考虑细长杆件不同坠落角度的海洋平台甲板损伤预报方法

Ocean platform deck damage prediction method considering different falling angles of elongated members

  • 摘要:
      目的   在海洋平台吊装作业中,因吊机设备老化以及违规操作等而造成的坠物事故在海洋平台作业中时有发生,其中在杆件结构,如套管、钻铤等设备方面的问题最为常见,因杆件坠落时接触面积小,常会导致板架结构的损伤破坏。
      方法  选取细长杆件坠物撞击甲板结构的场景开展结构损伤研究。在此基础上,考虑坠落角度对结构损伤的影响,确定结构损伤变形模型,并运用塑性力学理论,建立考虑杆件坠落角度影响的结构损伤解析预报方法。
      结果  结果显示,小角度坠落场景下的结构损伤变形大,结构吸能高,根据结构响应可将坠落角度分为4个角度区间;解析计算结果与仿真计算得到的吸能曲线在数值以及变化趋势上相近。
      结论  在杆状结构以一定角度撞击甲板结构时,甲板产生的塑性变形区域形状会随着撞深而产生变化,针对各阶段甲板变形特点的解析计算对海洋平台甲板板架结构抗撞设计评估具有一定的指导意义。

     

    Abstract:
      Objectives  Due to the aging and illegal operation of crane equipment during hoisting operations on offshore platforms, dropped object accidents are the most prevalent type of accident, of which the dropping of slender rod-like objects such as drill collars and casings is the most common. Due to the small contact area and high velocity, the failure of the partial-plate structure is often caused, which requires attention.
      Methods  This paper studies the specific deformation mechanism of a deck under the impact of dropped slender rods at different impact angles while considering the influence of the impact angle on damage to the deck. A new deformation model is proposed for decks subject to impact loads at different impact angles. Based on this new deformation model, a prediction method which considers the influence of the impact angle is obtained on the basis of the plastic mechanics theory.
      Results  The results show that a small impact angle will cause great structural damage and deformation, as well as high structural energy absorption. According to the structural response, the impact angle can be divided into four angle intervals. The energy absorption curves obtained from the analytical method and simulation are similar in value and change trend.
      Conclusions   When a rod-like structure hits a deck at a certain angle, the shape of the plastic deformation area of the deck changes with the depth of the collision. The analytical results of the deformation characteristics of the deck at each stage can provide valuable references for the preliminary structural design and assessment of the crashworthiness of the deck structures of offshore platforms.

     

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