塑性工作内衬复合材料气瓶结构设计研究

Structure Design Study of Composite Overwrapped Pressure Vessel with Plastically Working Liner

为提高航天复合材料压力容器(COPV)性能因子,COPV壳体常采用超薄壁塑性工作金属内衬和高强碳纤维缠绕的双层壳体结构。通过对传统的网格理论进行优化,提出了塑性工作内衬COPV结构静力学计算的算法,联立求解各内压载荷阶段的静力学平衡方程和应变协调方程,对COPV纤维与内衬应力应变进行计算和分析。利用ANSYS有限元软件,根据复合材料层合板理论和内衬弹塑性理论完成了COPV的有限元建模和分析计算,有限元应力分析结果和本算法解析解法计算结果一致。根据本算法对卫星推进系统用COPV进行了结构设计和工程研制,COPV工作压力和爆破压力分别为30MPa和60MPa,COPV鉴定试验结果满足技术要求。结果表明:本算法能够得到塑性工作内衬COPV准确的应力应变解析解,可用于塑性工作内衬COPV的结构设计。

The shell structure with ultra-thin metal liner and carbon fiber reinforced plastic(CFRP)has been widely applied to composite overwrapped pressure vessel(COPV)in order to increase the performance factor of COPV used in space system. A novel design theory was proposed for calculating stress distribution in COPV,which allows the liner to be designed to cycle plastically during operation,based on traditional grid theory optimization. The stress distribution of liner and CFRP was calculated by solving static equilibrium equations and strain continuity equations systematically. The finite element analysis(FEA)of composite layers and the titanium liner were carried out in terms of laminated plate theory of CFRP and elastic-plastic theory of liner respectively by ANSYS software. The results show that the FEA is good agreement with the calculation of the grid theory.The COPV was fabricated for the propulsion system of satellite and was tested for qualification program,and its working pressure and burst pressure are 30 MPa and 60 MPa,respectively. The test results meet the design requirement. The results show that the precise calculation of stress and strain distribution can be obtained by the present theory,and it can be used to the structure design of COPV with plastically working liner.