Evaluation and correction of cutting position's effects on quality indicator measurement of self-piercing riveted joint

Abstract

This study systematically investigated the influences of cutting positions on the measurement accuracy of the self-piercing riveted joint quality indicators. Evaluation and correction methods were proposed for the first time to estimate and compensate the interlock error caused by improper cutting positions. It was found that the measurement accuracy of the rivet head height was not influenced, but the accuracy of the interlock and the remaining bottom sheet thickness were affected by the joint cutting position. A pure offset distance could lead to an overestimated interlock while a solo rotation angle could result in an underestimated interlock. For the studied joint configurations, the relative interlock error was found in the range of −5%–5% with the offset distance smaller than 1.0 mm and the rotation angle less than 10°. The offset distance and rotation angle can cause larger errors on the remaining bottom sheet thickness around the joint central area than around the rivet tip. Moreover, the proposed correction strategy for the interlock has been proved effective and the relative interlock error could be reduced to 1%–3%.