Applied Mechanics and Materials Vols. 409-410

Abstract: Maintenance and servicing to the EMU, in order to guarantee the operation safety, often need to stop high voltage power supply, using the ground power supply. As a result, need to provide a safe, stable and reliable ground auxiliary power supply for the EMU, ensure the normal maintenance, servicing and operation of various types of EMU. To this end, this paper based on the deployment of the ministry of railways and the requirements for configuration of ground power supply to the EMU, Analyze requirements of the auxiliary power supply system to the CRH2 EMU, on this basis, design the auxiliary power supply and its control system.

Abstract: Based on statistical data of domestic and foreign fire accidents of passenger cars, positions of fire sources and igniting causes of car fires were studied. Fires causes were classified to five types in which electrical failures and mechanical failures were considered as the most common issues leading to fire. According to the cause analysis, relevant countermeasures were proposed to prevent and control fire of cars, which can be referenced for safe design by vehicle factories.

Abstract: Abstract. The expert system that based on knowledge base of association rule and to discuss fault diagnosis expert system for the application of fault diagnosis in the Electrical Multiple Unit (EMU) was described. Through the analysis of failure data of EMU operation group to find out the potential relationship between the state data and fault data from a large number of operation and maintenance history data of EMU. This kind of relationship was stored in the knowledge base. Fault diagnosis expert system model is established, which based on the fault intelligent diagnosis expert of EMU. It can achieve dynamic fault diagnosis of the EMU in the process of running and ensure its safe operation.

Abstract: Based on the shallow water wave potential flow theory and slender ship assumption, the mathematical model is established for calculating wave caused by ship moving at supercritical speed. The wave pattern caused by ship moving at supercritical speed in shallow water was calculated by using the finite difference method. The effects of channel wall were analyzed. The computed results were compared with the ones calculated by Fourier integral transform method and experiment. A good agreement exists between the calculated with experimental results. The mathematical model and the calculation method were validated.

Abstract: While sailing, VLCC is affected by a very large resistance, and consumes a large amount of fuel. How to reduce the fuel consumption has become a hot issue of research. In navigation, VLCCs attitude has an obvious influence on resistance. Due to the complexity and irregularity of the shape of VLCCs underwater part, it is difficult to use formula to calculate and forecast how the navigation attitude influences the resistance. Seeking for a fast and accurate method to study the influence of VLCCs navigation attitude on resistance is very significance. CFD method was used in this work to find the difference of resistance when the trims were different. A full-scale 3D model of a VLCC was made, and computational domains of flow field were defined according to different trims. Hexahedral meshes of the computational domains were made and boundaries were defined. By numerical simulation with FLUENT, resistances were calculated in different trims, when the VLCC was full loaded and ballast loaded. The best trims were found when the resistances were least under different loading conditions. It is the best navigation attitude to save fuel.

Abstract: Some parameters, such as cabin pressure and Relative Humidity (RH), in a civil cabin environment, are significantly lower than those at sea level when the civil aircraft is in its cruise conditions at high altitude. The common PMV thermal comfort assessment model is not suit for this environment. Therefore, a Corrected PMV (CPMV) model is adopted to analyze the impact of these two parameters on thermal comfort in a cabin. From the simulations, we can draw conclusions that, within a normal operative range of RH and cabin pressure, the low RH and pressure can lead to a negative deviation and a positive deviation of thermal sensation values, respectively, but their impacts on thermal comfort of passenger are limited. The CPMV model is further applied to assess the thermal comfort of investigated flights.

Abstract: The cold-chain transportation industry has just started, so energy waste in cold-chain logistics is very serious. At the same time, costs got raised, resulting in profits shrinking. In this paper, measures about improving the body heat insulation material are put forward from the angle of energy consumption which is on the basis of the heat balance model of retaining structure.

Abstract: This thesis mainly describes the investigation and experiment in the improvements of engine cabin temperature of the CDK6121CAR urban bus with a four-stroke natural gas engine. The aim of this project is to improve its fuel economy. It introduces an engine cabin temperature modified project of an urban bus in Chengdu, it use various measures to change conduct heat and air movement in engine cabin. The bus gas consumption of one hundred kilometers is downgraded from 60.5 m³ to 57.6 m³. It reduces nearly five percentages. This project has characteristics of energy saving and environmental friend.

Abstract: In the secondary suspension of urban rail vehicles and high-speed passenger trains, combination of air springs and anti-roll torsion bar is widely used. However, in its practical use, cracks appear in the anti-roll torsion bar and vehicle curve performance is lower. Through analysis of anti-roll torsion bar, acceleration being taken into account, the dynamics models of anti-roll torsion bar and the vehicle itself are established. The results indicate that the combination of anti-roll torsion bar and rubber joints is superior to present a more reasonable anti-roll stiffness, to ensure better dynamic performance of the train, and also to lengthen the life of the anti-roll torsion bar.

Abstract: To seize the feature of brake groan and the relay route of the vibration and noise,an experiment is done on brake groan and all signals are done the auto-power spectrum analysis and coherence analysis. The result of experiment and analysis shows that brake groan is a low frequency vibration and noise happened under the low vehicle speed and low brake pressure, the noise of the interior of cab has good coherence with the noise beside the brake caliper when the brake groan takes place, and also with the vibration of tangent orientation of brake caliper, Y orientation of vehicle coordinate system on arm of cross pattern and Z orientation on the top dead center of suspension. The coherence analysis roughly illustrates that the relay route of the brake groan have two paths, the vibration and noise are transferred from the arm of cross pattern and suspension to automobile chassis and body Keywords: brake groan, experimental,spectrum analysis,relay route