基于一个二维修正水弹性方法的集装箱船体梁动态前极限强度评估研究

海上极端波因其巨大的波高常常导致船体的极限破坏。该文提出了一个二维的修正水弹性方法来研究一个集装箱船船体梁在极端波中的动态前极限强度。传统的极限强度评估基于准静态方法，没有动态效应被考虑。而船体在波浪下的动态结构响应是基于水弹性方法，传统的水弹性方法并不能计算船体梁的动态非线性强度。该二维修正的水弹性方法考虑时域波浪和非线性船体梁之间的耦合，将水弹性方法和Smith方法结合，用Smith方法计算船体梁的刚度，而其刚度与船体梁的强度和变形曲率有关。所以该时域的非线性刚度被用于修改水弹性方法里的常数项的结构梁刚度。几组极端波模型被用以产生船体梁的大变形和非线性动态垂向弯矩。文中分别采用修正水弹性方法和普通水弹性方法，通过改变四个重要的极端波参数如极端波最大波高、规则波的波高、波速和波长等来研究其对船体梁船中处的大变形转角和非线性垂向弯矩的影响，通过采用修正的水弹性方法计算得来的结果与水弹性方法计算得来的结果相比较，得到了一些差异和结论。

Dynamic Pre-ultimate Strength Evaluation of Containership based on a 2D Modified Hydroelasticity Method in Extreme Waves

Extreme waves have led to many accidents and losses of ships at sea. In this paper, a 2D modified hydroelasticity method is proposed as a means of studying the dynamic pre-ultimate strength of a containership instead of post-ultimate strength when traversing extreme waves, while con-sidering the ultimate strength of the ship. Traditional ultimate strength evaluations are undertaken by a quasi-static assumption and the dynamic wave effect is not considered. And, the dynamic response of a ship as induced by a wave is studied on the basis of the hydroelasticity theory so that the non-linear structural response of the ship cannot be obtained for large waves. So, a 2D modified hydroe-lasticity method, which takes the coupling between time-domain waves and the nonlinear ship beam into account, is proposed. This method is based on a hydroelasticity method and a Smith method that combine the wave load and the structural nonlinearity. A dynamic reduction in rigidity related to de-formation could influence the strength and curvature of a ship’s beam; So, it is input into a dynamic hydrodynamic formula rather than being regarded as a constant structural rigidity in a hydroelastic e-quation. A number of numerical extreme wave models are selected for computing the modified hydroe-lasticity, such that large deformations occur and nonlinear dynamic VBM is generated when the ship traverses these extreme waves. Four important extreme wave patterns such as maximum wave height, regular wave height, wave speed, and wave length ratio are changed to study their influence on modi-fied hydroelastic results including nonlinear dynamic VBM and deformational angle at midship, and the modified hydroelastic results are computed and compared with results obtained with the hydroe-lasticity method, some differences are observed and conclusions are drawn.