CNG复合材料缠绕气瓶的安全分析
发布时间：2018-11-08 13:26
【摘要】：面对日益恶化的环境和石油资源的枯竭，使得作为清洁能源应用典型的CNG气瓶的使用逐年增加，CNG汽车在国内逐渐推广使用。CNG-2气瓶由金属内衬和外层缠绕的高强度纤维增强复合材料组成，，由于其质量轻、强度高和安全可靠等优点得到了广泛的应用。使用过程中，CNG气瓶也出现了一些故障和爆炸事故，从而导致气瓶的安全分析和研究越来越受到关注。论文以CNG-2气瓶为研究对象，探讨了气瓶的应力分析、疲劳分析、缺陷分析三个方面的内容。 论文借助ANSYS有限元分析软件，对钢内胆玻璃纤维缠绕的CNG-2气瓶进行了分析，利用有限元前处理程序建立了可以用于复合材料气瓶计算的力学模型。通过建模分析，得到了气瓶在自紧压力、水压、零压、工作压力及爆破压力下的应力分布，验证了自紧的必要性；对计算过程是否需要考虑几何非线性的影响作了讨论，结果显示几何非线性会对应力分布产生一定的影响。 论文研究了CNG-2气瓶的自紧原理及其实现方案，探讨了自紧压力对气瓶最大应力分布、整体应力分布及气瓶疲劳寿命的影响，并对自紧压力进行了优化。计算表明，随着自紧压力的增大，卸载后（即零压力下）内胆的环向压应力线性增大；工作压力下内胆的Von Mises应力减小而纤维层的应力线性增大，从而证明，合理的自紧工艺可以显著改善工作压力下内胆和纤维的应力分配，而平均应力则随着自紧压力的增大而降低。综合考虑，得出了最佳自紧压力为36MPa的结论。 论文介绍了钢内胆和复合材料的疲劳机理及提高抗疲劳性能的途径，在此基础上，分别对复合材料和内胆进行了疲劳分析，结果表明自紧后内胆的疲劳寿命由20240次增至100000次，提高了内胆的疲劳寿命。 论文参照GB/T19624-2004《在用含缺陷压力容器安全评定》标准对CNG-2气瓶存在的凹坑缺陷进行了安全分析和评定，分析表明，这类缺陷对气瓶的内胆和纤维层的最大应力及应力幅有较大影响，在缺陷长度和宽度保持不变的情况下，随着凹坑深度的增大，内胆的应力幅随之增加，而纤维层的最大Von Mises应力亦增大，因此，缺陷会缩短气瓶使用寿命，带来安全隐患。
[Abstract]:In the face of the worsening environment and the depletion of petroleum resources, the use of CNG cylinders, which are typical of clean energy applications, is increasing year by year. The CNG-2 cylinder is composed of high strength fiber reinforced composites with metal lining and outer winding, which is widely used because of its advantages of light weight, high strength, safety and reliability. In the process of application, there are also some failures and explosion accidents in CNG cylinders, which leads to more and more attention to the safety analysis and research of gas cylinders. In this paper, the CNG-2 cylinder is taken as the research object, and the stress analysis, fatigue analysis and defect analysis of the cylinder are discussed. In this paper, the ANSYS finite element analysis software is used to analyze the glass fiber wound CNG-2 cylinders in steel, and a mechanical model for the calculation of composite gas cylinders is established by using the finite element preprocessing program. Through modeling and analysis, the stress distribution of the cylinder under self-tightening pressure, water pressure, zero pressure, working pressure and blasting pressure is obtained, and the necessity of self-tightening is verified. Whether the influence of geometric nonlinearity should be considered in the calculation process is discussed. The results show that geometric nonlinearity will have a certain effect on the stress distribution. In this paper, the self-tightening principle of CNG-2 cylinder and its realization scheme are studied, and the effects of self-tightening pressure on the maximum stress distribution, integral stress distribution and fatigue life of the cylinder are discussed, and the self-tightening pressure is optimized. The calculation results show that the circumferential compressive stress increases linearly after unloading (i.e. zero pressure) with the increase of self-tightening pressure. The Von Mises stress of the inner bile decreases and the stress of the fibrous layer increases linearly under the working pressure, which proves that the reasonable self-tightening process can significantly improve the stress distribution between the inner bile and the fiber under the working pressure. The average stress decreases with the increase of self-tightening pressure. It is concluded that the best self-tightening pressure is 36MPa. This paper introduces the fatigue mechanism of steel inner tank and composite material and the ways to improve the fatigue resistance. On the basis of this, the fatigue analysis of the composite material and the inner bravery is carried out respectively. The results show that the fatigue life of the inner tank increases from 20240 times to 100000 times after self-compaction. The fatigue life of the inner gallbladder is improved. In this paper, the safety analysis and evaluation of the concave defects in CNG-2 cylinders are carried out with reference to the GB/T19624-2004 Standard for Safety Assessment of pressure vessels with defects. The analysis shows that, These defects have a great effect on the maximum stress and stress amplitude of the inner tank and fiber layer of the cylinder. When the length and width of the defect remain constant, the stress amplitude of the inner bile increases with the increase of the pit depth. The maximum Von Mises stress of the fiber layer also increases, therefore, the defect will shorten the service life of the cylinder and bring about the hidden danger of safety.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH49;TB33
本文编号：2318634
[Abstract]:In the face of the worsening environment and the depletion of petroleum resources, the use of CNG cylinders, which are typical of clean energy applications, is increasing year by year. The CNG-2 cylinder is composed of high strength fiber reinforced composites with metal lining and outer winding, which is widely used because of its advantages of light weight, high strength, safety and reliability. In the process of application, there are also some failures and explosion accidents in CNG cylinders, which leads to more and more attention to the safety analysis and research of gas cylinders. In this paper, the CNG-2 cylinder is taken as the research object, and the stress analysis, fatigue analysis and defect analysis of the cylinder are discussed. In this paper, the ANSYS finite element analysis software is used to analyze the glass fiber wound CNG-2 cylinders in steel, and a mechanical model for the calculation of composite gas cylinders is established by using the finite element preprocessing program. Through modeling and analysis, the stress distribution of the cylinder under self-tightening pressure, water pressure, zero pressure, working pressure and blasting pressure is obtained, and the necessity of self-tightening is verified. Whether the influence of geometric nonlinearity should be considered in the calculation process is discussed. The results show that geometric nonlinearity will have a certain effect on the stress distribution. In this paper, the self-tightening principle of CNG-2 cylinder and its realization scheme are studied, and the effects of self-tightening pressure on the maximum stress distribution, integral stress distribution and fatigue life of the cylinder are discussed, and the self-tightening pressure is optimized. The calculation results show that the circumferential compressive stress increases linearly after unloading (i.e. zero pressure) with the increase of self-tightening pressure. The Von Mises stress of the inner bile decreases and the stress of the fibrous layer increases linearly under the working pressure, which proves that the reasonable self-tightening process can significantly improve the stress distribution between the inner bile and the fiber under the working pressure. The average stress decreases with the increase of self-tightening pressure. It is concluded that the best self-tightening pressure is 36MPa. This paper introduces the fatigue mechanism of steel inner tank and composite material and the ways to improve the fatigue resistance. On the basis of this, the fatigue analysis of the composite material and the inner bravery is carried out respectively. The results show that the fatigue life of the inner tank increases from 20240 times to 100000 times after self-compaction. The fatigue life of the inner gallbladder is improved. In this paper, the safety analysis and evaluation of the concave defects in CNG-2 cylinders are carried out with reference to the GB/T19624-2004 Standard for Safety Assessment of pressure vessels with defects. The analysis shows that, These defects have a great effect on the maximum stress and stress amplitude of the inner tank and fiber layer of the cylinder. When the length and width of the defect remain constant, the stress amplitude of the inner bile increases with the increase of the pit depth. The maximum Von Mises stress of the fiber layer also increases, therefore, the defect will shorten the service life of the cylinder and bring about the hidden danger of safety.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH49;TB33
【引证文献】
相关期刊论文 前1条
1 郭崇志;甘平燕;付小立;;复合材料缠绕层缺陷深度对CNG-2气瓶强度影响的研究[J];压力容器;2013年03期
相关硕士学位论文 前1条
1 甘平燕;带缺陷的CNG-2气瓶安全评估与分析[D];华南理工大学;2013年
本文编号：2318634
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