Efficient method of positioning error analysis for aeronautical thin-walled structures multi-state riveting

The riveting process of aeronautical thin-walled structures (ATWS) with "Frame-type" automated riveter systems is always multi-state. The changing of fixtures and datum in riveting process would lead to the difficulty of positioning error analysis, and the positioning error will influence the tolerance characteristics of final product and the fatigue durability. This paper presents an efficient method for positioning error analysis in ATWS multi-state riveting. Firstly, the whole riveting process is divided into two stages according to the changing of riveting fixtures, and the model of positioning error in each stage is developed on base of the mismatch error analysis. Secondly, by defining key characteristic points (KCPs) according to anchor points and joining points, the positioning error of ATWS is represented as the error of KCPs, and the scheme of anchor points and joining points is developed according to the "N-2-1" positioning principle. Thirdly, on base of positioning error propagation analysis in each stage, components of positioning error are discussed in detail, and the mathematical model of each component is developed, according to the manufacturing error, position accuracy as well as the mismatch error. Lastly, a wing panel which is made up of a skin and four stringers is studied as a case to calculate the positioning error. The comparison between computing result and measurement proves that the purposed positioning error analysis method can solve the positioning error analysis problem for ATWS multi-state riveting efficiently.