冰−弹性平板相互作用的试验研究

Experimental study of ice-elastic plate interaction

  • 摘要:
    目的 为探究结构弹性对冰−结构相互作用过程的影响,在低温实验室开展冻结冰−弹性平板挤压模型试验。
    方法 改变结构刚度和挤压速率,推动弹性平板与冻结冰试件在冰脆性破坏范围内进行挤压,记录不同工况下总载荷时程曲线和冰破坏模式。
    结果 试验发现相互作用过程可分为“松接触”和“紧接触”2个典型阶段,部分压力−位移曲线在紧接触阶段呈现出锯齿状形式的“多级失效”。统计发现最大松接触位集中在0~1.5 mm内,紧接触阶段多级失效发生占比为43.3%且多发生在结构刚度较小的工况。冰破碎图像显示多级失效是接触面不断剥落小块造成压力下降形成的。冰−弹性平板耦合系统在紧接触阶段的系统刚度几乎保持不变,说明耦合系统在冰脆性破坏下呈现线性关系,满足双弹簧模型。
    结论 本研究揭示了冰与弹性结构相互作用过程的典型特点,可为冰区船舶冰载荷的准确预报提供理论基础。

     

    Abstract:
    Objective To explore the effect of structural elasticity on the ice-structure interaction process, model tests on the interaction between frozen ice and elastic plates were conducted in a low-temperature laboratory. This study aims to provide a theoretical basis for understanding the ice-structure interaction mechanism and predicting ice loads on ships operating in ice-covered areas.
    Method In the experiments, the stiffness of the elastic plates was adjusted by varying their thickness. Two loading rates within the strain-rate range associated with brittle ice failure were selected. A universal testing machine was used to record load-time history data, and a CCD camera was employed to capture the ice failure modes under different test conditions.
    Results The interaction process consists of two typical phases: the loose contact phase and the tight contact phase. Loose contact results from the uneven contact between the plate and the top of the ice specimen, with maximum displacements generally ranging from 0 to 1.5 mm. In the tight contact phase, about 43.3% of the load-displacement curves show a saw-tooth shape, representing multi-stage failure modes. Stiffer plates are more likely to cause single-stage ice failure, while more flexible plates tend to result in multi-stage failures. Multi-stage failures are associated with ice flaking at a 45° angle due to shear failure. During multi-stage failure, the slope of the load-displacement curve remains nearly constant, suggesting constant stiffness of the ice-elastic plate coupling system in the tight contact phase.
    Conclusion Although the structure in this study is simplified as a plate, the experimental results provide valuable insights for designers of ice-going ships into the complex interaction mechanics between ice and ship structures. This research also provides a foundation for further studies on more complex structures and accurate ice load predictions.

     

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