Study Of The Life And Cost Of Military Fleet During Service Period

A variaty of new technologies and materials as well as measuring means are applied on military aircraft extensively with high-speed development of science and technology which greatly improves synthetical properties but makes the life cycle cost of military aircraft dramatic rising. The cost of military aircraft in-service period has been risen sharply. Relative studies show that the cost proportion in-service period is 60 to 70 percent of life cycle cost of military aircraft which afford the cost has become a serve problem for user of military aircraft to face.This dissertation studies the life cycle (LC) and life cycle cost (LCC) of military aircraft and especially stress on the LC and LCC in-service period of military fleet. The main contents are summarized as follows:1. Based on studying combat readiness storage of operational life (CRSOL) of military fleet, the traditional ideal of All the same is analyzed critically. The reasonableness and necessity of modifying the storage up to 40 percent total LCC are demonstrated in-depth with its factors and level of operation life combat readiness storage of military fleet in detail. Some mathematical models are proposed and their reasonableness is proved through practical application.2. The overhaul of aircraft is the way to the life supplement, overhaul imitate new is carefully studied. A mathematical model to determine overhaul period limitation and a practical criterion to evalute economical overhaul are suggested in the dissertation. Also some ways to extend overhaul period and improve its economy are proposed for enginerring practice. The theoretical models and logical judgement graphics are applied to some typical overhaul cases of military aircraft and its some important assemblies.3. With help of economical theory, a large amount of historical data for relative maintanence are analized and dealt with. For military aircraft, its overhaul cost is decomposed structurally and the margin is determined, some cost compositions and mutual relations are found. Applying linear regression method and grey theory, a predicting model for aiecraft overhaul cost is proposed, some practical evalutions shows that the model is crrect and better with its precision.4. The LCC composition of military aircraft is studied carefully and its LCC model and cost prediction models of each stage are put forward respectively. The LCC control principle is suggested and the economical lives are evaluated respectively for a single type aircraft and the mixed service of old and new one.5. The maintenance economy of military aircraft during service period and the factors influencing maintenance cost are studied and modeled. Mathematical analysis to reliability-centered maintenance gives a maintenance cost function, making use of which, a maintenance cost control strategy is drawn. Moreover, the aging problems of out-of-service military aircraft is studied specially, a out-of-service settlement route is proposed.