船体纵骨上附连挺筋软踵形状参数优化

Shape Optimization of the Stiffener Soft Heel Attached to Longitudinals

船体纵骨上附连挺筋与纵骨面板连接处往往会因几何突变而出现应力集中现象,造成结构失效或损坏。对此,根据协调共同结构规范(HCSR)中图示推荐表和国内各大船厂的典型节点图册,选取3种工程中常用的软踵形式建立参数化模型,并利用Isight集成有限元建模软件Patran和计算软件Nastran进行形状参数优化计算,得到应力极值最小的软踵形状;同时,根据HCSR对3种最优的软踵形式进行疲劳强度校核,对比不同开孔形状下结构的疲劳寿命。计算结果表明,建议的优化流程能有效减小结构的应力峰值,提高节点疲劳寿命,得到不同船体位置处疲劳强度、屈服强度更优的软踵开孔形式及参数,有较强的工程实用价值,可应用到其他类似结构的节点设计中。

The stiffener attached to hull longitudinals is one of the most typical structural nodes in ships. Stress concentration would occur when a sudden geometrical change happens at the intersection point of the attached stiffener and the plate of longitudinals, which may lead to structure failure or damage. According to the diagrams illustrated in the Harmonized Common Structural Rules (HCSR) and the drawings of typical structural nodes produced by the domestic shipyards, three types of stiffener soft heel are chosen to establish parametric models. Finite element modelling softwarePatran and calculation software Nastran are integrated into Ishight to realize shape optimization and to obtain the soft heelshape with the minimum stress extremum. Meanwhile, the fatigue strength of the three types of optimal soft heel ischecked according to HCSR, and their fatigue lives corresponding to different opening shapes are compared. The resultshows that the proposed optimization procedure can effectively reduce the stress extremum of the structure, increase the fatigue life, and obtain the optimized opening shape and parameters at different hull locations with better fatigue strength and yield strength. It has good application value and could be used for the node design of other similar structures.