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Existing Design (existing + design)
Selected AbstractsEffect of train dynamics on seismic response of steel monorail bridges under moderate ground motionEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2006Chul-Woo Kim Abstract This study is intended to investigate the seismic response of steel monorail bridges using three-dimensional dynamic response analysis. We particularly consider monorail bridge,train interaction when subjected to ground motion that occurs with high probability. A monorail train car with two bogies with pneumatic tires for running, steering and stabilizing wheels is assumed to be represented sufficiently by a discrete rigid multi-body system with 15 degrees of freedom (DOFs). Bridges are considered as an assemblage of beam elements with 6 DOFs at each node. Modal analysis is used for dynamic response analysis under moderate earthquakes. The seismic response of an advanced monorail bridge that adopts a simplified structural system and composite girders is investigated through comparison with seismic responses of a conventional bridge. The acceleration response of a monorail train is also calculated to investigate the effect of structural types of bridges on the train's dynamic response during earthquakes. Results show that the seismic responses of the advanced bridges are greater than those of the conventional monorail bridge because of the simplified structural system and increased girder weight that is attributable to composite girders of the advanced bridge. Moreover, the train on the advanced bridge shows greater dynamic response than that on the conventional bridge. Observations reveal that the dynamic monorail train system acts as a damper on the monorail bridge. That fact shows that the existing design, which considers a train as additional mass, yields a conservative result. Copyright © 2006 John Wiley & Sons, Ltd. [source] Reactive CFD simulation of an FCC regeneratorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2007M. Philip Schwarz Abstract A computational fluid dynamic (CFD) model including coke combustion and heat transfer has been developed of the fluidised bed in the regenerator vessel of the fluidised bed catalytic cracker unit (FCCU) at the BP Bulwer Island Refinery. The model has been used to test various design modifications aimed at improving oxygen utilisation efficiency by reducing short-circuiting of solids through the vessel. A catalyst return distributor design has been determined that gives significantly better mixing, and hence significantly reduced breakthrough of oxygen and CO into the freeboard compared with the existing design. When the modification was implemented at the plant, excess O2 was reduced significantly Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] CFD-based optimization of aerofoils using radial basis functions for domain element parameterization and mesh deformationINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 8 2008A. M. Morris Abstract A novel domain element shape parameterization method is presented for computational fluid dynamics-based shape optimization. The method is to achieve two aims: (1) provide a generic ,wrap-around' optimization tool that is independent of both flow solver and grid generation package and (2) provide a method that allows high-fidelity aerodynamic optimization of two- and three-dimensional bodies with a low number of design variables. The parameterization technique uses radial basis functions to transfer domain element movements into deformations of the design surface and corresponding aerodynamic mesh, thus allowing total independence from the grid generation package (structured or unstructured). Independence from the flow solver (either inviscid, viscous, aeroelastic) is achieved by obtaining sensitivity information for an advanced gradient-based optimizer (feasible sequential quadratic programming) by finite-differences. Results are presented for two-dimensional aerofoil inverse design and drag optimization problems. Inverse design results demonstrate that a large proportion of the design space is feasible with a relatively low number of design variables using the domain element parameterization. Heavily constrained (in lift, volume, and moment) two-dimensional aerofoil drag optimization has shown that significant improvements over existing designs can be achieved using this method, through the use of various objective functions. Copyright © 2008 John Wiley & Sons, Ltd. [source] Response Adaptive Designs with a Variance-penalized CriterionBIOMETRICAL JOURNAL, Issue 5 2009Yanqing Yi Abstract We consider a response adaptive design of clinical trials with a variance-penalized criterion. It is shown that this criterion evaluates the performance of a response adaptive design based on both the number of patients assigned to the better treatment and the power of the statistical test. A new proportion of treatment allocation is proposed and the doubly biased coin procedure is used to target the proposed proportion. Under reasonable assumptions, the proposed design is demonstrated to generate an asymptotic variance of allocation proportions, which is smaller than that of the drop-the-loser design. Simulation comparisons of the proposed design with some existing designs are presented. [source] | ||||||||||