Graduation and Master's Thesis

Yagawa lab.

(1) Application of the Enriched Free Mesh Method on the crack problem

About Enriched Free Mesh Method, which is the highly precise technique of Free Mesh Method, the convergent evaluation in a three-dimensional elastic problem and the examination on the efficiency to crack analysis were performed. From the results of numerical analysis, it was confirmed that the precision improved sharply as compared with the conventional method.

(2) The crack progress inhibition simulation by the circle hole using a neural network

The purpose is preventing the destruction which takes place when a crack progresses.We can prevent the crack progress by placing the circle hole. In this analysis, the Free Mesh Method is applied, which is the nodal point treatment type finite element method. The neural network is used in prediction of the optimal circle hole position that can prevent crack progress. The calculation result is verified in three-point bending test analysis.

(3) Large-scale adaptive analysis using a clone class mesh

In order to build a class mesh, we have to put all Mother mesh on a memory. Therefore, the size of a class mesh had restriction. In this research, generation of a large-scale mesh was enabled by putting two or more class mesh in order and connecting them.

(4) Highly-precise-izing of the dynamic analysis by introduction of EFMM

Generally, in the finite element method analysis, the high order element which has an intermediate node is used for the improvement in analysis precision. However, there are various problems when we use the high order element. Since it is necessary to solve simultaneous equations for every step when using an implicit method for the solution of dynamic analysis, a matrix is enlarged and calculation efficiency falls sharply. By this research, it was shown that it is possible by using EFMM to conduct dynamic analysis which raised analysis precision, without using a high order element.

(5) Large-scale parallel analysis by Enriched Free Mesh Method

The purpose of this research is verification of the affinity of EFMM and parallel calculation. Now, parallelization efficiency equivalent to FMM is surveyed in the two-dimensional static structural problem solved by the parallel CG method. The number of computer nodes used for parallel analysis is 70, and an analysis scale is a 100 million degree-of-freedom scale. From now on, it mounts to a three-dimensional problem.

(6) Large-scale characteristic vibration analysis using the stiffness matrix of EFMM

It is known that the stiffness matrix of EFMM is narrow as compared with FEM, and the low frequency wave range is crowded in eigenvalue distribution. The purposes of this research are to solve the parallel eigenvalue analysis which used the stiffness matrix of EFMM at good parallelization efficiency, and to make it develop into the acoustic analysis of EFMM. The technique used for parallel eigenvalue analysis is the Lanczos method.

Ezawa lab.

(1) Research of phase optimization

One of the optimization techniques of structure is phase optimization. It is optimizing using various kinds of techniques, such as densimetry. Moreover, the analysis of vibration of the cone of a speaker and the case are also conducted as research relevant to engineering acoustics. The situation of vibration changes in cone form and we are searching for the form which can remove the factor which soils a sound.

(2) Research of game programming

In the game program, exact evaluation of an aspect of affairs serves as an important element. Then, the influence which the evaluation function of an aspect of affairs has on the strength of a game is investigated by making othello into an example, and it is being studied whether what I should do for strengthening more. Moreover, it is an important theme whether what I should do for increasing the speed of search.

(3) Research of corrosion-proof

In the corrosion of metal piping, the flow velocity of a pass, a velocity gradient, an electric potential place, etc. are related to corrosion. Then, the simulation of those influences is carried out quantitatively, and it is being studied whether what we should do with better corrosion prevention, using together various kinds of optimization techniques and the inverse problem technique.

(4) Research of development of the finite element for CAE

In the finite element method, element fractionation is a still important theme. Here, it is inquiring on the theme of exploring the highly precise element which is easy to carry out element fractionation contrary to the former.

Tamura lab.

(1) Development of the fluid analysis technique based on a picture

In order to analyze the flow of the circumference of complicated actual geometry, the detailed three-dimensional data about the object form is required. Moreover, it is known that even if it carries out with a tool for exclusive use and program, remarkable time and effort for generating a calculation lattice (element) based on it is required. Then, in order to perform fluid analysis without such detailed data, the method of solving the flow area by using a picuture is studies.

(2) Use of the fluid analysis technology in a medical field

Although the fluid analysis by a computer called in CFD (Computational Fluid Dynamics) are remarkable, the practical use field is restricted still more. Here, it is inquiring especially about the application of CFD to a medical field for the purpose of extending the scope of CFD. Specifically, it is analyzing about the flow in the therapy by a supersonic wave, and a blood vessel, the cavitation in the inside of the body, etc.

(3) Development of the high resolution fluid analysis technique

Although related to topic (1), it is difficult to prepare beforehand enough lattice and elements to ensure precision required for analysis at complicated form and a complicated flow area. Moreover, although the calculation scale is large, there is a limitation in computer resources. Then, the technique of the ability to acquire precision practically sufficient with realistic computer resources is developed by combining the scheme from which high resolution is obtained in the same lattice and the solution conformity lattice which makes a lattice fine automatically in a required range.

Shioya lab.

(1) Development of three-dimensional structure-analysis software

In this research, the function about the treatment of a boundary condition was added as a function of the general-purpose structure-analysis software which performs large-scale finite element parallel computing, and it incorporated as a function of a solver. As a result, it became possible to deal with the analysis for which the boundary condition conversion tool was conventionally required without using an external tool. As an example of analysis, it applied to the model of the garage.

(2) Research on nonsteady-heat-conduction analysis

A backward difference method and a Crank-Nicolson method was compared and examined efficacy to evaluation of each technique, and some problems about the non-steady analysis function of the general-purpose heattransfer analysis software which performs large scale finite element parallel computing. Since finite element size became small, the large scale problem considered optimization of time step width.

(3) Development of network type CAE software

In this research, the remote use experiment between Kanto and Kyushu was conducted by performing joint research with Kyushu University on the network type CAE system which uses the parallel computer system employed in a remote place through the Internet. About the large scale problem of the 3 million degree-of-freedom scale, analysis for which it seldom depends on network load was realized.

(4) Three-dimensional adaptive analysis

In this research, the adaptive analysis for three-dimensional crack analysis is performed by combining the free mesh method which are the partial mesh generation techniques and large-scale parallel finite element analysis program. The simulation of the three-dimensional progress phenomenon of the complicated shape crack in a large-scale structure was performed using component technique, such as the fracture mechanics parameter computation method.

(5) Convergent examination in an iteration method

In this research, we performed examination about the influence which the form of a model has on convergency when using a iterative type solver in a finite element analysis. We verified about the relevance of a problem scale and convergency on the case where element form, which has relatively small influence in the large scale problem, gets extremely bad.

Nakabayashi lab.

(1) Application of numerical fluid analysis to the optimization problem

Various design problem and optimization problems are treated using the analysis system of an incompressible viscous fluid. An analysis model can be automatically generated in a certain constraints and the optimization problem in consideration of a hydrodynamic effect can be solved by carrying out iterative calculation by a genetic algorithm.

(2) Research on a multi agent system and artificial intelligence

The multi agent system is developed on the topic of the RoboCup soccer simulation league. In addition to soccer simulation league 2D which has participated from the 18 fiscal year agent development of soccer simulation league 3D was also started from this year.

(3) Research on ubiquitous computing

We try to apply various information machines to a numeric simulation as well as equipment of the computer environment centering on the conventional PC. Specifically, we are developing the cluster system which used the general-purpose handheld game machine and the cellular phone and the image base CAE system using a digital camera, etc.

(4) Research on the application of calculation dynamics to the sport

Especially we deal with soccer also in the sport, and are solving the mechanism of a curve ball by the flow analysis of the circumference of a soccer ball. Moreover, the system which supports a free kick as an inverse problem is developed.