Riveting parameter design that satisfies requirements for driven rivet head dimensions

摘要

Riveted joints are extensively adopted in designing aircraft structures. Riveting implies a squeezing process of the rivet with large plastic deformations to form the driven rivet head. The driven rivet head dimensions (height H, diameter D) depend on riveting force (X-1), rivet length and diameter tolerance (X-2 and X-3), as well as rivet hole tolerance (X-4). Incorrect selection in these parameters could induce the excessive stress concentration that results in initial crack and also results in improper rivet head deformation leading to loose rivet. The present research is conducted on a MS2047AD6-6 rivet and 2.286mm thick aluminum alloy sheets and mainly focuses on the design of riveting parameters X-1, X-2, X-3, and X-4 using the proposed three-step statistical experiment designs including fractional factorial design, steepest ascent design, and central composite design while satisfying the quality requirements for driven rivet head dimensions (H, D) mentioned in Standard Aircraft Handbook. Fractional factorial design is used to evaluate the impact of riveting parameters X-1, X-2, X-3, and X-4 on H and D. Based on the effective ranges of the significant riveting parameters obtained from steepest ascent design, a five-level central composite design is proposed to derive the statistical relations between H, D and the significant riveting parameters, and the statistical models are used to find the feasible region resulting from the combination of the significant riveting parameters while satisfying the quality requirements for H and D. Finally, the feasible ranges of X-1, X-2, X-3, and X-4, namely 16,470N 22,730N, -0.1491mm 0.3891mm, -0.0466mm 0.1216 mm, and -0.0375mm 0.2125 mm, are determined from the perspective of adjustable accuracy of X-1 and that of the manufacturability for X-2, X-3, and X-4. It implies that any combination of X-1, X-2, X-3, and X-4 that falls within this feasible region can result in a good quality riveted joins, namely that the quality requirements for the driven riveting head dimension (H, D) can be satisfied.