Applied Mechanics and Materials Vol. 577

Abstract: In the case of the column materials to determined, the lower natural frequency of column is determined by the number of coupling bolts and bolt arrangement. In this paper, by three-dimensional modeling software of Solidwork column model of hobbing is set up, then by using ANSYS finite element analysis software. The initial four order natural frequency to the different number of connection bolts and the different arrangement of bolt are respectively calculated. After the initial four order natural frequency are contrasted, we conclude that in the case of merely considering dynamic stiffness this study reach it is the most reasonable to select 8-12 bolts in the hobbing of YKQ31300, and different bolt arrangement of effects on the dynamic stiffness of the column is very small and can be ignored.

Abstract: The precision dicing machine is adopted as the research object in the paper, the technology of grating sensor is selected to overcome the shortcoming of traditional compensation methods for inaccurate return compensate. The measurement is done through the grating sensor, with the aid of neural network feedback method, the fitting and compensation of the data measured by the grating sensor is completed, the deviation caused by vibration during the spindle run-time is eliminated. And the purpose of improving the precision of spindle is realized.

Abstract: The mechanism of four-bar linkage for the 8m hydraulic support is designed and optimized with the help of graphing method. The 3D model of the 8m hydraulic support is created using the software Solidedge. The virtual prototype is built in the circumstance of multi-body dynamics analysis software Adams. The dynamic simulation is made for the hydraulic support from the maximum working height 8 meters to the minimum working height 5 meters. The movement trail of the front point of the hydraulic support is obtained which can explain and demonstrate the performance of the four-bar linkage. Meanwhile, the displacement, velocity and acceleration curves of the gravity center for the major components including the top beam, shield beam, front link and rear link are discussed.

Abstract: In order to improve quality of wheelset assembly, a method for calculating interference between two sliding asperities that corresponding to the wheelset assembly interference is presented. A finite element model of sliding spherical asperity has been built with the finite element software ABAQUS to analyze the interaction among mating surface roughness, stress-strain state and press-fit curve. This study shows that final fitting force greatly increases with roughness when roughness is lower then 1.8μm and it is unpredicted when roughness is higher. Contact stress and friction coefficient between mating surfaces increase with roughness.

Abstract: The objective of this paper is to study performance of triangular elbow transmission mechanism for servo press. Then kinematics models are deduced and given. Kinematics curves along slider motion direction are drawn. Moreover, under the same driving condition, the effects of different link ratios on slider output motion are examined and compared with common six bar transmission mechanism in the article. Through motion curves comparison, it can be seen that this triangular elbow mechanism has significant force increasing effect and good quick-return characteristics. In addition, we carried on triangular elbow servo press virtual design and simulation. The case study provides more visual and reliable decision basis for designer. The results would be useful reference for optimization design of transmission mechanism.

Abstract: To simulate the combustion species for direct-injection diesel engines, the new flamelet model is presented and used. The model is based on stoichiometric mixture fraction space, and a way of separating the numerical effort associated with the solution of the turbulent flow field from that of solving the chemistry is offered. The new species equations are carried out through coordinates transformation. The results from the species equation are developed and three-dimension entity model with the mixture fraction is got. Then the boundary conditions are put into the new flamelet model. Furthermore the pollutions emissions are calculated and compared with the experimental data. It gives a new way to predict the pollutants for direct-injection diesel engine.

Abstract: Taking a hydropower station as the research object, the establishment of a numerical model that contains the full passage Tubular Turbine is given. Based on the transient incompressible N-S equations, a three-dimensional unsteady flow research is conducted. Numerical simulation of steady turbulent flow channel is calculated as the initial condition, the detached eddy simulation (DES) and slip grid technology are adopted to simulate the static-dynamic interference in the unsteady turbulent flow, The instantaneous pressure distribution in full channel and vorticity distribution of the representive section are obtained, so the three-dimensional transient vortex structures in full flow channel of the hydraulic turbine are captured. These studies aiming to explore the mechanism for the formation of vortex-induced vibration of hydro-turbine are valuable for the engineering reference.

Abstract: In order to investigate the effect of swirl intensity on the performance of the diesel engine, the 4JB1 diesel engine was taken as the research subject and KIVA-3V program was used to calculate the temperature, pressure, NO_x and SOOT in cylinder and the performance of dynamic and economy of the diesel engine by changing the value of swirl ratio. The results show that increasing the swirl ratio in the cylinder can make the hybrid combustion of fuel and air sufficiently, improving the combustion temperature and pressure in the cylinder, enhanced the power of the diesel engine and reduced fuel consumption. The generation of NO_x increased with the increases of swirl ratio and the production of SOOT decreased with the increases of swirl ratio.

Abstract: In this paper, combining with PRO/E4.0 software, getting the general design idea of the hydraulic turbine, and aiming at systematic analysis and research the key technologies of development design system process of hydraulic turbine. The key technologies include the pro/toolkit interface technology, menu design MFC dialog box as well as the establishment and access of database. Based on the two modes’ characteristics of PRO/TOOLKIT application, determining to use the DLL mode of the synchronous mode for the system design model's mode; Combining with the structure of the main parts of the hydraulic turbine, aiming at the characteristics of the pro/toolkit interface technology, menu design and MFC dialog box ,concluded the development processes of the pro/toolkit interface technology, menu design and MFC dialog box; Combining with the PRO/TOOLKIT interface technology and the characteristics of technology of MFC dialog box, selected the required software which is used to create and access database, and the specific development process. This provides important technical Supports for design system of Hydraulic turbine's development.

Abstract: Element Free Galerkin Method is based on a set of nodes information construct the approximation function of meshless Method andit is not dependent on the grid. EFGM in civil engineering problems also played a huge potential.It through the establishment of civil engineering problem of EFGM model, through the EFGM-FE boundary coupling method to deal with problems, through the specific numerical example it is concluded that the EFGM-FE coupling method is effective and feasible.