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| 船舶应急抛锚沉贯过程动力大变形数值模拟研究 |
| Dynamic LDFE simulation on the depth of emergency penetration of ship anchors |
| 投稿时间：2024-09-14 修订日期：2024-10-31 |
| DOI： |
| 中文关键词: 霍尔锚 抛锚深度 砂土 抛锚速度 |
| 英文关键词:Hall anchor anchor penetration depth sand impact velocity |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 中文摘要: |
| 海床中通常有管线、隧道以及光缆等结构物。如果船舶在该海域中应急抛锚，就应考虑船锚的沉贯是否对海底结构物的安全产生影响。通过大变形有限元模拟探究了船用霍尔锚在砂土中的抛锚沉贯深度和土体被扰动的深度，研究了抛锚速度、锚重以及砂土相对密实度对沉贯深度和被扰动土体深度的影响。在大变形模拟中，采用应变软化的摩尔-库仑本构模型表征中密砂和密砂的应变软化与剪胀特性。数值模拟结果表明：17.8 t和42 t的船锚在砂土中的抛锚沉贯深度均小于2.0 m。根据数值模拟结果，建立了抛锚深度、锚的总能量(动能和重力势能)和砂土土性参数之间的经验公式。在对砂土中的船锚受力分析的基础上，结合牛顿第二定律建立了霍尔锚在砂土中动力贯入时的运动微分方程，实现了对锚的沉贯深度-下落速度曲线的预测。 |
| 英文摘要: |
| There exist pipelines, tunnels and optical cables in the seabed. If a ship needs to drop anchors emergently in such area, the potential effect of the anchor’s penetration on the safety of the subsea structures must be considered. Large deformation finite element simulations are conducted to investigate the penetration depth of ship anchors and the depth of disturbed soil during anchor dropping in sand. The effects of penetration velocity, anchor weight, and relative density of sand on the penetration depth and disturbed soil depth are studied. In the large deformation simulations, a Mohr-Coulomb model with strain softening was adopted to reflect the strain softening and dilatancy characteristics of medium-dense and dense sands. The numerical results indicate that the penetration depths of 17.8-t and 42-t anchors in sand are both less than 2.0 m. Based on the numerical results, empirical formulae are established to relate the anchor penetration depth, the total energy (kinetic and potential energy) of the anchor and the sand parameters. Based on the force analysis of anchors in sand and Newton's second law, the differential equation of motion for the dynamic penetration of a Hall anchor in sand is derived, enabling the prediction of the anchor's penetration depth-velocity curve. |
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