飞机结构健康监测系统数据处理及在线应用

阐述了飞机结构健康监测的概念和基本组成部分,从监测结构和监测量方面梳理了常见的监测对象;评述了近期结构健康监测数据处理的典型研究成果,主要包括数据采集和预处理、数据分析两个方面,可以看到智能计算的思想和方法越来越多地应用在其中;展望了飞机结构健康监测未来走向大范围在线工程应用的趋势,有针对性地提出了三个要点,分别是机载化在线监控系统硬件的研发、算法的开发和行业的标准化,然后梳理了飞机结构健康监测传感器技术的近期研究案例,并介绍了新兴算法应用于在线监测系统中的案例,为进一步推动飞机结构健康监测系统研究提供参考与借鉴。     

飞机结构健康监测技术发展研究

介绍了结构健康监测技术（Structural Health Monitoring, SHM）的概念以及主动和被动损伤监测方法 的原理, 分析了飞机结构健康监测技术的国内外研究现状, 阐述了比较真空监测（Comparative Vacuum Monitoring, CVM）传感技术、智能涂层传感器技术、光纤传感技术、压电传感器（Piezoelectric Sensors, PZT）技 术和无线传感器网络（Wireless Sensor Network, WSN）等目前较为先进的传感技术的原理以及传感器技术在各类 装备上的应用情况,介绍了飞机结构健康监测技术在F-35联合攻击机（Joint Strike Fighter, JSF）上的典型应用。 指出飞机结构健康监测技术正向智能化方向发展;未来需要重点研究传感器网络的智能诊断技术、复杂环境下 的SHM技术、基于结构健康监测的健康管理技术、智能材料 / 结构健康监测技术,并将深度学习、数字孪生等 前沿技术应用于航空领域,以推动我国飞机结构健康监测技术发展。     

ARALL: A materials challenge for the next generation of aircraft

The development of new aircraft is significantly influenced by the introduction of new structural materials. A driving force behind such developments is the perpetual incentive of reducing the aircraft operating costs of which the most important aspects are fule consumption and maintenance.

The structural weight of the aircraft has a high impact on the fuel consumption. Reduction of the weight can be achieved by the introduction of advanced structural design techniques together with new materials which have low density and high (static and dynamic) stress level capabilities. Maintenance costs can be reduced mainly by enlarging the inspection periods of the aircraft. These two aspects, together with the new damage tolerance requirements (FAR and JAR) and durability questions in view of increasing aircraft lives, make the design of an aircraft with low operating costs very complex and difficult.

In this whole process the selection of materials becomes a critical issue. This is illustrated by considering three potential families of materials:

1. - aluminium alloys (both new and conventional)

2. - composites

3. - aramid aluminium laminate (ARALL).

Special attention is given to the development and possible applications of the ARALL material.     

Development of life extension strategies for Australian military aircraft, using structural health monitoring of composite repairs and joints

The DSTO Centre of Expertise for Structural Mechanics (COE-SM) has recently developed methodologies for simulating structural health monitoring (SHM) systems for adhesively bonded composite repairs to Australian military aircraft. System design, interrogation strategy, and sensor placement are discussed, with particular emphasis on the development of techniques for embedding optical fibre sensors for optimal SHM system response.     

Training of the maintenance personnel to prevent failures in aircraft systems

The aircraft maintenance process plays a vital role in aviation safety. The quality of the maintenance process and the qualifications of the aircraft maintenance personnel are important factors in the safety of aircraft.In this study the aircraft maintenance training model has been developed by especially taking in to account the EASA Part 66 regulations. The progression of the aircraft maintenance personnel training was investigated and suggestions to improve training process were given so as to prevent failures in aircraft systems.     

Airport pavement responses obtained from wireless sensing network upon digital signal processing

Abstract

The intelligent measurement-based technology of Fibre Bragg Grating (FBG) sensor was proposed for establishing a wireless sensing network of airport asphalt pavement for structural information monitoring at Chongqing International Airport. Given the complicated natural environment and aircraft loadings, obtaining key information (i.e. dynamic response amplitude, duration and distribution, aircraft driving offset, speed, etc.) from the monitoring database is a crucial prerequisite to analyse pavement performance. Moving average filter and Fast Fourier Transform (FFT) filter were utilised to process and acquire vital dynamic responses information. The interval of the wandering determination sensors within the aircraft loading determination matrix was discussed and designed based on signal sampling theorem and three-dimensional finite element analysis. The batch program for aircraft taxiing speed calculation was compiled upon signal correlation method which was compared and verified using time difference method. Results show that the allowed interval of the wandering determination sensors is related to the aircraft gear sizes and sensor sizes simultaneously. The computed taxiing speeds using signal correlation method, which reveals higher calculation efficiency, are in good agreement with the results that employ the time difference method. The duration of dynamic response of aircraft shows an inverse proportional relationship with speed, while the forward and backward propagation distances of stress and strain are irrelevant to speed. Once the monitoring system could integrate all critical features, it becomes more useful for pavement health monitoring.     

A Comprehensive Structural Analysis Process for Failure Assessment in Aircraft Lap-Joint Mimics Using Intramodal Fusion of Eddy Current Data

In the aerospace industry, nondestructive evaluation (NDE) techniques are commonly used for structural health monitoring, including finding manufacturing and service-induced discontinuities and defects such as corrosion and cracks. A comprehensive structural analysis process is presented for quantizing and evaluating characteristics of aircraft lap-joint mimics. The process investigated here consists of NDE data acquisition, defect detection and characterization involving material loss estimation, three-dimensional structural model generation, finite-element modeling to simulate fatigue damage and comparison with actual tensile fatigue-induced structural analysis data (mechanical loading). The structural analysis process is examined using five test panels consisting of stacked and riveted aluminum plates, configured as lap-joints, four of them with different corroded patches at different layers of the lap-joints and one painted pristine panel used as a reference. The test panels were subjected to three rounds of incremental and cyclical tensile fatiguing with the final round resulting in complete fatigue failure. Eddy current data was obtained from the test panels prior to each round of mechanical loading. Comparing the simulated fatigue loading and the mechanical loading results for identifying susceptible-to-failure areas on the test panels, this comprehensive structural analysis process found the correct location of failure areas at rates as high as 88.9%.     

Smart bolts: an example of self-healing structures

Structural health monitoring has taken off as a research topic in the past ten years. Currently, there is at least one conference per year devoted to structural health monitoring and several biennial conferences. More importantly, many companies are looking to health monitoring as part of their new business plans to sell service rather than just products. Accordingly, companies have a keen interest in reducing maintenance schedules and downtime for failures causing an increased reliance on health monitoring. The field of structural health monitoring is a natural for combining with smart materials because many of the best algorithms require known or controlled excitation and sensing rather than just sensing. Thus, the actuation ability of smart materials becomes key in health monitoring and diagnostics. The actuation ability of smart materials also has the potential to provide force to a smart structure to counteract damage once it is detected, introducing the possibility of self-healing structures. This article focuses on the use of smart materials to create self-healing structures and provides an example of a self-healing system in the form of a smart bolt.The objective of this study is to reduce significantly resources that are dedicated to inspection routines of joint connections and allow systems to function longer between maintenance. We investigate the feasibility of creating smart structural bolted connections, which consist of structural members joined together by bolt and nut combinations equipped with piezoceramic and shape memory alloy elements. These combinations can be used to monitor bolt tension and connection damage. When damage occurs, temporary adjustments of the bolt tension can be achieved actively and remotely in order to restore lost torque for continued operation.     

Optimal planning of structural performance monitoring based on reliability importance assessment

Recently, the effective use of information from structural health monitoring (SHM) has been considered as a significant tool for rational maintenance planning of deteriorating structures. Since a realistic maintenance plan for civil infrastructure has to include uncertainty, reliable information from SHM should be used systematically. Continuous monitoring over a long-term period can increase the reliability of the assessment and prediction of structural performance. However, due to limited financial resources, cost-effective SHM should be considered. This paper provides an approach for cost-effective monitoring planning of a structural system, based on a time-dependent normalized reliability importance factor (NRIF) of structural components. The reliability of the system and the NRIFs of individual components are assessed and predicted based on monitored data. The total monitoring cost for the structural system is allocated to individual components according to the NRIF. These allocated monitoring costs of individual components are used in Pareto optimization to determine the monitoring schedules (i.e., monitoring duration and prediction duration).     

极寒条件下航空机务服数字化设计应用研究

目的 研究服装数字化技术在航空机务服设计中的应用。方法 运用文献研究法、案例分析法及实验法,对航空机务服数字化设计应用研究的相关情况进行概述,研究服装数字化技术在航空机务服设计中应用的可行性及其优势。结果 以航空机务服设计过程为例,证实服装数字化技术适用于工作服的定制化设计生产,将在研究航空机务服设计各环节的基础上,进行设计模块的数字化技术研究。结论 随着人们对服装设计生产制造过程的数字化、自动化、智能化的需求不断增长,服装二维及三维的相关数字化技术也渐趋成熟。服装数字化技术在工作服定制化服务中具有良好的发展前景,通过服装数字化技术设计的极寒条件下的工作服能够满足航空机务员的需求,保障了航空机务员户外工作的顺利开展,进而维护了航空的飞行安全。     

复合材料连接结构健康监测技术研究进展

连接结构是大型复合材料结构的关键环节,对保证复合材料结构的完整性具有重要作用。由于复合材料连接结构存在复杂的非线性耦合因素,使得复合材料连接结构的强度和破坏模式分析十分困难,因此,必须对复合材料连接结构的健康状态进行监测、诊断、评价和预测,通过在线监测获得的信息实时掌握结构的健康状况与对外界载荷的响应,并在此基础上对未来可能发生的缺陷和故障进行预报,以便能在合适时间段内采取措施,以保证复合材料结构的安全服役并取得最大的经济效益。以飞行器复合材料连接结构为背景,首先简要分析了复合材料胶接连接、机械连接和混合连接形式的损伤和失效模式,然后重点介绍了基于波传播法、阻抗法、智能涂层监测法、真空比较监测法、光纤传感监测法和混合集成监测法的复合材料连接结构健康监测(SHM)技术的研究进展,最后讨论了飞行器复合材料连接结构健康监测技术的发展趋势和面临的挑战。      

Hierarchical Colored Timed Petri Nets for Maintenance Process Modeling of Civil Aircraft

Civil aircraft maintenance process simulation model is an effective method for analyzing the maintainability of a civil aircraft. First, we present the Hierarchical Colored Timed Petri Nets for maintenance process modeling of civil aircraft. Then, we expound a general method of civil aircraft maintenance activities, determine the maintenance level for decomposition, and propose the methods of describing logic of relations between the maintenance activities based on Petri Net. Finally, a time Colored Petri multi-level network modeling and simulation procedures and steps are given with the maintenance example of the landing gear burst tire of a certain type of aircraft. The feasibility of the method is proved by the example.     

Identification of crack and disbond fronts in repaired aircraft structural panels with bonded FRP composite patches

Structural health monitoring of fatigue-cracked aircraft structural panels repaired with bonded FRP composite patches for extending the service life of aging aircraft has received wide attention. In this paper a method for identifying the locations and shapes of crack and disbond fronts in aircraft structural panels repaired with bonded FRP composite patches is presented. The identification is performed by minimizing the residual norm between the measured in-plane strain range on a strain measurement plane in the FRP composite patches and the calculated in-plane strain range. Several numerical examples of identification of the locations and shapes of crack and disbond fronts are examined. The effects of the number of strain measurement points, position of the strain measurement plane, and measurement errors of the in-plane strain ranges on the identification results are discussed. The validity of this identification method is verified by comparing the identification results with the exact ones.     

基于熵权-TOPSIS方法的民机直接维修成本分配模型

民机直接维修成本分配是飞机研制阶段一项重要的经济性设计环节,本文对民机维修成本的分配方法进行研究。应用熵权-TOPSIS（technique for order preference by similarity to ideal solution）方法确定类似机型设计参数的权重,再利用加权距离计算机型的相似度,建立了一种新的民机直接维修成本分配模型。通过实例分析,文中方法所得结果比功能分解法和函数逼近法更为精确,效果良好。     

Non-baseline Damage Detection Based on the Deviation of Displacement Mode Shape Data

The early detection of damage and structural health monitoring should be an important process for structural maintenance. The baseline information of the structural reference state is not available since the structure was not instrumented prior to the damage. This work offers a global-deviation approach to detect damage by measured data only without available data at the intact state. This work shows that the damage exists at the measurement locations to represent large and abrupt variation deviated from global mode shape curve. The proposed method is compared with the GSM (Gapped-Smoothing Method) provided by Ratcliffe and Bagaria and its superiority and effectiveness are illustrated in a numerical simulation and an experiment.     

综合利用率评估的民机结构维修间隔确定方法

确定结构维修间隔是民机结构维修大纲中的关键内容之一,民机利用率对维修间隔制定的合理性有很大影响。基于环境损伤条件下的民机结构,通过分析不同利用率下影响金属结构环境损伤的指标的敏感性,提出了民机结构维修间隔与利用率匹配模型。在该模型中,应用序关系分析法-属性重要度相结合的组合赋权方法,对不同利用率下影响金属结构环境损伤的指标进行组合权重评估,确定金属结构环境损伤的总等级,并根据环境损伤等级-维修间隔回归方程确定了不同利用率下的民机结构维修间隔,最后采用灰色关联分析法验证了不同利用率下各指标评价值与理想值的关联度。以某型飞机中央盒段上壁板内表面维修间隔确定为例,对所提出的模型进行验证分析,利用模型得到的维修间隔与维修审查委员会报告（maintenance review board report,MRBR）规定相比偏小,鉴于该文件规定的为最低工程要求,从而确定该维修间隔满足要求,证明了模型的有效性。研究成果表明,建立的民机结构维修间隔与利用率匹配模型的适用性较强,可以有效解决国产飞机结构维修大纲中维修间隔确定时利用率考虑不足的问题,具有较高的工程应用价值。     

Method for determining maintenance interval of civil aircraft structure combined with assessment of utilization ratio

One of the core contents of the civil aircraft structure maintenance outline is determining the maintenance interval of structure. The utilization ratio has a great influence on the rationality of the maintenance interval. Based on the structure of civil aircraft under environmental damage,a matching model of maintenance interval and aircraft utilization ratio civil aircraft structure was established by analyzing the sensitivity of indicators that affect the environmental damage of metal structures under different utilization ratios. In this model, the combined-weighting method combined the rank-correlation analysis with the attribute-importance was applied to evaluate the combined weight of the indicators affecting the environmental damage of metal structures under different utilization ratios, and the total level of environmental damage of metal structures was determined. The maintenance interval of civil aircraft structure under different utilization ratios was determined based on the damage grade-maintenance interval regression equation. Finally, the grey correlation analysis method was used to verify the correlation between the evaluated value and ideal value of each factor under different utilization ratios. Taking the maintenance interval determination of the upper wall inner surface of the central box section in a certain aircraft as an example, the proposed model was verified and analyzed. The maintenance interval obtained by the model was inferior to the maintenance review board report (MRBR) regulations. In view of the minimum engineering requirements specified in this document, it was determined that the maintenance interval met the requirements, which proved the validity of the model. The research results indicate that the matching model of maintenance interval and utilization ratio of civil aircraft structure has strong applicability, and it can effectively remedy the problem of inadequate utilization ratio consideration in the maintenance interval of domestic aircraft structural maintenance outline, and has high engineering application value.     

某钢结构梁高温切割全过程的监测与分析

为保证某大型生产车间钢框架平台梁在设备荷载作用下改造过程中的安全性,采用ANSYS软件对改造方案进行了有限元分析,并采用光纤光栅传感器对其改造全过程进行了实时可视化监测。通过钢梁的有限元结构分析以及高温切割过程中钢梁温度场分析,确定了钢梁的切割方案,同时为相应高温环境下的结构实时监测方案设计、传感器的布设以及实时监测预警阀值的设定提供了依据。监测过程中实时获取了现场钢梁的工作状态,并对实时监测数据进行了快速分析和评价,从而判断钢梁的安全性,以保证钢梁切割过程的顺利进行。监测结果表明,根据监测方案可以快速评价钢梁的受力状态,为切割机的前进速度提供指导,同时表明光纤光栅应变和温度传感器完全满足高温环境下的测量要求。可视化监测方案在快速预警方面的成功应用可为类似的结构改造提供结构健康监测依据。