基于渐进损伤的纤维全缠绕铝内胆气瓶自紧工艺

采用渐进损伤的分析方法对纤维全缠绕铝内胆气瓶的力学行为进行分析。基于三维Hashin失效准则,自定义刚度折减方案,编译VUMAT子程序,实现了复合材料层合板损伤的产生和演化过程的模拟。依据经典网格理论并结合实际情况,建立气瓶有限元模型。分析了复合材料层渐进损伤发展和累积的过程,验证了自紧工艺对提高气瓶承载力的必要性,提出了合理的自紧力范围。研究结果表明,损伤发生的顺序或可能性:基体拉伸拉伸分层纤维拉伸/基体压缩,且损伤大都从螺旋缠绕层开始。除基体拉伸损伤由封头向筒体发展,由复合材料外层向内层发展,其余损伤大都从筒体中部向两端发展,由内层向外层发展。当自紧力为最大工作压力的1.5~1.65倍时,气瓶的应力分配得到改善,承载能力得到提高。从减少复合材料的损伤和最大程度降低内衬应力的角度,最优自紧力应为最大工作压力的1.5倍。

Autofrettage Process Technology of Fiber Overwrapped Aluminum Liner Cylinder by Progressive Damage Analysis

The progressive damage analysis was used to explore the mechanical behavior of the fiber overwrapped aluminum liner cylinder. The plan of stiffness degradation was designed by the Hashin failure criteria, and the VUMAT subroutine was programmed. The generation and evolution of the damage for the composite laminates are simulated. According to the classical grid theory and the actual situation, the finite element model of the cylinder is established. The development and accumulation of progressive damage for composite layer is analyzed. The necessity of autofrettage technology to improve the bearing capacity of cylinder is verified, and the range of reasonable force of autofrettage is put forward. Results show that the order or possibility of damage is matrix tension damage > tensile delamination damage > fiber tension damage/matrix compression damage. Most of the damage starts from the spiral winding layer. In addition to the matrix tension damage from the head to the cylinder and the outside composite layer to the inside, most damages develop from the inner layer to the outer layer. The stress distribution and the carrying capacity of the cylinder structure are improved, when the force of autofrettage is 1.5~1.65 times of the maximum working pressure. The optimum force of autofrettage should be 1.5 times of the maximum working pressure from the standpoint of reducing the damage of composite material and minimizing the stress of lining.