飞行器关键构件的超声导波损伤诊断成像方法研究

发布时间：2018-01-08 04:26

本文关键词：飞行器关键构件的超声导波损伤诊断成像方法研究　出处：《大连理工大学》2016年博士论文　论文类型：学位论文

【摘要】：飞行器对效率和安全的追求是永恒的,因而对航空航天飞行器结构的性能要求日益提高,结构趋于大型化和复合材料化,安全性问题日益突出。利用嵌入式的智能传感网络,实时监测、诊断和评价结构健康状况是提高飞行器可靠性、安全性和先进性的重要技术手段。损伤引起的结构失效是结构健康监测技术预防和关注的重点。与传统超声波相比,超声导波更适合于板状或管状飞行器关键构件的大面积损伤监测,相关研究受到研究者越来越多的关注。近几年来,研究者们在金属／复合材料平板和大口径管状金属构件上开展了大量超声导波损伤监测研究,发展了多种能直观反映损伤位置的诊断成像方法。但由于超声导波的传播具有多模态、频散等特性,其导波信号处理解释的难度与结构复杂度息息相关,目前导波技术的损伤监测效率和精度尚且不足,使得其在大面积薄壁复杂构件和飞行器管路系统等真实飞行器关键构件应用方面的研究还相对滞后。因此,进一步探索真实飞行器关键构件上的超声导波损伤诊断成像方法有助于推动飞行器结构健康监测的工程应用。本文的目的是基于加权分布诊断成像方法进一步发展损伤定位和尺寸评估的各项关键技术,提高稀疏传感网络的损伤定位精度,探索可用于飞行器复杂结构的高效率、高精度损伤诊断新策略和新方法。为此,本文从诊断成像的影响因素分析和传感网络优化,飞行器大面积薄壁复杂构件损伤诊断和管路周向裂纹诊断成像技术等方面开展了深入研究。文章的研究内容和结果主要包括：(1)在加筋肋复合材料板上,对加权分布诊断成像不同参数组合的损伤定位精度进行了研究,结果表明加权分布诊断成像中监测中心频率、传感路径网络和路径加权因子会显著影响损伤定位的精度。为抑制监测中心频率选择的影响,提出了一种多频率综合诊断成像方法,通过融合多频率的诊断图像可提高了损伤定位精度和可靠性。分析了传感路径网络对不同位置损伤的定位结果,发现了传感网络布设差异造成的“过度加权”现象。这种“过度加权”会造成加权分布诊断成像的监测灵敏度对不同位置损伤存在差异,严重时会降低损伤定位精度,甚至产生“伪损伤”误诊。为抑制加权分布诊断成像的“过度加权”,提出了基于单位权值分布函数的传感网络优化方法。对加权分布诊断成像相关影响因素的深入分析也为后续改进该成像方法奠定了基础。(2)深入分析了大面积薄壁复杂结构损伤定量化面临的挑战,讨论了其应对策略。提出了一种基于权值补偿的改进加权分布诊断成像方法,在加筋肋复合材料板上对该方法进行了实验研究,对比了改进前后的损伤定位结果,并对诊断成像的相关参数进行了分析。提出了一种基于诊断图像峰值的损伤尺寸评估方法,在加筋肋复合材料板上对损伤严重程度与诊断图像峰值的关联性进行了研究,得到了两者的关联模型,依据模型对不同大小的若干损伤进行测试来验证方法的有效性。提出了一种多损伤因子综合评价机制来进一步提高损伤定位的精度和可靠性,最后在复合材料机身壁板原型结构上对上述方法进行了实验研究。(3)对超声导波在飞行器管路中传播特性进行了分析,结果表明兰姆波近似理论对小管径圆管不再适用。提出了一种可提高飞行器管路焊缝周向裂纹识别能力的超声导波损伤诊断成像技术,该技术通过评价传感器激励的导波声场位移圆周分布选择激励中心频率,保证了损伤诊断的准确性。之后通过识别焊缝处周向微小裂纹来验证该技术的有效性。结果表明该技术可准确识别裂纹的周向位置,在管路焊缝周向裂纹识别中具有巨大潜力。研究成果对于更好的开展飞行器结构健康监测工程应用,提高损伤位置识别与尺寸评估的准确性和可靠性,拓展导波技术应用于飞行器不同类型部件等方面具有重要意义。
[Abstract]:The pursuit of efficiency and safety of the aircraft is eternal, so the performance requirements of aerospace vehicle structures increasing, large scale and structure of composite materials tend to be, security issues have become increasingly prominent. The use of real-time monitoring of intelligent sensor network, embedded system, diagnosis and evaluation of the health status is an important technical means to improve vehicle reliability and safety and advanced. The structural damage caused by failure of structure health monitoring technology is the focus of prevention and attention. Compared with the traditional ultrasonic, ultrasonic guided wave damage monitoring of large area is more suitable for the key components of plate shaped or tubular aircraft, related research has been more and more attention of researchers. In recent years, researchers the metal composite plate and large diameter tubular metal components to carry out monitoring of a large number of ultrasonic guide wave damage, a variety of development can reflect the damage location The diagnostic imaging method. But due to the propagation of ultrasonic guided waves with multiple modes, dispersion characteristics, the difficulty and the structure of guide wave signal processing and interpretation complexity is closely related to the efficiency and accuracy of damage monitoring is currently guided wave technology, makes its application in the key components of real aircraft large complex thin-walled components and aircraft pipeline other aspects of the system research is lagging behind. Therefore, to further explore the key components of real aircraft. The ultrasonic guided wave damage diagnostic imaging method is helpful to promote the engineering application of vehicle structural health monitoring. The purpose of this paper is the key technology of the weighted distribution diagnostic imaging method for damage location and size of the further development of the evaluation based on improved damage positioning accuracy sparse sensor networks, can be used to explore the vehicle complex structure and high efficiency, a new strategy and method of high accuracy and damage diagnosis. Therefore, this article from the impact of diagnostic imaging factors analysis and optimization of wireless sensor networks, a large area of aircraft complex thin-walled member damage diagnosis and pipeline circumferential crack diagnostic imaging technology and other aspects to carry out in-depth research. The research contents and results are as follows: (1) in stiffened composite plate, the positioning accuracy of weighted damage the distribution of diagnostic imaging of different parameters were studied, the results showed that the monitoring center frequency weighted distribution diagnostic imaging, sensing network path and path weighted factors can significantly affect the damage location accuracy. In order to suppress the influence of monitoring center frequency selection, presents a multi frequency comprehensive diagnostic imaging method by image fusion, multi frequency diagnosis the injury can improve the positioning accuracy and reliability. The analysis of sensing path network positioning results of different damage location, found the sensor network layout difference Differences caused by "excessive weight" phenomenon. This "over weighted" will cause the monitoring sensitivity weighted distribution diagnostic imaging has different damage in different locations, which will reduce the damage of the positioning accuracy, and even have a "pseudo damage" to suppress the misdiagnosis. The weighted distribution of diagnostic imaging over weighted, proposed sensor network optimization method the unit weight distribution function based on weighted imaging diagnosis. The distribution of in-depth analysis of the factors for the improvement of the imaging method of the foundation. (2) the in-depth analysis of the large complex thin-walled structural damage quantification challenges, discussed its coping strategies. This paper proposed an improved weighted weight compensation distribution diagnosis the imaging method based on the experimental study of this method in stiffened composite plate, the damage location results before and after the improvement of diagnostic imaging and contrast. The related parameters are analyzed. This paper proposed an evaluation method of damage diagnosis based on peak image size, the stiffened composite plate is studied on the relationship between injury severity and diagnostic image peak, the correlation model between them, the validity of the tests to verify some methods based on the damage model of of the same size. A damage factor evaluation mechanism to further improve the damage localization accuracy and reliability, experiments were carried out at the end of this method in the composite fuselage panel prototype structure. (3) to analyze the propagation characteristics of ultrasonic guided waves in the pipeline in the aircraft, results show that Lamb wave approximation the theory of small diameter tube is no longer applicable. A vehicle can improve the pipeline weld circumferential ultrasonic crack detection ability of guided wave damage diagnostic imaging technology, the technology. Evaluation of sensor excitation of guided wave field displacement distribution of circumferential center frequency selective excitation, to ensure the accuracy of diagnosis of injury. After identification of weld circumferential crack to verify the validity of the technique. The results show that the method can accurately identify the crack circumferential position, has great potential to crack identification in pipeline weld week the research results for the development of aircraft structural health monitoring application better, improve the reliability and accuracy of the identification of damage location and size evaluation, has important significance to expand the guided wave technique is applied to different types of aircraft parts.

【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：V267

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