Advanced Materials Research Vols. 479-481

Abstract: Stability of static liquid layer in mass transfer process accompanied by concentration-driven Marangoni effect was modeled and analyzed by utilizing the linear stability theory. The critical condition of the onset of the Marangoni convection was obtained. It is found that the liquid layer becomes more unstable with the increase of the Schmidt number, and it becomes the most volatile when the Biot number is about 0.85. The critical time to mark the onset of Marangoni convection can be predicted with the established model. The research results show that the concentration gradient is the main factor to initiate the Marangoni convection.

Abstract: The phases composition and forming mechanism of the coating defects on the galvanized cables produced by different manufacturers have been analyzed and compared by SEM and EDS. The results showed that: the white phases in the coating of the galvanized cables were mainly the ZnO2 phase and the gray ones were the zincilate. The coating quality could be improved by optimizing the galvanization process parameters and assurancing the compactness of the coating and its adhesion to the matrix.

Abstract: Abstract. Under the action of high speed train and the repeated heavy vehicles, the granular ballast bed produce degradation and deformation that do not restore, tamping homework is an effective method that is being used to recovery the elastic of the track. In this article, the discrete element method is be used to establish a cross discrete particle flow simulation model between ballast track bed and tamping picks, and to simulate the movement and vibration characteristics of the granular ballast particles while tamping. The three main work are included in this paper. With the large commercial software EDEM, the first main work is to research the modeling method of ballast particles. The second work is to establish firm-soft coupling particle flow simulation model among ballast 、sleeper and tamping picks. The third work is to validate the ballasts' mechanical properties' change rule under the railway sleeper, while different tamping working condition and out load are being implemented. The research shows the discrete element method is effective for solving the vibration problem produced during the process of tamping homework.

Abstract: The response of functionally graded material (FGM) flat spherical shell under mechanical loading is studied using the method of lines. Based on the Kirchhoff straight normal hypothesis and Von Karman's geometrically nonlinear theory, the governing equations of the response of FGM flat spherical shells are obtained. A semi-analytical numerical method, i.e. the method of lines was introduced, and then the partial differential equations were transformed into ordinary differential ones. The effects of the material gradient parameters on the responses are discussed in details. The numerical results of flat spherical shells are given and compared with the finite element method ones.

Abstract: Based on software Pro/ENGINEER and Visual C++ 2005，sub-module of parametric design of assembly with wide universality was done by using Pro/TOOLKIT, and the design procedure was introduced in details. Assembly relation of sub-components is transformed into binary tree structure to store and search parts, and the assembly relation is displayed by CTreeCtrl control. The corresponding parts can be quickly found in the binary tree. Engineering drawing was automatically generated and displayed by ProductView after loading a part, and in this way dimensions of different parts can be modified according to engineering drawing in asynchronous mode. The sub-module can meet the needs of parametric design of parts in the integrated simulation system.

Abstract: According to principle of hobbing, this paper set up accurate model of gear processed by full radius hob based on ANSYS/LS-DYNA software. A dynamic contact analysis of gears are completed and we gets stress distribution of tooth root as time changes, making foundation for future study and optimization design of full radius hob.

Abstract: Some problems involved in the cooling and control system of a pneumatic disc brake are presented in this paper. The selection foundation of the friction torque is deduced when do strength check and thermal analysis to the brake. The heat transfer conditions when the brake safely works on the worst braking condition is investigated also; to propose that the coefficient of rib of the friction plate be more than 3.6. In addition, the control system of the brake is discussed. In terms of the design of the brake, for the cooling and control system, the parameters including the angular speed and torque of the shaft of the drawworks, the temperatures of the coolant at the inlet and the outlet, the pressure of the compressed air need to be monitored or controlled.

Abstract: A new type of spherical gear drive, which takes micro-segment involute profile as tooth profile, is presented in this paper. The generation principle of the spherical gear is described. The mathematical models including the equation of micro-segment involute profile, the equation of the conjugate tooth profile and the engagement equation, are established based on the meshing theory. This new type of spherical gear drive has the potential to improve the load capacity and the performance of spherical gear transmission.

Abstract: The key factor of product innovation design is analyzed in this paper. Among these factors, the construction of product innovation design knowledge service system is most important to enhance ability of innovative design. The process of innovative design is divided into conceptual layer, system layer and parts layer, and that the design process and knowledge class of different layer is totally different. Innovation design process of products is always along with the flow and inte-gration of different knowledge. The integration pattern and evaluation formula of knowledge ser-vice is put forward in the paper and finally the knowledge service system supporting innovation design in distributed resources.

Abstract: A method of wheel load variation simulation for automobile ABS performance test bench is presented in the paper. To simulate the wheel load variation of the detected vehicle, the wheel placement angle on the rollers can be changed by adjusting the wheelbase between the ABS performance test bench’s two rollers, which support the same wheel. Equivalent wheel load is defined to reflect wheel load variation simulation, and the relationship among the equivalent wheel load, roller adhesion coefficient and wheel placement angle is also be analyzed. The simulation results show that the equivalent wheel load is not only can greater than wheel load many times, but also can less than wheel load. The minimum equivalent wheel load is determined by the critical wheel placement angle.