Research On Major Technology And Method For Civil Aircraft MRBR Development

Development of aircraft maintenance review board report(MRBR) is the key technology for civil aircraft maintenance engineering analysis. Although related international specifications are available, how to imply them to newly developed aicraft is still lack of valid procedure and logical decision methods. The major problems are as follows:(1) The identification of maintenance task for major maintenance item is lack of supportting methods and tools.(2) The determination of maintenance interval for maintenance task has no valid theory foundation, but depends on the recommendation of suppliers. With the steady progress for the development process of large passenger aircraft, these problems need to be solved urgently. Under S3000 L aircraft maintenance analysis framework, this thesis focuses on MRBR development technology based on MSG-3, especially to explore the logical decision method of maintenance task identification, to study the thory and method of the computing maintenance interval. The main achievement are as follows:(1) In terms of lacking of valid procedure and logical decision method for civil aircraft MRBR development, this thesis explores MSG-3 anlaysis method according to S3000 L, for further, studys MRBR logical decision procedure. Combined with the domestic large passenger aircraft research and development, this research systematically constitutes operable logical decision procedure based on MSG-3 for system and power plant, structure, zone, and L/HIRF scheduled maintenance analysis. Finally, engineering applications explain its validity.(2) For the problem of lacking of statistical data during identification maintenance interval for newly developend civil aircraft MRBR, the unit life lower confidence limits are computed using Monte-Carlo simulation, fault tree, and performance degradation. At last, system maintenance interval is given combined engineering judgment.(3) Aiming at the problem of maintenance interval determination for aircraft structure AD/ED, the aircraft structure inspection interval is studied. Engineering judgement method for determining aircraft metallics and Composite Materials structure’s AD/ED rating is studied, and then aircraft structure damage rating table is given. Next, principle for aircraft maintenance interval rating classification is discussed, and maintenance interval rating table is given combine experience and similar type aircrafts. And finally, ED assessment modle is established according to fuzzy theory, and the correspondence between the EDR and the maintenance interval is obtained.(4) It’s difficult to determine structure FD maintenance interval, therefore, this thesis utilizes damage tolerance analysis and dispersion coefficient to identify maintenance interval in the desigen stage according to structural strength design data. On the other hand, single crack growth equation is established on the basis of obtaining crack propagation law. Further more, crack propagation life is determined by establishing the MSD crack rapid calculation method. Considered the functional inspection and monitoring methods, the CBM decision-making model--delay time model was studied to optimize the Inspection/ check interal subjected to availability and reliability. Example shows that method is reasonable and effective.