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

本文采用基于虚功率原理的动态显式方法进行数值模拟。首先研究了具有快速位移的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进行迭代，并且由于节点之间物理变量的独立性，不需要大量的存储空间。另一方面，计算的时间步长必须非常小。本文提出了一种新的时间增量控制方法。并证明了控制的有效性。研究了并行计算，建立了并行计算集群系统，并对大自由度结构分析进行了实例验证。建立了计算中CPU时间和内存空间的估算方法。将导流梯度算法应用于分区法中，由于收敛速度快，对大型结构问题是有效的。最后，利用梯度法建立了柔性浮体水弹性问题的数学模型。

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.