超大型船舶带纵倾漂浮出坞分析

Analysis of Ultra-large Ships of Undocking with Large Trim Value

针对某30万吨级超大型船舶的大纵倾漂浮出坞进行结构安全评估,制定一种适于工程应用的带纵倾漂浮出坞结构安全评估流程。基于简化梁理论建立综合考虑船体梁刚度、坞墩弹簧刚度及重力浮力载荷交互作用的连续梁数值计算模型,分析大纵倾漂浮出坞过程坞墩支反力变化规律,确定漂浮配载各阶段对应的坞墩支反力分布。建立艏尖舱和艉部机舱区域局部双层底有限元模型,将最危险坞墩支反力反加至模型上进行结构强度校核,并提出相应的加墩措施。计算结果表明,通过坞墩支反力反算船体局部结构安全,坞墩支反力的计算精度在工程上可以接受,且进出坞的漂浮浮态应尽量接近正浮或者在纵倾安全限制值以内,确保漂浮出坞的安全性。

The structural safety assessment of the large trim floating undocking of a 300000 t ultra-large ship was carried out,and a assessment process for floating undocking with trim suitable for engineering applications was formulated.Based on the simplified beam theory,a numerical calculation model of a continuous beam considering the interaction between hull beam stiffness,dock spring stiffness and gravitational buoyancy load was established to analyze the variation law of dock pier support reaction in the process of large trim floating undocking,and determine the corresponding dock pier support reaction force distribution in each stage of floating loading.The local double-bottom finite element model of the bow tip cabin and stern nacelle area was established.The most dangerous dock pier support reaction force was added to the model for strength assessment,and the corresponding pier reinforcement measures were proposed.The calculation results showed that the local structural safety of the hull can be calculated by the dock pier support reaction;the calculation accuracy of the dock pier support reaction force is acceptable in engineering;the floating state of the docking and the undocking should be as close as possible to the normal float or within the trim safety limit value to ensure the safety.