Application of Dic Technique for Monitoring of Deformation Process of Spr Hybrid Joints / Zastosowanie Techniki Dic Do Obserwacji Procesu Deformacji Hybrydowych Połaczen Typu Spr

Abstract

Digital Image Correlation (DIC) technique gives possibility to observe deformation process in many applications including self-piercing riveting (SPR) hybrid joint. The hybrid SPR joint consists of simple SPR joint made of two adherends, steel tubular rivet (total length of 5 mm) and an adhesive. The adhesive was applied before piercing process. For specimen preparation two different aluminum alloys were used: 2024 and 5005 (2mm thickness both) with tensile strength 400 and 160MPa, respectively.For better understanding of joint forming process and to allow DIC strains observation during the joint creation, a special holder was designed with precisely polished die. The tests were performed by application of the 100kN servo-hydraulic machine, which recorded time, load, displacement and was synchronized with the DIC system.The joint forming process was carried out with 2 mm/min constant speed. During piercing process rivet and upper surface of the adherend were observed and the major strain states were estimated. The uniaxial tensile tests of single lap joints (SLJ) up to the final failure were performed and the displacements and the strains were recorded. In particular the rivet deformation was observed also during the whole loading process.The hybrid SPR joints are very effective, because the load capacity and energy absorption increase more than 1.5 times in comparison to the simple SPR joints.