493 publications from this institution
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An oblique shock wave in a supersonic flow field was measured and visualized using Particle Tracking Velocimetry (PTV). The beginning of the velocity drop at the shock wave was sharper than that detected by general Particle Image Velocimetry (PIV). The location of the shock wave in the obtained velocity vector was in good agreement with that in Schlieren images because PTV has the advantage of high spatial resolution. The statistical values of turbulence in the airstream were successfully estimated. Another advantage of PTV is low calculation load. Real-time PTV was developed in this study. The image capture and the tracking calculation were performed in real time and the obtained vector data were sent to another computer using a network socket. It is considered that the transdisciplinary approach between experiment and numerical simulation can be performed using velocity vectors which will be sent to a supercomputer in real time. It is conformed that the obtained vector data and the real-time PTV are capable of realizing a transdisciplinary measurement system in future.
Hot blast flow control valves which can control the flow rate of hot blast at each tuyere and their control system have been developed and applied to Keihin No. 1 BF. These technologies contribute to stable and rational operation compared with conventional ones. This presentation describes the technology of hot blast flow control valves and its implications on the control of heat load at the lower part, the removal of scab, and the control of tapping conditions.
Collins らにより提案された修正圧縮場理論を, ひずみ・応力勾配を持つRC断面に拡張した解析手法の開発を行い, せん断補強筋を持たないRC断面の斜めせん断破壊耐荷力を解析的に評価する手法を示した. さらに, せん断耐荷力に及ぼす各種要因の影響を解析的に明らかにすると共に, 解析値が既往の実験回帰式とよく一致することを示した. 特に, RCはりのせん断耐荷力に対する寸法の影響に関しては, 本手法に有効高さを考慮したコンクリートの引張軟化曲線を用いることで, 解析的に評価し得る.
A time-dependent structural analysis method under multi actions in consideration of drying shrinkage due to moisture transfer and rebar corrosion due to chloride ions penetration as well as external load actions was developed. The Rigid-Body-Spring Networks (RBSN) model and the truss networks model were used for structural analysis and mass transfer analysis, respectively. In addition, mass transfer through bulk concrete and mass transfer through cracks by setting truss networks on the boundaries of Voronoi particles, was also considered. The developed method was confirmed to simulate well the deterioration process due to mass transfer for initial cracking behavior and ultimate behavior of concrete structures.
A full-size model of a typical cooling and heating system for a vacuum vessel was manufactured and examined in order to clarify and enhance the efficiency and reliability of the designed system. The model consisted of two parts; one of which had the same structure as the other and was located facing each other to simulate the adiabatic condition of the vacuum-side of a vacuum vessel. Its components were rectangular plates, eletric heater units, cooling pipes inside of which water and air flew as cooling fluid. A lot of kinds of tests and measurements were performed to evaluate efficiency and reliability on the model. The numerical and theoretical analyses on the system were also carried out using the dimensional finite difference technique. The analytical results agreed pretty well with the experimental.
軸方向圧縮力およびせん断スパン比をパラメータとしたRC梁のせん断破壊実験を行い, 現状では十分と言えないこの種の実験データの充実を図ると共に, 実験結果に基づいて軸方向圧縮力がせん断耐力に及ぼす影響を検討した. その結果, 軸方向圧縮力の影響はせん断スパン比によって変化しないとする現行のコンクリート標準示方書のデコンプレッションモーメント法では, 実験結果における軸方向圧縮力の影響を正確に再現することができないことを明らかにし, 斜めひび割れ耐力に及ぼす軸方向圧縮力の影響はせん断スパン比が小さくなるに従って直線的に増加すること, 同様に, せん断圧縮破壊の場合には, せん断スパン比が小さくなるに従って軸方向圧縮力によるせん断耐力の増加率が直線的に減少することを示した.
