Advanced Materials Research Vols. 156-157

Abstract: Solar grade silicon (SoG-Si) is the key material for photovoltaic applications. In this study, the silicon grain size, concentration of HF, leaching time and leaching temperature were investigated by orthogonal methods. The results showed that the silicon grain size is the most important factor for the purification of silicon. Furthermore, the obvious removal efficiency of iron and aluminum was observed when the mannitol used as the chelated reagent in HF leaching process. Inductive coupled plasma atomic emission spectroscopy (ICP-AES) results indicated that the purity of the samples improved to a large extent with the chelated reagent.

Abstract: This paper presents an efficient tool path plan for machining the impeller with a 5-axis numerically controlled machine. A method of assigning key tool orientations is reported and B-spline interpolation is used to produce smooth and interference-free tool orientation. The final tool paths generated by the proposed method are verified by using the cutting simulation function. A machining experiment is performed on a Mikron machine tool. Experimental results show that the present method is feasible and can produce interference-free tool path.

Abstract: A reliability-based multidisciplinary design optimization (RBMDO) frame work for Centrifugal compressor was presented. Multidisciplinary feasible method was used to decouple the multidisciplinary analysis and the fourth moment method for reliability analysis was recommended systematically. Based on the approximation, the RBMDO framework was finished. The case study shows that optimization efforts could improve obviously the performance of centrifugal compressor under the requirements of reliability. This framework could make the design reach the best performance with a good reliability. It indicates that the proposed optimization method is available and feasible for the engineering application.

Abstract: A new type of metal composite material can be manufactured by controlling heating temperature and designing the layout of cooling pipes in hot forming process of ultra high strength steel. The yield strength of this type of metal material varies from 380 MPa to 1000 MPa continuously, and its strength limitation varies from 480 MPa to 1600 MPa continuously. In this new hot forming technology, boron steel named as 22MnB5 is stamped by one-step process of hot forming to obtain the metal composite material and manufacture the part consisting of the metal composite at the same time. The hot forming technology of U-shaped part consisting of the metal composite material is provided. Then the microstructure of the U-shaped metal composite material is analyzed and the tensile test is also implemented. The experimental results show the material properties have the characteristics of continuous distribution along the main direction of energy absorption during crash process, which indicates the feasibility of hot forming technology of the metal composite material. The top-hat thin-wall structure consisting of U-shaped metal composite material is employed to analyze the crashworthiness of the new type of metal composite material. By distributing the single phase material of U-shaped composite part properly, the energy absorption ability is increased by 58.7% and the crash force is decreased by 23.4%, which indicate the new type of metal composite material has the comprehensive performance of every single phase material. So the metal composite is a good alternative material in application of crash resistance.

Abstract: A simulation model is established base on ANSYS software in line with the generating mechanism of the rolling resistance, and then the analytical process of rolling resistance is present. Fourier Series is applied to fit the strain and stress, and order 31 Fourier function is chosen to fit the curves of stress and strain of each element in the rolling course of tire. 2D and 3D finite element model of a 7.00-14 16 PR bias tire is established to solve the strain and stress in a rolling cycle. The rolling resistance of 7.00-14 16 PR bias tire in the case of the rated working condition is simulated and compared with the related empirical equation. The simulation result is basically consistent with that obtained by the empirical equation. The simulation method is conducive to the structural design of tire and computation or prediction of rolling resistance of tire.

Abstract: Based on micro-fluid control, a rapid metal forming method with high efficiency is proposed. At first, the basic principal is introduced. The metal liquid flows out of a large number of micro-pores, and the multipoint parallel crystallization is thus realized. During the forming process, the open or close of micro-pores is controlled by surface tension to obtain required shape of part. Then the technological parameters are deduced. Preliminary experiment shows that rapid open and close of micro-pore can be realized acted on surface tension. This method has the basic characteristics of rapid prototyping technology and continuous casting technology, which can overcome the shortcomings of inefficient and difficulty to create high melting point metal parts for current rapid prototyping.

Abstract: Today, high technology is transforming traditional industry. The science, suitable measuring technique and data application method are the basis of large-scale manufacture realizing, which not only meet individual consumer demand, but also are meaningful to raise the economic efficiency and reduce production cycle of custom-made. Custom-made enterprise always has its own contact measuring method and mechanism, which uses uniform size clothing to wear or measurement by manual re-confirm to obtain data.The efficiency of this method is low and its accuracy is poor. But non-contact measuring method has problems in application of equipment and can not completely replace manual operation. How make manual measuring method and laser measuring instruments work together to get data is the demand of practical management and production improvement in enterprise, but there is no data standard between the two methods. This research based on national size standard and professional normative measuring method, and used manual and three-dimensional laser measuring ways to collect sample data in identical situation. Under designed data standard, the research used mathematical statistics to analyse data, and then made comprehensive assessment in aspects of instrumental stability and data correlation. This paper is the case of practical application, among which used to study the tolerance range of the standard data was initial issue (sci-tech novelty report was attached).

Abstract: A finite element model of a water lubricated rubber bearings system is established by using ABAQUS software. A complex eigenvalue analysis of the bearings system is performed. The occurrence propensity of noise is evaluated on the basis of positive and negative of the real parts of eigenvalues. If there are one or more positive real parts, the system is considered to have the propensity of noise occurrence. In the ABAQUS approach, the direct contact coupling at the shaft/bearing interface is applied to obtaining normal contact forces and there is no need to introduce contact springs at the interface. The approach is easily used to establish a non-flat sliding contact model for noise. By using the ABAQUS finite element model, effects of the friction coefficient, the properties of rubber material and the thickness of rubber are studied. The results show that the friction coefficient, the properties of rubber material and the thickness of rubber have distinct effects on the occurrence of noise.

Abstract: Thermal design, finite element analysis and experiment verification of a satellite borne power amplifier are introduced in this paper. Some methods were adopted to help heat conduct and a simplified computing model was built. The analysis results show that the temperature scope of the main structure is from 45.3°C to50.7°C in high temperature work case and -9.7°C to -4.3°C in low temperature work case, and all of junction temperatures of components with high heat power consumption are lower than the derated maximum junction temperatures themselves and leave enough design margins. The experimental results show that the computing values are very close to experimental values and the largest error is 1.9°C, which proved that the simplification of model and the values of computing parameters are reasonable. Thermal analysis with reasonable model simplification and computing parameters would be helpful for production design.

Abstract: In the process of Finite Element Analysis (FEA) of mechanical structural system, the bolt pretension was often simulated in bolt fastening with components. Three methodology of Pretension Elements Method, Falling Temperature and Penetrative Contact Method as well were proposed and compared with each other using FEA technology in ANSYS. The simulation result was close to the theoretical value when using Pretension Elements Method, while was much bigger than the theoretical one when using the way of Falling Temperature as well as Penetrative Contact. It has been proved to be a very good way as well as reliable theory and application foundation for Pretension Elements Method in simulating real preloading in jointed bolt using Finite Element Analysis.