基于动力效应的船体远场冰载荷测量与识别

Measurement and identification of ice loads on hull structures in far field based on dynamic effects

  • 摘要:
    目的 提出一种基于动力效应的冰载荷反演识别方法。
    方法 针对船−冰相互作用过程和结构响应特性之间的卷积关系,使用格林函数建立描述冰载荷的卷积积分方程。针对“天恩”号极地运输船的北极航行,安装应变传感器测量船艏区域的冰激响应。对于求解矩阵的病态性与测量中的随机噪声,引入正则化方法解决识别计算中的不适定问题,并获取动冰载荷时程的数值近似稳定解。依托“天恩”号极地运输船的北极航行实测数据,通过船体在海冰作用下的应变响应对冰载荷进行反演识别。
    结果 结果表明,格林函数能够有效识别远场冰载荷的时间历程。
    结论 载荷识别的有效性受应变信号强度的影响较为明显。此外,在不同海冰破坏模式下,浮冰尺寸和船−冰接触面积是影响冰载荷特征的关键因素。

     

    Abstract:
    Objectives This study presents an identification method for ice loads which takes the dynamic effect into consideration.
    Methods  Due to the convolution relation between ice-ship interaction and structural response, the ice load described by the convolution integral equation can be established with Green's functions. Considering the ill conditions of the solution matrix and the influence of random noise, a regularization method is introduced to solve the ill-posed problem in the identification calculation, and the numerical-approximate stable solution of the time history of the dynamic ice load is obtained. For the arctic voyage of the polar class carrier vessel Tian'en, the ice-induced response was measured by installing strain sensors on the bow. Based on the full-scale measurement of Tian'en, the ice load is identified from the ice-induced strain during navigation in icy waters.
    Results The results show that the Green's function method can effectively identify the time history of far-field ice loads.
    Conclusions  The effectiveness of load identification strongly depends on strain signal intensity. In addition, the size of ice and ice-structure contact area are key factors which dominate the ice load characteristics in different ice failure modes.

     

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