a b s t r a c tAn efficient analytical method for vibration analysis of a Euler-Bernoulli beam with Spring Loading at the Tip has been developed as a baseline for treating flexible beam attached to central-body space structure, followed by the development of MATLABÓ finite element method computational routine. Extension of this work is carried out for the generic problem of Active Vibration Suppression of a cantilevered Euler-Bernoulli beam with piezoelectric sensor and actuator attached as appropriate along the beam. Such generic example can be further extended for tackling light-weight structures in space applications, such as antennas, robot's arms and solar panels. For comparative study, three generic configurations of the combined beam and piezoelectric elements are solved. The equation of motion of the beam is expressed using Hamilton's principle, and the baseline problem is solved using Galerkin based finite element method. The robustness of the approach is assessed.
a b s t r a c tDue to rapid development of boundary element method (BEM), this article explores the evolution of BEM over the past half century. We here summarize the overall development and implementation of several well-known BEM variants that includes collocation BEM, galerkin BEM, dual reciprocity BEM, complex variable BEM and analog equation method. Their theoretical and mathematical backgrounds are carefully described and a generalized Laplace's equation (and Poisson's equation) is utilized in demonstrating the different approaches involved. An up-to-date review on characteristics and implementation for each of the five variants is presented and also highlighted their significant contributions in boundary element research. In addition, this article tries to cover whole aspect of interests including efficiency, applicability and accuracy in order to give better understanding of BEM evolution. Comparisons and techniques of improvement for these variants are also discussed.
With the progress and development of Coandă Micro Air Vehicle (MAV) to date, various configurations have been proposed and developed. For the purpose of designing a Micro Air Vehicle (MAV), that could meet the desired mission and design requirements and can operate effectively in various environmental conditions, a workable theoretical analysis is to be developed. With such motivation, capitalizing on the basic fundamental principles, the aerodynamic forces acting on Coandă MAV configurations are revisited and analysed on the bases of the Fluid Dynamics and Flight Mechanics of a semi-spherical Coandă MAV configuration. The major objective of this paper is to analyse the forces and moments acting on the Coandă MAV as related to the geometry, flow, and motion parameters, using mathematical modelling. The mathematical model and derived performance measures in hover and translatory motion are shown to be capable in describing the physical phenomena of the flow field of the semi-spherical Coandă MAV. Results obtained are assessed and considered viable for preliminary design of such air vehicles and further elaborated development, including more flight dynamic manoeuvres.
Purpose-The purpose of this paper is to reformulate the governing equations incorporating major variables and parameters for the design a Micro Air Vehicle (MAV), to meet the desired mission and design requirements. Design/methodology/approach-Mathematical models for various spherical and cylindrical Coanda˘ MAV configurations were rederived from first principles, and the performance measures were defined. To verify the theoretical prediction to a certain extent, a computational fluid dynamic (CFD) simulation for a Coanda˘ MAV generic models was performed. Findings-The major variables and parameters of Coanda˘ MAV have been formulated into practical guidelines, which relate the lift (or thrust) produced for certain input variables, particularly the Coanda˘ MAV jet momentum coefficient. The influences of the geometrical parameters are elaborated. Research limitations/implications-The present analysis on Coanda˘ jet-configured MAV is focused on the lift generation due to the Coanda˘ jet effect through a meticulous analysis. The effects of viscosity, the Coanda˘ jet thickness, the radius of curvature of the surface and the stability of Coanda˘ jet are not considered and will be the subject of the following work. Practical implications-The results obtained can be used for sizing in the preliminary design of Coanda˘ MAVs. Originality/value-Physical and mathematical models were developed which can describe the physical phenomena of the flow field near the Coanda˘ MAV surfaces influenced by Coanda˘ jet sheets and for obtaining a relationship between relevant variables and parameters to the lift of practical interest.
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