A Local-to-Global Dimensional Error Calculation Framework for the Riveted Assembly Using Finite-Element Analysis

Abstract

Mechanical structures of large-scale antennas are sheet metals connected by thousands of rivets. The antenna dimensional error after riveting often violates the limit allowed. The prediction of the global dimensional error induced by many rivet connections requires a rapid and accurate assembly deformation calculation method. Main process parameters of these local rivet connections are the local connection dimension, material property, local clamp position, rivet upsetting direction, and the hammer time-to-displacement impact, except for the riveting sequence. We neglect the process parameter uncertainties and consider that the main riveting parameters equate to a dynamic finite-element (FE) model of single rivet connection. The dynamic FE analysis result yields an inherent strain database for the riveted local parts. Then, we propose an iterative loop of static FE analyses for the global structure taking the inherent strain database and possible former static FE analysis result as the boundary conditions. The loop forms a local-to-global framework. Two examples are involved through the framework representation and realistic application. Framework advantages include: (1) a good balance between the cost and precision of dimensional error calculation; (2) the sequence simulation of all the riveting operations; and (3) supporting the further assembly process optimization to reduce the global dimensional error of the assembly with thousands of rivets.