Proposal of Vibration Table in an Extended World by Grid Computing Technology for Assembled Structures

The finite elements are extensively utilized to solve various problems in engineering fields with the growth of computing technologies. However, there is a lack of methodology for analyses of huge assembled structures. The mechanics on the interface of each components, for instance, contact, bolt joint and welding in assembly is a key issue for important huge structure such as nuclear power plants. On the other hand, it is well known that as finite element models become large and complex, construction of detailed mesh becomes a bottleneck in the CAE procedures. To solve these problems, the authors would like to introduce component-wise meshing approach and bonding strategy on the interface of components. In order to assemble component-wise meshes, the penalty method is introduced not only to constrain the displacements, but also to introduce classical spring connection on the joint interface, although penalty method is claimed that it is not suitable for iterative solver. In this paper, the convergence performance of an iterative solver with penalty method is investigated and the detailed component-wise distributed computation scheme is described with numerical examples.

Component-Wise Meshing Approach and Evaluation of Bonding Strategy on the Interface of Components for Assembled Finite Element Analysis of Structures

Abstract To design fast reactor (FR) core components, seismic response must be evaluated in order to ensure structural integrity. Sophisticated analysis method has been developed to study the seismic response of FR core. The fast reactors consist of several hundred core assemblies which are hexagonal flexible beams embedded at the lower support plate in hexagonal arrangement, separated by small gaps, and immersed in a fluid. Core assemblies have no support for fixing to avoid the influence of thermal expansion and swelling. So a nonlinear analytical model needs to contain the collision and the friction between adjacent core assemblies and the fluid-structure interaction in horizontal direction, and behavior of raising from the lower support plate in vertical direction. If a big earthquake occurs, large displacement and impact force of each core assembly may cause a trouble in control rod insertability and core assembly strength. Therefore, it is very important to understand the behavior of core assemblies. This paper summarizes the details of the core assembly vibration analysis code in three dimensions (REVIAN-3D) to calculate three dimensional displacement and impact force of core assemblies.

Development of seismic analysis method of fast reactor core

A study of the dynamic response of BWR core structures to earthquakes is reviewed in this paper. A structure which vibrates in a liquid is significantly affected by fluid inertia. A BWR core consists of several hundred of fuel elements and these fuel elements, being submerged in hot water, are hydrodynamically coupled with each other, when they are vibrated by an earthquake. A practical method is devised to analyze the vibration of the fuel-elements/water system. Dynamic characteristics of a core are identified by the method and checked by a series of experiments. Finally a simple ingle-degree-of-freedom model is shown to be effective in the seismic design analysis of a BWR core.

Analysis of Response of BWR Core Structures to Earthquakes

Stochastic flutter of nonlinear aeroelastic structures with parameter random fluctuations

This paper analyzes the vibrational response of square cylinders enclosed in a vessel of liquid and subjected to forced vibrations. Inertia force acting on each cylinder and damping effects are clarified by solving Navier-Stokes equation of motion for fluid under the assumption of viscous flow and using the fluid field network theory, in which the non-steady flow in cylinder-to-cylinder clearance is assumed to be two-dimensional. Comparing and checking the experimental and analytical results from various models of submerged square cylinders arranged symmetrically, we find that both agree well qualitatively and quantitatively.

Study on the Coupled Vibration of Square Cylinders in a Liquid : First Report, Comparison of Experimental and Analytical Results

Vibration Measurements and Analysis for Equipment and Piping Systems of Nuclear Power Plants( Earthquake and Aseismic Technology)

Estimation of the variance of steady vibration responses of structures with random parameters and method to compute the allowable variance of the parameters

Makio Kaga

Papers

Study on the Coupled Vibration of Square Cylinders in a Liquid : First Report, Comparison of Experimental and Analytical Results

Vibration Measurements and Analysis for Equipment and Piping Systems of Nuclear Power Plants( Earthquake and Aseismic Technology)

Estimation of the variance of steady vibration responses of structures with random parameters and method to compute the allowable variance of the parameters