• 代表取締役社長　最高経営責任者
• 斎藤　保

• 資源・エネルギー・環境事業領域責任者　取締役
• 浜村宏光

• 海洋・鉄構セクター長兼ソリューション統括本部長
• 安部昭則

• 産業・ロジスティックスセクター長兼高度情報マネジメント統括本部副本部長
• 大谷宏之

• 航空・宇宙・防衛事業領域責任者　取締役　常務執行役員 航空宇宙事業本部長兼高度情報マネジメント統括本部副本部長
• 満岡次郎

• 執行役員　技術開発本部長
• 館野　昭

• 航空宇宙事業本部

• 航空宇宙事業本部

• 産業・ロジスティックスセクター

• 社会基盤セクター

• 海洋・鉄構セクター

• 回転機械セクター

• 車両過給機セクター

• エネルギー・プラントセクター

• 原子力セクター

• 新事業推進部

• 技術開発本部

• 技術開発本部

• 土木学会100周年記念誌編集委員　元大東文化大学講師
• 三浦基弘

• 編集事務局

• 甲斐聡流，大谷章仁，金子尚昭

Conventional response spectrum analysis is used for piping seismic design in Japan. When piping is supported by restraints and structures fixed on multiple buildings or floors, the envelope of the response spectra of all supporting points is typically applied for the piping under multiple excitations. The local vibration mode of long piping is difficult to excite by the far input from the vibrating part, so the analysis will overestimate the response. Considering each input from each building or floor can estimate more reasonable seismic response of the piping. The researches about seismic response analysis by multiple input excitations have been performed since 1960s and the analysis methods are used for piping design in the United State. There are a few experimental researches to verify the validity of the analysis method by multiple excitations. So an excitation test by multiple excitations planned to verify the validity of the application. This current study was performed as a preliminary investigation for the excitation test and it was to obtain the seismic response of a piping model by multiple excitations. Several kinds of analysis methods are compared and the characteristics of them are discussed. 東日本大震災以降，原子力発電プラントに要求される地震条件は更に厳しくなり，機器・配管系の構造成立性は困難になりつつある．配管系の耐震評価をより現実的なものとし，構造成立性を向上させる一つの手法として，多入力地震応答解析法の適用が挙げられる．配管系モデルに対して複数種類の多入力地震応答解析を実施し，その特徴や適用性について検討を行った．

• 品川　幹，社本英二

工作機械の機械仕様（各部の剛性と減衰）をびびり振動発生の観点から検討し設計指針を獲得することを目的とする．工具部，フレームおよび駆動部と案内部の摩擦（減衰）に注目し「摩擦減衰を含む2自由度系工作機械モデル」を提案，モデルを用いたびびり振動安定性の予測解析，試験装置を用いた切削実験による検証を行った．予測解析と実験結果は良く一致し，開発段階でのびびり振動抑制の検討に有効である．また装置の各部剛性と減衰を最適化することで，より大きなびびり振動安定性が得られることも新たに確認した．

• 山根功士朗，安田秀幸，杉山　明，柳楽知也，吉矢真人，上杉健太朗，梅谷啓二，牛込智章，佐藤彰洋

Solidification of hypereutectic cast iron (CE4.8) with 0.04 mass%Mg was observed in-situ by using time-resolved X-ray imaging. Since holding melt reduced Mg concentration due to vaporization, the observations were performed three times for each specimen to verify influence of Mg content on the microstructure evolution. At the first run, graphite particles with spherical shape grew in the melt and were surrounded by γ-dendrite or γ-graphite eutectic. The typical diameter of graphite particles was 30 μm. At the second and the third runs, graphite particles with spherical shape grew in the initial stage and then the particles transformed from spherical to flake shape before the graphite particles were surrounded by γ- dendrites and γ-graphite eutectic. The reduction of Mg in melt due to melting led to decrease in graphite nucleation. In addition, the temperature range in which the graphite particles grew as the primary phase increased with decreasing Mg concentration. The observation also suggested that Mg content in the melt influenced graphite nucleation frequency (kinetic effect), phase equilibrium of graphite-austenite-liquid phases (thermodynamic effect) and morphology of graphite. The graphite growth was followed by growth of the austenite phase which tended to nucleate in the vicinity of the graphite particles and to grow along the graphite particles. The eutectic solidification of the austenite and the graphite was finished behind the austenite dendrite tips.