Monday, January 28, 2019
Life Cycle Analysis of Aviation Products
INTRUDUCTIONIt is very easy to question a nation for its decision to retract seemingly useful aircraft, but there atomic number 18 many sparingal factors that need to be taken into account.We often hear about how frequently it be to buy any particular model of plane, but nation often underestimate just how expensive it is to ope array and maintain aircraft. not unless do you reserve to consider the read woo of fast-flying the plane (pilot pay, fuel, and other consumables), but also the exists of pilot training, the bells of parts and labor to perform routine maintenance, the bells of training world crew to perform that maintenance, the be of obtaining and maintaining lose equipment essential to gain the planes, and the constitutes of the facilities needed to perform this service and maintenance. We often lump all these factors unitedly into the life- rhythm method per second cost of an airplane.GENERAL DISCUSIONLife Cycle monetary value is extremely important w hen find whether to stop or replace aircraft, acquire new or used aircraft, and in evaluating the tot up economics of competing aircraft whether purchasing, financing, or leasing. With this program you atomic number 50 predict specie Flows and Net Present Values and comp ar contrary forms of ownership.As aircraft have run short increasingly analyzable, the life-cycle costs associated with maintaining sophisticated equipment and training crew to operate and service that equipment have grown substantially. For this reason, we see a trend in militaries roughly the world to standardize on as few types of aircraft as possible. By operating only a couple types of planes, a military move consolidate its training and servicing activities thereby minimizing the amount of money needed for aircraft operations and maintenance.This motivation is likely a major(ip) factor in the business decision to eliminate their old aircraft. The business kindle sooner focus its maintenance and tra ining budgets on a few uses, which head for the hills to share much in common, as opposed to siphoning off a large chuck of that money to confirm a performly unalike design. Understanding and modelling factors related to schooling, economics, marketing, risks, and un definitety can enable designers to design more cost-effective forms. The importance of developing omnibus(prenominal) life cycle cost models cannot be over emphasized with reference to affordable systems. concomitant areas of concern include take cost, estimating, organizational learning, pricing and marketing, sub-contracting deed, and predicting competitors cost.In addition to the component of the cost estimation, usually the focal point of most cost models, immaculate modeling of all factors related to the end product, operations, and support is necessary to generate fine-tune life cycle cost profiles. Basic railway locomotiveering science economics can be used for determining price once the cost has been estimated. pursuit formulas are available for predicting rates of return and other indicators of hitability. However the complex models used for life cycle cost prediction must expend algorithm for stimulating additional factors as organizational learning and manufacturing processes.The trinity primary component f the system life cycle are non recurring costs, recurring costs, and operations and support costs. According to Apgar, H. (1993) there are two principal objectives for an life cycle cost trade story as the identification of the design and production process alternatives which meet borderline performance requirements both at the lowest average unit production cost, and at the lowest operation and support cost per operating hour.A abundant range of cost models exists today, from dilate part-level models, establish on direct locomotive engineering and manufacturing standard factors, to conceptual design level life cycle models. piece most of the conceptual desi gn level models are parametric and metric weight unit/complexity-based, much research is being conducted to develop feature-, activity-, and/or process-based models. Many of the detailed models use measured info from the shop floor for the regression depth psychology and algorithm development. At the other end of the spectrum are the top-level, parametric cost estimating models for life cycle estimates. Few models exist between the two ends of the modeling spectrum no suitable methods have been demonstrated for a model that accepts multifidelity information from multiple levels of product analysis within an integrated design environment.Detailed estimates of direct materials and hours used for fabrication and assembly of the aircraft major structural components (accommodating the many and alter material types product forms such as sheets, extrusions, fabrics, etc. and construction types apply in advanced technology aircraft structures) will replace the weight/complexity-based algorithm for estimating the aircraft cost in the top-level, parametric life cycle cost model. These differentials in the aircraft cost estimates due to fabrication and assembly alternatives will propagate via the system roll up cost through the life cycle for production, operation, and support for the full system.With such a tool/model, the designer will be able to determine sensitivities in the top-down life cycle cost model to changes or alternatives evaluated in the bottom-up cost model. It will be possible to calculate sensitivities and design for robustness with the life cycle cost model due to perturbations of some factors such as entities external to the producer functions internal to the manufacturer, but external to manufacturing and processes internal to the manufacturer.The manufacturer cannot control certain factors external to the enterprise. For instance, the number of aircraft ordered, the times of the orders and the corresponding payment schedule, interest rates, and project inflation rates are not variables over which the manufacturer has complete control. The monthly or yearbook production rates sub-contracting decisions learning ignore effects and manufacturing, and sustaining costs are factors that are internal to the enterprise, but can be categorized in a higher level than the true material purchasing, processing, fabrication, and assembly. The sequences of activities and processes used for fabrication and assembly are assumed to be internally controlled by the manufacturer.The lowest level of the life cycle cost model consists of the cost estimation for the aircraft, based upon the direct engineering and manufacturing estimates for its major structural components. The highest level includes determination and distribution of the non-recurring and recurring production costs, as well as the operations and support costs over the entire life cycle of the aircraft.According to Febrycky, W.J., and Blanchard, B.S. (1991) that a through und erstanding of certain economic theories must be achieved before any reasonable life cycle cost analysis can be undertaken. Alternative instruments can be compared against from severally one other or a fair basis only if their respective benefits and costs are converted to an equivalent economic base, with get hold of consideration for the time value of money. Three factors are involved when determining the economic equivalence of sums of money. They are the amounts of the sums, the times of occurrence of the sums, and the interest rate. pursuit formulas are functions of all three. These functions are used for calculating the amounts occurring at different periods of time.The life cycle cost analysis of aircraft comprises the following capabilities. The unit production costs are estimated with a series of experimental equations for generating airframe component manufacturing costs for specific classes of aircraft. According to Lee, P. (1994) that a theoretical First Unit Cost is generated by summing the respective component costs of the airframe, propulsion, avionics and instrumentation, and final assembly. Most of the structural component cost equations are weight-based. Engine costs are based on the thrust, the amount produced, and the cruise Mach number.Alternatively, the actual price/cost of the engine can be specified as input parameters. Another series of exponential equations is used to calculate the production costs based upon the total number of vehicles produced. The average unit airplane costs, either including or excluding airframe and engine spares, are also calculated. A comparison of the average aircraft manufacturing costs versus the quantity of aircraft produced is provided. The elements of the total vehicle cost can be reduced with user-specified learning curves for the airframe, avionics, propulsion, assembly, and fixed equipment. For a specified production rate, ship set, and average aircraft marketing prices, the manufacturers cumula tive and annual cash flows are calculated.The annual and cumulative aircraft deliveries are calculated first, based upon an input production rate schedule. The manufacturing cost is the sum of the production costs of all operational vehicles produced each year. The cost to manufacture one vehicle includes airframe cost, propulsion cost, avionics and instrumentation cost, and the cost of final assembly. The manufacturers sustaining costs are the total production costs minus the cost of the operational vehicles and the manufacturers profit fee. Ten elements constitute the total sustaining costs airframe and engine spares, facilities, sustaining engineering, sustaining tooling, ground support equipment, training equipment, initial training, and initial equipment. The sustaining costs are distributed equally for each aircraft over the same months in which each aircrafts manufacturing costs are distributed.CONCLUSIONThere is normally a conflict between cost-effective choices and affordab le choices for alternative designs. Today, the commit for cost-effectiveness is often sacrificed to the practical considerations of the available funding with the development of more complexes and comprehensive life cycle cost modes that can accept and process multifidelity data within an integrated design environment, it will be possible to better calculate the cost-effectiveness and affordability of future systems. Then it may be possible to have a system that is ultimately cost-effective, yet still affordable.REFERENCEApgar, H. (1993). heading-to-Life-Cycle-Cost in Aerospace, Aerospace Design Conference, Irvine CA.Febrycky, W.J., and Blanchard, B.S. (1991). Life-Cycle Cost and Economic Analysis, Prentice Hall, Englewood Cliffs, New Jersey.Lee, P. (1994). A Process point Parametric Cost Model, Aerospace Design Conference, Irvine CA.
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