多层板材电磁无损检测技术研究
发布时间：2019-06-22 15:44
【摘要】：无损检测是保障重大工程装备制造质量和运行安全的关键技术。多层材料由于其特殊的结构和性能在核工业、航空航天等关键领域中得到了广泛的应用,保障这些关键部件的质量至关重要。多层材料由于其复杂的结构、通常具有的厚度、材料属性的多样性以及实际检测环境的限制,对大多数无损检测技术提出了挑战。电磁无损检测技术是通过电磁感应原理来检测被测件中的损伤和不连续,具有快速、非接触、不需耦合剂以及非破坏性等优点,本论文主要通过两种先进的电磁无损检测技术,涡流热成像和远场涡流无损检测技术,分别对碳纤维复合材料中的冲击损伤和多层异种金属粘接结构中的粘接缺陷检测问题进行了系统地对比研究。分析两种先进电磁无损检测技术对多层结构质量检测各自的优缺点。本文的主要研究内容如下:1)涡流脉冲热成像中缺陷及物理特征的多维挖掘。涡流脉冲热成像是一种新兴的电磁无损检测技术,在获取热像视频后,目前通常的方法是通过从中人为选取一帧图像进行缺陷的检测和评估,这种人为帧图的主观选择不可避免地对检测结果造成影响。本论文通过基于能量的小波分析方法,对热成像检测信号在空间-时间-频等多维域进行数据挖掘分析,提出了涡流热成像检测中自动选取帧图像和缺陷特征提取的方法。2)碳纤维复合材料中微弱冲击损伤的检测。对带有冲击损伤的碳纤维复合材料层压板在反射模式下进行体积型感应加热,用热像仪记录整个加热阶段和冷却阶段试件表面的热响应。得到检测热像图序列后,使用小波分析工具对热像视频进行分析,通过一些标准选择最佳的观测尺度和最优母小波函数,最终成功将热像图中的纤维编织信息和冲击损伤信息分离开来,并成功检测到位于低频成分中的冲击损伤。3)研究了涡流热成像和远场涡流两种无损检测技术对多层异种金属粘接结构粘接质量的检测性能。涡流热成像在反射模式下受到趋肤效应的限制只能检测到表面缺陷,在透射模式下单次脉冲产生的热量无法透过试件,多次脉冲激励的方式可以解决热量无法穿透试件的问题,但同时受到横向热扩散使缺陷信息变得模糊。远场涡流可以有效检测到两层铅钢粘接结构内部缺陷,对四层铅钢粘接结构内部缺陷检测仍然存在困难。未来需要展开针对四层铅钢粘接结构的传感器设计,并且配合X-Y工作台实现对多层异种金属粘接结构更精确的检测。
[Abstract]:Nondestructive testing is the key technology to ensure the manufacturing quality and operation safety of major engineering equipment. Because of its special structure and properties, multi-layer materials have been widely used in nuclear industry, aerospace and other key fields, so it is very important to ensure the quality of these key components. Multi-layer materials challenge most nondestructive testing technologies because of their complex structure, thickness, diversity of material properties and limitations of the actual testing environment. Electromagnetic nondestructive testing technology is based on the principle of electromagnetic induction to detect the damage and discontinuity in the tested parts, which has the advantages of fast, non-contact, no coupling agent and non-destructive. In this paper, two advanced electromagnetic nondestructive testing technologies, vortex thermal imaging and far-field eddy current nondestructive testing technology, are mainly adopted. The impact damage in carbon fiber composites and the detection of bonding defects in multi-layer dissimilar metal bonding structures were systematically compared and studied. The advantages and disadvantages of two advanced electromagnetic nondestructive testing techniques for multi-layer structure quality testing are analyzed. The main contents of this paper are as follows: 1) Multidimensional mining of defects and physical characteristics in vortex pulse thermal imaging. Eddy current pulse thermal imaging is a new electromagnetic nondestructive testing technology. After obtaining the thermal image video, the common method is to detect and evaluate the defects by artificially selecting a frame image from the middle. The subjective selection of this artificial frame graph inevitably affects the detection results. In this paper, the data mining of thermal imaging detection signal in multi-dimensional domain such as space-time-frequency is carried out by wavelet analysis method based on energy, and a method of automatic selection of frame image and defect feature extraction in Eddy current thermal imaging detection is proposed. 2) the detection of weak impact damage in carbon fiber composites. The volume induction heating of carbon fiber composite laminates with impact damage was carried out in reflection mode. The thermal responses of the whole heating stage and cooling stage were recorded by thermal imager. After the thermal image sequence is detected, the thermal image video is analyzed by wavelet analysis tool, and the optimal observation scale and optimal parent wavelet function are selected through some standards. finally, the fiber weaving information and impact damage information in the thermal image are separated successfully. The impact damage in low frequency composition was successfully detected. 3) the bonding properties of multi-layer dissimilar metal bonding structure were studied by vortex thermal imaging and far-field eddy current nondestructive testing. Eddy current thermal imaging can only detect surface defects under the limitation of skin effect in reflection mode, and the heat generated by a single pulse can not pass through the specimen in transmission mode. The problem that heat can not penetrate the specimen can be solved by multiple pulse excitation, but at the same time, the defect information becomes blurred by transverse thermal diffusion. The internal defects of two-layer lead-steel bonding structure can be effectively detected by far-field eddy current, but it is still difficult to detect the internal defects of four-layer lead-steel bonding structure. In the future, the sensor design for four-layer lead steel bonding structure needs to be carried out, and the multi-layer dissimilar metal bonding structure can be detected more accurately with X / Y worktable.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB302.5
本文编号：2504731
[Abstract]:Nondestructive testing is the key technology to ensure the manufacturing quality and operation safety of major engineering equipment. Because of its special structure and properties, multi-layer materials have been widely used in nuclear industry, aerospace and other key fields, so it is very important to ensure the quality of these key components. Multi-layer materials challenge most nondestructive testing technologies because of their complex structure, thickness, diversity of material properties and limitations of the actual testing environment. Electromagnetic nondestructive testing technology is based on the principle of electromagnetic induction to detect the damage and discontinuity in the tested parts, which has the advantages of fast, non-contact, no coupling agent and non-destructive. In this paper, two advanced electromagnetic nondestructive testing technologies, vortex thermal imaging and far-field eddy current nondestructive testing technology, are mainly adopted. The impact damage in carbon fiber composites and the detection of bonding defects in multi-layer dissimilar metal bonding structures were systematically compared and studied. The advantages and disadvantages of two advanced electromagnetic nondestructive testing techniques for multi-layer structure quality testing are analyzed. The main contents of this paper are as follows: 1) Multidimensional mining of defects and physical characteristics in vortex pulse thermal imaging. Eddy current pulse thermal imaging is a new electromagnetic nondestructive testing technology. After obtaining the thermal image video, the common method is to detect and evaluate the defects by artificially selecting a frame image from the middle. The subjective selection of this artificial frame graph inevitably affects the detection results. In this paper, the data mining of thermal imaging detection signal in multi-dimensional domain such as space-time-frequency is carried out by wavelet analysis method based on energy, and a method of automatic selection of frame image and defect feature extraction in Eddy current thermal imaging detection is proposed. 2) the detection of weak impact damage in carbon fiber composites. The volume induction heating of carbon fiber composite laminates with impact damage was carried out in reflection mode. The thermal responses of the whole heating stage and cooling stage were recorded by thermal imager. After the thermal image sequence is detected, the thermal image video is analyzed by wavelet analysis tool, and the optimal observation scale and optimal parent wavelet function are selected through some standards. finally, the fiber weaving information and impact damage information in the thermal image are separated successfully. The impact damage in low frequency composition was successfully detected. 3) the bonding properties of multi-layer dissimilar metal bonding structure were studied by vortex thermal imaging and far-field eddy current nondestructive testing. Eddy current thermal imaging can only detect surface defects under the limitation of skin effect in reflection mode, and the heat generated by a single pulse can not pass through the specimen in transmission mode. The problem that heat can not penetrate the specimen can be solved by multiple pulse excitation, but at the same time, the defect information becomes blurred by transverse thermal diffusion. The internal defects of two-layer lead-steel bonding structure can be effectively detected by far-field eddy current, but it is still difficult to detect the internal defects of four-layer lead-steel bonding structure. In the future, the sensor design for four-layer lead steel bonding structure needs to be carried out, and the multi-layer dissimilar metal bonding structure can be detected more accurately with X / Y worktable.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB302.5
【参考文献】
相关期刊论文 前1条
1 郭兴旺;邵威;郭广平;刘颖韬;;红外无损检测加热不均时的图像处理方法[J];北京航空航天大学学报;2005年11期
，本文编号：2504731
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