CNG-2型气瓶缠绕层应力损伤机理研究

发布时间：2018-07-06 11:52

本文选题：CNG气瓶 + 多尺度建模　；参考：《浙江理工大学》2017年硕士论文

【摘要】：CNG-2型气瓶是由钢制内胆和外部的缠绕层复合材料组成。气瓶在自紧工艺中缠绕层会出现一定程度的树脂开裂,并在充放气的过程中产生环向裂纹,这样使得缠绕层复合材料在外界酸性环境中更容易被腐蚀。使用过程中气瓶内部要保持一定的压力,高压作用下使得缠绕层具有一定的内应力,在应力和腐蚀共同作用下使得缠绕层产生应力腐蚀裂纹。气瓶缠绕层复合材料是一种单向纤维复合材料,传统研究气瓶力学的方法是将气瓶缠绕层力学性质看做是一种连续均匀的材料,通过宏观力学分析的方法进行研究。但在气瓶工作压力下,缠绕层的屈服极限、断裂强度均远远大于其所受到的应力,通过宏观力学并不能对缠绕层树脂开裂及应力腐蚀裂纹的产生机理进行深入研究。针对这一问题,本文首先分别对新出厂气瓶和由于缠绕层应力腐蚀裂纹而报废的气瓶的缠绕层进行取样,然后通过扫描电子显微镜(SEM)观察复合材料纤维和基体的破坏形式。根据扫描电镜拍摄的气瓶缠绕层复合材料破坏形式提出一种气瓶多尺度建模的方法。利用所提出的多尺度模型,首先通过微观力学的方法探讨气瓶缠绕层的含胶量和纤维直径这两大重要设计参数对树脂开裂程度的影响,并对环向裂纹对应力腐蚀裂纹扩展的影响进行了研究;然后在所建立的多尺度模型基础对纤维引入破坏层研究了应力腐蚀裂纹的破坏机理。本文结合复合材料微观力学的研究方法对气瓶缠绕层的应力损伤机理进行了研究,实验表明气瓶多尺度模型在气瓶仿真分析中是切实可行的。同时提出气瓶缠绕层树脂开裂的影响因素以及应力腐蚀裂纹的破坏机理,这对CNG-2型气瓶的缠绕层的设计、缠绕张力等都提供了很好的理论参考。
[Abstract]:CNG-2 gas cylinder is composed of steel inner tank and outer winding layer composite material. In the process of self-tightening, the winding layer of the gas cylinder will have a certain degree of resin cracking, and a ring crack will occur in the process of gas filling and discharging, which makes the composite material of the winding layer more easily corroded in the external acidic environment. It is necessary to maintain a certain pressure in the gas cylinder during the operation. Under the action of high pressure, the winding layer has certain internal stress, and the stress corrosion crack occurs in the winding layer under the combined action of stress and corrosion. The composite material of gas cylinder winding layer is a kind of unidirectional fiber composite material. The traditional method of studying cylinder mechanics is to regard the mechanical properties of gas cylinder winding layer as a kind of continuous and uniform material, and to study it by means of macroscopic mechanical analysis. However, under the working pressure of gas cylinder, the yield limit and fracture strength of the winding layer are far greater than the stress of the winding layer. The mechanism of the cracking and stress corrosion cracking of the winding layer resin can not be deeply studied through macroscopic mechanics. In order to solve this problem, the winding layer of the newly manufactured gas cylinder and the gas cylinder which was abandoned due to the stress corrosion cracking in the winding layer were sampled respectively, and then the failure modes of the composite fiber and matrix were observed by scanning electron microscope (SEM). A multi-scale modeling method of gas cylinder was proposed according to the destruction mode of composite material of gas cylinder winding layer taken by scanning electron microscope (SEM). By using the proposed multi-scale model, the influence of two important design parameters, the rubber content and the fiber diameter, on the cracking degree of the resin is discussed by means of micromechanics. The influence of circumferential crack on stress corrosion crack propagation is studied, and the failure mechanism of stress corrosion crack is studied on the basis of multi-scale model. In this paper, the stress damage mechanism of gas cylinder winding layer is studied by means of micromechanics of composite materials. The experimental results show that the multi-scale model of gas cylinder is feasible in the simulation analysis of gas cylinder. At the same time, the influence factors of gas cylinder winding layer resin cracking and the failure mechanism of stress corrosion cracking are put forward, which provides a good theoretical reference for the design and winding tension of CNG-2 gas cylinder winding layer.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH49

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