Engineering structures are often designed and optimized to meet multiple and possibly conflicting objectives such as the minimum weight and maximum strength. The merit of multiobjective optimization is to obtain a wid...
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Engineering structures are often designed and optimized to meet multiple and possibly conflicting objectives such as the minimum weight and maximum strength. The merit of multiobjective optimization is to obtain a wide range of choices of structural design so that the best trade-off among different objectives can be achieved. This paper presents a multi-objective optimization of elastic beams for minimum radiated sound power and weight. The transfer matrix method is used to compute the structural and acoustic responses of the beam accurately andefficiently. Both Euler-Bernoulli and Timoshenko models are considered. The multi-objective particle swarm optimization technique is applied to search the Pareto optimal solutions representing various compromises between the weight and sound radiation. Several constraints are imposed, which substantially reduce the volume fraction of feasible solutions in the design space. Two cases of elastic beams with different boundary conditions are studied to demonstrate the multi-objective optimal designs of the structure. We have discovered that when the practical constraints such as the smoothness and lower bound of the fundamental frequency of the structure are imposed, the feasible solutions can be found only in a very small subset of the design space. Numerical results of multi-objective optimal design of non-uniform beams with two different boundary conditions are presented. We have shown that the optimized non-uniform beam indeed has smaller radiated sound power and radiation efficiency in the targeted frequency range as compared with the uniform beam of the same mass.
In this paper we present an electro-hydraulic load simulation method for the helicopter booster. Based on electro-hydraulic servo control technology, we construct the load simulation system. And then, the mathematical...
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This work describes a nonlinear diffusion acceleration (NDA) method for the first order SN equations that discretizes both the transport equation and the associated diffusion system using discontinuous finite elements...
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ISBN:
(纸本)9781510825734
This work describes a nonlinear diffusion acceleration (NDA) method for the first order SN equations that discretizes both the transport equation and the associated diffusion system using discontinuous finite elements;the diffusion system is solved on a potentially coarser mesh and with a coarser energy group structure than the SN equations. The developed method differs from current methods by allowing the SN and diffusion system to be discretized with arbitrary FEM bases and by using an additive update of the SN system. The benefit of this capability is extension of the stability region to optically thicker mesh cells without underrelaxing the iterative algorithm. The presented method introduces the notion of consistency of the SN and diffusion solutions and derives suitable definitions of the cross sections, drift vectors, and element face closures. The NDA equations are solved using a Picard iteration scheme. Numerical results are presented for the C5G7 benchmark problem highlighting the effectiveness of the methods when deployed with the diffusion system discretized on the same mesh as the SN system. Additional results are presented for cases where the diffusion system features a coarser mesh, coarser energy group structure, or both, demonstrating its stability and effectiveness in these cases. It is observed that the effectiveness of the NDA method reduces when reducing the resolution of the associated diffusion system.
According to former study on oxygen diffusion, Nb-Zr solid reaction and Uo2-zr solid reaction, models of oxidation, solid reaction in fuel meat and relocation of molten fuel meat are developed based on structure and m...
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ISBN:
(纸本)9781510811843
According to former study on oxygen diffusion, Nb-Zr solid reaction and Uo2-zr solid reaction, models of oxidation, solid reaction in fuel meat and relocation of molten fuel meat are developed based on structure and material properties of Uo2-zr plate. The new models can supply theoretical elements for safety analysis of core assembled with dispersion plate-type fuel under severe accident.
The process of using one image to guide the filtering process of another one is called Guided Image Filtering (GIF). The main challenge of GIF is the structure inconsistency between the guidance image and the target i...
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A coupled neutronics/thermal-hydraulics three dimensional code system SNTA is developed for SCWR core steady state analysis by modular coupling the improved neutronics nodal methodological code and SCWR thermal-hydrau...
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A 3rd generation reactor called HuaLong is developed by China National Nuclear Corporation (CNNC). S econdary passive system (PRS) is designed to remove the residual heat during 72 hours after the reactor trips. To ve...
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ISBN:
(纸本)9781510811843
A 3rd generation reactor called HuaLong is developed by China National Nuclear Corporation (CNNC). S econdary passive system (PRS) is designed to remove the residual heat during 72 hours after the reactor trips. To verify the ability of PRS system, the test facility ESPRIT is built in Chengdu which is 1:1 in heigh t and 1/62.5 in power. Tests are consisted by three Steady-states and one transient. One model of RELAP5 mod3.2 is developed and used to simulate the steady and transient tests. The results of RJELAP5 show con sistent with facility results, but the early phenomenon during transients is different between RELAP5 and tests as RELAP5 underestimates the direct-contact condensation power.
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