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Process capability information, combined with simplified component geometric models and assembly variation transfer functions built from Monte Carlo simulations, can give aircraft designers early estimations of product variability. Such predictions traditionally must wait for detailed component designs-after many important sourcing and production decisions have been made and when alternative designs are no longer an option. An additional benefit of early variation analysis is identification of major contributors to critical assembly variation. This information can alert downstream part designers of potential problem areas and also identify key manufacturing processes capabilities that must be verified, measured, and/or improved. This paper presents an efficient, top-down approach to move assembly variation analysis into early stages of aircraft development.

In aircraft assembly, a burr left at the interface of any joint is considered a source of potential fatigue life degradation. Burrs can act as an additional stress concentration, leading to fretting, inducing failures. It could also open moisture paths resulting in corrosion. Burrs can affect the fatigue life of various structures differently depending on the type of joint, material, fastener, and installation process. Traditionally, we have disassemled and deburred the interface with various tools such as sand paper, file, chamfer tool, hook, or other tools. Disassembly and deburring of airplane major parts are time consuming and costly. In addition achieving “one up assembly” is not viable unless interfacial burr can be eliminated or reduced to the point where it will not affect fatigue life. In this investigation, the possibility of “one up assembly” via creation of concentric and adjacent clamping in various materials is studied.