Design and Manufacturing of Aerospace Composite Structures, State-of-the-Art Assessment

Abstract

The results ofan assessment ofthe state of theartin the design and manufacturing of largecompositestructures are described. The focus of the assessment is on the use of polymeric matrix composite materials for large airframe structural components, such as thosein commercial and military aircraft and spacetransportation vehicles. Applications of composite materials for large commercial transport aircraft, general aviation aircraft, rotorcraft, military aircraft, and uninhabited rocket launch vehicles are reviewed. The results of the assessment of the state of the art include a summary of lessons learned, examples of current practice, and an assessment of advanced technologies under development. The results of the assessment conclude with an evaluation of the future technology challenges and advancements associated with applications of composite materials to the primary structures of commercial transport aircraft and advanced space transportation vehicles. These future technologies include breakthroughs in materials and process methods, next generation design tools, and nondestructive examination methods. I. Introduction A N assessment of the design and manufacturing practices for large composite structures has been conducted to determine the current state of the art for these technologies. The background that motivated the assessment was a series of unexpected manufacturing and design problems with the composite structures of several NASA experimental vehicles currently under development. The focus of the assessment is on the use of polymeric matrix composite materials for large airframe structural components such as those in commercial and military aircraft and space transportation vehicles. The baseline for the assessment is the historical evolution of the use of composite materials in actual aerospace vehicles. The assessment emphasizes the application of composite structures in moderately to heavily loaded aerospace vehicles. Applications of composite materials are reviewed for large commercial transport aircraft,generalaviation aircraft,rotorcraft, military e ghteraircraft, and military transport aircraft. The baseline also includes the application of composite materials for uninhabited rockets and space transportation vehicles. The assessment of the state of the art includes a summary of lessons learned, examples of current practice, and an assessment of advanced technologies under development. The assessment concludes with an evaluation of the future technology challenges associated with applications of composite materials to the primary structure of commercial aircraft and advanced space transportation vehicles. As a preamble to assessing the state of the art in the design and manufacturing of composite structures, the design requirements for aerospace vehicles are briee y reviewed. Because of the universal design requirement to minimize the gross takeoff weight of all aerospace vehicles, aerospace structural components are designed at or near zero margin of safety. Whereas the margin of safety is not