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

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.