Advanced Materials Research Vols. 706-708

Abstract: Suction valve is a critical and vulnerable component in fluid end of large scale diaphragm pump. Slurry flowing state in suction valve affects transport efficiency and operational life span of diaphragm pump directly. It is necessary to analyze internal flow field of suction valve for confirming structural factors which affect flowing state of slurry. In this paper, suction valve of three-cylinder single-acting diaphragm pumps as a research subject, internal flow fields of suction valves which have different structures are simulated by finite element analysis software ADINA. Velocity distribution graphs and vector graphs of flow field can be obtained from analysis results. Flowing characteristic regulations affected by inner structure of valve are summarized. The research results in the paper provide some theoretical guidance for researching and developing of suction valves and relevant products.

Abstract: A finite element analysis for a bilayer functionally graded cantilever beam is developed. The elastic modulus of each graded layer of the beam varies with the thickness as an arbitrary function respectively. The graded function of modulus can be dealt with easily by using MSC.Marc analysis code, which can increase the efficiency of calculation. By comparing finite element method (FEM) results with theory results, it can be found that the 8 node 2nd order element is more precise than the 4 node linear element, due to the former could eliminate the shear locking phenomenon effectively. Comparing to the method of equivalent coincident nodes, the forced displacement coupling on the perfect bonded interface is more appropriate. Finally, it is also shown that the results of finite element analysis are more rational than the theory results around the ends of the beam.

Abstract: The level of the mould design directly influence the quality of track slab , influence the smoothness and stability of the a high-speed railway further .Precast casing pipe unit is one of the key parts in the mould, which definitely influence the quality of track slab. Combined with the track slab manufacturing in Nanjing-Anqing special line, we have discussed five schemes on precast casing pipe unit of the mould, and the best scheme been formed after comparison and optimization. It is proved by the process of the track slab production that the best scheme can ensure precision of track slab, be operationally convenient, bring obvious benefit and is worth spreading.

Abstract: To optimize the supply and exhaust stroke of electro-pneumatic changeover valve (EP valve), a basic structure of proportional solenoid which used in the EP valve is designed, and a computational model of proportional solenoid and EP valve simulation model are established based on the AMESim. Then the electric magnetic characteristic curves of proportional electromagnetic valve and EP valve output side air pressure curves of different supply and exhaust stroke are obtained by simulations. Through the analysis of the simulation results to optimize the supply and exhaust stroke of the EP valve.

Abstract: As one of the most considerable methods to study hypersonic flight vehicle, the numerical simulation of supersonic combustion ramjet (scramjet) has drawn an ever increasing attention at present. Nevertheless, the traditional serial simulation is ungratified for current research requirements because of high calculation precision, avaricious memory overhead and overlong computation time. Meanwhile, the efficiency of parallel simulation using the domain decomposition method is not very satisfactory. In this paper, we study on a general algorithm for scramjet design, and subdivide the computing domain by using a multilevel hypergraph partitioning algorithm. In order to reduce computation while enhancing the degree of parallelism, overlapping communication with computation and non blocking communication is adopted to decrease the communication time when dealing with global communication. Finally, experimental results testing on a China-made supercomputer show the smallest value of parallel efficiency is more than 48% when the number of processors is 256. In conclusion, the result indicates that our parallel algorithm is simple, effective and practical in scramjet simulation.

Abstract: The authenticity and reasonability of the medium hydraulic excavator simulation model parameters was the foundation to ensure the effectiveness of the simulation model. Based on the bond graph theory, a dynamic simulation model of a medium excavator was established. By the comparison of experimental data and simulation data, the response surface of unknown parameters and the error function of the system model were built. Subsequently, the genetic algorithm was employed to optimize the response surface and obtained optimal value. And then the calibration of the unknown parameters was automatically completed. It was proved that the model simulation curve and with experimental curve fitted better when response surface-genetic algorithm method was used for automatic optimization and calibration of unknown parameters. Furthermore, this method could also function to reduce effectively the number of trials of parameter calibration.

Abstract: For the thermal load of a heavy vehicle is too high in plateau environment, based on Hiroyasu spray model and predictive combustion model, a turbocharged diesel engine model with environmental adaptive predictive ability was established. The experimental results of 3700m revealed that the simulation result relative errors were less than 5%. The research of combustion chamber temperature field was made. This method provides a fundamental basis for further design of the combustion chamber.

Abstract: In the process of milling special helicoid , there is a cusp point between its profile curve and linear esicoaginal junction . Ordinary milling cutter can't processing .If milling tool profiles are calculated and designed by smooth connection, the findings of milling tool profiles will appear profiles jagged or profiles detached phenomena. For separation of milling cutter blade shape, in order to prevent point was cut off, it can be treated with the method of open groove, but the two point easy to wear and affect the durability of the cutting tool. Solving method of transitional profiles of detached section is given.

Abstract: The transmission of planetary gears has the nature of great efficiency, calmness and vibration resistance. It is often used in reducers. In the traditional design charts in handbooks and formulas in dynamics are use to get gears parameters. This ways spend long time and great work, but the result is not so reliable. In the modern design the Reliability Method and Optimization device are introduced by means of computers, and look for the best parameters on the base of the maximum reliability.

Abstract: Voltage sag is one of the most critical power quality problems. This paper calculates voltage sag propagation through YNd11 and Dyn11 winding connected transformers in series using symmetrical components, thus obtaining the voltage transfer matrix. Then the voltage sag propagation of single line-to-ground fault is computed using the transfer matrix. Simulation result proves the correctness of the analytical calculation, providing reference for the further study of voltage sag influence and estimation.