Advanced Materials Research Vols. 562-564

Abstract: It has been a key problem that the analytical computation of a throttle slice deformation, for the design of shock absorber valves parameters. In this paper, the mechanics model of throttle slice under a spring pre-tightening was simplified into that under a micro-circle pressure. Using boundary and continuity constraints, the general equation for throttle-slice deformation under a micro-circle pressure was given, and by mathematical transformation, an analytical formula was established. With the practical example, the deformation of throttle slices on spring pre-tightening force at any radius was computed, and was testified by ANSYS. It is known that the results computed are close to that simulated, and the deviation is only 6.6 mm. It is shows that the method of deformation analysis of a throttle slice under micro-circle pressure is reliable, which has important reference value for throttle valves parameters design and characteristic simulation of shock absorbers.

Abstract: A djustable ejector flow control can be achieved to export in a stable area, thus reducing the jet inlet parameters on the export parameters as well as the impact of the entire system, widening of the jet's effective operating range. In this paper, the establishment of an effective mathematical models and computational methods to commercial CFD software FLUENT 6.3 as a platform for the adjustable jet to simulate the internal flow process and performance research, exploration and analysis of the main needle is moved (ie the nozzle throat orifice area change) operating parameters (including the working fluid inlet pressure, inlet pressure and the lead body jet mixing fluid outlet pressure) on the adjustable jet performance of the law, for the adjustable jet to provide important parameters to optimize the design. Studies show that: ① the needle device with adjustable spray jet in a non-rated conditions, can increase the coefficient of the jet injector; ② other parameters remain the same circumstances, the adjustable jet to varying degrees, increased work pressure , suction pressure, discharge pressure and outlet flow range.

Abstract: The natural frequency at lower orders for hydrostatic supported worktable system may easily give rise to vibration as in resonance with excitation frequency. This paper is concerned with the geometrical optimum design and dynamic modal analysis for system with hydrostatic oil fluid and worktable simultaneously. The variations of eigenfrequency, respect to oil film thickness, outer radius of worktable, recess shape and number, were discussed. The results show that, under linear increment/decrement of geometry dimension, frequency increase/decrease but in nonlinear regularity. Therefore there exists an optimum dimension resulting the optimum frequency that deviate from the rotary frequency at work and its multiple ones. Then two-phase optimization strategy was effectively programmed to get involved with finite element analysis software. It is theoretically critical to get the optimum parameter of hydrostatic supported worktable on how and practically important to guide the design in engineering.

Abstract: The ejector technology is a commonly used in nature gas exploration. In this article the pressure-exchange ejector is introduced and researched to solve the low efficiency problem of common ejector during low pressure ratio condition. The results show that when pressure ratio is kept fixed, ejection rate decreases with the compression ratio increase, an optimum ratio exist; the pressure-exchange ejector have higher isentropic efficiency and ejection rate when the pressure ratio is under three, it also applies to wilder operation condition. It is both practical valuable and theoretical significant to research on pressure-exchange ejector for China’s gas and oil fields.

Abstract: At present, the common method of testing noise generated by vehicle transmission before delivery is to measure the noise sound pressure level by means of sound level meter. Since the measurement result is susceptible to background noise, the method can only be operated in anechoic chamber. In this paper, in order to measure sound pressure level directly on production-line, a new vibration measurement method and its relevant formula are presented. The proposed method can effectively avoid being affected by background noise and obtain the sound pressure level of transmission noise on production-line by testing the vibration acceleration signals of transmission box. It’s proved that the new method makes the delivery test of transmission noise more convenient and effective. Moreover, it can improve the delivery quality of transmission as well as the performance of whole vehicle.

Abstract: This article presents a direct position analysis of a reconfigurable 2PRS-2PUS parallel mechanism. Based on the structural features of this new mechanism, take the absolute coordinates of the four balls vice center on movable platform as the output variables, a direct position analysis which using elimination method is presented. The solution is verified by a group of numerical examples, which given by matlab. In addition, graphical representations of the real solutions are presented.

Abstract: This paper numerically calculates the pressure distributions of a rudder of a ship for structure strength design. The sections profile of the rudder is NACA0020 airfoil. The viscous flow is simulated by FLUENT commercial software, while the model and mesh is generated by GAMBIT software. A 2D viscous flow around a NACA0020 airfoil is calculated firstly. Some notices are given here about the magnitude of computing domain, the density distribution and the numbers of grid nodes on the airfoil surface in order to gain better results. Then, based on these experiences, the viscous flow around a 3D rudder is simulated. The calculated pressure coefficients on the rudder’s section are compared with the experiment results and BEM results of the potential theory. At the attack angles and , the three results agree well with each other. However, when the attack angle is , the viscous results from FLUENT give better agreement with the experiment results than the BEM results. This conclusion confirms that the viscosity effect is great in the case of large attack angles.

Abstract: To explore the influence of slide stroke curves on deep drawing and solve the problems of cracking and wrinkling during drawing, the deep drawing processes of box shaped part with the conventional mechanical press and servo press were simulated, respectively. The variation rules of cracking and wrinkling for box shaped part by different slide stroke curves were obtained. It shows that the qualified parts can be obtained more easily when drawing with servo presses by decreasing the rotational speed of servo motor at the forming stage due to its variability; drawing cycle can be shorten effectively by adjusting the variable displacement-velocity curves of servo press.

Abstract: Flow-induced vibration widely exists in fluid power machinery, and there is a great relation between the vibration and engineering construction. In this paper, prototype valve experiment and three-dimensional simulation has been done on the pre-opening sleeve valve. High-frequency minute dynamic pressure sensors are adopted in the valve in experiment. Vibration data with dynamic pressure in different conditions are collected and measured to find out the pulsation characteristics of the valve disc during the experiment. Meanwhile, three-dimensional numerical simulation and analysis on the internal flow field of the valve has carried out, in order to discover the factors of vibration induced by fluid flow. The result shows that the main cause of flow-induced vibration varies in different conditions. At the condition of large opening and large pressure difference between valve inlet and outlet, it is mainly due to vortex-induced vibration. Several ways such as improving damping, avoiding the resonance frequency and changing the type of the valve profile can be taken to weaken the vortex-induced vibration.

Abstract: In order to analyze suspension’ impact on vehicle ride comfort and road-friendly and the way to chose reasonable suspension parameters，a two DOF suspension model was established. Taking RMS of sprung mass acceleration and dynamic load of unsprung mass, a multi-objective suspension parameters optimization model was carried out by optimal points method. After the optimization，the RMS of body decreases by 36.24%,and the RMS of dynamic load decreases by 17.71%.As is stated above, optimal suspension parameters can improve the ride comfort as well as road-friendly.