Z-pin增强复合材料结构缺陷的红外检测技术研究

发布时间：2018-06-27 08:56

本文选题：复合材料 + Z-pin增强　；参考：《南京航空航天大学》2017年硕士论文

【摘要】：Z-pin增强技术通过在未固化层合结构中植入适量体积分数的Z-pin(0.5%~4.0%)来提高复合材料的层间断裂韧性。该技术对复合材料面内性能影响较小且能大幅度提高复合材料的层间性能,实用性高且成本较低,因而得到了广泛关注。在Z-pin植入与后固化过程中,由于工艺的不稳定性,得到的复合材料结构不可避免的会存在各种类型的缺陷,对其进行无损检测是保障其质量的重要方法。本研究基于红外热像无损检测技术,采用实验与仿真技术相结合的方法分析了Z-pin增强复合材料典型缺陷对其传热性能的影响,针对红外热像图边缘模糊和Z-pin结构的特点,应用不同算法研究了缺陷边缘细节强化技术。本研究主要工作如下:(1)通过自制Z-pin增强复合材料与破坏性试验,研究了Z-pin增强复合材料在制造与服役过程中出现的典型缺陷与损伤,并对其结构缺陷与损伤的红外检测可行性进行了分析。(2)本研究以Z-pin增强碳纤维复合材料层合板为检测对象,采用有限元软件ANSYS高级分析技术APDL建立了含不同缺陷类型的有限元模型,通过提取最大温差与最大对比度等可检测信息参数,分析了不同尺寸富树脂区、不同深度的断裂缺损Z-pin、不同倾斜程度的Z-pin对层合结构整体导热行为及其表面温度分布的影响,有限元模拟结果为进一步的检测实验提供了技术支撑与理论支持。(3)应用红外热像无损检测技术对自制带有不同缺陷类型的Z-pin增强碳纤维复合材料层合板试件进行了检测研究。检测结果表明:红外热像无损检测技术对Z-pin增强复合材料典型缺陷具有良好的检测效果,缺陷较为清晰,该技术可应用于Z-pin增强复合材料结构的无损检测中。(4)针对红外热像图边缘模糊、噪声干扰大的特点,应用不同算法对缺陷边缘进行了强化处理,研究了一种基于缺陷中心点灰度阈值的旋转边缘跟踪增强技术。结果表明:该算法在边缘强化处理方面优于传统的经典微分算子,缺陷定位准确、轮廓清晰、边缘闭合性好。
[Abstract]:Z-pin reinforcement technique improves the interlaminar fracture toughness of the composites by inserting appropriate volume fraction of Z-pin (0.5% and 4.0%) into the unsolidified laminated structure. This technique has little influence on in-plane properties of composites and can greatly improve the interlaminar properties of composites. It has high practicability and low cost, so it has been paid more attention to. During the process of Z-pin implantation and post-curing, the structure of the composite material will inevitably have various kinds of defects due to the instability of the process. Nondestructive testing is an important method to ensure the quality of the composite material. Based on the infrared thermal image nondestructive testing technique, the influence of typical defects of Z-pin reinforced composite on its heat transfer performance is analyzed by combining experimental and simulation techniques, aiming at the characteristics of infrared thermal image edge blur and Z-pin structure. The defect edge detail enhancement technique is studied by using different algorithms. The main work of this study is as follows: (1) the typical defects and damages of Z-pin reinforced composites during manufacture and service were studied by self-made Z-pin reinforced composites and destructive tests. The feasibility of infrared detection of structural defects and damage was analyzed. (2) the Z-pin reinforced carbon fiber composite laminates were used as the detection objects. The finite element model with different defect types was established by using the advanced analysis technology APDL of ANSYS. By extracting detectable information parameters such as maximum temperature difference and maximum contrast, the resin rich regions with different sizes were analyzed. The effect of Z-pinand Z-pin with different depth on the overall thermal conductivity and surface temperature distribution of laminated structure. The finite element simulation results provide technical support and theoretical support for further testing experiments. (3) the infrared thermal image nondestructive testing technique is used to detect Z-pin reinforced carbon fiber laminates with different defect types. The results show that the infrared thermal image nondestructive testing technique has a good effect on the typical defects of Z-pin reinforced composites, and the defects are relatively clear. This technique can be used in nondestructive testing of Z-pin reinforced composite structures. (4) aiming at the characteristics of infrared thermal images with blurry edges and large noise interference, different algorithms are used to strengthen the defect edges. A rotating edge tracking enhancement technique based on gray threshold of defect center is studied. The results show that the proposed algorithm is superior to the classical differential operator in edge enhancement, and the defect location is accurate, the contour is clear and the edge is closed.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB302

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