Advanced Materials Research Vols. 472-475

Abstract: The current flow and pressure drop of ER valve which is a new type power control valve could be adjusted by the electric field signal directly .In this paper, the fluid power control performance of concentric cylindrical ER valve and parallel plate-type ER valve based on ER principal is comparative studied .First power control equation has been analysed, and then flow simulation of internal flow field of ER valve has been taken based on FLUENT software. The results show that with the increasing of the strength of excitation field, the flow through the two different type of ER valve decreases, the pressure drop between import and export is even greater; and the fluid power control performance of parallel plate-type ER valve is superior to concentric cylindrical ER valve under the same control volume.

Abstract: The clinching process of magnesium alloys has a great potential of being high efficient joining method, but it is restricted by the limited formability of magnesium alloys at room temperature. To form acceptable joints without cracking, it is usually required to heat the parts to about 220°C. However, the pre-heating times of traditional forming method is more than 3 to 6 seconds, the application of clinching for magnesium alloys is restricted by the over long periods of heating time. A new joining process with a contoured die is introduced to offer great benefits, especially in pre-heating time. Then the heat transfer process is simulated with DEFORM-3D software. The results show that the pre-heating time reduced to less than 1 second. Thus it is efficient and reliable in joining of magnesium alloys parts.

Abstract: The flow characteristics in mini/micro sonic nozzles have been studied in this paper using the computational fluid dynamics (CFD) method. The result shows that the flow rate of the parallel combined nozzles is not equal to but smaller than that of the sum of the nozzles. The reason is the each effect of the air after nozzles, which changes the flow field parameters .The more number of the parallel combined nozzles, the bigger error exits between actual flow rate and that of the sum of the nozzles. The result is consistent to the experiment. The study also shows the smaller of the nozzle’s diameter, the bigger error exits.

Abstract: Since the appearance of the continuous extrusion process, the section shape of the feedstock is round. The shape of the feedstock directly affects metal deformation and metal flow characteristics during the continuous extrusion process. Based on finite element method (FEM), using the Deform-3D software, this paper simulates continuous extrusion forming process for copper bus bar, and analyzes the effect of different feedstock shape on metal flowing temperature, velocity, rotating torque. The results show that: the size of the rectangular feedstock must be within a reasonable range, otherwise the continuous extrusion process can not be established; the rectangular feedstock is benefit to the flow uniformity comparing with the round feedstock; the temperature of the billet and tooling with rectangular feedstock is lower than that with round feedstock, as the feedstock width increases, the temperature decreases and the area of high temperature becomes smaller; the change of the feedstock shape and size has no effect on the extrusion wheel torque value.

Abstract: As the lightest metal, magnesium is used as the basis for constructional alloys. A well-designed runner and gating system is very important to obtain a good quality die casting. Two types of runner and gating system for magnesium piston are designed and analyzed based on CAE software. The filling process, temperature distribution and quality predication are given respectively. Combined the solidification law, the distribution of the gas hole is effectively predicted and an optimized design is chosen. The research shows that trapezoidal gating system is better than point gating system for magnesium piston. Numerical simulation can be considered as the most cost-effective way in optimization of the runner and gating system.

Abstract: The wire electrical discharge machining (WEDM) has been widely used in the field of metal cutting, mold industry, aerospace and so on. However, in the discharge machining, it is very important to restrain the wire-tool vibration for the improvement of machining accuracy. In this paper, it is created a model of the wire vibration with double-ended fixed, established the differential equation of vibration, and derived its full theoretical solution to analysis the vibration factors. Simulations of the wire vibration with ANSYS Transient dynamics analysis were given. An orthogonal design of the wire vibration using L9 orthogonal table was made, and the experiment found that minimize the servo voltage, reduce the pulse width, and select the appropriate wire tension and pulse interval, which can reduce the wire vibration.

Abstract: The solidification shrinkage of liquid steel has an important impact on thermal deformation behavior of high-temperature thin shell. Solidification shrinkage of liquid steel is an important basis for structure and shap optimization of the mould. In this paper, a direct coupled model was built on heat transfer in solidification and stress-strain by using the ANSYS software. And solidification shrinkage of liquid steel with the interior temperature and stress distribution were studied in the process of steel solidification, and it provided a theoretical basis for the further optimization of shape of the thin slab FTSC mould. This study was based on analysis of temperature and stress, deriving calculation of solidification shrinkage of steel’s phase change on macro-state by calculating the variation discipline of the distance between nodes.

Abstract: According to the main parameters of the jaw crusher PC5282, structure of the back frame was designed, and three-dimensional model of the back frame was also set up. Finite element analysis of the back frame under static load was done in COSMOSWORKS. The distribution laws of stress, displacement and deformation were revealed. Optimization design was also finished, and the weight of the back frame was reduced.

Abstract: API external upset (EU) tubing connection was applied extensively, which could ensure the enough joint strength. The end upsetting of EU tubing was the complex forming process containing upsetting, expanding and extruding, which played the important role in the EU tubing manufacture process. In this paper, the numerical simulation of end upsetting process of EU tubing was performed, which was helpful for optimization of technical process and mould.

Abstract: The rock breakage process is the interaction process between TBM and rock mass, which is affected by TBM specifications, such as thrust force, cutter tip width and profile, cutter spacing, RPM, and torque, and rock mass properties mainly including rock material strength, rock brittleness, joint spacing and orientation. In this study, based on the systematic study of the existed rock constitutive model achievements and introduction of rock breaking mechanism, main failure mode of rock in the breaking process of disc cutter is added and revised in order to meet the actual situation. The method of establishing finite element model of disc cutter breaking process using ANSYS AUTODYN-3D software is introduced. After the dynamic simulation, we can obtain that geotechnical interface disturbance insulted by disc cutter. Based on plenty of experiments, it confirms reliability of numerical methods and provides a method to study cutting performance for different geological conditions.