This paper proposes a simplified deformation analysis methodology for the three-dimensional body in the first order analysis (FOA). A simplified finite element is developed for the tension and compression, and bending deformation as well as shear deformation of the body by extending concept of beam element. The simplified finite element analysis via developed element can estimate approximate deformations of complicate 3D-body, and the results of the analysis are useful for consider the load transmitting path of the structure and for designing the better structure by changing the stiffness of structural components

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In the many practical structural design problems, the design variable is large-scale and the objective function has multipul peak. On the problems, a two steps search technique is effective. That is, the first step is to search the quasi-optimal topological solution in the large domain by the heuristic techniques as the GA, and the second step is to search the optimum solution as the size problem of the solution by the mathematical techniques. By the technique, a truss and a continuum structural problems which have multipul peak are analyzed as the phase and size determination problem. From the results, it is obvious that the technique is effective to the large-scale structure problems

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An artificial satellite design requires several design objectives such as performance, reliability, mass, robustness, and cost. To solve the conflicted requirements at the same time, multi-objective optimization is becoming more popular Using the optimization, it is usual to get many solutions, such as Pareto, quasi-Pareto, and feasible solutions. The alternative solutions, however, are very difficult to be adapted to practical engineering decision directly. Therefore, to make a decision, proper information about the solution in the parameter space and real design space should be provided. In this paper, a new approach for the interpretation of the solutions is proposed based on multidimensional visualization and clustering. As a practical engineering application, the proposed approach is applied to a thermal robustness and mass optimization problem of a heat pipe shape for an artificial satellite panel. The information gleaned from the propose approach can support the engineering decision for artificial satellite heat pipe design

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This paper proposes a method for identifying the position of a sound source in an infinite space by the use of the Extended Kalman filter. The position of the sound source is estimated by making modifications on the assumed position so that the difference between the sound pressure by the actual source and that by the source at the assumed position both of which are calculated with BEM may become small. Through numerical simulations, the validity of this technique is shown and the influence of several parameters and error due to measured data on inverse analysis is discussed

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On the topological optimization problem of structure, it is desirable to set up the large design domain at the point that can search for the solution widely. However, to set up the large design domain is to increase the design variables. It will become difficult to search the optimum solution. In this study, a technique to prevent the increase of the design variable under the large design domain is proposed by performing space management of a design domain using the quad-tree. By using the technique, a structural problem optimizing the plate thickness is analyzed. In the optimization the GA is used and the optimum topological solutions are obtained

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Mech generations of 4-node tetrahedral elements are easy. However, the conventional 4-node tetrahedral element is often cited as one of bad performance elements unless a very fine mesh is used and 10-node tetrahedral elements are suggested instead for practical applications. At the same time, the 20-node brick element stands solidly as one of excellent general purpose quadratic elements. But mesh generations of it, due to limitation of geometric shape of the domain of interest, are relatively difficult. In the paper, a good performance 4-node tetrahedral element is proposed on the basis of a concept of "generalized node". It is demonstrated through a cantilever benchmark problem that the newly developed 4-node tetrahedral element possesses higher accuracy than the 10-node tetrahedral element and has same good performance of the 20-node brick element whereas the mesh-generation of it is completely same simple as the conventional 4-node tetrahedral element.

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Navier-Stokes equations for incompressible flow can be derived from a Lagangian with incompressible constraints. In this article, a particle method is developed from a discretization of the Lagrangian which describes incompressible fluid flow. This particle method is a Hamiltonian system and RATTLE as a symplectic scheme with holonomic constraints is adopted. Some preliminary calculation indicates superior conservation property of the method.

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