Multiple-site damage in riveted lap-joints: experimental simulation and finite element prediction

The multiple-site damage (MSD) phenomenon is discussed, and exemplified by the behaviour of riveted lap-joint specimens of aluminium alloy 2024-T3 alc lad. The tests performed, on which the paper is based, are part of the cont ribution of IDMEC to a project on the fatigue behaviour of ageing aeronauti cal structures-the BRITE-EURAM project 'SMAAC', partially funded by the Eur opean Union. The study involves fatigue testing under constant amplitude lo ading of 1.6-mm-thick riveted lap-joints, and includes examination of the s pecimens during and subsequent to testing (post-mortem analysis of the frac ture surface in a scanning electron microscope) in order to determine the t ime of occurrence, location and extent of fatigue damage. Crack growth rate s are determined from periodic crack length measurements with a travelling microscope. Stress measurements are made using extensometry and the SPATE i nfrared technique to determine loading distribution of the lap-joints and r edistribution due to cracking of fastener holes. Data on the initiation and growth of cracks and on residual static strength are used to assess the pr edictive model based on the finite element method. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.