Advanced Materials Research Vols. 538-541

Abstract: In today’s world of growing competition, all industries are trying their best to give the components of high quality with minimum expenditure. So in present work a new semi-elliptical boom has been selected to replace the conventional boom, which is usually made of rectangular. In particular, the study wants to substitute the rectangular section for Semi-elliptical section. This change lightens the weight of the boom. For this purpose, boom with semi-elliptical cross-section has been modeled using cad software pro/E wildfire 4.0. Using VB program automatic calculation module (UPAS), the static force at different working condition of the boom calculated. Then Finite element analysis has been done to determine the static stress at a given load condition using software ANSYS 12. The result shows that total weight is reduced by 5%. The value of maximum stress and displacement is 115.663MPa and 12.885 mm respectively. Thus the structure is capable of withstanding the maximum stress. The structure is failsafe. In this paper only static stress analysis is done.

Abstract: Taking large scale steel casting for example; View Cast software was introduced to the designing process of the large scale steel casting technique. Solidification results show that the annular pop gate is beneficial to the casting. The side risers are used but it cannot eliminate the shrinkages because of the limited feeding distance according to the simulation results. So a top riser replaced it and some chills are used in the necessary regions. The results show that the new feeding system can help to progressive solidification and the shrinkages are eliminated. The temperature distribution is very clearly and the solidified part of casting is transparent which improved the visible effect and made it easy to read. People can estimate the shrinkage position easily.

Abstract: In this paper, based on elastic-plastic and thermal-stress coupling finite element method (FEM), the centrifuge pipe mould was molded by Pro/E, and imported into the MARC after meshing, and performed finite element analysis to extrusion stability and the process of hot extrusion by MARC. By summarizing the 3D deformation regulation of the hot extrusion centrifuge pipe mould, the stress changing and mechanical property parameters during the process of hot extrusion , providing reference for the design of equipment in radial hot extrusion. At last, the study could be useful for the device design of radial hot extrusion of the centrifuge pipe mould. At the same time, this method could be use to analyze the other relative thermal extrusion processing.

Abstract: One of the responsibilities of a Civil Engineer is to make decisions regarding preservation of infrastructure; therefore, there have been established concepts such as risk and risk analysis. Risk analysis, is a methodology applied to determine and evaluate the risk magnitude. From the structural engineering point of view, it is required that any structure become secure, this means that the capacity to withstand external actions (strength) will be higher than these actions (loads). In order to determine the structural safety, it is required to define the failure of the structure that it is not strongly related with the collapse of the structure; the failure criteria needs to be fixed depending on the use of the building and the consequences associated with the interruption of services provided by the facility. The failure then, is calculated by means of a limit state function in where it is established the failure criteria; failure is reached when a specific condition (strength) is surpassed by the actions over the structure. The present work aims to propose a preliminary Finite Element Model (FEM) that represents a pier used as support for vehicular bridges. This FEM is required for the assessment of mechanical behavior of the structure that will be used for the determination of the limit state function needed for risk assessment. Most of the simulations with FEM presented in literature are very used for modeling of masonry walls, but it is not usual to model structures such as bridge piers.

Abstract: In the text through analyzing the maintenance and support system of surface-to-air missile equipment is given a process model for the corrective maintenance, preventive maintenance. Spare parts supply and support equipment usage. The model can be used for the surface-to-air maintenance and support analysis and has reference to the maintenance and support simulation research for the other equipment with its good universality.

Abstract: The vibration of the exhaust system has led to cars vibration and high noise. Without doubt, they affect the performance and especially make the people particularly uncomfortable who ride in the car. The paper will resolve the trouble by the application software of the SOLIDWORKS. It establishes the exhaust system model then makes its finite element analysis of frequency to research the relationship between lugs hanging positions and amplitudes. Obtain a conclusion is to change the hanging position can reduce the maximum amplitude of the exhaust system. The article will show how to finish the all working process from building a model to getting the optimization scheme of reducing the exhaust system vibration and the best hanging position. Thus it provides a simple feasible method as the paragon of designing other parts.

Abstract: A new analytical model for the configuration of a four-high rolling mill stand is proposed in this article. Using the model, the dominant sources of stiffness in the fifth octave and the third octave models are identified. The assumptions made for the derivation of the model are that the work rolls are isotropic linear elastic, that there is no gap or separation between the work roll and the backup roll at all times. In addition, only the vertical interactions of the work roll and the roll-bite are considered. The nonlinear characteristics of this dynamic system are contributed from the contact area of the work roll and the backup roll. Analyses show that the natural frequency of the nonlinear analytical model matches the fifth octave rolling chatter, and the dominant parameters of the dynamic instability are characterized. The effects of inter-stand tensions, rolling speeds, friction between the work roll and the metal sheet roll-bite, and the thickness of the metal sheet on rolling chatter are discussed in the analysis of the dynamics of the rolling model.

Abstract: The purpose of this study is to use ordering theory (OT) to determine existing hierarchies among items with specifically learning style. Furthermore, an empirical data of capacity concepts testing for algebra learning was analyzed based on the integrated method student-problem chart (S-P Chart) is adopted to classify all students into proper learning styles. Cooperating S-P chart and OT are as an integrated method of cognition diagnosis. The empirical data is algebra concepts test of university students. The results showed that cognition diagnosis would be feasible for remedial teaching and design of teaching materials. Finally, some suggestions and recommendations for future research and educational research are provided.

Abstract: Based on the Palmgren-Miner linear cumulative fatigue damage theory, the blade root fatigue loads in different effective turbulence intensities were calculated and analysed. The results show that when the air density and the wind speed are constant, the blade root fatigue loads increase linearly with the effective turbulence intensity increasing, and the slopes increase linearly with the wind speed increasing. According to these results, the main source of the blade root fatigue loads under different wind conditions can be estimated to provide a theoretical basis for WTGS type selection in the special sites.

Abstract: The experiment is carried out in a 13-meter-high circulating fluidized bed(CFB) to investigate gas-solid two-phase flow by pressure sensor. The axial pressure and pressure fluctuation are measured in different solid mass fluxes. With the solid mass flux increasing, pressure gradually increases, and pressure gradually decreases along the riser upwards. The characteristic of pressure fluctuation in the riser is analyzed, which indicates that pressure fluctuation in the riser originates from the inlet. The intensity of the pressure fluctuation decreases along the riser upwards. This pressure fluctuation is composed of two types: one is of low frequency and high amplitude, which is resulted from unstable feeding to the riser and keeps coherent along the axial direction. And the other is of high frequency and low amplitude, which is the result of a variety of factors, such as cluster movement, gas-solid interaction and gas velocity fluctuation.