Research on dynamic instability of plates in high speed ship structure

TSL(Techno Super Liner)高速船是日本近年来为实现运输方式转变而发展起来的。这些高速船的壳体表面与湍急的水流接触。这些板很薄，重量很轻，因此可能会出现像颤振现象这样的动态不稳定现象。这种动力失稳会导致船体结构的剧烈倒塌或疲劳裂纹。对于这类高速船，需要研究其动力失稳的可能性，本研究的目的是研究由于水流的快速流动而导致船体外板发生动力失稳的可能性。采用板的有限元方法和周围流体的边界元方法对流固耦合问题进行了数值分析。本文开发的数值程序ISAP-TSL用于研究质量比、各种边界条件对船体临界相对航速的影响以及固有频率的降低。此外，还从数值结果中讨论了板的动力特性与连续板的动力特性的区别。

High speed ships TSL (Techno Super Liner) have beecn developed recently for realization of modal-shift of transportation in Japan. The shell surfaces of these high speed ships are in contact with a rapid flow of water. These panels are so thin for light weight that dynamic instability like flutter phenomena can occur. Such dynamic instablity can cause a drastic collapse or fatigue cracks in the ship structure. The possibility of dynamic instability should be studied for this kind of high speed ship.The purpose of the present study is to investigate the possibility of dynamic instability of the outer panels of ships due to rapid flow of water. Finite element approach for plates and boundary element approach for surrounding fluid are used for the numerical analysis of this fluid-structure interaction problems. The numerical code, ISAP-TSL,developed in the study is used for investigation of the effect of mass ratio, various boundary conditions on critical speed of relative speed of the ship and the reduction of natural frequencies. Moreover the difference between the dynamic characteristics of the plate and those of a continuous plate is discussed from the numerical results.