复合材料气瓶应力分析及性能优化

发布时间：2018-05-08 14:06

本文选题：复合材料气瓶 + 自紧优化　；参考：《大连理工大学》2015年硕士论文

【摘要】：复合材料气瓶作为一种气体储罐,以其比强度和比刚度高、抗疲劳性能好、质量轻等诸多优点,在航空航天、交通运输、化工、医疗等领域得到广泛应用。然而,复合材料气瓶的安全性问题也逐渐凸显,已受到相关学者和政府的普遍关注。复合材料气瓶在正常工作时要不断地进行气体充放,故对其强度和疲劳性能要求较高；且复合材料气瓶是由两种力学性能差异较大的材料分别构成内衬层和复合材料层,应力分布沿着壁厚方向较不均匀。因此,有必要对复合材料气瓶进行性能优化,减少甚至杜绝危险事故发生。本文对复合材料气瓶进行应力分析和性能优化,主要的研究工作和结论如下：(1)借助ANSYS软件建立复合材料气瓶的有限元模型,分析复合材料气瓶在自紧压力、零压、水压试验压力、工作压力以及爆破压力下的应力分布,并根据复合材料气瓶强度失效准则对其强度进行校核。结果发现：复合材料气瓶内衬层内壁应力水平高于外壁,复合材料层应力远小于其材料抗拉强度；内衬层和复合材料层的强度均满足要求。(2)通过介绍复合材料气瓶的自紧原理,对比自紧处理前后复合材料气瓶在各工况下的应力分布情况,讨论了自紧处理的必要性,进而对复合材料气瓶进行自紧压力优化。结果表明：通过自紧处理,能有效降低复合材料气瓶内衬的应力水平,改善其应力分布,提高复合材料层的纤维利用率；通过自紧优化得到复合材料气瓶的最佳自紧压力为37.9MPa,并经过37.9MPa压力处理后,工作压力下复合材料气瓶的承载能力提高了11.93%,复合材料层纤维的利用率提高了1.5倍左右。(3)将纤维混杂法应用于复合材料气瓶材料和结构性能的优化,在提出“当量厚度比”的基础上,分析混杂比和纤维铺层方式对复合材料气瓶应力分布的影响。结果表明：混杂比为2：5时,复合材料气瓶的综合性能达到最优：层间混杂比夹芯混杂更有利于提高复合材料气瓶的承载能力。经过优化,工作压力下复合材料气瓶的承载能力提高了3.3%；气瓶复合材料层的体积减少了30.3%,质量降低了36.3%,在提高复合材料气瓶承载能力的同时实现了复合材料层厚度的优化。(4)研究自紧处理和纤维混杂对复合材料气瓶疲劳性能的影响,分析应力幅、平均应力、许用循环次数和累积损伤随自紧压力和纤维混杂比的变化情况。结果发现：自紧处理能有效降低复合材料气瓶内衬的平均应力,进而提高其疲劳性能；通过在复合材料层混入一定量的高强度碳纤维,复合材料气瓶内衬的应力幅和平均应力逐渐降低,许用循环次数增加,累积损伤降低,有效提高了气瓶的疲劳性能和使用寿命。
[Abstract]:As a kind of gas storage tank, composite gas cylinder has been widely used in aerospace, transportation, chemical industry, medical treatment and other fields because of its advantages such as high specific strength and stiffness, good fatigue resistance, light weight and so on. However, the safety problem of composite gas cylinders has been widely concerned by scholars and governments. Composite gas cylinders need to be continuously filled with gas in normal operation, so the strength and fatigue properties of composite cylinders are high, and composite gas cylinders are made up of two kinds of materials with different mechanical properties, which are inner lining layer and composite material layer, respectively. The stress distribution is uneven along the direction of wall thickness. Therefore, it is necessary to optimize the performance of composite gas cylinders to reduce or even eliminate dangerous accidents. In this paper, stress analysis and performance optimization of composite gas cylinders are carried out. The main research work and conclusions are as follows: (1) the finite element model of composite gas cylinders is established by using ANSYS software, and the self-tightening pressure and zero pressure of composite gas cylinders are analyzed. The stress distribution of hydraulic test pressure, working pressure and blasting pressure, and the strength of composite cylinder were checked according to the failure criterion of composite gas cylinder strength. The results show that the stress level of the inner wall of the composite cylinder liner is higher than that of the outer wall, and the stress of the composite layer is much less than the tensile strength of the material, and the strength of the inner liner and composite layer both meet the requirements. By comparing the stress distribution of composite gas cylinders before and after self-tightening treatment, the necessity of self-tightening treatment was discussed, and then the self-tightening pressure of composite gas cylinders was optimized. The results show that the stress level of the composite cylinder liner can be effectively reduced, the stress distribution can be improved and the fiber utilization ratio of the composite layer can be increased by self-tightening treatment. The optimum self-tightening pressure of composite gas cylinder is 37.9MPa by self-tightening optimization. After 37.9MPa pressure treatment, Under working pressure, the bearing capacity of composite gas cylinders was increased by 11.93, and the utilization ratio of composite fiber layer increased by about 1.5 times.) the fiber hybrid method was applied to optimize the material and structure properties of composite gas cylinders. On the basis of "equivalent thickness ratio", the influence of hybrid ratio and fiber lamination on the stress distribution of composite cylinder is analyzed. The results show that when the hybrid ratio is 2:5, the comprehensive properties of composite gas cylinders reach the optimum, and interlaminar hybrid is more favorable than sandwich mixing to improve the bearing capacity of composite gas cylinders. After optimization, Under working pressure, the bearing capacity of composite cylinder increased by 3.3%, the volume of composite layer decreased by 30.3 and the mass decreased by 36.3. The thickness of composite layer was optimized by increasing the load-carrying capacity of composite cylinder at the same time. The effects of self-tightening treatment and fiber mixing on the fatigue properties of composite gas cylinders were studied. The variation of stress amplitude, average stress, allowable cycles and cumulative damage with self-tightening pressure and fiber hybrid ratio is analyzed. The results show that the self-tightening treatment can effectively reduce the average stress of the liner of the composite gas cylinder and then improve its fatigue performance, by mixing a certain amount of high strength carbon fiber into the composite layer, The stress amplitude and average stress of the composite cylinder liner decrease gradually, the allowable cycle times increase and the cumulative damage decreases, which effectively improves the fatigue performance and service life of the cylinder.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TQ053.2

【参考文献】