Research On Key Technologies Of Maintainability Concurrent Design For Civil Aircraft

Maintainability as an important characteristic of civil aircraft product has decisive influence on its life cycle cost. Maintainability design is a significant way to improve maintainability of product. In order to overcome the shortages of traditional maintainability design method such as long cycle, high cost and difficulty for design modify, key technologies of maintainability concurrent design for civil aircraft product are deeply studied, .and corresponding models and theories are established to support maintainability concurrent design.The maintainability concurrent design framework is studied. The process of maintainability concurrent design is studied based on axiomatic design theory, and detailed design steps and related work is determined. Concurrent method of maintainability work is proposed based on micro-design-cycle theory, and the relationship among kinds of information related to maintainability design is described. And cooperative work mode of maintainability concurrent design team is presented.Maintenance disassembly analysis for concurrent design is studied roundly. The component-joint graph model oriented to maintainability concurrent design is developed by describing the relationship between component-modules and joint-parts with incidence matrix. Disassembly direction of component-module is determined by interference matrix, and the disassembly sequence planning method of component-modules is proposed based on ordered search method by taking as minimum of disassembly expense as optimization objective. The whole disassembly sequence planning method is proposed based on genetic algorithm of gene pair crossover and mutation by taking minimum of tools change times as optimization objective. An application instance, used to illustrate the effectiveness of these methods, is presented combined with nose landing gear system of a certain civil aircraft.The maintenance process modeling theory and method is thoroughly studied. The predictive and corrective maintenance work is determined by reliability centered maintenance theory and fault tree analysis respectively, and calculation method of maintenance task is proposed based on MOD method. In terms of modeling method for maintenance process elements and logical relationship of maintenance task, the maintenance process model simplified as MPBC based on Colored Stochastic Time Petri Net is established. According to MPBC model, the analysis methods of maintenance resource parameters are represented, and the maintenance time simulation model based on Monte Carlo method is proposed. A case combined with nose landing gear system of a certain civil aircraft is given to show the advantage of the models mentioned above. The maintainability evaluation model is researched roundly. The calculation method of quantitative parameters of maintainability is based on MPBC model. The evaluation method of maintenance accessibility and ergonomics are given respectively. Based on multiple attribute decision-making theory and fuzzy theory, the pretreatment methods of maintainability attribute values is given, and the maintainability comprehensive evaluation model is built for civil aircraft product. As well, a case is given to the effectiveness of the methods mentioned above.Maintenance process virtual simulation system is developed based on DELMIA that is the digital enterprise lean manufacturing interactive application software. Standard parts library of maintenance tools based on three-dimensional feature is built by using parametric design technique; and the basic posture library of maintenance personnel is built with manikin attribute tools provided by DELMIA. The maintenance disassembly process of nose landing gear wheel is used as a maintenance process virtual simulation instance, and accessibility and ergonomic analysis is conducted on some key maintain task to realize the maintainability virtual assessment for product.