Applied Mechanics and Materials Vols. 271-272

Abstract: In combination with the author's experiences in design for integrated unit for natural gas field gathering and transmission, this paper describes conventional practices and technical characteristics of integrated unit in the processes of standardization design and modularization establishment and analyzes the initial application of pneumatic control ball valve, wedge-shaped flowmeter and other new technologies for surface facilities in the gas field. As a result, a new design idea is proposed in this paper, i.e., to improve the integration level of surface facilities, to minimize power consumption and maintenance works and to realize unattended work mode.

Abstract: This paper studied the fine registration techniques of measuring data of complex product and proposed a new registration method based on triangle constraint. Firstly, the paper made a research on specifying the proper measuring reference points and the setting of reference coordinate system, and afterwards proposed a fine registration algorithm of measuring data, Which is about realizing the fusion of reference coordinate system based on the congruent judgment of reference triangle and fulfilling precise match of data with measuring error on the basis of controlling the rotation of data blocks and minimizing the registration error.

Abstract: 3D CAPP has become trend. Based on recognition of manufacturing features, the design model is reconstructed. First, the features of the engine case are classified. The workflow of reconstruction is put forward. Then, the detail ways to identifying manufacturing features are illuminated, and the functions are listed. The design model is reconstructed by redefining geometric and no-geometric information, including surfaces, holes, slots, text, sizes, and so on. The model of the engine case is reconstructed in the developed system.

Abstract: In various fields of positioning engineering, it is important to clarify the sliding motion, especially the stick slip phenomenon, for a wide range of scales positioning stage which works at a relative low sliding speed. In this paper, the sliding system of stick-slip motion is modeled based on a mass-spring-dampness system which includes four parameters. Meanwhile, a numerical simulation based on the Pro/ENGINEER software was conducted in order to study the relationship between stick slip behavior and its impact factors, such as the mass, stiffness, friction coefficient and damping coefficient. Moreover, experiments results are also provided to show the rationality of the theoretical analysis and the computer simulation.

Abstract: In order to promote the technical progress of pressure reducing valve in nature gas transport system, a high pressure pilot operated axial-flow pressure reducing valve was designed and developed. The three-dimensional modeling of the natural gas pressure reducing valve internal flow passage was found by using Solidworks software. Import the flow channel model into meshing in CFD software based on the internal flow channel geometry and flow characteristics. The ideal gas compressible fluid model of natural gas and improved RNG k-Epsilon model were used to solve the pressure and velocity distribution as well as other flow related parameters of the natural gas pilot operated pressure reducing valve. The flow fields of the pressure reducing valve with different valve plug shape were analyzed. Changes of valve plug shape were made to improve the performance of the valve.

Abstract: Multi-position progressive stamping is widely used in industrial fields, such as electronic, automobile and appliance, etc. Finite element numerical simulation has been an effective method to analyze the deformation of multi-position progressive stamping, the progressive die with 13 positions for the high strength steel automotive soleplate component part was manufactured based on the FEA simulation results obtained by multi-position multi-operation modeling method, and the corresponding progressive stamping experiments were carried out. The experimental results of the forward deep drawing of position 3 were further compared with the simulation ones, the results conform well to each other.

Abstract: The computational fluid dynamics (CFD) technique is employed to predict the flow of quenchant in a large quench tank. The characteristics of flow field in the existing quench tank are investigated, and the major deficiency occurred in the tank structure design is analyzed. Two different schemes for improving the tank structure design are brought forward, and further numerical simulations are carried out. Results show that the non-uniform flow field is generated throughout the quenching zone in the existing large quench tank. There is clear difference in flow rate in the regions near the inner surface of workpiece and the outer, which may cause the workpiece distortion and even cracking. Reduction in ring pipe intermediate diameter can not obviously enhance the uniformity of flow field in the quench tank. By adding an inner core in the center zone of the tank, the flow rate in the region near the inner surface of workpiece can be increased effectively, and the flow rate difference found in the quenching zone reduced significantly, which are beneficial to guarantee the quenching quality of workpiece.

Abstract: According to the analyses on the forming principle of the pellet mill and the relative motion state between the roller and the die during the extrusion process, the mathematical models of the extruding height of material and the extruding velocity of the material were developed. Based on the models, the influences of the radius ratio λ of the roller and the die and the maximum seizing angle θ on the maximum extruding height of material hmax and the pellet quality were analyzed and calculated. The calculation results show that the increases of θ and λ in a certain range are beneficial to the production yield, increasing the effective work area, and improving the pellet quality. The results provide a theoretical basis for optimizing structural design of the pellet mill.

Abstract: There are periodic changes of meshing teeth in electromechanical integrated toroidal drive, that lead to time-varying meshing stiffness. By converting time-varying stiffness into the form of Fourier series, dynamics model and the corresponding differential equation of parametric vibration system are established. Then approximate analytical solution of the system is obtained by multi-scale method, and time domain response curves of damping vibration system are given. The analysis results show that free vibration of the system not only include natural frequency, but also contains combination frequencies between natural frequency and meshing frequency. So there are multi-resonance frequency sections. Those will provide more theoretical supports for system dynamic design and optimization.

Abstract: This article establish a coupled thermo-hydraulic mathematical model for steam network by adopting a set of equations The model is simplified according to steam flow features in pipe networks. It is concluded that coupled iteration can be employed in steam network. It is well-known fact that, Steam Network mathematical model must be identified first. Here, identification is defined as process in which a number of Steam Network model parameters are adjusted until the model mimics behavior of the real Steam Network as closely as possible. The case study demonstrates that the integrated identification method gives modelers the maximum flexibility to improve the model accuracy and robustness. Test result indicates the advantage of genetic algorithm.