Abstract A new model for the simulation of large motions of porous tensile structures and their interaction with the surrounding fluid is developed in this paper. The discrete structure is represented by several non-linear elastic bars and knots connecting up to four bars. An implicit system of equations is derived from the fundamental relations of dynamics, kinematics and material and solved using an improved Newton’s method. The Navier–Stokes equations are solved in a numerical domain to account for the interaction with the fluid. The presence of the porous structure is respected in these equations through an additional forcing term based on a modified Lagrangian–Eulerian coupling algorithm. Here, the forces on the structure are distributed on multiple Lagrangian points embedded in the fluid domain. Integration over a suitable Kernel function is applied to distribute these forces on the surrounding fluid. The derived numerical model is suitable for simulating the interaction of porous tensile structures of arbitrary geometry, non-linear material and under large motion with fluids including complex free surfaces. This is in contrast to existing models which either neglect important non-linearities, the physical interaction with the fluid or rely on explicit time integration. The validation process shows excellent agreement between the numerical simulations and existing experimental data and demonstrates the applicability of the new methodology for a wide range of applications.

中文翻译：

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一种用于模拟多孔拉伸结构与流体相互作用的动力学的非线性隐式方法

摘要 本文开发了一种用于模拟多孔拉伸结构的大运动及其与周围流体相互作用的新模型。离散结构由几个非线性弹性杆和连接多达四个杆的结表示。隐式方程组源自动力学、运动学和材料的基本关系，并使用改进的牛顿方法求解。Navier-Stokes 方程在数值域中求解以解释与流体的相互作用。通过基于改进的拉格朗日-欧拉耦合算法的附加强制项，在这些方程中考虑了多孔结构的存在。在这里，结构上的力分布在流体域中嵌入的多个拉格朗日点上。应用在合适的核函数上的积分以将这些力分布在周围的流体上。导出的数值模型适用于模拟任意几何形状的多孔拉伸结构、非线性材料以及在大运动下与包括复杂自由表面在内的流体的相互作用。这与忽略重要非线性、与流体的物理相互作用或依赖显式时间积分的现有模型形成对比。验证过程表明数值模拟与现有实验数据之间具有极好的一致性，并证明了新方法对广泛应用的适用性。导出的数值模型适用于模拟任意几何形状的多孔拉伸结构、非线性材料以及在大运动下与包括复杂自由表面在内的流体的相互作用。这与忽略重要非线性、与流体的物理相互作用或依赖显式时间积分的现有模型形成对比。验证过程表明数值模拟与现有实验数据之间具有极好的一致性，并证明了新方法对广泛应用的适用性。导出的数值模型适用于模拟任意几何形状的多孔拉伸结构、非线性材料以及在大运动下与包括复杂自由表面在内的流体的相互作用。这与忽略重要非线性、与流体的物理相互作用或依赖显式时间积分的现有模型形成对比。验证过程表明数值模拟与现有实验数据之间具有极好的一致性，并证明了新方法对广泛应用的适用性。