD) with the aid of noncommercial software GSAS-EXPGUI. A known weight of crystalline internal standard (10% CaF2) was added to the calcium silicate slag to calculate the fraction of amorphous phase and other crystalline phases on an absolute basis. Besides, the calcium silicate slag was characterized by X-ray fluorescence (XRF) and thermo gravimetric (TG) differential scanning calorimetry (DSC) to test the QPA results and investigate its other characters. Finally, the results show that the amorphous fraction is 17.5% (hereinafter, the percentages refer to the mass fraction), and the major crystalline phases detected in the calcium silicate slag consist of 23.5% Beta-Ca2SiO4, 10.0% bredigite, 10.3% Ca3Al2O6 (C3A) and 21.6% CaCO3. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Modelling upgrading maintenance policy in the one-dimensional renewing warranty period
    Tian Z.; Jia Y.; Li X.; Wang P.
    2016, 21 (6):  737-743.  doi: 10.1007/s12204-016-1788-y
    Abstract ( 17 )   PDF (463KB) ( 28 )  
    In the one-dimensional renewing warranty period, the quality of the spares for product is likely to be improved during the warranty period. Therefore, upgrading maintenance becomes more and more common. Then the manufacturers (customers) may have to decide whether or not to provide (buy) the warranty considering upgrading maintenance. This paper presents a mathematical model considering upgrading maintenance for products with multiple failure modes. Upgrading maintenance is taken into account with the assumption that the warranted item is upgraded one time during the warranty cycle. The upgrading maintenance is carried out, when the corrective maintenance is taken place. After upgrading maintenance, the high-quality spares are used to replace the failed item. In the numerical example, the results of the models are calculated. Monte Carlo simulation results are compared with the analytical results to demonstrate the correctness and efficiency of the proposed models considering upgrading maintenance. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    The dynamic scheduling model of battlefield rush-repair tasks
    Chen W.; Chen C.; Liu Y.; Zan X.; Liu D.
    2016, 21 (6):  744-749.  doi: 10.1007/s12204-016-1789-x
    Abstract ( 21 )   PDF (292KB) ( 29 )  
    During the war, equipment is constantly being damaged with limited battlefield rush-repair time and power. Therefore, some military problems are presented in this paper. In order to get more fighting time for damaged equipment to participate in operation again as much as possible, three problems should be considered properly. The first problem is how to dynamically choose the most suitable damaged equipment for each repair group. The second one is how to divide tasks between different groups. The third one is how to determine execution sequence in the same group. A mathematical model is established to solve the dynamic battlefield rushrepair task scheduling problem (DBRTSP) in wartime. A variant genetic algorithm is designed to dynamically track the change of the optimal solution. A scheduling example is solved through Matlab. Results show that the proposed model is not only scientific and reasonable, but also convenient and efficient. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Evolutionary game on oil and gas companies’ pollution treatment
    Zhang T.; Guo C.; Quan L.; Fu F.
    2016, 21 (6):  750-756.  doi: 10.1007/s12204-016-1790-4
    Abstract ( 18 )   PDF (169KB) ( 29 )  
    This paper presents a dynamic model of pollution treatment strategies, driven by the bargaining relationships between governments, oil and gas companies and local residents. The results show that government plays a dominating role and government environmental policies have significant impact on other two parties’ behavior. To achieve better pollution treatment in the future, we put forward the following suggestions. An improvement in the legal system is required, and the legal enforcement needs to be strengthened. In terms of pollution treatment, responsibilities and obligations of these three parties need to be clearly defined. A wellfunctioned reward and penalties system needs to be established for minimizing the environment damage in the future. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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    Serum levels of RBP4 might not be determined by diabetes mellitus but by kidney function and renal replacement therapy
    Lu Z.; Zhang G.; Xie Y.; Li J.; Wang N.; Yan C.; Wang F.
    2016, 21 (6):  757-762.  doi: 10.1007/s12204-016-1791-3
    Abstract ( 24 )   PDF (345KB) ( 27 )  
    It has been reported that retinol-binding protein 4 (RBP4) is associated to adiposity, insulin resistance, and type 2 diabetes. Meanwhile, circulating RBP4 levels are also affected by renal function. The aim of the present study is to investigate whether serum levels of RBP4 are primarily associated with different stages of chronic kidney disease (CKD) or type 2 diabetes, if there is more potential relevance between RBP4 and renal replacement therapy. The serum levels of RBP4 were assessed by commercial competitive enzyme-linked immunosorbent assay (ELISA) kit in 212 patients with the CKD stages 1—5 and in 24 healthy controls, while its correlation with clinical and metabolic parameters was analyzed. The serum level of RBP4 had a strong correlation with estimated glomerular filtration rate (eGFR) (P < 0.001). Stratified by eGFR and treatment, no more differences in RBP4 serum concentration were detected between type 2 diabetic and non-diabetic subjects [CKD stages 1—5, non-dialysis (ND), hemodialysis (HD) and peritoneal dialysis (PD); P >0.05 for all]. The elevation of RBP4 become higher in HD than in PD and ND in CKD5 patients (P = 0.008 and P = 0.04, respectively), while there was no significant difference between PD and ND groups. Multivariate linear regression analysis demonstrated three independent predictors of eGFR (β = −0.676, P < 0.001), C-reactive protein (CRP) (β = −0.573, P < 0.001) and creatine (β = 0.509, P = 0.024) in the study population. The study results demonstrated that the serum level of RBP4 was negatively related to the eGFR, whether diabetes mellitus (DM) affected the blood concentration of RBP4 or not. And the serum level of RBP4 exhibited significant difference in different renal replacement therapies. © 2016, Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.
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