带缺陷的钢内胆复合材料环缠绕气瓶安全评估技术研究

发布时间：2018-03-31 13:13

本文选题：复合材料　切入点：缺陷气瓶　出处：《华南理工大学》2015年硕士论文

【摘要】：钢内胆环缠绕气瓶具有轻质、高强度、耐腐蚀及生产成本低等优点而广泛用于汽车行业。然而在使用过程中，气瓶容易产生不同的缺陷，影响气瓶使用安全。缺陷主要分为两类：一是内胆缺陷，主要来源于充装气体不符合要求而产生的腐蚀性缺陷和反复加载产生的疲劳缺陷；二是缠绕层缺陷，主要是由于摩擦、划伤等外界因素造成的缺陷。本文主要对内胆和缠绕层缺陷展开研究，考虑了三个位置缺陷（内胆中部、缠绕层中部、缠绕层端部），两种缺陷尺度（深度和长度）。首先考虑缺陷单独出现在内胆中部内壁面，然后在其基础上，同时考虑出现在缠绕层的情况，最终得到本文研究的三种缺陷模型（内胆中部存在缺陷模型、内胆和缠绕层中部存在缺陷模型、内胆中部和缠绕层端部存在缺陷模型）。本文利用ANSYS建立了无缺陷和有缺陷3D气瓶模型，研究工作状态下应力分布，，然后采用设定路径分量叠加的方法得到软件无法直接得到的缺陷气瓶工作状态下的实际应力、应力强度、等效应力和界面应力等分布，比较分析不同位置缺陷和尺寸对气瓶强度性能的影响。参照分析设计标准中疲劳分析的方法，计算不同余压和缺陷尺寸下气瓶的疲劳寿命，比较不同缺陷位置、余压、缺陷深度和长度对疲劳寿命的影响：结果发现，相同余压下，缺陷位于筒体中部（仅内胆中部缺陷或者内胆和缠绕层中部存在缺陷）时，缺陷深度存在一临界值，在临界值以内气瓶疲劳寿命与缺陷深度无关，而超过临界值，缺陷深度将直接决定气瓶的疲劳寿命；缠绕层端部缺陷对疲劳寿命的影响与端部无缺陷时的变化趋势完全不同，此时疲劳寿命随缺陷深度的增大而减小。爆破和疲劳试验进一步验证了模拟和疲劳分析结果的合理性和准确性。分析还寻找到了气瓶最大环向应力和疲劳寿命与余压和不同位置缺陷尺寸的变化规律，比较了不同缺陷模型对气瓶疲劳寿命的影响；拟合了缺陷气瓶内胆外壁上最大环向应力和疲劳寿命与余压和缺陷深度的关系，为缺陷气瓶寿命预测提供了一种评估方法。
[Abstract]:Steel tank ring winding gas cylinders are widely used in automobile industry due to their advantages of light weight, high strength, corrosion resistance and low production cost. However, gas cylinders are prone to produce different defects in the process of use. The defects are mainly divided into two categories: one is the inner bile defect, which mainly comes from the corrosive defect caused by the filling gas which does not meet the requirements and the fatigue defect caused by repeated loading; the other is the wound layer defect, which is mainly caused by friction, The defects caused by external factors, such as scratches, are studied in this paper, and three defects are considered: the middle of the inner bile, the middle of the winding layer, the middle of the winding layer, the middle of the winding layer, and the defect of the winding layer. At the end of the winding layer, there are two kinds of defect scales (depth and length). First, it is considered that the defect appears separately on the inner wall of the middle part of the inner bile, then on its basis, and at the same time, the case of the winding layer is taken into account. Finally, three kinds of defect models (the middle of the inner bile duct, the middle of the inner bile and the winding layer, the defect model of the middle of the inner bile and the end of the winding layer) are obtained. In this paper, ANSYS is used to establish the model of non-defect and defect-free 3D gas cylinder. The stress distribution in working state is studied, and then the actual stress in the working state of defective gas cylinder can not be directly obtained by using the method of setting path component superposition. The distribution of stress intensity, equivalent stress and interfacial stress were compared and analyzed, and the effects of defects and sizes of different positions on the strength properties of gas cylinders were compared and analyzed. Referring to the fatigue analysis method in the analytical design standard, the fatigue life of gas cylinder under different residual pressure and defect size is calculated, and the effects of different defect location, residual pressure, defect depth and length on fatigue life are compared. When the defect is located in the middle of the tube (only in the middle of the inner bile or in the middle of the inner tank and winding layer), there is a critical value in the depth of the defect, within which the fatigue life of the cylinder is independent of the depth of the defect but exceeds the critical value. The depth of defect will directly determine the fatigue life of gas cylinder, and the effect of wound end defect on fatigue life is completely different from the change trend of the end without defect. At the same time, the fatigue life decreases with the increase of defect depth. Blasting and fatigue tests further verify the rationality and accuracy of the simulation and fatigue analysis results. The maximum circumferential stress, fatigue life and fatigue life of gas cylinder are also found. The variation of residual pressure and defect size in different positions, The effects of different defect models on the fatigue life of gas cylinders are compared, and the relationship between the maximum circumferential stress and fatigue life, residual pressure and defect depth on the inner and outer wall of the defective gas cylinders is fitted, which provides an evaluation method for the life prediction of defective gas cylinders.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ053.2;TB33

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