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放生, 明廣 ; 茶谷, 明義 ; 佐々木, 芳彦
概要:
A constitutive equation dependent on the strain rate was proposed and was applied to carbon steels . It was derived from the approximation of two different dislocation movements, that is, one being dominant at low strain rates
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and the other at high strain rates. Compressive tests for four carbon steels (0.19%C, 0.37%C, 0.45%C and 0.57%C) were conducted under various constant strain rates ranging from 10^<-4> to 1 000/sec by using three types of the strain rate hysteresis effect on the stress-strain relation. The present constitutive euation was applied to the measured stress-strain relation. As a result, it agreed well with the experimental values. The experimental constants included in the equation were found to be determinable from a comparatively small number of experiments. So, the present consititutive euation seems to be a valid for practical use.
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| 2.
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桝谷, 浩 ; Masuya, Hiroshi
概要:
本研究ではロックシェッドに代表される落石防護構造物に日常的に生じる低速度衝突に関して、緩衝材を有する場合の構造物の耐衝撃性能・破壊機構の解明を行い，性能設計評価方法の具体的な提案を行った．長年鋭意研究を進めてきた実際の衝撃荷重を用いて，簡易
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な解析による衝撃荷重作用時の塑性変形の推定法を具体的に明らかにした．長年待ち望まれてきたレベル２落石荷重に対する防護構造物の性能設計法を提案した．これは明確な安全性が要求される防護構造物の設計法を飛躍的に合理的で信頼性の高いものにしたものである.<br />In this research, with regard to low-speed collisions that occur routinely in rock fall protection structures typified by rock sheds, the impact resistance performance and failure mechanism of the structure with a buffer material are clarified, and the proposal of the performance design evaluation method has been concretely specified. Using the actual impact load, which has been extensively studied for many years, the method of estimating plastic deformation under impact loading have been clarified by a simple analysis. The performance design method of the protection structure against the level 2 falling rock load has been proposed, which has been awaited for many years. This is a dramatic rational and reliable design method of protective structures that require clear safety.<br />研究課題/領域番号:16K06462, 研究期間(年度):2016-04-01 - 2019-03-31
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桝谷, 浩 ; Masuya, Hiroshi
概要:
金沢大学自然科学研究科<br />本研究では,部材のハードな衝撃破壊と部材ソフトな衝撃破壊の解明と個別要素法等による構造部材の衝撃破壊への数値シミュレーションの応用に関する一連の研究を行った.概要は下記の通りまとめられる.1.部材のハードな
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衝撃破壊衝撃による破壊試験の前に比較データを得るために各種コンクリート部材の静的載荷実験行ない、破壊形式および荷重変位関係から破壊に要するエネルギーなどを詳細に調べた.その後、衝撃実験装置を用いて重錘による打ち抜き実験を行ない、破壊形式、貫通エネルギー、クラック面積,構造の衝撃挙動などを調べ、RC構造の飛来物に対する評価式検討のための基礎データを提示した.2.緩衝材が敷かれた部材のソフトな衝撃破壊飛来物の衝突点にクッション材(砂,ゴム)コンクリート部材を用いて1.と同様に静的載荷実験および衝撃破壊実験を行ない、緩衝効果について明らかにした.また、部材のハードな衝撃破壊との対比としてのクッション材が存在する場合のコンクリート部材の衝撃破壊評価方法について検討した.3.個別要素法による衝撃破壊の数値シミュレーション手法の応用粒状体のような不連続体の数値シミュレーションに有効である個別要素法を用いてコンクリート版の打ち抜きのシミュレーション方法を開発応用し、打ち抜きに関するより一般的な問題に適用可能とした.鉄筋コンクリートはりに関しては円柱要素を用いた2次元の個別要素法を,板構造に対しては3次元要素のよる解析法を開発し,弾性問題のみならず弾塑性衝撃問題への適用可能なことを示した.<br />In this research, a series of research on the application of the numerical simulation to the impulse kill of a structural material by the clarification of a hard impulse kill of the material and the impulse kill of a soft material and the individual element methods, etc. was done. The outline is brought together as follows.1.Failure of member by hard impactWe achieved static experiments of various concrete members to compare with impact behaviors before achievement of the failure experiments by hard impact failure mode. Energy required for failure from the load displacement relations of static experiment under various concrete members were examined in detail. Afterwards, a destruction form, penetration energy, crack area, and structural impact behavior etc. were examined using a heavy weight with an impact experiment device and the basic data for the evaluation type examination of the coming flying thing of the RC structure was presented.2.Failure of member by soft impactWe carried out series of static and relatively soft impact tests utilizing shock-absorbing materials (sand and r rubber.) on the collision point between concrete member and weight. Characteristics of these failures and shock absorbing ability have bee made clear. Moreover, the method of evaluating the impact failure of a concrete material comparing with a hard impact was examined.3.Application of distinct element method to the numerical simulation of impact failureWe applied distinct element method to failure of concrete structure that is effective for analysis of discontinuous body like the grainy bodies. We also developed it perforation of concrete plate. Method using cylinder element was concretely shown for two dimensions problem, and an analytical method on which three dimension elements depended was also developed. It has been shown that it is very effective to not only the elasticity problem but also the plasticity impact problem for the plate structure.<br />研究課題/領域番号:15560403, 研究期間(年度):2003 – 2004<br />出典：「衝撃などの偶発荷重による構造破壊と耐衝撃性能設計」研究成果報告書 課題番号15560403（KAKEN：科学研究費助成事業データベース（国立情報学研究所））（https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-15560403/155604032004kenkyu_seika_hokoku_gaiyo/)を加工して作成
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