油气管道环向表面裂纹玻璃纤维增强复合材料修复补强研究

发布时间：2018-06-26 00:35

本文选题：油气管道 + 环向表面裂纹　；参考：《西南交通大学》2017年硕士论文

【摘要】：管道是现代能源输送工程中的重要结构形式之一,油气管道更已成为当今国民经济发展的能源命脉。而在铺设或服役过程中,往往由于施工或服役条件恶劣,管道中将不可避免地存在各类缺陷。这些缺陷若不及时修复,轻则导致输送介质泄漏,严重时甚至导致爆管事故发生,对生态环境、人身安全和经济发展构成重大威胁。环向表面裂纹及可以当量化为等效环向表面裂纹的缺陷作为一类重要缺陷的代表,其修复技术一直受到普遍关注。玻璃纤维增强复合材料(Glass Fiber Reinforced Polymers,简称GFRP)修复技术作为一种新型的管道修复技术,因具有许多传统修复加固技术无法比拟的优点,在近年来得到了广泛的应用,但主要集中在对含体积损失缺陷的管道的修复方面。目前对GFRP修复技术在含环向表面裂纹缺陷管道的修复中的作用与效果认识尚不十分清晰,具有较大的研究空间。据此,本课题以GFRP修复含环向表面裂纹缺陷的油气管道为研究对象,采用试验测试与有限元模拟相结合的研究方法,对GFRP修复前后,管道在组合载荷作用下的状态进行了对比分析,并对GFRP修复层参数对修复效果的影响进行了较为细致的讨论,主要内容如下:首先,进行了高强玻璃纤维方格布/环氧树脂增强复合材料的性能测试试验,为GFRP管道修复试验与数值模拟提供了数据基础。在静水压和弯矩组合载荷作用下,进行了有/无GFRP修复的含环向表面裂纹缺陷管道的破坏试验,并分析了 GFRP对含环向表面裂纹缺陷管道的修复作用与效果。结果表明:当载荷条件不足以使管体发生屈服时,GFRP修复技术对管体的修复效果有限;而当载荷条件足以使管体发生屈服后,GFRP能够显著抑制所包覆管体屈服;对含环向表面裂纹管道而言,明显提升了管道失效载荷。其次,基于试验管道尺寸参数,建立了有限元仿真模型。结合Newman-Raju理论公式,对有限元模拟结果准确性进行了校验。证明了采用数值模拟方法进行扩展试验的可行性与准确性。再次,采用有限元方法,对含深度相同,长度不同和长度相同,深度不同的两组表面裂纹的未修复管道模型进行了数值模拟。讨论了裂纹尺寸不同时,裂纹前缘最深点J积分随外载荷的变化规律,结果表明J积分随外载荷变化规律与半椭圆形表面裂纹尺寸无关。并进一步对裂纹前缘最深点J积分与裂纹侧面中部管材轴向应变的绝对值关系进行了探讨,初步阐明了与裂纹深度和长度无关,二者随外载荷的变化规律具有一定的相关性。最后,结合测试试验结果,验证了 GFRP修复含环向表面裂纹缺陷管道有限元模拟方法的可行性与准确性。结合未修复管道模型的分析结果,给出了 GFRP修复技术对环向表面裂纹的修复效果随GFRP包覆层宽度、厚度及GFRP包覆层与管钢粘结胶层模量的变化规律。最终,为GFRP修复含环向表面裂纹缺陷管道时参数选取问题提出了一些合理化建议。
[Abstract]:Pipeline is one of the important structural forms in modern energy transmission projects, and oil and gas pipelines have become the lifeblood of the development of national economy. However, in the course of laying or service, various kinds of defects will inevitably exist in the pipeline due to the bad construction or service conditions. If these defects are not repaired in time, light will lead to leakage of transport medium, and even lead to pipe burst accidents, which pose a great threat to ecological environment, personal safety and economic development. As the representative of a class of important defects, the repair technology of toroidal surface cracks and defects which can be quantified as equivalent toroidal surface cracks have been paid more and more attention. Glass Fiber reinforced Polymer (GFRP) repair technology, as a new type of pipeline repair technology, has been widely used in recent years because of its many advantages that can not be compared with the traditional repair and reinforcement technology. However, the main focus is on the repair of pipelines containing volume loss defects. At present, the function and effect of GFRP repair technology in the repair of pipeline with annular surface cracks are not clear, and there is a large research space. Therefore, this paper takes GFRP repair of oil and gas pipeline with circumferential surface crack as the research object, and adopts the research method of combining test and finite element simulation to study before and after GFRP repair. The state of pipeline under combined load is compared and analyzed, and the influence of GFRP repair layer parameters on repair effect is discussed in detail. The main contents are as follows: first, The performance test of high strength glass fiber lattice cloth / epoxy resin reinforced composite was carried out, which provided the data basis for GFRP pipeline repair test and numerical simulation. Under the combined load of hydrostatic pressure and bending moment, the failure test of the pipeline with and without GFRP repair was carried out, and the effect and effect of GFRP on the repair of the pipeline with ring surface crack were analyzed. The results show that the effect of GFRP repair is limited when the load condition is not enough to yield the tube, but when the load condition is sufficient to make the tube yield, the GFRP can significantly inhibit the yield of the coated tube. For a pipe with a circumferential surface crack, the failure load of the pipe is obviously increased. Secondly, the finite element simulation model is established based on the size parameters of the test pipe. Combined with Newman-Raju formula, the accuracy of finite element simulation results is verified. The feasibility and accuracy of the extended test using numerical simulation method are proved. Thirdly, two groups of unrepaired pipe models with the same depth, different length, same length and different depth are numerically simulated by finite element method. The variation law of J-integral with external load at the deepest point of crack front is discussed. The results show that the variation of J-integral with external load is independent of the crack size of semi-elliptical surface. Furthermore, the relationship between the J-integral of the deepest point of the front edge of the crack and the axial strain of the tube in the middle of the crack profile is discussed. It is preliminarily clarified that there is no relationship between the crack depth and the length of the crack, and that there is a certain correlation between them with the variation of the external load. Finally, the feasibility and accuracy of the finite element simulation method for GFRP repair of pipes with circumferential surface cracks are verified by combining the test results. Based on the analysis results of the unrepaired pipe model, the effect of GFRP repair technology on the ring surface crack is given. The variation of GFRP coating width, thickness and the modulus of GFRP cladding layer to pipe steel bond layer are given. Finally, some reasonable suggestions are put forward for the parameter selection of GFRP repairing pipeline with circumferential surface crack.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE973;TQ327.1

【参考文献】