充气式索膜结构的找形分析  

Form finding of inflatable cable-membrane structure

作　　者：陈政 赵海涛[1] 陈吉安[1] CHEN Zheng;ZHAO Haitao;CHEN Ji’an(School of Aeronautics and Astronautics,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学航空航天学院,上海200240

出　　处：《哈尔滨工业大学学报》2020年第12期84-90,共7页Journal of Harbin Institute of Technology

摘　　要：充气膜结构本身需要通过压差作用才能形成完整的结构,从而具备一定的刚度来支撑自重和外载荷.为加强结构的承载能力,通常会增设强度更大的索结构进行调整.对于充气式索膜结构,找形分析在形状设计和优化中具有十分重要的作用,而压差对结构的形态分布有显著的影响,是找形分析中的重要因素.针对充气式索膜结构受压差作用的特点,基于非线性有限元找形方法,提出压差预置法的概念,并且与节点平衡法相结合来实现优化.在此基础上,针对飞艇索膜结构的具体设计要求,提出了多目标优化的找形分析方案,先结合使用压差预置法和节点平衡法,寻找出满足索和膜结构的应力比值的几何外形;然后,通过等比例缩放的方法调整大小,最终得出满足设计体积大小的几何形状.结果表明,采用该方法找形后的索的应力为找形前的2倍,更加充分的发挥了增强索的承载作用,同时,膜的最大应力有所降低,应力分布更加均匀,整体结构的承载能力得到了加强,对于解决实际工程问题具有重要的参考意义.An inflatable membrane structure derives its structural integrity from pressure difference,so as to support its self-weight and other external loads.To increase the bearing capacity of membranes,cables with more strength are added to adjust the shape and stress distribution.Form finding is critical for inflatable cable-membrane structures,and pressure difference is the key factor that influences the shape and stiffness of the inflatable structure.Based on the nonlinear finite element theory,the concept of pressure difference presetting was proposed and combined with the nodal equilibrium method for optimization.According to the design goals of airships,the form finding scheme was put forward to achieve multi-objective optimization.First,the geometric shape that satisfies the specific stress ratio between the cable and the membrane was obtained by combining the pressure difference presetting method and the nodal equilibrium method.Then,the final shape with expected volume was achieved by scaling up and down.Results show that the stress of the cable after form finding was twice as large as that before form finding,where the cable fully exerted its load-bearing effect.In addition,the stress distribution of the membrane was more uniform,and the bearing capacity of the overall structure was strengthened.The study can provide reference for solving practical engineering problems.

关 键 词：充气式索膜结构 找形分析 压差预置法 非线性有限元 节点平衡法 

分 类 号：V273[航空宇航科学与技术—飞行器设计]