Fluid-Structure Coupling Analysis for Fracturing process by High Energy Release

连续离散元法（C-DEM）是通过引入连续介质力学的概念来再现偏应力的方法。利用C-DEM对冲击问题、爆炸与金属相互作用、冲击波与水柱相互作用进行了数值模拟，并将计算结果与理论和实验结果进行了比较，沿着与可靠的商用程序进行了比较，验证了本文方法和程序的正确性。本研究的主要结论如下：1.建立连续数字高程模型对弹簧应变的获取方法进行了改进。这使得通常用于非连续分析的离散元法能够应用基于连续介质力学计算的本构关系。通过应用人工粘度，使分析结果更加稳定.通过冲击分析验证了C-DEM的有效性。 ...更多信息 价值观金属的二维塑性变形已经定性地再现了实验结果。通过理论计算与另一种方法计算结果的比较，对一维碰撞问题进行了计算。C-DEM和AUTODYN[○！R]显示SUS 304飞片与靶板的二维碰撞结果具有良好的一致性.一维冲击波与金属相互作用的数值模拟通过在耦合边界上交换压力和质点速度来再现冲击波与金属的相互作用。虽然在接触爆轰的情况下，通过单向分析获得的压力和粒子速度被高估，但双向分析与AUTODYN[○！R]。在爆轰波作用下，弱爆轰波仅导致粒子速度相差很小。然而，波在目标中的传播可能会导致耦合边界处的压力升高，这表明在任何耦合分析情况下都有必要进行双向计算.激波与水柱相互作用的模拟由于相互作用的不稳定性，在变形前模拟就结束了。然而，漩涡的形成表明实验的质量再现。通过用四棱柱体代替圆柱体进行数值试验，证实了水的变形和涡旋的发展是相互促进的。Less

Continuous-DEM (C-DEM) was proposed by enabling the reproduction of the deviatoric stress by introducing the concept of continuum mechanics. Simulations of impact problems, interaction between blast and metal, shock and water column was performed by the C-DEM. Validation of the suggested method and the code was carried out by comparing the results with theoretical and experimental results along with results obtained by reliable commercial codes. The conclusions of this study are summarized as follows.1. Establishment of the Continuous-DEMImprovement in the procedure of obtaining spring strains was conducted. This implement in the C-DEM enabled the DEM, usually applied to discontinuous analysis, to apply constitutive laws based on continuum mechanics calculation. Stabilization of the analytical results was additionally attained by application of artificial viscosities.2. C-DEM validation by impact analysisOne-dimensional (1D) results of impact to rigid wall well agreed with theoretical … More values. Two-dimensional (2D) plastic deformation of metals has qualitatively reproduced experimental results. 1D impact problem was evaluated by comparing the results theoretically and by another method. The C-DEM and AUTODYN[○!R] showed good agreement in 2D impact between SUS 304 flyer and target.3. Simulation of one-dimensional blast-metal interactionThe interaction between blast and metal was reproduced by exchanging pressure and particle velocity at the coupled boundary. While pressure and particle velocity obtained by the one-way analysis was overestimated in the case of contact detonation, the two-way analysis achieved good agreement with the AUTODYN[○!R]. In the case of standoff detonation, the weak blast resulted only small difference in terminal particle velocity. However, the wave propagation in the target may result pressure rise at the coupled boundary, suggesting necessity of two-way calculation in any case of coupled analyses.4. Simulation of interaction between shock and water columnThe simulation ended before deformation due to the instability of the interaction. The formation of vortex, however, denoted qualitative reproduction of the experiment. By conducting numerical experiments by substituting the cylindrical column with a quadrangular column, the water deformation and the development of the vortex was confirmed to mutually progress these particular events Less