Cost Estimation For Composite Airframe With Applications To Integrated Design Of Aircraft

Reasonable trade-off of costs increasing and weight savings are very important for composite application in aircraft design. Cost estimation method of composite airframe is needed for estimating the economic efficiency of composite application. The manufacturing and maintenance cost estimation method for the composite airframe structures was developed based on the composite manufacturing technology and maintenance technology. Based on the cost estimation methods the composite application scheme was used for a case study. The influence of composite application on aircraft cost and weight was carried out in the process of aircraft conceptual design. An evaluation method was proposed to quantify the benefit for composite application for the airliner design by combination of the cost estimation method and synthesis program for the airliners conceptual design. A multi-objective optimization method was developed by integrating the manufacturing cost model into the traditional wing structural optimization. The main contents are as follows:1) The manufacturing cost estimation methods were classified into three categories for composite airframe structure: the cost estimation methods based on overall characteristic parameters for the aircraft conceptual design phase; the cost estimation methods based on airframe structural features of components and manufacturing technology for the preliminary design stage; the cost estimation model based on the manufacturing process for the detailed design stage. For different design stages of aircraft, the different levels of detailed solutions are needed. Therefore, manufacturing cost estimates of the fuselage should adopt appropriate methods and models. In the composite structure maintenance costs assessment, the factors of affecting cost of maintenance were researched, and the quantitative assessment methods of composite application maintenance costs impact on the fuselage were figured out.2) Taking large aircraft composite applications in the overall design phase as an example, the cost estimation methods are applied to an all-metal aircraft and several typical composite airframe aircraft for manufacturing and maintenance cost of airframe. And the results of three typical applications of composite and all-metal were compared, and the effects of the method of manufacturing composite airframe on costs were analyzed.3) The influence of composite application on aircraft cost and weight was carried out in aircraft preliminary design stage. The correction model of weight and cost was developed. The impact of composite application on direct operating cost(DOC) of aircraft was assessed based on an analysis and optimization synthesis program for the airliners. The results show that a quantitative evaluation method, which can predict impact of the percentage of composite materials in aircraft structure on aircraft DOC, is feasible. The integrated analysis and optimization computing environment established in this work is effective, which can reasonably address the benefit assessment of composite application in aircraft conceptual design.4) The manufacturing cost should be considered in the composite wing structure design. A two level optimized design method for trade-off composite wing structure between weight and manufacturing cost was presented. The design variables include structural layout parameters and size parameters. The process of establishing the composite wing structure optimization was elaborated with considering manufacturing costs. The cases show that this method can obtain the optimal solution set for the composite wing structural weight and manufacturing costs, and provides an effective way to balance the weight and manufacturing costs for composite wing structure design.