Applied Mechanics and Materials Vols. 97-98

Abstract: There is increasing demand for a finer atomization of fuel spray in order to improve the engine performance and mileage, reduce exhaust emissions and then improve the transient response. In general, for an engine to comply with this demand, exhaust turbocharger and EGR are necessary especially electronic fuel injection system. As a key part of electronic fuel injection system, the performances of electronic gasoline injector improve the engine power outlet and fuel economy. In other words, electronic gasoline injector can achieve a wonderful dynamic response to improve the combustion process and reduce the exhaust emissions in engine. The aim of this paper is to define a CFD methodology for the simulation of gasoline injector. A two-step work procedure has been adopted. First, three-dimensional computational models of gasoline injector with two kinds of valve seat are created. Then, the simulations are conducted for different geometric parameters of nozzles with properly initialized. The results are used to analysis pressure distribution and the changes of average velocity in the nozzles.

Abstract: To research the aerodynamic characteristics of minibus, the simplified model is studied with simulation and wind tunnel test. The validated method was adopted in the numerical simulation, the wind tunnel test were carried out in order to validate the results of numerical simulation. The tests include aerodynamic drag measure, filament method, and laser flow visualization. Through the contrasted research the results of simulation and test, the aerodynamic characteristics of minibus was analyzed and the characteristic of field around minibus was discovered. The conclusions provide the theoretical foundation for styling optimization of minibus, which are very helpful to develop new vehicle styling.

Abstract: This paper is mainly about improving vehicle use friction material and reducing vehicle braking noise. With the improvement of friction sheet material prescription as breakthrough point, we aim at raising the friction performance and high temperature capability, so that we can reduce the friction of mating plate efficiently and reduce brake noise. In this experiment combinatorial friction materials research is conducted. Raw materials used are screened by two criteria:1、 select those raw materials which have good wear resistance when they combine with group raw materials; 2、 select those raw materials that have the function of reducing brake noise。 Golden Section approach is utilized for experimental formulations design. Comprehensive index of raw materials is obtained by the relational grade analysis. The fuzzy overall merits method is utilized to judge comprehensive index and evaluates merits of multi-objective friction material formulations, so that we can determine one friction material formulation with the best friction performance. Using fixed-velocity D-MS friction experiment machine we test the crucial property for the autonomous new brake friction material. Test content includes mainly: hot decline, wear rate, blow energy and the friction coefficient of test piece in different experiment temperatures. On fixed-velocity friction experiment machine, we adopt advanced friction vibration and noise experiment methods, use HY104A model of the ordinary sound level analyzer to test in some fixed points, and take autonomous strengthened new brake friction material for object. We analyze and study brake noise that some kinds of friction flats produces. Through observing and analyzing the property of friction material and experiment phenomenon and data, we discover the strong weak level of noise has close relation with friction material formulation and the composition of material. Eventually we can decide the best formulation to degrade the brake nose. Brake friction material is a crucial factor to influence vehicle traveling safety. Through the research of this program we can offer some reference about how to select reasonable friction material group and improve the property of friction flats.

Abstract: Automobile steer by wire system (SBW) is a novel steering system. Firstly, the linear four degree of freedom dynamics model with steering torque as the input is built. Then the design ,simulation and multi discipline optimization parameterized platform of SBW is built based on Matlab Graphic User Interface, which can design and simulate steering system performances quickly. Effects of different parameters such as velocity, moment inertia of steering wheel and tire cornering stiffness on handling and stabilities are analyzed. Finally parameters are optimized to minimize the response total variance under torque input and improve the response under steering torque input.

Abstract: In this paper, an efficacious and accurate method for analyzing random vibration and fatigue lifespan of coaches with high degrees of freedom is developed. Based on the design requirements for structure strength and fatigue lifespan of a coach, the finite element model of its body structure was used to investigate the dynamic behavior of the coach running on a randomly uneven road. The vibration characteristic was derived using the pseudo excitation method (PEM). The fatigue lifespan is discussed by means of the Miner rule, and the fatigue resistance is also studied. The reliability of the proposed method is numerically verified.

Abstract: An active differential is introduced with its basic structure and working principle, it consists of a couple of slip clutches for torque transfer and some planetary gears which generate the differential speeds of the slip clutches. A mathematical model of active differential dynamics is developed and it is used for a theoretical analysis of torque transfer and energy loss. Modeling and simulation of the active differential are carried out by using MATLAB/Simulink, the results demonstrate that active differential generates the direct yaw moment by torque transfer between right and left tires and is possible to improve the overall performance of vehicle dynamics properties.

Abstract: The efficiency of traffic hub will affect the efficiency of transportation network; furthermore, it will affect the efficiency of social economy. We must keep the scientific rationality of traffic hub system. The necessity of construct a complete traffic hub system is also pointed out in the paper. The author uses a traffic hub function matrix based on function to divide different traffic hub. Guangdong province is used as an example to explain the strong practicality of the method.

Abstract: Ship launching is an important step in the whole process of ship construction. In modern shipbuilding industry, longitudinal gravity launching method is suitable for most kinds of ships, and is still widely used in many shipyards. Exactly calculation of the ship’s floating state and force acting on the hull and sliders is very important for security of launching ships. The present paper investigated the floating state and hydrostatic force and moment acting on a multi-purpose cargo ship based on some useful data such as Bonjean curves, distribution of ship mass, coefficients of ship form and arrangement of slipway. The variations of buoyancy and draughts at bow and stern with slipping distance are calculated and compared for two cases.

Abstract: Due to the target ship in the traditional ship handling simulator have not the ability to give way to other ships automatically to avoid collision, this paper put forward a new idea that bringing the hydraulic servo platform, six degrees of freedom ship mathematical model, the actual traffic flow, researching achievement of automatic anti-collision in research of the new pattern ship handling simulator, and successfully develop the Intelligent Ship Handling Simulator(ISHS for short). The paper focuse on the research on the network communication model of ISHS. We took the entire simulator system as three relatively independent networks, proposed a framework of communication network that combined IOCP model based on TCP with blocking model based on UDP, and gave the communication process and protocols of system. Test results indicate that this is an effective way to improve the ownship capacity of ship handling simulator and meet the need of multi-ownship configuration of desktop system of ship handling simulator.

Abstract: Pilot should control the aircraft manually when encountering low altitude wind shear during takeoff and landing. For wind shear escape and flight safety research, an effective human pilot model together with wind shear and flight dynamics model should be built with high fidelity. A skill-based human pilot model was built which can describe pilots’ characteristics such as experiences, skills, emotions, reaction abilities, etc. A fuzzy controller was designed for lateral and longitudinal escape control in pilot model. Since single pilot could not represent a group of pilots’ control behavior, some of the model parameters were set to be stochastic, then the Monte Carlo method was adopted to obtain a numerical approximation of safety analysis results. With the probabilistic pilot model, escape strategies and safety analysis can be studied by simulation with high fidelity.