Experimental study on dynamic behavior of CFRP-to-steel interface

Abstract

Carbon fiber reinforced polymer (CFRP) sheets/plates have been gradually used to strengthen the deteriorated steel structures in recent years. The efficiency of the FRP strengthening technique is generally dependent on the bond between the CFRP composites and the steel. A number of research studies developed so far have focused on examining the bond behavior of CFRP-to-steel interface under static loading. In this paper, the dynamic bond behavior of CFRP-to-steel was experimentally investigated through the drop-mass impact test method. Three impact heights were adopted in order to highlight the effect of the loading rate on the bond strength. Experimental findings showed that the strain distribution gradient and the ultimate capacity of the CFRP-to-steel interface under impact loading were larger than those under static loading, and the bond strength was influenced significantly by loading rate, while the effective bond length is insensitive to the impact loading. Furthermore, the mechanism analysis on the improvements of ultimate capacity for CFRP-to-steel interface under impact loading can be deduced considering the influence of strain rate on shear strength of the adhesive. A formula was also proposed to conservatively predict the ultimate capacity of CFRP-to-steel interface under impact loading.