Study on the Effect of Clamping Sequence on Bulk Stress Redistribution of Long Edge

Abstract

For a given assembly process, fixture-related operations contribute to the dimensional variations of compliant part. When the manufactured components are within the specified tolerances, the bulk stresses distribution of the assembly are respected. In addition to fixture geometric errors and clamping forces, the clamping sequence can also affect part bulk stress redistribution. This paper presents a numerical simulation of bulk stress redistribution in a long edge assembling with different clamping sequences. A finite element model of the plate with residual stresses after quenching and stretching is constructed. The edge is milled from the numerical plate, and the edge with the initial deformation and residual stresses is ready for clamping. The contact model between the clamper and edge is constructed to simulate the practical clamping process, especially considering the friction contact between the clamper and edge. Then the edge is virtually clamped in different clamping sequences, and its deformation and bulk stresses are obtained. The simulation results show that there are differences in the stains of edge under different clamping sequences, and the edge’s bulk stresses under different clamping sequences are different with each other also. The proposed numerical model could predict the edge’s bulk stresses under different clamping sequences. It will help obtaining optimal stresses of the edge by certain clamping sequence, and help systematically improving the compliant assembling efficiency in civil aircraft industry.