Applied Mechanics and Materials Vol. 189

Abstract: This paper presents a FEA method for vibration characteristics analysis of aero-engine compressor disc. An actual modal analysis of a certain aero-engine compressor disc is made based on this method. The first ten natural frequencies and modes of this compressor disc in fully constrained boundary condition and in free vibration condition are obtained respectively. And also, the vibration characteristics of each natural mode and its effect on compressor disc and other accessories are analyzed in depth. The analysis process and results presented in this paper can be references for further study on optimal design and vibration safety verification for this aero-engine compressor disc.

Abstract: This paper introduces a FEA method for vibration characteristics analysis of an aero-engine shrouded turbine blade and makes an actual modal analysis of this shrouded blade based on this method in UG software environment. The first six natural frequencies and mode shapes of this shrouded blade are calculated. And also, the dynamic characteristics of the shrouded turbine blade are discussed in detail according to the analysis results. The FEA method and the vibration characteristics analysis results in the paper can be used for optimal design and vibration safety verification of this aero-engine shrouded turbine blade.

Abstract: Numerical studies are conducted to research the performance of a kind of lift-drag type vertical axis wind turbine (VAWT) affected by solidity with the CFD method. Moving mesh technique is used to construct the model. The Spalart-Allmaras one equation turbulent model and the implicit coupled algorithm based on pressure are selected to solve the transient equations. In this research, how the tip speed ratio and the solidity of blade affect the power coefficient (Cp) of the small H-VAWT is analyzed. The results indicate that Cp curves exhibit approximate parabolic form with its maximum in the middle range of tip speed ratio. The two-blade wind turbine has the lowest Cp while the three-blade one is more powerful and the four-blade one brings the highest power. With the certain number of blades, there is a best chord length, and too long or too short chord length may reduce the Cp.

Abstract: The computer simulation methods have become more and more widely used technique in materials science research. This paper discusses the importance of the application of computer simulation in the field of materials science. There are many application areas of computer simulation in materials science including the heat treatment, material microstructure, corrosion and protection, casting, and material design areas. It can be seen from the results of these applications that computer simulation technology is an efficient, realistic way to fully reflect the variation of the sample in a variety of research process. It can get rid of a rough qualitative estimate of production of the backward state.

Abstract: Due to their unique structure and performance, great attention to nanosized materials has increased in past years. Advanced information and simulation technologies provide an understanding of nanosized materials at the atomic scale with an unprecedented level of detail and accuracy and make nanosized materials design and performance prediction possible. Computer simulation theory and methods in the research of nanosized materials are summarized. The progress in computer simulation of nanosized materials, especially their mircostructure, mechanical, thermodynamic, electric, magnetic properties, is discussed in detailed. Some basic problems in structure and performance research of nanosized materials are also elaborated.

Abstract: Due to the fact of immeasurable inner temperature of inverter-fed traction motor, three-dimension finite element model of part of rotor iron core and half a rotor bearing were established. The convective heat transfer coefficient between the air gap of motor and rotor surface were calculated by the heat transfer and fluid mechanics theory. The influence of temperature rise on the stator and rotor resistance was considered for thermal loss calculation. The influence of the end of stator and rotor on axial temperature distribution was also taken into account. Then three-dimensional transient temperature field of the motor was simulated at the rated load. Temperature field with different loads was also computed. The aim has been to optimize the design with respect to the transient stresses. According to contrastive analysis compared with other method, it demonstrated the accuracy of simulation model and thermal field calculation results.

Abstract: DEFORM-3D is a finite element method(FEM) system which is based on a process simulation system, especially analyzing 3D flow of all kinds of steels forming process. The simulation analysis of metal forming and heat treatment process have been widely used. 16MnR is a common pressure vessel material. However, the material database in DEFORM-3D is lack of 16MnR, so it is urgent to improve the database. In the basis of the DEFORM-3D original material database，16MnR material database was increated by the second development. 16MnR material database and DEFORM-3D finite element simulation software is integrated seamlessly. The improved material database has great significance to numerical simulation in all aspects of the practical application in pressure vessel.

Abstract: Computational materials and materials design combined with computer techniques are very important contents in materials science. The paper used computer simulations and modeling to study the structures and characteristics of functional materials. It used first principle theory or molecular dynamics methods to study the electronic structures, conductive properties and their relationship of the cathode material. It used molecular dynamics method to study the embedded light small atomic or molecular lamellar graphite thermal behavior of the system; the use of first principles methods to manually control the formation of chemical bonds in the scientific field of single molecule and its characteristics.

Abstract: The paper used computer simulation techniques to model the failure process of brittle materials. The simulation method is the finite element method. We have prepared a quad tree method program, through which the unit discrete planes structure, and the quick automatic generation of quadrilateral elements of good quality, and the discrete units of information and node information. We use object-oriented method of preparation of the finite element program, and use it for displacement in the destruction of the simulation, stress analysis. We simulate the failure process of brittle materials. Simulation, the choice of failure criteria and damage model are two key, they choose the proper relationship to the simulation results, good or bad. According to the characteristics of brittle materials, select the first strength theory as a failure criterion and a damage model suitable for brittle materials. The model assumes that a crack in the destruction of the cell boundary, and then through the crack surfaces and the distribution of the load to compensate for the energy released when the virtual cracks. Finally, the destruction of the material is given by the computer graphics form.

Abstract: The composite material is made by two or more of the same nature, substance or material combinations together new material. Through appropriate methods, different materials are to be combined with each other sets’ advantages of various materials into one, and to be available to the various properties of new materials. This is the fundamental reason for the rapid development of composite materials and composite technology. The fiber reinforced composite fibrous material in such materials as filler, in order to play an enhanced role. The fiber reinforced composite materials and fiber reinforced ceramic matrix composites are discussed in detailed. OpenGL is used to implement visualization of composites' material microstructure, which can specify fiber parameters to gain a basis of visualization.