Investigation of Riveting Parameters Influence on the Riveted Joints Deformation during Slug Rivet Installation

Slug rivet is widely used in aircraft assembly due to the higher interference fit level and the longer fatigue life. However, the inhomogeneity of riveting interference value along the thickness direction of the aircraft panels always leads to inevitable deformation, which significantly degrades the dimensional accuracy of the final products. In this study, a quantitative model is established to describe the relationship between several riveting parameters (i.e. squeezing force, buck cavity, upsetting rise time, upsetting dwell time and clamping force between sheets) and the deformation of a formed slug rivet joint. Then the coefficient of variance (CV) is introduced to evaluate the homogeneity of deformation. Subsequently, an optimized combination of the presented parameters is obtained by using finite element method (FEM) simulation so as to generate more uniform deformation. Finally, the FEM model is validated by a series of orthogonal experiments conducted in G86 fully automated C-frame riveting machine and the results show that the squeezing force and the buck cavity are the main significant factors and contributors to the riveted joints deformation, and the sequence of this effect from the high to low are: upsetting dwell time, clamping force, and upsetting rise time. The results also indicate that the developed FE model can be used for further analysis, including the prediction of large component riveting deformation and the mechanical properties of riveted joint.