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Experimental Results Shows (experimental + result_shows)
Selected AbstractsA theory of tie-set graph and its application to information network managementINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 4 2001Norihiko Shinomiya Abstract This paper presents a new circuit theoretical concept based on the principal partition theorem for distributed network management focusing on loops of an information network. To realize a simple network management with the minimum number of local agents, namely the topological degrees of freedom of a graph, a reduced loop agent graph generated by contracting the minimal principal minor is proposed. To investigate the optimal distribution of the loop agents, a theory of tie-set graph is proposed. Considering the total processing load of loop agents, a complexity of a tie-set graph is introduced to obtain the simplest tie-set graph with the minimum complexity. As for the simplest tie-set graph search, an experimental result shows that the computational time depends heavily on the nullity of the original graph. Therefore, a tie-set graph with the smallest nullity is essential for network management. Copyright © 2001 John Wiley & Sons, Ltd. [source] Developments in Failure and Damage Modeling for UD, 2D, and 3D Composite Materials,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Lucio Raimondo This paper outlines three examples of original solutions for the modeling of three classes of composite materials, which have increasing fiber architectural complexity. Results are presented from application of a novel approach for dynamic elastic and failure modeling of UD composites, and novel failure and damage modeling approaches for 2D and 3D composites, respectively. A comparison between numerical and experimental results shows that the newly proposed strategies have excellent predictive capabilities. [source] Probabilistic high cycle fatigue behaviour of nodular cast iron containing casting defectsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 4 2009A. NASR ABSTRACT Theoretical and experimental investigations were combined to characterize the influence of surface casting defects (shrinkages) on the high cycle fatigue (HCF) reliability. On fracture surfaces of fatigue samples, the defect is located at the surface. The shape used for the calculation is a spherical void with variable radius. Finite-element simulations were then performed to determine stress distribution around defects for different sizes and different loadings. Correlated expressions of the maximum hydrostatic stress and the amplitude of the shear stress were obtained by using the response surface technique. The loading representative point in the HCF criterion was then transformed into a scattering surface, which has been obtained by a random sampling of the defect sizes. The HCF reliability has been computed by using the Monte Carlo simulation method. Tension and torsion fatigue tests were conducted on nodular cast iron with quantification of defect size on the fracture surface. The S,N curves show a large fatigue life scattering; shrinkages are at the origin of the fatal crack leading to the final failure. The comparison of the computed HCF reliability to the experimental results shows a good agreement. The capability of the proposed model to take into account the influence of the range of the defect sizes and the type of its statistical distribution has been demonstrated. It is shown that the stress distribution at the fatigue limit is log-normal, which can be explained by the log-normal defect distribution in the nodular cast iron tested. [source] Buffeting in transonic flow prediction using time-dependent turbulence modelINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2005A. Kourta Abstract In transonic flow conditions, the shock wave/turbulent boundary layer interaction and flow separations on wing upper surface induce flow instabilities, ,buffet', and then the buffeting (structure vibrations). This phenomenon can greatly influence the aerodynamic performance. These flow excitations are self-sustained and lead to a surface effort due to pressure fluctuations. They can produce enough energy to excite the structure. The objective of the present work is to predict this unsteady phenomenon correctly by using unsteady Navier,Stokes-averaged equations with a time-dependent turbulence model based on the suitable (k,,) turbulent eddy viscosity model. The model used is based on the turbulent viscosity concept where the turbulent viscosity coefficient (C,) is related to local deformation and rotation rates. To validate this model, flow over a flat plate at Mach number of 0.6 is first computed, then the flow around a NACA0012 airfoil. The comparison with the analytical and experimental results shows a good agreement. The ONERA OAT15A transonic airfoil was chosen to describe buffeting phenomena. Numerical simulations are done by using a Navier,Stokes SUPG (streamline upwind Petrov,Galerkin) finite-element solver. Computational results show the ability of the present model to predict physical phenomena of the flow oscillations. The unsteady shock wave/boundary layer interaction is described. Copyright © 2005 John Wiley & Sons, Ltd. [source] Performance evaluation of decision making strategies for an embedded lane departure warning systemJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 10 2002Woong Kwon An on-board lane departure warning system embedded in a vehicle is composed of a localization module and a decision making module. The decision making module detects unintended lane departure so as to warn the driver of the danger. The performance of a decision making module is crucial to the performance of the total embedded system. This article proposes two heuristic decision making strategies: a lateral offset (LO) based strategy and a time-to-lane crossing (TLC) based strategy. The performance criteria of decision making strategies are proposed as: (1) false alarm rate, and (2) alarm triggering time (ATT). Numerical parameters of both strategies are optimized through numerical simulation, taking the performance criteria into consideration. The proposed strategies are incorporated into the prototype system and evaluated in real expressway experiments. The comparative study of both methods with experimental results shows the applicability of the on-board lane departure warning system. © 2002 Wiley Periodicals, Inc. [source] Studies on Regime Transition, Operating Range and System Stability in a Liquid-Solid Circulating Fluidized BedCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 4 2009P. Natarajan Abstract In the present work, the variations in the solids circulation rate and solids holdup were analyzed to study the behavior of a liquid-solid circulating fluidized-bed (LSCFB) regime. The results confirm the existence of two regions in the regime of LSCFB. A new concept of critical liquid velocity, jlc, is proposed in the present work for demarcation between region,1 and region,2, which is found to be a constant value of about 1.3,ut for all particles considered. The operating range of the LSCFB regime is obtained for the various particles and a correlation is developed from the data to estimate the maximum total liquid velocity. The predicted maximum liquid velocity was compared with the experimental values and found to be in good agreement within ±9,%. The effects of total liquid velocity, particle size and density on the stable operating range are discussed. Analysis of the experimental results shows that stable operation prevails both in region,1 and region,2. 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