Numerical and experimental investigation of bulk stress distribution in edge under different clamping sequence

Abstract

Purpose The edge is a typical aero-structural compliant part, whose length-width ratio is about 60:1 and height-thickness ratio is about 30:1. Distortion of the edge is mainly caused by the bulk stresses which come from the manufacturing process of the plates. This paper aims to investigate the effect of clamping sequence on the bulk stress distribution in the edge. Design/methodology/approach The paper conducts the numerical and experimental investigations to predict the bulk stress distribution in the edge under different clamping sequences. A finite element model of the plate with residual stress after quenching and stretching is constructed. The edge is milled from the plate numerically and is ready for clamping. The contact model between the clamper and the edge is constructed to simulate the clamping process. Then the edge is virtually clamped in different clamping sequences, and different deformations and bulk stresses are obtained. An experimental edge milled from the plate and a designed clamping platform are used to precisely control clamping force to verify the effect of clamping sequence on the bulk stress distribution in the edge. The experimental edge’s distortions, relative displacements between the edge and the clamper and clamping forces validate the proposed numerical model. Findings The primary cause of bulk stress redistribution is the friction between the rigid clamper and the compliant edge. The edge exhibits different deformation under different clamping sequences because of its compliant characteristics. Originality/value The proposed numerical model of the edge could predict the bulk stress distribution in the edge under different clamping sequence. The developed clamping platform could be used to conduct clamping experiments, including experiments with different clamping forces, sequences and different clamping positions. It will help to systematically improve the compliant assembling efficiency in civil aircraft industry.