The investigation of mechanical properties of a structural adhesive via digital image correlation (DIC) technic

Abstract

The most important point to be taken into consideration in the use of bonding joints is the reliability of the joints created with the adhesive. Therefore, many analytical, experimental and numerical studies have been done to determine the mechanical properties of adhesives and to ensure the reliable use of adhesively bonding joints. This study presents the first stage of the two-stage study, which aims to determine the mechanical properties of the DP410 structural adhesive in the first stage and the mechanical behavior of the adhesively bonded single lap joints formed using the same adhesive in the second stage. In the study, mechanical properties of the DP410 structural adhesive were investigated experimentally via two dimensional Digital Image Correlation (DIC) technique. Bulk (tensile, Iosipescu and Arcan) and joint form (TAST) specimens were produced from structural bicomponent liquid adhesive (DP410) and subjected to uniaxial tensile and shear loads in the study. Mechanical properties of the DP410 bulk specimens were determined by two different measurement methods (DIC and video extensometer). It was observed upon comparing the results obtained that the DIC technique yielded reproducible results in the determination of the mechanical properties of adhesives and this method of optical measurement could be an alternative to other strain measurement methods. Shear mechanical properties of the DP410 adhesive were obtained via two different strain measurement methods, (DIC and contact extensometer) in the TAST specimens. When the results obtained from TAST specimens were examined, it was observed that the results obtained from DIC method were compatible with contact extensometer and it could be an alternative to contact extensometer. In addition, since local strain distributions can be obtained in the DIC method, it has been observed that this method allows to performe damage analysis of the specimens in bulk and joint form and to obtain the strain values at the desired positions. In this study, the accuracy of the results obtained from the 2D DIC analysis can be increased by using the software which allows to perform the 3D DIC analysis via high resolution cameras and by preparing the sample with the right methods.