Research on simulation of fluid-structure interaction problem by dynamic explicit method

本文研究了基于虚功率法原理的动态显式数值模拟方法。首先，研究了快速位移框架结构的大变形问题。显式方法的优点是不需要在每个时间步长迭代，并且由于节点之间的物理变量的独立性而不需要大的存储空间。另一方面，计算的时间步长必须非常小。本研究提出了一种新的时间增量控制方法。这种控制的有效性已经得到了证明。将该方法应用于板结构的壳有限元大变形问题，取得了良好的效果。对并行计算进行了研究，建立了并行计算集群系统，并对大自由度结构进行了分析。建立了在计算中估算CPU时间和内存空间的方法。将导通梯度法应用于区域划分法，由于收敛速度快，对大型结构问题是有效的。最后，用导管梯度法对柔性浮体的水弹性问题进行了求解。

Numerical simulation using dynamic explicit method applied based on principle of virtual work rate has been investigated in the present research. Firstly large deformation problem of framed structure with rapid displacement has been performed. The explicit mathod takes advantage that no iteration at each time step is needed and that large memory space is not necessary because of independence of physical variables between nodes. On the other hand, time step for calculation has to be very small. In the present research, a new control methods of time increment has been proposed. And the effectiveness of the control has been shown. This methods is also applied to large deformation problem of plate structure by use of shell finite elements and proved to be effective.Pararell computing is studied and cluster system for pararell computing has been established and structural analysis with large DOF problem is demonstrated. The mehods which estimate CPU time and memory space in calculation have been built. Condugate gradient algorithm applied to divided region method is effective to large structural problem because of the rapid convergence. Finally formulation for hydroelastic problem of flexible floating structure is performed by using of the condugate gradient method.