Applied Mechanics and Materials Vols. 110-116

Abstract: Quad rotor vehicles are gaining prominence as Unmanned Aerial Vehicles (UAVs) owing to their simplicity in construction and ease of maintenance. They are being widely developed for applications relating to reconnaissance, security, mapping of terrains and buildings, etc. The control of the quad rotor is a complex problem. As a precursor to developing a model based design, the simulation of the mathematical model of the quad rotor is implemented. This will facilitate easier implementation of the model based design using Matlab Simulink©.

Abstract: Man, as a mechanical system, is extremely complex and its mechanical properties readily undergo change. There is a very little reliable information on the magnitude of forces required to produce mechanical damage to the human body. As in the case for many other dynamic systems, the human body has been found to exhibit resonance when exposed to vibration stimuli such as ground transportation vehicles.

Abstract: In this paper in order to develop high efficiency and high head deep-well pump, a L9 (34) orthogonal experiment was performed with four factors and three values including outlet angle, outlet width, the outside diameter of impeller back shroud, etc. 9 impellers were designed. The whole flow field of new-type two-stage deep-well pump at the operating point for design was simulated by FLUENT 6.2 using the standard model, SIMPLEC algorithm, second-order upwind scheme to solve, and analyze the independent of the number of the grid. 9 groups of the efficiency and head in design scheme were obtained. The effects of geometrical parameters on efficiency, head were researched using Latin square test method. The primary and secondary factors of the design parameters were acquired by way of variance analysis. According to the test result, an optimum program to further design was put forward. After manufactured and tested, the efficiency and head of the final optimal design models were significantly improved. The productions show good energy saving and material saving characters and could replace traditional pumps for deep well in the future, the comprehensive technical indicators achieve international advanced levels. The results would be instructive to the design method of new-type deep well pump.

Abstract: - Optimization of multi-criteria problem is a great need of producers to produce precision parts with low costs. Many methods such as Taguchi and Response surface methodology have been employed for optimization of turning operation. However there are few researches involve the optimization of multi-response problem in turning process. The attempt of this paper is to optimize multi-performance characteristics of turning process using grey relational analysis based on factorial design with response surface methodology. The response table and response graph for each level of the machining parameters is obtained and optimal levels of turning parameters including cutting velocity, feed rate, depth of cut, tool nose radius and concentration of lubricants are found. The multiple performance characteristics including tool wear rate, cutting force and chip-tool interface temperature is considered.

Abstract: In this paper an experimental setup to simulate spacecraft dynamics is presented. First, the dynamics of the spacecraft is briefly revised and a set of models to simulate spacecraft dynamics are described. Second, the various models are evaluated based on robustness, accuracy, easiness of measurement, rigidity and space requirement and Stewart platform is selected. Third, mechanical design of Stewart platform under static consideration is presented. Fourth, the layout of experimental platform is presented. Final section summarizes the research work and outlines the plan for future work.

Abstract: Computational analyses such as computational fluid dynamics and computational structural dynamics have made major advances towards maturity as engineering tools. Computational aero elasticity (CAE) is the integration of these disciplines. As CAE matures, it also finds an increasing role in the design and analysis of aerospace vehicles. This paper presents a survey of the current state of CAE with a discussion of recent research, success and continuing challenges in its progressive integration into multidisciplinary aerospace design. It approaches CAE from the perspective of the two main areas of application: airframe and turbo machinery design. An overview will be presented of the different prediction methods used for each field of application. Differing levels of nonlinear modelling will be discussed with insight into accuracy versus complexity and computational requirements. Subjects will include current advanced methods (linear and nonlinear), nonlinear flow models, use of order reduction techniques and future trends in incorporating structural nonlinearity. Examples in which CAE is currently being integrated into the design of airframes and turbo machinery will be presented.

Abstract: Several methods have been adopted by different researchers to test for isomorphism in Planetary Gear Trains (PGT) and out of these isomorphic PGTs, one PGT is selected at random. There is no definite basis for selecting a particular PGT out of the isomorphic graphics for further generation process. Structural aspects and rating of the PGTs are useful in selecting one such PGT for further generation. Symmetry in PGTs is one such aspect. PGTs with symmetry generate more possible higher level graphs than PGTs with no symmetry.

Abstract: The stresses and its distribution in complex shape chain plate geometry play a critical role in the fatigue life performance of a chain assembly. However, it is difficult to identify the stress distribution and stress concentration zones precisely using only the conventional industrial friendly tools such as routine quality control test, breaking load test and numerical computations. In this context the transmission photoelastic technique has made it possible to identify the stress distribution, its concentration and also to quantify the stress and strain at any point in the chain plate. This paper explains how transmission photoelastic technique is used to estimate the stress distribution and its concentration zones in a complex chain plate when it is loaded.

Abstract: To measurement Air speed, there are many methods, for example Hot Wire, Ultrasonic measurement and etc. This method use transistor for measurement. The h_fe of transistor is variable in different Thermo. In flow of air, the h_fe is not equal without flow.

Abstract: Miniaturization is the rule of the day. This has even extended to optical domain where entire sensor arrays complete with laser or led source and pin photodiode are fabricated within a single chip. The device discussed and analyzed in this paper is a MOEMS accelerometer which consists of uniform micro cantilever on one arm of MZI structure. The refractive index is assumed to vary even along the direction of pulse propagation along with the frequently analyzed refractive index profile perpendicular to the light pulse path. The efficiency of device is increased by numerous optimization measures. A dual approach of optimal curved waveguide with increased difference is found to maximize power in waveguide core with minimal leakage to the cladding. This effectively translates to increased sensitivity as greater power is available for accurate detection process. The analysis is supported by appropriate simulations.