Variation modeling for fuselage structures in large aircraft digital assembly

Abstract

Purpose – The aim of this paper is to present a new variation modeling method for fuselage structures in digital large aircraft assembly. The variation accumulated in a large aircraft assembly process will influence the dimensional accuracy and fatigue life of airframes. However, in digital large aircraft assembly, variation analysis and modeling are still unresolved issues. Design/methodology/approach – An elastic structure model based on beam elements is developed, which is an equivalent idealization of the actual complex structure. The stiffness matrix of the structure model is obtained by summing the stiffness matrices of the beam elements. For each typical stage of the aircraft digital assembly process, including positioning, coordinating, joining and releasing, variation models are built using the simplified structure model with respective loads and boundary conditions. Findings – Using position errors and manufacturing errors as inputs, the variations for every stage of the assembly process can be calculated using the proposed model. Practical implications – This method has been used in a large fuselage section assembly project, and the calculated results were shown to be a good prediction of variation in the actual assembly. Originality/value – Although certain assumptions have been imposed, the proposed method provides a better understanding of the assembly process and creates an analytical foundation for further work on variation control and tolerance optimization.