Behavior Investigation of CFRP-Steel Composite Members Using Digital Image Correlation

Abstract

The two types of carbon fiber reinforced polymer (CFRP) applications used in steel structures are bond-critical application and contact-critical application, and the major failure modes for these two applications are debonding failure and buckling failure, respectively. Conventional electrometric techniques may not provide precise results because of the limitations associated with single-point contact measurements. Therefore, the nondestructive full-field measurement technique may be a suitable replacement for conventional methods. In this study, the digital image correlation (DIC) technique was adopted to investigate the bond behavior and buckling behavior of CFRP-steel composite members. The CFRP-to-steel bonded joint and the CFRP-strengthened square hollow section (SHS) steel column were tested to examine the suitability of the DIC technique. The stereo-DIC technique was utilized to measure continuous deformation. The bond-slip relationship of the CFRP-to-steel interface was derived using the DIC data. Additionally, a multi-camera DIC system consisting of four stereo-DIC subsystems was applied to the compressive test of CFRP-strengthened SHS steel column. The buckling location and CFRP delamination of the column were identified. The experimental results confirm that the stereo-DIC technique can provide effective measurements for investigating the behaviors of CFRP-steel composite members.