碳纤维布加固压力管道补强效果研究

发布时间：2018-07-04 16:19

本文选题：压力管道 + 碳纤维布　；参考：《西南科技大学》2015年硕士论文

【摘要】：压力管道的腐蚀缺陷常分为内腐蚀和外腐蚀,一般外腐蚀缺陷又分为:全面积均匀腐蚀、局部腐蚀、点蚀、组合腐蚀四类,而缺陷的主要形状一般为方形或椭圆形。同时压力管道常常含有沿轴向、沿环向、沿轴向和环向同时分布的多个点蚀缺陷,因其靠得太近会产生相互作用。非金属纤维材料在结构修复加固中的应用逐渐广泛,但是在修复含缺陷压力管道尚属起步阶段,对其补强效果的评价仍处于探索阶段,缺少评价准则。本文主要研究碳纤维布加固含全面积均匀腐蚀缺陷以及椭圆形点蚀缺陷这两类缺陷的压力管道的补强效果,为实际的压力管道加固工程提供一些参考性意见和建议。在全面积均匀腐蚀方向上,采用试验和数值模拟两种方法分别对其进行研究。且在数值模拟方法上采用“三维实体-接触-壳元”有限元模型,反复斟酌后选择合理单元类型,并基于基础试验得到相关参数,然后使用这些基础参数反过来完善模型,确保建模正确性。而试验和数值模拟的结果又相互匹配,进一步间接验证了建模的正确性。在点腐蚀方向上,采用数值模拟方法进行研究得到相关结论。结果表明:碳纤维布加固全面积均匀腐蚀缺陷压力管道的补强效果出现边际效益递减的情况,整个加固区从中间到两端滑移距离逐渐增大。单个椭圆形点蚀缺陷的管道缺陷形状越尖锐、深度越深,则应力集中系数越大、补强层数越多。压力管道壁厚对应力集中系数的影响主要是因为缺陷深度占管道壁厚的比例(深厚比)发生了变化。同时对比缺陷群的深度、轴向间距、环向间距对压力管道应力集中系数的影响,可知缺陷群深度对其影响最大,轴向间距次之,因此当对含缺陷群压力管道进行补强计算时主要考虑缺陷群深度和轴向间距对其的影响。
[Abstract]:The corrosion defects of pressure pipeline are usually divided into internal corrosion and external corrosion. The general external corrosion defects are divided into four categories: uniform corrosion of the whole area, local corrosion, pitting corrosion and combined corrosion, and the main shape of the defects is generally square or elliptical. At the same time pressure pipelines often contain multiple pitting defects distributed simultaneously along the axial circumferential axial and circumferential directions because they interact with each other when they are too close. The application of non-metallic fiber materials in structural repair and reinforcement is gradually widespread, but the repair of pressure pipes containing defects is still in the initial stage, the evaluation of its reinforcement effect is still in the exploratory stage, and the evaluation criteria are lacking. This paper mainly studies the reinforcement effect of carbon fiber sheet in strengthening pressure pipeline with uniform corrosion defects and elliptical pitting defects, and provides some reference opinions and suggestions for practical pressure pipeline strengthening projects. Both experimental and numerical simulation methods were used to study the uniform corrosion direction of the whole area. In the numerical simulation method, the finite element model of "three-dimensional solid contact shell element" is adopted, the reasonable element type is selected after repeated consideration, and the relevant parameters are obtained based on the basic test, and then the model is improved by using these basic parameters in turn. Make sure the modeling is correct. The results of experiments and numerical simulations match each other, which further indirectly verifies the correctness of the modeling. In the direction of pitting corrosion, the numerical simulation method is used to study the relevant conclusions. The results show that the reinforcement effect of uniform corrosion defect pressure pipeline strengthened by carbon fiber sheet decreases with the increasing of marginal benefit, and the slip distance from middle to both ends increases gradually. The more sharp the defect shape and the deeper the depth of the single elliptical pitting defect, the greater the stress concentration factor and the number of reinforcing layers. The influence of pressure pipe wall thickness on stress concentration factor is mainly due to the change of the ratio of defect depth to pipe wall thickness (depth ratio). At the same time, comparing the influence of depth of defect group, axial distance and circumferential spacing on stress concentration factor of pressure pipeline, it can be seen that the depth of defect group has the greatest influence on the stress concentration factor of pressure pipeline, and the axial spacing is the second. Therefore, the influence of defect group depth and axial spacing on the reinforcement of pressure pipes with defects is considered.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U178

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