Three methods of assessing response of a building subjected to impact load due to collision of an airplane were investigated using simple models. Main method was to compute time history response subjected to impact load with triangular shape and duration which were based on findings obtained by the full-scale aircraft impact test. The other two methods were based on the conservation of momentum and transfer of energy using coefficient of restitution of 0. The main method can possibly evaluate impact response of building due to collision of airplane in the range of smaller τ/T.

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[in Japanese]

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Molecular behavior of two nano clusters in a nano scale flow filed was investigated by the classical molecular dynamics method. Tiny butane molecular clusters and an aluminium surface were employed to simulated the interaction processes of two nano clusters and a metallic filter. The size of the second nano cluster affected the molecular adsorption behaviors on the filter adsorbed by the first cluster molecules.

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In order to investigate combustion processes in fuel gas and in fuel liquid droplet systems, molecular dynamics simulations were carried out with a simple particle model for combustion. After giving sufficient kinetic energy into a small region, one dimensional flame propagation and the interaction between the flame and a liquid droplet were observed.

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Molecular dynamics simulations of C0_2-water-electrolyte systems were carried out to investigate the mechanism of CO_2 gas absorption by aqueous solutions. The CO_2 model developed by Murthy and Singer was found to have much less solubility than experiments. The mass transfer coefficient of the model was almost independent of the salt concentration. To reproduce solubility, the Lennard-Jones potential parameter between water and CO_2 is being tuned.

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Structure-H hydrate is the crystalline compounds in which the water molecules form a cavity enclosing guest molecule and the other guest molecule, which is called LMGS. The stability of structure-H hydrate is strongly dependent on LMGS. Structure-H hydrate is thought to be the new means of storage and transportation of natural gas. The stability of hydrate should be clarified. In this study, Molecular dynamics (MD) simulation has been carried out so as to investigate the stability of structure-H hydrate. The stability of structure-H hydrate is evaluated by Free energy difference, which is calculated directly by MD simulation. LMGS is treated as Lennard-Jones one site model so as to compare the free energy difference easily. The free energy of structure-H is minimized when a of LMGS is about 6〓, while it becomes lower as ε is increased. All simulation is performed on special purpose computer, MDGRAPE-2.

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Pattern formation process attracts broad attentions in various areas of materials science including phase transition and deformation processes. In the present report, we discuss how the patter formation can be described in the theoretical tools at our hands. Phase Field Method(PFM) is a potential tool applicable to versatile transition processes such as order-disorder transition and crystal growth phenomena. PFM, however, is based on phenomenological description of free energy and it is not applicable to multi-scale phenomena. One needs to incorporate/hybridize atomistic free energy via coarse graining operation. Cluster Variation Method has been known as one of the most reliable theoretical tools to evaluate free energy from the atomistic scale. It is demonstrated how the CVM free energy is hybridized in the PFM. Also, Diffusion-Reaction equation is solved to analyze the pattern formation process due to dislocations motion. The common principle behind these two methods are discussed.

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