| The civil aviation transport industry in China is developing rapidly,and playing an important role in the fields of economy,politics,science and technology.The operating cost of civil aviation in China is significantly higher than that of other countries.Optimizing the supply cost of aviation materials is the most potential control point to improve the operating status of airlines,and the sharing of aviation materials is an important means.Under the premise of ensuring the safety and guarantee rate of aviation material supply,it is of great significance for airlines and even the whole aviation industry to explore a better management and operation mode of aviation material.The decision-making process of air material-sharing is characterized by great uncertainty and complicated interest relationship among multiple subjects.Only by clarifying the relationship between relevant subjects and establishing stable cooperation mechanism,can the sustainable development of air material-sharing mode be facilitated.The “aviation material sharing” for the joint stock for civil aircraft moving pieces can realize a variety of tasks including AOG support,maintenance and repair,claims management,reliability improvement,modification and upgrade,delivery guarantee for supplements,material support without tries limit,transport guarantee for dangerous goods,MEL release parts support,and aircraft leasing and off-lease parts support.The uncertainty of turnover parts failure rate and repair rate,high cost for spare parts purchase and maintenance and downtime loss,and complex sharer interest coordination relationship bring many difficulties to the joint inventory management of civil aircraft turnover parts.In view of these difficulties,this paper constructed a series of new models and methods,which are summarized as follows:(1)Design of the joint inventory model for civil aircraft turnover parts.According to the characteristics of the joint inventory management of turnover parts in civil aviation companies,such as the high uncertainty of turnover parts failure rate and repair rate,the high cost of turnover parts inventory management,and the complex sharing and coordination mechanism,this paper pointed out the difficulties in the construction of the joint inventory sharing mode of turnover parts in civil aviation companies.This paper summarized and analyzed the mode of joint inventory sharing of turnover parts of civil aviation companies,focused on the key nodes and transfer parameters of the operation process under the mode of industry aviation materials sharing platform,and designed the corresponding model framework for the key issues in the management of joint inventory of turnover parts of civil aviation companies.(2)Demand forecast for the civil aircraft turnover parts under uncertain parameters.There is limitation when the transition probability matrix based on the parameters with fixed failure rates and repair rates is applied to deal with the queuing system problems which are influenced significantly by environmental factors such as running environment,parts wear,and maintenance level,and characterized as significant fluctuation in the time dimension,for it is hard to master the law of actual system and the security decisions made accordingly are prone to ineffective.Previous studies have focused on the solution and modeling of deterministic parameters,which brings some difficulties to practical engineering prediction and decision making.In view of the repairable parts of civil aircraft with inventory strategy,the failure rate and repair rate of the repairable parts were represented by the ash number,and a grey birth and death process with uncertain parameters was constructed to predict the demand of the repairable parts.Based on the queueing process and stochastic simulation,the models with and without the queueing properties were studied respectively,which enriched the modeling method of the quantity prediction of turnover parts.(3)The optimal decision problem of the turnover cost of civil aircraft under the constraint of guarantee rate.No matter what kind of inventory model is adopted,the cost is an important decision-making unit.There are a lot of parameters influencing the cost of fleet turnover parts inventory in the process of fleet operations,which include spare parts purchase and maintenance costs,the costs of hiring the mechanics,component maintenance costs,and single machine downtime loss.Based on the grey birth death process,the number of spare parts is characterized as the expected number under a certain security probability standard.Therefore,the cost in this kind of decision model becomes uncertain.The optimal decision model of the turnover cost of civil aircraft parts with the constraint of guarantee rate was established,the relationship between the failure repair rate and cost was studied,and the optimal allocation scheme for the number of the mechanics and the level of spare parts,so as to provide a solution for the optimization of the operation and maintenance cost of the turnover parts of civil aircraft.(4)Design of horizontal transfer strategy of civil aircraft turnover parts combined inventory based on grey birth and death process.Based on the operation of the industry aviation material sharing platform mode,this paper discussed the design scheme of the joint inventory sharing strategy for the turnover parts of civil aircraft under the multi-level inventory condition.In this part,a multi-level inventory spare parts prediction model is constructed based on the grey birth and death process.With the guarantee rate as the constraint and the cost as the goal,the design of the turnover spare parts sharing scheme for civil aircraft with horizontal allocation mechanism was discussed.The original algorithm with deterministic parameters was adjusted based on the understanding of the grey birth and death process and the nature of the cost planning model.Some meaningful deductions were given,which would provide a solution for the design of joint inventory sharing scheme of turnover parts.(5)Cost sharing problem of turnover parts of civil aircraft under the condition of uncertain demand.The civil aircraft turnover parts sharing alliance,as an important cooperation means among airlines,was proved effective in the aspects of reducing the cost of spare parts storage,increasing revenue and reducing the risk of guarantee rate.The calculation result of the inventory management cost of the shared alliance under the horizontal transport strategy revealed that there was room for cost reduction under the shared alliance cooperation.Therefore,a new problem arose: how do the airlines joining the airline alliance share the cooperation cost? This problem would have a significant impact on the economic efficiency of the airlines involved and the stability of the airline alliance.The failure rates and repair rates of the fleet were set as uncertain parameters in the above-mentioned model,which brought new challenges to the commercial cost allocation of a shared alliance.Therefore,this paper,on the basis of Shapley cooperation game model,discussed the sharing cost allocation model with divergent constraint qualifications,in order to provide corresponding solutions to the problems.In general,the grey birth and death process was an attempt in the model construction for the failure repair process with uncertain parameters.The quantity prediction and cost decision optimization of spare turnover parts of civil aircraft under non-queuing and queuing background provided the basis for the design of sharing optimization strategy.Finally,the cost allocation model based on cooperative game theory provided solutions for the operation mechanism of sharing model. |
