基于局部密集应变响应的海洋平台冰载荷反演方法

IDENTIFYING ICE LOAD ON OFFSHORE PLATFORM BASED ON LOCALLY CONCENTRATED STRAIN RESPONSE

冰载荷的现场测量工作对于描述冰载荷与海洋平台的相互作用规律十分重要。回顾了自六十年代以来的各地冰载荷的测量情况,针对在采用压力盒进行直接测量和利用结构整体响应进行间接反算的过程中存在的困难,提出了一种利用局部应变响应信息来有效反演海洋平台冰载荷的新方法,并设计了用于反演的附加套筒结构模型。阐述了反演的基本原理,从理论上分析了反演的误差来源以及误差的稳定性,并讨论了反演时载荷作用区域的判断方法和测点的布置原则。最后,通过计算机仿真的反演算例和一缩尺模型的反演实验(包括模型应变响应的动态标定)验证了这种方法的可靠性。

Ice load measurement is important in characterizing the interaction between ice and offshore platform. This paper reviews ice load measurement around the world since 1960s. Some common difficulties are discussed regarding direct measurement using pressure cells and indirect estimation using structural response. A new method of measuring ice load using locally concentrated strain response of offshore structures is proposed to overcome the difficulties. A sleeve-like structure attached to the offshore platform is designed for the purpose. The basic principle of the method is discussed, and the sources of solution error and solution stability are analyzed theoretically. Some principles are also discussed on how to estimate the loading area and how to select the measurement points for the proposed method. Finally a numerical simulation and the experimental validation using a scaled sleeve-like model, including dynamic strain response calibration under concentrated load, are performed respectively to prove the effectiveness of the method.