Current Issue : October - December Volume : 2012 Issue Number : 4 Articles : 5 Articles
A dynamic stiffness element for flexural vibration analysis of delaminated multilayer beams is developed and subsequently used to\r\ninvestigate the natural frequencies and modes of two-layer beam configurations. Using the Euler-Bernoulli bending beam theory,\r\nthe governing differential equations are exploited and representative, frequency-dependent, field variables are chosen based on the\r\nclosed form solution to these equations. The boundary conditions are then imposed to formulate the dynamic stiffness matrix\r\n(DSM), which relates harmonically varying loads to harmonically varying displacements at the beam ends. The bending vibration\r\nof an illustrative example problem, characterized by delamination zone of variable length, is investigated. Two computer codes,\r\nbased on the conventional Finite ElementMethod (FEM) and the analytical solutions reported in the literature, are also developed\r\nand used for comparison. The intact and defective beam natural frequencies and modes obtained from the proposed DSM method\r\nare presented along with the FEM and analytical results and those available in the literature....
A computational fluid dynamics (CFDs) method utilizing unstructured grid technology has been employed to compute vortical\r\nflow around a 65? delta wing with sharp leading edge, which is specially known as the geometry of the second international vortex\r\nflow experiment (VFE-2). In VFE-2, 65? delta wings with different leading edges had been broadly investigated by experiments,\r\nwhich resulted in a special database for CFDs codes validation. The emphasis of this paper is to investigate the effectiveness of an\r\nadjoint-base grid adaptation method for unstructured grid in capturing concentrated vortices generated at sharp edges or flow\r\nseparation lines of lifting surfaces flying at high angles of attack. Earlier experiences in vortical flow simulations had indicated that\r\nthe vortex behavior is highly dependent on the local grid resolution both on body surface and space. The adjoint-based adaptation\r\nmethod used here is hoped to save grid points with a reasonable grid resolution for vortical flow simulations. The basic idea is\r\nto construct a new adaptive sensor in a grid adaptation process with the intent to tell where the elements should be smaller or\r\nlarger by introducing an adjoint formulation to relate the estimated functional error to local residual errors of both the primal and\r\nadjoint solutions....
Segmentation is an important step in fingerprint recognition system, in which the region of interest can be extracted. This paper present the implementations of Gabor filter for fingerprint recognition using VHDL. This work demonstrates the application of Gabor Filter technique to enhance the fingerprint image. The incoming signal in form of image pixel will be filter out or convolute by the Gabor filter to define the ridge and valley regions of fingerprint.This paper presents a novel fingerprint image segmentation method aiming at dealing with low quality fingerprint images. The memory is used to store the incoming image pixel and the coefficient of the Gabor filter before the convolution takes place. The result was the signal convoluted with the Gabor coefficient....
The main aim of this work is to show that such a powerful optimizing tool like evolutionary algorithms (EAs) can be in reality used\r\nfor the simulation and optimization of a nonlinear system. A nonlinear mathematical model is required to describe the dynamic\r\nbehaviour of batch process; this justifies the use of evolutionary method of the EAs to deal with this process. Four algorithms\r\nfrom the field of artificial intelligentââ?¬â?differential evolution (DE), self-organizing migrating algorithm (SOMA), genetic algorithm\r\n(GA), and simulated annealing (SA)ââ?¬â?are used in this investigation. The results show that EAs are used successfully in the process\r\noptimization....
Many tall halls of big space volume were built and, to be built in many construction projects in the Far East, particularly Mainland\r\nChina, Hong Kong, and Taiwan. Smoke is identified to be the key hazard to handle. Consequently, smoke exhaust systems are\r\nspecified in the fire code in those areas. An update on applying Computational Fluid Dynamics (CFD) in smoke exhaust design\r\nwill be presented in this paper. Key points to note in CFD simulations on smoke filling due to a fire in a big hall will be discussed.\r\nMathematical aspects concerning of discretization of partial differential equations and algorithms for solving the velocity-pressure\r\nlinked equations are briefly outlined. Results predicted by CFD with different free boundary conditions are compared with those\r\non room fire tests. Standards on grid size, relaxation factors, convergence criteria, and false diffusion should be set up for numerical\r\nexperiments with CFD....
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