船底板被圆锥形礁石撕裂变形的机理研究

Analytical model of bottom plate torn by a cone-shape rock during ship grounding accident

研究搁浅场景中船底板撕裂变形机理,提出新的针对圆锥形剖面礁石搁浅场景下板材撕裂机理解析计算模型。该模型由摩擦、膜拉伸、弯曲及断裂等分析板材撕裂机理,并据塑性力学理论求出稳定状态下板材撕裂受力解析解;通过与Muscat-Fenech实验结果对比分析,验证该机理模型的准确性;利用LS_DYNA软件进行一系列典型船舶双层底结构搁浅于锥形礁石场景的仿真计算,所得搁浅力与利用等效板厚法计算的解析结果吻合良好。该研究对船底耐撞性结构设计、性能评估具有一定指导意义。

A theoretical method for plate tearing by a rigid cone was developed. The studied model is an idealization of ship grounding damage. The observed mode of deformation was idealized as a simplified kinematical admissible deformation mode, and the rate of internal energy dissipation in friction, stretching, bending and fracture was quantified accordingly by analytical expressions. Based on the upper-bound theorem, the plate tearing resisting force in the moving direction of the cone was calculated by the proposed analytical formula. The analytical results were compared with a series of Muscat-Fenech experimental results, and they agree reasonably well. The non-linear finite element program LS DYNA was used to simulate several grounding scenarios of a typical ship double bottom structure running aground on a cone-shape rock. By adopting equivalent plate thickness, the analytical method proposed was verified by the simulation results. The analytical calculation formula obtained can be used to calculate and assess the crashworthiness of a ship during its design phase.