深海复合材料悬链线立管基于可靠度的优化设计

Reliability-Based Design Optimization of Deep-Water Composite Catenary Risers

研究基于可靠度的方法,对深海复合材料悬链线立管进行优化设计分析。对于正交各向异性层合复合材料结构而言,叠层顺序不同、各层铺角变化以及层间厚度差异等都会影响到结构的承载能力,因此,有必要引进可靠度作为优化设计指标。首先,根据经典层合板理论计算整体模型的等效属性,建立悬链线立管整体分析模型,得到关键截面响应,以此作为局部分析模型的约束;然后,运用试验设计方法构建Kriging近似模型;最后,利用蒙特卡罗撒点方法对比分析确定性优化与可靠性优化的结果。研究表明:优化后的深海复合材料立管在满足应力强度设计的要求下可有效降低结构重量,所提出的基于可靠度的优化设计复合材料悬链线立管具有可行性。

A reliability-based design optimization method is proposed in this paper for the deep-watercomposite catenary risers. Since the load carrying capacity of anisotropic laminated structures is very sus-ceptible to changes in the sequence, orientation, and thickness of plies, it is necessary to introduce a reli-ability index as a boundary condition during the optimization process. Compared to traditional steel risers,the composites have a broader application prospects due to several advantages, such as high specificstrength and stiffness as well as high fatigue and corrosion resistance. The classic lamination theory is usedto compute the equivalent mechanical properties of composite risers, and the global model is then estab-lished to obtain the response of the key section that serves to be the boundary for the local model. In addi-tion, the Design of Experiment（DOE）method is used to construct an approximate model, and the MonteCarlo method is utilized to analyze the result of the Deterministic Optimization（DO）and the Reliabili-ty-Based Design Optimization（RBDO）. This study shows that the optimized results not only satisfy thestrength requirements but also possess a lower weight and a better reliability,which are feasible for com-posite catenary risers.