Applied Mechanics and Materials Vols. 380-384

Abstract: Based on CFD software platform, numerical simulation of 3-D with the internal characteristic of hydraulic retarder with different shape of circulation circle was simulated, and the RNG turbulence was adopted. Through the result show that under model circle shape of the shape of circulation circle of hydraulic retarder has the biggest static pressure and the fastest velocity magnititude and the biggest moment.

Abstract: The thermal deformation of machine tools has a great influence on machining accuracy. Studied on thermal effects of TH6213 CNC boring and milling machine spindle system, bearing heat grows with load and boring spindle extending length, and brings about a changeable temperature difference, which is hard to reduce. A subsection cooling scheme was proposed to reduce the spindle system temperature as well as the temperature difference to reduce the thermal deformation effects.

Abstract: Vehicle crash acceleration was essential for automotive passive safety analysis. Especially in CAE analysis and sled test, B-pillar lower accelerations are considered as vehicle acceleration and often used as crash pulse to reproduce the real crash conditions. But for frontal offset impact, the magnitudes and directions of the B-pillars lower accelerations were significantly different,which made the selection of vehicle acceleration very complicate. In this paper,a prediction algorithm based on Circle of Constant Acceleration method that can calculate the acceleration of any point on vehicle was presented. And then it is verified with the full scale impact data. The results show that both the trend of the acceleration curves and the curve peak of the calculated value have a strong consistency with the measured value.

Abstract: Shotcrete machines plunger displacement, velocity, acceleration, and the trajectory of swash plates ball socket are analysed according to the principle of working of shotcrete machine, using graphic analytic analysis of the shotcrete machines instantaneous and theoretical throughput according to the analysis of movement. The theoretical analysis for the design of the shotcrete machine can provide theory basis for improvement and perfect of shotcrete machine.

Abstract: Petticoat valve is the key component of the concrete delivery system in the shotcrete machine. Its working conditions are very bad and it has to bear the delivering pressure, the severe wear of pebble and sand and the corrosion of cement and water. Based on the force analysis and simulation with Fluent software for petticoat valve, the pressure distribution can be obtained, which has the guiding significance for design and use of petticoat valve.

Abstract: The 3d model of miter gate has been set up based on skeleton model of Pro/E, and it has been imported into ANSYS Workbench module for static structure analysis and modal analysis. In the process of finite element simulation, the rotational constraints has been imposed on the top and bottom pivot according to the actual operation situation of the miter gate, and obtain the first several order frequencies and corresponding modal vibration mode of the miter gate, which can show the hydrodynamic vibration stress and strain distribution. According to the results of the finite element simulation analysis, the prototype vibration test of the miter gate has been done. The test results show that the vibration amplitude and the stress and strain distribution of each part of the miter gate are corresponding to the vibration test.

Abstract: In this paper, the external flow simulation has been carried out on a simplified passenger car model with two schemes adopted: a smoothed complex underbody and a flat underbody. The aerodynamic characteristics and the flow field structure of the passenger car model were obtained with CFD method, and the drag coefficients of the smoothed complex underbody and the flat underbody are respectively 0.275 and 0.251. According to the simulation, flow separation and energy loss of fluid was caused by protuberances on the complex underbody. As there are many differences between the aerodynamic characteristics of the smoothed underbody and the flat one, its suggested to use a smoothed complex underbody not a flat underbody in the studying of aerodynamic drag reduction of a passenger car.

Abstract: The sound transmission loss (STL) of the acoustic parts in the vehicle was proposed to be computed using the Sound Pressure Level measured at the several locations inside the vehicle and the transmitted Sound Intensity Level on the vehicles exterior panel, which the acoustic treated vehicle passenger compartment is assumed as a small reverberation room. The necessary parts retrofits and acoustic treatments for Sound transmission loss tests of the acoustic parts in the vehicle were listed. The values of the appropriate number and positions of the loud speakers, microphones and sound intensity probes for Sound transmission loss of the acoustic parts in the vehicle were recommended. The in vehicle sound transmission loss tests of the acoustic parts such as the doors, carpets, wheel house etc. were achieved in the semi-anechoic room. Based on the door system, the correlation work has been done among the methods of the proposed in vehicle STL test, the reverberation - semi-anechoic chamber buck STL test and SEA analysis.

Abstract: In this paper, an experimental study on the powertrain in vehicle sound power test was presented. The necessary parts retrofits and acoustic treatments for the powertrain sound power test in the vehicle were listed. The criteria and correction method of the appropriate background noise level for the powertrain sound power level test in the vehicle were discussed. The powertrain sound power tests in the vehicle were achieved in the low noise chassis Dynamometer in the semi-anechoic chamber. Based on the test results, the acoustic component contributions for the powertrain sound power levels were given .

Abstract: Journal bearing in high-speed working conditions will generate a lot of heat, which affects its working performance. Based on hydrodynamic lubrication theory, a model of the thermal hydrodynamic lubrication was built, and the distributions of temperatures and pressures of the oil film were obtained from the simultaneous solution of generalized Reynolds, energy and viscosity-temperature equations. The results show that the temperature will increase and the pressure decrease of the lubrication oil film with the rising of the rotating speed, which will make the the bearing capacity decrease. Compared with the traditional isothermal model, the thermal hydrodynamic lubrication model is more consistent with the engineering practice.