Analysis of the Local Phenomena during Riveting Process

Abstract

The riveting still remains the most popular and basic method of joining metal parts in airframes. At the same time, the rivets are critical from the fatigue point of view. The paper presents the selected investigations of local phenomena during the riveting process. At the beginning, some results from the literature, concerned on the riveting process influence on fatigue of the three-row lap joint were shown. The analysis of these results leads to the conclusion that the increase in fatigue life caused by higher riveting force is so high that the more beneficial residual stress cannot be the only explanation, but the new phenomena in riveting process occurs and it is a reason of huge increase in fatigue life. The working hypothesis has been assumed that during the riveting process adhesive joint (called cold welding) were formed between the rivet shank and the sheets. Several microstructure tests were conducted in order to verify this hypothesis. The tests include riveting the specimens for various configurations and analyses of the microsection of selected specimens with the use of optical and scanning electron microscope. In the case of several specimens the punctual and linear welding between rivet shank and sheets were observed. The paper presents the investigation and selected results. The authors are going to continue presented researches.