【作者】 王烨；

【导师】 左洪福；

【作者基本信息】 南京航空航天大学 ， 载运工具运用工程， 2009， 博士

【摘要】 航空工业是我国的战略性高科技产业,我国自主研制的新支线飞机ARJ21完成总装并已开始试飞,C919大飞机项目也已在紧锣密鼓的进行当中,所有的这些对于提升我国航空工业在国民经济中的地位及国际影响力有着举足轻重的作用。民机产品可靠性评估在整个飞机的方案论证、工程研制、投入生产及交付使用、维护等各个阶段都非常重要,可以衡量产品的可靠性是否达到了预期的设计目标,验证产品可靠性设计的合理性,指出产品的薄弱环节,为改进产品的设计、制造、工艺及维修优化指明方向。因此,民机产品可靠性评估技术的研究对于我国民机事业的发展具有非常重要的意义。本文以此为背景,针对民机研制和使用过程中所采集的可靠性信息特点,深入研究了相关的可靠性评估理论和技术,同时开发了实用化的民机信息数据库和可靠性评估系统。主要研究内容和结论包括:(1)研究了基于小样本寿命信息的民机产品可靠性分析评估方法。根据民机研制过程中的小样本可靠性寿命信息,对其进行分布的假设检验,并充分利用专家的经验信息,用基于模糊贝叶斯的方法进行融合,判断产品的寿命分布,并计算其可靠性参数;若在评估过程中没有专家经验信息或其他信息可以利用时,提出将机器智能研究领域的统计学习理论运用到小样本寿命信息的可靠性分析中去,在样本数目有限的情况下,可以获得很高的评估精度,充分显示了其在小样本可靠性分析方面具有的独特优势。(2)传统的可靠性信息仅仅记录产品的失效数量和时间,而高可靠性长寿命民机产品的试验和使用包含着准确、丰富且与寿命紧密相关的性能退化信息,故本文从产品性能参数的变化入手,对产品的性能数据进行连续测量,获得退化数据,利用支持向量机算法在函数逼近中的优秀性能对产品的退化轨迹进行建模,获得产品在失效阈值下的寿命数据,分析了性能退化轨迹与寿命分布之间的关系,进而对产品的可靠性进行评估,由此可以在较少的退化样本下对高可靠长寿命产品的可靠性进行分析,具有广泛的适应性。(3)在民机复杂系统可靠性评估方面,为了充分挖掘产品多种来源的可靠性信息,提出了基于环境因子和信息熵综合法的可靠性评估技术,将不同时间环境下的试验信息融合为工作环境下的等效试验信息,将零部件和子系统的工作环境试验信息融合为系统的等效试验信息,最后利用系统的综合试验信息进行可靠性评估。用此方法对ARJ21襟翼收放系统的可靠性进行了评估,经工程实践验证,效果很好。(4)民机发动机的寿命与可靠性管理是一项非常重要的工作。本文针对发动机的多个状态参数,提出了采用以单一寿命预测模型为基础,由能够综合利用不同模型带来的有效信息的免疫粒子群组合预计方法(IA-PSO方法)对发动机的在翼寿命进行预测,在此基础上对在翼寿命的可靠性分布进行了拟合优度检验,得到了寿命的分布及相应的分布参数。并提出了民航发动机使用时的在翼寿命控制方法。(5)最后,从民机产品可靠性评估的实际问题出发,根据论文依托项目的需求,结合先进的数据库及应用程序设计技术,开发了一套民机产品可靠性评估系统RASAP。文中的理论和方法及开发的系统在西安飞机设计研究院取得了良好的应用效果。这一工作为我国在民机研制及运行使用方面的可靠性评估分析及维修优化提供了方便、实用的方法和工具。更多还原

【Abstract】 Aviation industry is one of the most important hi-technology strategy industries in our county. The new ARJ 21(Advanced Regional Jet 21st) has already finished its assembly and flight test successfully; the C919 commercial aircraft project is also in progress. All these have been done is of great importance in improving the position in national economy and international power of our country’s aviation industry. The reliability assessments for civil aircraft products are significant in the process of total aircraft’s project demonstration, engineering research & development, production, consignation into use and maintenance. It can evaluate whether the productions’reliability reaching the original object, validate the rationality of reliability design, point out the productions’weakness and demonstrate direction in elevating the civil aircraft’s design, manufacturing, technics and maintenance optimization. Therefore, Researches on technique of reliability assessment for civil aircraft productions are of great significance to develop our county’s civil aircraft projects. With the background of the situation, according to the reliability information’s characteristics gathering in the aircraft design and operation’s process, this paper puts emphasis on the researches about the theory and technique of reliability assessments, at the same time we have developed practicable aircraft information database and reliability assessments system. The main research contents and conclusions include:(1) The reliability assessment method for civil aircraft productions based on small sample life information is proposed. According to the small sample reliability life information gathered during the aircraft’s design and operation process, the paper has tested the hypothesis of distribution, proposed a fuzzy-bayes method fusing the experts experience information, evaluated the productions’life distribution and finally computed the reliability parameters; When there are no experts experience information or other information available, research on the reliability analysis with small sample life information is carried out by using Statistical Learning Theory in machine intelligence research fields. Under the circumstances of limited sample, the method can achieve high precision in the assessment, fully indicating the particular advantages in the reliability analysis of small sample.(2) Traditional reliability information is merely recorded the failure number and time. However the tests and operation of high-reliability and long-life civil aircraft products include accurate, ample performance degradation information related to the life closely. So, in order to make full use of the performance degradation data, a Support Vector Machine (SVM) based reliability method is established by modeling the degradation track, acquiring the degradation data, analyzing the relationship between the track and the life distribution, evaluating the products’reliability. This method can be used to analyze the high-reliability and long-life civil aircraft products on the condition of less degradation sample and has comprehensive applicability.(3) On the aspect of assessing complex systems of aircraft products, in order to fully mine the reliability information from all sources of databases, the reliability assessment technique based on the environment factor and integrated information entropy is proposed. The method fuse the test information gathered under different circumstances into equivalent test information of working circumstances and evaluate the reliability of aircraft products based on the systems integrated test information eventually. In this paper, the method is used in assessing the reliability of ARJ 21’s flap operation system and has good effects through engineering practice.(4) The life and reliability management of civil aeroengine is an important work. In this paper, according to several aeroengine parameters, a combined prediction method named IA-PSO is brought forward to predicting the life on wing. Multiple single models was based in this method, Particle Swarm Optimization algorithm (PSO) improved by Immunity Algorithm (IA) was used to set weights for every single model which attended combing, and different kinds of information form different single models could be integrated by it. Based on the prediction, the distribution of the life on wing and its parameters can be achieved. Finally, a method which is used to control the life on wing is established.(5) According to the requirements of the projects this paper relied on, a set of reliability assessment system of aircraft products (RASAP) is developed by using the technology of advanced database and application in order to solve the problems of reliability assessments. The theory and methods including the developed system mentioned in this paper have received high estimation. The work provides convenient and practical methods and tools for the reliability assessments and maintenance optimization in the fields of our county’s civil aircraft design and operation.更多还原