DEMによる試料作製方法が粒状体のせん断挙動に及ぼす影響の定量的評価  [in Japanese] DEM SIMULATIONS FOR EVALUATING EFFECTS OF SAMPLE PREPARATION METHOD ON THE SHEAR BEHAVIOR OF GRANULAR MATERIALS  [in Japanese]

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Author(s)

    • 片桐 淳
    • (独)産業技術総合研究所 メタンハイドレート研究センター 生産モデル開発チーム

Abstract

DEMにより3種類の方法で試料を作製し,それらの単純せん断シミュレーションを行った.試料作製方法は,粒子間摩擦を小さくして圧縮する方法(FC),圧縮時間を変える方法(TC)および繰返し単純せん断(CC)による圧縮の3種類であり,それぞれの方法で作製した複数の試料についてのシミュレーションを行った.その結果,FC法で作製した試料は,CC法の試料に比べて,同程度の間隙比の試料であっても初期試料内に作用する粒子間せん断力が小さく,初期配位数が大きいことがわかった.また,その後の単純せん断での応力‐ひずみ関係においては前者の試料の方が後者よりも広い弾性領域が得られた.しかし,一旦接触点が滑り出すとその影響は失われ,ピークせん断強度に達する程度まで変形が進むと大きな差異が見られなくなることが明らかとなった.

 In order to evaluate the effects of sample preparation method on the shear behavior of granular assemblies, three types of specimens were prepared: FC-specimens compacted by controlling inter-particle friction angle, TC-specimens compacted by controlling compaction time, and CC-specimens compacted by cyclic simple shear loading, respectively. A series of simple shear simulations by DEM on these specimens showed that the relationship between the void ratio and friction angle obtained in simple shear computed for the peak strength was unique irrespectively of the sample preparation methods. However, the shear moduli in small strain range were different for FC-, TC- and CC-specimens. To identify the reason for this difference, the micro-mechanical information such as coordination number, distribution of inter-particle forces were quantitatively evaluated. As a result, the granular packing structures were found to be different between three types of specimens, which might affects the deformation behavior in small strain range.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM))

    Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)) 68(1), 67-77, 2012

    Japan Society of Civil Engineers

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