Advances in Mechanical Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Severe Slugging in Air-Water Hybrid Riser System Wed, 26 Nov 2014 09:51:14 +0000 http://www.hindawi.com/journals/ame/2014/953213/ In the subsea pipeline gathering system, severe slugging flow is prone to occur. Severe slugging flow brings major threat to production and flow assurance in oil and gas industry due to periodical pressure oscillation and large liquid volume. Currently many researchers pay much more attention on -shaped riser, catenaries, and -shaped riser; little research has been made on hybrid riser, which is applied in the Africa West and Gulf of Mexico oil fields. Flow characteristics simulation for hybrid riser is made in this paper, using the one-dimensional and quasi-equilibrium model to simulate not only the riser-base pressure, severe slugging period, and the liquid slug length of the whole system but also base-pressure in the flexible pipe section. The calculated results match well with the experiment data. Besides, the influence of flexible pipe to the severe slugging characteristics of hybrid riser system is analyzed, which are significant for the determination of riser structure. Jing Gong, Zhiyuan Yang, Liang Ma, and Ping Wang Copyright © 2014 Jing Gong et al. All rights reserved. Guaranteed Cost Nonfragile Robust Controller for Walking Simulation of Quadruped Search Robot on a Slope of VRML Model Sun, 23 Nov 2014 14:22:33 +0000 http://www.hindawi.com/journals/ame/2014/948795/ The problem of walking simulation for the quadruped search robot on a slope is described as an uncertainty system. In order to create the virtual ramp road environment, VRML modeling language is used to build a real environment, which is a 3D terrain scene in Matlab platform. According to the VRML model structure of the quadruped search robot, a guaranteed cost nonfragile robust controller is designed for ramp road walking simulation. The constraint inequation is transformed into a strict linear inequality by using two equalities; the controller and the guaranteed cost upper bound are given based on the solutions of the linear matrix inequality. And the approaches of designing the controller are given in terms of linear matrix inequalities. The walking stability of quadruped search robot is observed using the VRML model established with the change of gravity curve. Simulation results show that the gravity displacement curve of the robot is smooth. The results given by linear matrix inequalities indicate that the proposed guaranteed cost controller is correct and effective. Peng Wang, Jixiang Li, and Yuan Zhang Copyright © 2014 Peng Wang et al. All rights reserved. CQFB and PBP in Diagnosis of Local Gear Fault Wed, 19 Nov 2014 14:02:56 +0000 http://www.hindawi.com/journals/ame/2014/670725/ The vibration signal of local gear fault is mainly composed of two components. One is the resonant signal and noise signal and the other one is the transient impulse signal including fault information. The quality factors corresponding to the two components are different. Hence, a method to diagnose local gear fault based on composite quality factor basis and parallel basis pursuit is proposed. First, two different quality factors bases are established using wavelet transform of variable quality factors to obtain the decomposition coefficient. Next, the parallel basis pursuit is adopted for the optimization of the decomposition coefficient. With the derived optimal decomposition coefficient, the resonant components with different quality factors can be reconstructed. By discussing the sparsity of signals treated with different quality factors bases, the suitable composite quality factor basis is selected to perform sparse decomposition on the signal. Besides, the obtained resonant component with low quality factor is subject to demodulation analysis, so as to derive the fault information. The feasibility and validity of the algorithm are shown by the results from simulation signal and practical application of local gear faults. Lingli Cui, Na Wu, Daiyi Mo, Huaqing Wang, and Peng Chen Copyright © 2014 Lingli Cui et al. All rights reserved. Numerical Investigation of Viscous Flow Velocity Field around a Marine Cavitating Propeller Wed, 19 Nov 2014 13:32:06 +0000 http://www.hindawi.com/journals/ame/2014/272316/ Velocity field around a ship cavitating propeller is investigated based on the viscous multiphase flow theory. Using a hybrid grid, the unsteady Navier-stokes (N-S) and the bubble dynamics equations are solved in this paper to predict the velocity in a propeller wake and the vapor volume fraction on the back side of propeller blade for a uniform inflow. Compared with experimental results, the numerical predictions of cavitation and axial velocity coincide with the measured data. The evolution of tip vortex is shown, and the interaction between the tip vortex of the current blade and the wake of the next one occurs in the far propeller wake. The frequency of velocity signals changes from shaft rate to blade rate. The phenomena reflect the instability of propeller wake. Zhifeng Zhu Copyright © 2014 Zhifeng Zhu. All rights reserved. Newly Developed Software Application for Multiple Access Process Planning Wed, 19 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/539071/ The purchase of a complex system for computer aided process planning (CAPP) can be expensive for little and some middle sized plants, sometimes an inaccessible investment, with a long recoupment period. According to this fact and the author's experience with Eastern European plants, they decided to design a new database application which is suitable for production, stock, and economic data holding as well as processing and exploitation within the manufacturing process. The application can also be used to process a plan according to the selected criteria, for technological documentation and NC program creation. It was based on the theory of a multivariant approach to computer aided plan generation. Its fundamental features, the internal mathematical structure and new code system of processed objects, were prepared by the authors. The verification of the designed information system in real practice has shown that it enables about 30% cost and production time reduction and decreases input material assortment variability. Katarina Monkova and Peter Monka Copyright © 2014 Katarina Monkova and Peter Monka. All rights reserved. Influence of Partitioning Process on the Microstructure and Mechanical Properties of High Deformability Oil-Gas Pipeline Tue, 18 Nov 2014 17:12:32 +0000 http://www.hindawi.com/journals/ame/2014/869481/ Multiphase structure of bainite and M/A constituent can be obtained for X80 oil-gas pipeline through a novel heat online partitioning (HOP) technology. The effects of partitioning temperature on the microstructure and mechanical properties of the experimental steels were researched by means of mechanical properties test, microscopic analysis, and X-ray diffraction. The results show that with the increase of the partitioning temperature, the strength of the experimental steel decreases and the ductility increases because of the increase of bainite lath width, the decrease of dislocation density, the increase of retained austenite content, and carbides coarsening. The decrease of the volume content and stability of retained austenite is the key factor, which leads to the increase of strength and the decrease of plasticity in a high range of partitioning temperature. Jing Ma, Xiaoyong Zhang, Shixia Cheng, and Huilin Gao Copyright © 2014 Jing Ma et al. All rights reserved. Numerical Study on the Thermal Performance of a Shell and Tube Phase Change Heat Storage Unit during Melting Process Tue, 18 Nov 2014 16:38:40 +0000 http://www.hindawi.com/journals/ame/2014/360283/ This work presents a numerical study of the thermal performance in a shell and tube phase change heat storage unit. Paraffin wax as phase change material (PCM) is filled in the shell space. The heat transfer fluids (HTFs: air and water) flow through the tube and transfer the heat to PCM. A mathematical model involving HTF and PCM is developed to analyze the thermal performance of the phase change heat storage unit and is validated with experimental data. Numerical investigation is conducted to evaluate the effect of HTF inlet velocity on the HTF outlet temperature, Nu, and melt fraction when air or water is used as HTF. Results indicate that the air inlet velocity has a great effect on the air outlet temperature and heat transfer rate, and the water inlet velocity has little effect on the water outlet temperature. The investigated results can provide a reference for designing phase change heat storage system. Wei Li and Chengcheng Kong Copyright © 2014 Wei Li and Chengcheng Kong. All rights reserved. Design and Fabrication of Multipurpose Diagnostic in IR-T1 Tokamak Tue, 18 Nov 2014 16:21:11 +0000 http://www.hindawi.com/journals/ame/2014/491804/ The first results of the movable multipurpose probe (MPP) experiments performed on the IR-T1 Tokamak are presented. For this purpose, a moveable MPP was designed, constructed, and installed on the IR-T1 Tokamak for the first time. MPP can measure radial variation of floating potential and ion saturation current, electrostatic fluctuation, magnetic fluctuation, and flow velocity simultaneously. The relation between gradient of Reynolds stress and poloidal particle flux can be investigated by MPP. It can measure the radial variation of radial electric field and poloidal electric field. The most advantage of MPP is to measure electric and magnetic plasma fluctuations simultaneously. MPP is composed of three sections: electrical part, magnetic part, and flow measurement section. This is a compact probe in which do not disturb plasma. The results are presented and discussed. M. Lafouti, M. Ghoranneviss, A. Salar Elahi, and S. Meshkani Copyright © 2014 M. Lafouti et al. All rights reserved. Study on the Interface Effects Based on Two-Dimensional Green’s Functions for the Fluid and Pyroelectric Two-Phase Plane under a Line Heat Source Tue, 18 Nov 2014 16:18:05 +0000 http://www.hindawi.com/journals/ame/2014/354738/ Two-dimensional Green’s functions for a line heat source applied in the fluid and pyroelectric two-phase plane are presented in this paper. By virtue of the two-dimensional general solutions which are expressed in harmonic functions, six newly introduced harmonic functions with undetermined constants are constructed. Then, all the pyroelectric components in the fluid and pyroelectric two-phase plane can be derived by substituting these harmonic functions into the corresponding general solutions. And the undetermined constants can be obtained by the interface compatibility conditions and the mechanical, electric, and thermal equilibrium conditions. Numerical results are given graphically by contours. Peng-Fei Hou, Wei Tian, and Ke Yuan Copyright © 2014 Peng-Fei Hou et al. All rights reserved. A Framework for Structural Systems Based on the Principles of Statistical Mechanics Tue, 18 Nov 2014 14:36:36 +0000 http://www.hindawi.com/journals/ame/2014/501802/ A framework is proposed in which certain well-known concepts of statistical mechanics and thermodynamics can be used and applied to characterize structural systems of interconnected Timoshenko beam elements. We first make the assimilation to a network of nodes linked by potential energy functions that are derived from the stiffness properties of the beams. Then we define a series of thermodynamic quantities inherent to a given structure (i.e., internal energy, heat, pressure, temperature, entropy, and kinetic energy). With the exception of entropy, all of them have the dimensions of energy. In order to test this new framework, a series of experiments was performed on four structural specimens within the elastic regime. Their configurations were taken from the seismic regulations known as Eurocode 8 in order to have a better based reference for our comparisons. The results are then explained within this new framework. Very interesting correlations have been found between the parameters given in the code and our concepts. Rabindranath Andujar, Jaume Roset, and Vojko Kilar Copyright © 2014 Rabindranath Andujar et al. All rights reserved. A Multiposture Locomotor Training Device with Force-Field Control Tue, 18 Nov 2014 14:33:42 +0000 http://www.hindawi.com/journals/ame/2014/173518/ This paper introduces a multiposture locomotor training device (MPLTD) with a closed-loop control scheme based on joint angle feedback, which is able to overcome various difficulties resulting from mechanical vibration and the weight of trainer to achieve higher accuracy trajectory. By introducing the force-field control scheme used in the closed-loop control, the device can obtain the active-constrained mode including the passive one. The MPLTD is mainly composed of three systems: posture adjusting and weight support system, lower limb exoskeleton system, and control system, of which the lower limb exoskeleton system mainly includes the indifferent equilibrium mechanism with two degrees of freedom (DOF) and the driving torque is calculated by the Lagrangian function. In addition, a series of experiments, the weight support and the trajectory accuracy experiment, demonstrate a good performance of mechanical structure and the closed-loop control. Jianfeng Sui, Yali Liu, Runze Yang, and Linhong Ji Copyright © 2014 Jianfeng Sui et al. All rights reserved. Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions Tue, 18 Nov 2014 14:20:43 +0000 http://www.hindawi.com/journals/ame/2014/507079/ Study on the influence of rotating stall on the aerodynamic noise of axial fan has important value to warn of the occurrence of stall through monitoring the noise variations. The present work is to analyze the aerodynamic noise before and after the phenomenon of rotating stall by solving Navier-Stokes equations, coupled with the throttle condition and the broadband noise sources model. The impeller exit rotational Mach number and rotational Reynolds number are separately 0.407 and . The results show that the aerodynamic noise source of the fan is mainly the rotation noise under the design condition. The vortex noise accounts for the major part of fan noise after the occurrence of stall, and the maximum acoustic power level of the fan appears in the rotor domains. In the evolution process from the stall inception to the stall cell, the high noise regions of the rotor develop along the radial, circumferential, and axial directions, and the area occupied by high noise regions increases from 33% to 46% impeller channels area. On rotating stall condition, the high noise regions occupying about 46% impeller channels area propagate with the stall cell along the circumferential direction at a half of rotor speed. Lei Zhang, Rui Wang, and Songling Wang Copyright © 2014 Lei Zhang et al. All rights reserved. Test of Robot Distance Error and Compensation of Kinematic Full Parameters Tue, 18 Nov 2014 14:19:13 +0000 http://www.hindawi.com/journals/ame/2014/810684/ In order to improve the positioning accuracy of robots in the workspace, the maximum cube of robots is solved according to ISO 9283:1998 standard. In addition, in order to efficiently test and identify the kinematic parameters of robots, a mapping from robot’s distance error onto kinematic parameter errors is presented based on Hayati’s modified D-H model. Then, by analyzing the condition number of distance error matrix, it is concluded that parameter can be deleted when parameter is added in the joint of the modified model. Furthermore, by analyzing the relationship among the parameters of the distance error model, it is found that the deletion of some unidentified kinematic parameters may not result in the accuracy decrease of kinematic error model. Finally, some compensation experiments of the proposed model without unidentified kinematic parameters are carried out by using a laser tracker system. The results show that the proposed method effectively reduces the distance error and greatly improves the positioning accuracy of robots. Tie Zhang, Liang Du, and Xiaoliang Dai Copyright © 2014 Tie Zhang et al. All rights reserved. Hydrodynamic Study of Oil Leakage in Pipeline via CFD Tue, 18 Nov 2014 14:17:08 +0000 http://www.hindawi.com/journals/ame/2014/170178/ This paper describes the transient dynamics behavior of oil flow in a pipe with the presence of one or two leaks through fluid dynamics simulations using the Ansys CFX commercial software. The pipe section is three-dimensional with a pipe length of 10 m, a pipe diameter of 20 cm, and leak diameter of 1.6 mm. The interest of this work is to evaluate the influence of the flow velocity, and the number and position of leaks on the transient pressure behavior. These new data may provide support for more efficient detection systems. Thus, this work intends to contribute to the development of tools of operations in oil and gas industry. Morgana de Vasconcellos Araújo, Severino Rodrigues de Farias Neto, Antonio Gilson Barbosa de Lima, and Flávia Daylane Tavares de Luna Copyright © 2014 Morgana de Vasconcellos Araújo et al. All rights reserved. Direct Numerical Simulation of a Free Particle-Laden Round Jet with Point-Particles: Turbulence Modulation Tue, 18 Nov 2014 14:16:29 +0000 http://www.hindawi.com/journals/ame/2014/983263/ Direct numerical simulation method is used to investigate the small scale turbulence modulation for a spatially evolving free round jet. Because the turbulence modulation phenomena can not be accurately measured by experimental method, the turbulence modulations are poorly understood. The particle diameter in our simulation is smaller than the Kolmogorov length scale , and the point force method can be accurately used for the research of small scale turbulence modulation based strictly on the theory of point force method. The simulation uses an explicit coupling scheme between particles and the fluid, which considers two-way coupling between the particle and the fluid. The DNS results are compared with experimental data with equal Reynolds number . The particles modulation on the fluid turbulence properties and coherent vortex structures are quantitatively given in our paper, and some new findings on the particles modulation are explicitly explained in this paper, which will further refine our understanding of intricate mechanism of small scale turbulence modulation for a spatially evolving free round jet. Debo Li, Qisheng Xu, Yaming Liu, and Yin Libao Copyright © 2014 Debo Li et al. All rights reserved. Analysis and Prediction of Micromilling Stability with Variable Tool Geometry Tue, 18 Nov 2014 14:04:09 +0000 http://www.hindawi.com/journals/ame/2014/870782/ Micromilling can fabricate miniaturized components using micro-end mill at high rotational speeds. The analysis of machining stability in micromilling plays an important role in characterizing the cutting process, estimating the tool life, and optimizing the process. A numerical analysis and experimental method are presented to investigate the chatter stability in micro-end milling process with variable milling tool geometry. The schematic model of micromilling process is constructed and the calculation formula to predict cutting force and displacements is derived. This is followed by a detailed numerical analysis on micromilling forces between helical ball and square end mills through time domain and frequency domain method and the results are compared. Furthermore, a detailed time domain simulation for micro end milling with straight teeth and helical teeth end mill is conducted based on the machine-tool system frequency response function obtained through modal experiment. The forces and displacements are predicted and the simulation result between variable cutter geometry is deeply compared. The simulation results have important significance for the actual milling process. Ziyang Cao, Hua Li, Zhen Yin, and Wei Liu Copyright © 2014 Ziyang Cao et al. All rights reserved. Recent Advances in Precision Machinery and Manufacturing Technology Tue, 18 Nov 2014 14:02:14 +0000 http://www.hindawi.com/journals/ame/2014/508592/ Chien-Hung Liu, Wen-Hsiang Hsieh, Zong-Yu Chang, Gow-Yi Tzou, Steen G. Hanson, and Yunn-Lin Hwang Copyright © 2014 Chien-Hung Liu et al. All rights reserved. Study on the Seismic Response of a Portal Frame Structure Based on the Transfer Matrix Method of Multibody System Tue, 18 Nov 2014 13:59:36 +0000 http://www.hindawi.com/journals/ame/2014/614208/ Portal frame structures are widely used in industrial building design but unfortunately are often damaged during an earthquake. As a result, a study on the seismic response of this type of structure is important to both human safety and future building designs. Traditionally, finite element methods such as the ANSYS and MIDAS have been used as the primary methods of computing the response of such a structure during an earthquake; however, these methods yield low calculation efficiencies. In this paper, the mechanical model of a single-story portal frame structure with two spans is constructed based on the transfer matrix method of multibody system (MS-TMM); both the transfer matrix of the components in the model and the total transfer matrix equation of the structure are derived, and the corresponding MATLAB program is compiled to determine the natural period and seismic response of the structure. The results show that the results based on the MS-TMM are similar to those obtained by ANSYS, but the calculation time of the MS-TMM method is only 1/20 of that of the ANSYS method. Additionally, it is shown that the MS-TMM method greatly increases the calculation efficiency while maintaining accuracy. Jianguo Ding, Wei Zhuang, and Pingxin Wang Copyright © 2014 Jianguo Ding et al. All rights reserved. Numerical Simulation of Particles Deposition in a Human Upper Airway Tue, 18 Nov 2014 13:59:28 +0000 http://www.hindawi.com/journals/ame/2014/207938/ Based on the CT scanned images, a realistic geometric model from nasal cavity to upper six-generation bronchia is rebuilt. In order to effectively simulate the particle movement and deposition, LES model is used and the particles are tracked in the frame of Lagrange. Seven kinds of typical particles, including micron particles (1, 5, and 10 μm) and nanoparticles (1, 5, 20, and 100 nm), and three representative respiratory intensities are adopted as computational case, respectively. Deposition efficiency (), deposition concentration (), and capture efficiency () are introduced. Furthermore, the locations of particle deposition are visualized. The results indicate that the injecting particles from different nasal inlet present “transposition effect.” The values of micron particles are much higher than nanoparticles. The particle diameter plays a weaker role in nanoparticle depositions than micron particles. The highest values of and both occur in nasal cavity, while the highest up to 99.5% occurs in bronchus region. Debo Li, Qisheng Xu, Yaming Liu, Yin Libao, and Jin Jun Copyright © 2014 Debo Li et al. All rights reserved. An Improved Method Based on CEEMD for Fault Diagnosis of Rolling Bearing Tue, 18 Nov 2014 13:43:34 +0000 http://www.hindawi.com/journals/ame/2014/676205/ In order to improve the effectiveness for identifying rolling bearing faults at an early stage, the present paper proposed a method that combined the so-called complementary ensemble empirical mode decomposition (CEEMD) method with a correlation theory for fault diagnosis of rolling element bearing. The cross-correlation coefficient between the original signal and each intrinsic mode function (IMF) was calculated in order to reduce noise and select an effective IMF. Using the present method, a rolling bearing fault experiment with vibration signals measured by acceleration sensors was carried out, and bearing inner race and outer race defect at a varying rotating speed with different degrees of defect were analyzed. And the proposed method was compared with several algorithms of empirical mode decomposition (EMD) to verify its effectiveness. Experimental results showed that the proposed method was available for detecting the bearing faults and able to detect the fault at an early stage. It has higher computational efficiency and is capable of overcoming modal mixing and aliasing. Therefore, the proposed method is more suitable for rolling bearing diagnosis. Meijiao Li, Huaqing Wang, Gang Tang, Hongfang Yuan, and Yang Yang Copyright © 2014 Meijiao Li et al. All rights reserved. Automatic Decision Method of Optimum Symptom Parameters and Frequency Bands for Intelligent Machinery Diagnosis: Application to Condition Diagnosis of Centrifugal Pump System Tue, 18 Nov 2014 12:42:14 +0000 http://www.hindawi.com/journals/ame/2014/603408/ A combination method of statistical filtering (SF) and the ant colony optimization (ACO) is proposed for automatic decision of optimum symptom parameters and frequency bands for machinery diagnosis. The noise of vibration signals is canceled by using SF. Similarity factor Ipq is defined to evaluate the filtering performance; the significance level α is optimized by genetic algorithms (GA). The optimum symptom parameters in different frequency bands, by which the states of rotating machinery can be sensitively distinguished, are automatically and sequentially selected by ACO based on the Mahalanobis distance between different machine states. Finally, the Mahalanobis distance is used to identify failure types based on the sequential diagnostic method. The new method proposed in this paper has been used to diagnose a centrifugal pump system for faults which often occur in the pump, such as impeller unbalance, shaft misalignment, and cavitation. The verification results of the condition diagnosis for a centrifugal pump show that the new method has good performance. Liuyang Song, Peng Chen, and Huaqing Wang Copyright © 2014 Liuyang Song et al. All rights reserved. Design and Evaluation of a Novel Self-Locking Quick Release Mechanism Featured by Heavy Load, Fast Response, and High Security Mon, 17 Nov 2014 09:51:48 +0000 http://www.hindawi.com/journals/ame/2014/590936/ A novel self-locking quick release mechanism featured by heavy load, fast response, and high security is proposed, designed, and evaluated. This new mechanism consists of two release arms, two compression linkages, one control rod, and some revolute joints. The load capability of this mechanism is high up to 15 tons. The characteristics of fast response and high security attributed to structural parameters and the butting-shaped self-locking, respectively, are the essential issues of the mechanism. A 3D model of the proposed mechanism is elaborated for design, evaluation, and simulation purposes. The research also includes the kinematic equations and force analysis to gain insights into the mechanical behavior of the mechanism. The principle of the butting-shaped self-locking is illustrated with the method of virtual work to obtain the critical equilibrium condition while this novel mechanism is not in the ideal position. Finite element method is employed to implement the stress and deformation analysis when the mechanism grasps an object of 15 tons tightly. By fabrication and evaluation of the self-locking quick release mechanism, the validity of the proposed mechanism is proved. Bing Xu, Pengpeng Dong, Junhui Zhang, Maoke Liu, and Jinjin Yao Copyright © 2014 Bing Xu et al. All rights reserved. Analysis and Optimization of the Fan-Pad Evaporative Cooling System for Greenhouse Based on CFD Mon, 17 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/712740/ A CFD model was presented to simulate the distribution of air velocity and temperature in a greenhouse adopting the fan-pad cooling system in summer. The Boussinesq hypothesis was applied for the simulation of gravitation; the k-ε turbulent model and discrete ordinates model were selected to predict the distribution of air velocity and temperature inside greenhouse using the commercial software Fluent. The differences between simulated and measured air temperature varied from 0.9 to 4°C and the differences of air velocity were less than 0.15 m/s, which proved that the CFD method can estimate the distribution of air velocity and temperature in the greenhouse rationally and effectively. The validated CFD model was then used to evaluate the cooling effect and design the installment of fan and pad in terms of the crop size. The results implied that Case 3 and Case 5 should be chosen when the height of crop canopy varies from 2 m to 3 m. When it varies from 1 m to 2 m, all the cases can be effective except Case 1. When the canopy height is below 1 m, all the cases can be selected. This paper suggested that the CFD model can be used as an optimal tool for fan-pad evaporative cooling system in the greenhouse. Jiaoliao Chen, Yanwen Cai, Fang Xu, Haigen Hu, and Qinglin Ai Copyright © 2014 Jiaoliao Chen et al. All rights reserved. Application of Real-Time Automated Traffic Incident Response Plan Management System: A Web Structure for the Regional Highway Network in China Sun, 16 Nov 2014 12:10:26 +0000 http://www.hindawi.com/journals/ame/2014/489623/ Traffic incidents, caused by various factors, may lead to heavy traffic delay and be harmful to traffic capacity of downstream sections. Traffic incident management (TIM) systems have been developed widely to respond to traffic incidents intelligently and reduce the losses. Traffic incident response plans, as an important component of TIM, can effectively guide responders as to what and how to do in traffic incidents. In the paper, a real-time automated traffic incident response plan management system was developed, which could generate and manage traffic incident response plans timely and automatically. A web application structure and a physical structure were designed to implement and show these functions. A standard framework of data storage was also developed to save information about traffic incidents and generated response plans. Furthermore, a conformation survey and case-based reasoning (CBR) were introduced to identify traffic incident and generate traffic incident response plans automatically, respectively. Twenty-three traffic crash-related incidents were selected and three indicators were used to measure the system performance. Results showed that 20 of 23 cases could be retrieved effectively and accurately. The system is practicable to generate traffic incident response plans and has been implemented in China. Yongfeng Ma, Wenbo Zhang, Junping Xie, and Jian Lu Copyright © 2014 Yongfeng Ma et al. All rights reserved. Energy Consumption Modelling of the Machining System Based on Petri Net Sun, 16 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/324819/ Increasing pressures from a variety of directives and standards have caused the manufacturing enterprises to consider and initiate implementation of energy assessment and energy quota practices to improve both their economic and environmental performance. Therefore, in view of the complexity of machining system’s energy consumption and the difficulty of data collection for energy analysis, a simplified and practical energy consumption model for machining system based on Coloured Petri Net (CPN) was proposed. Firstly, the energy flow of machining system was analysed. And then the energy consumption model of the machining system processing various tasks based on CPN was proposed, where the calculation method of energy use during production was simplified and it was determined by four parameters: idle power of machine, machining time, material pattern, and material removal volume. Finally, through the case study of a machining system with two tasks, the proposed energy model was simulated and the simulation results were proved to be significant in practice. Qiulian Wang, Xianglian Wang, and Suihong Yang Copyright © 2014 Qiulian Wang et al. All rights reserved. Analysis and Modeling of Driver’s Gaze Trajectories in Curves Driving Sun, 16 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/129601/ To explore the relation between drivers’ eye movements and vehicle steering performance, 25 participants were employed to drive a test vehicle on appointed tortuous routes. The drivers’ visual behavior was measured while they were driving, and experiment data collected on motorway on-ramps and interchanges were used to analyze the drivers’ visual characteristics. The distribution density of the fixation points showed that the drivers paid attention to the inner road edge when turning left and the outer road edge when turning right. Meanwhile, the heights of the gaze targets hardly changed. Therefore, a further investigation discovered that the gaze trajectory was parallel to the vehicle’s driving trajectory on one-way curves. Then, six types of gaze trajectories were derived, and models for each type were established. Combining these models with the fact that gaze points are always distributed along the nearby road edge, it was deduced that the starting point of the gaze trajectory when driving on curves has a salient influence on the driver’s gaze trajectory. Yuan-yuan Ren, Xian-sheng Li, Xue-lian Zheng, Zhe Li, Qi-chao Zhao, and Xiao-xia Chen Copyright © 2014 Yuan-yuan Ren et al. All rights reserved. Method to Determine Pedestrian Level of Service for the Overall Unsignalized Midblock Crossings of Road Segments Thu, 13 Nov 2014 14:46:19 +0000 http://www.hindawi.com/journals/ame/2014/652986/ This paper aims at developing a pedestrian level of service (LOS) model for the overall unsignalized midblock crossings of road segments from the perspective of the pedestrian’s perception of safety and convenience in Chinese midblock crossing environment. Firstly, the potential primary factors influencing pedestrian LOS at unsignalized midblock crosswalks were summarized from four respects: traffic conflicts, the distance between crosswalks, crossing facilities, and delay. Secondly, 948 participants’ real-time sense of safety and convenience when they were crossing the 30 selected unsignalized midblock crosswalks and the design and operational characteristics of the selected road segments were collected. The selected midblock crosswalks were typical of those prevalent in the medium-sized urban areas of China, and the participants of questionnaire survey covered a broad cross section of Chinese population of pedestrians. Finally, Pearson correlation analysis and stepwise regression analysis were carried out to develop pedestrian LOS model for the overall unsignalized midblock crossings of road segments. The results revealed that the factors significantly influencing pedestrian LOS of the overall unsignalized midblock crossings of road segments included volume of two-way motor vehicle, the distance between marked midblock crosswalks, and the distance between unmarked crosswalks. A reliable, statistically calibrated pedestrian LOS model was developed (R2 = 0.80). Lin Zhao, Yang Bian, Jian Lu, and Jian Rong Copyright © 2014 Lin Zhao et al. All rights reserved. Driver’s Comprehension and Improvement of Warning Signs Thu, 13 Nov 2014 12:57:40 +0000 http://www.hindawi.com/journals/ame/2014/582606/ Warning signs are effective only when users clearly understand their meaning. Three experiments were conducted in this study. In the first, the perception accuracy of warning signs was tested. This study investigated the role of age, gender, education background, and years of license in drivers’ comprehension of warning signs. The populations sampled were from Nanjing city in China. A total of 12 symbolic warning signs were investigated. A questionnaire prepared to collect the data was distributed to 550 drivers. The results showed that age, gender, and driving years have no significant influence on the sign comprehension. However, the divers with higher education background present better comprehension to warning signs than those with lower education background. In the second experiment, these signs of comprehension score less than 67% in the first experiment were screened and analyzed the cause of wrong responses using semantic analysis frequency distribution method. Using the semantic analysis method, the perception errors are researched by the four features, namely, meaningfulness, recognition, simplicity, and symbol design. In the third, improvement design of warning signs was provided. Lastly, through scheme comparison and the perception of warning signs, reasonable and improved warning signs are determined to better play management and service functions. Li Yuan, Yong-feng Ma, Zhi-yi Lei, and Peng Xu Copyright © 2014 Li Yuan et al. All rights reserved. Bi-Bayesian Combined Model for Two-Step Prediction of Dynamic Turning Movement Proportions at Intersections Thu, 13 Nov 2014 12:54:13 +0000 http://www.hindawi.com/journals/ame/2014/439031/ Short-term prediction of dynamic turning movement proportions at intersections is very important for intelligent transportation systems, but it is impossible to detect turning flows directly through current traffic surveillance devices. Existing prediction models have proved to be rather accurate in general, but not precise enough during every time interval, and can only obtain the one-step prediction. This paper first presents a Bayesian combined model to forecast the entering and exiting flows at intersections, by integrating a nonlinear regression, a moving average, and an autoregressive model. Based on the forecasted traffic flows, this paper further develops an accurate backpropagation neural network model and an efficient Kalman filtering model to predict the dynamic turning movement proportions. Using Bayesian method with both historical information and currently prediction results for error adjustment, this paper finally integrates both the above two prediction models and proposes a Bi-Bayesian combined framework to achieve both one-step and two-step predictions. A case study is implemented based on practical survey data, which are collected at an intersection in Beijing city, including both historical and current data. The reported prediction results indicate that the Bi-Bayesian combined model is rather accurate and stable for on-line applications. Pengpeng Jiao, Meiqi Liu, Jin Guo, and Tuo Sun Copyright © 2014 Pengpeng Jiao et al. All rights reserved. Study on Multicharacteristic of Antirotation Wire Rope Based on Linear Stiffness Coefficient Thu, 13 Nov 2014 12:07:29 +0000 http://www.hindawi.com/journals/ame/2014/512627/ In order to design antirotation wire rope, while considering the control of the axial strain and flexibility, the requirements that make the wire rope antirotation while making the axial strain little and flexibility excellent were presented. The relationship between axial force and twisting moment of wire rope with axial and rotational strain was given according to the linear stiffness coefficient. It was concluded that the twisting moment and axial strain under tensile load only depend on wire rope’s geometry parameters which consist of helical angle and wire diameter. And the expression of bending stiffness was given. Through the analysis of an example, we find that the outer strand has a stronger effect on the tensile, torsional, and bending stiffness. And the closer the strand’s helical angle is to 90°, the bigger the tensile stiffness and the bending stiffness are. The helical angles that give consideration to all the three stiffness coefficients can be found. These can be used for reference when designing antirotation wire rope. Jishan Xia, Guohua Cao, Yandong Wang, and Weihong Peng Copyright © 2014 Jishan Xia et al. All rights reserved.