Experimental investigation of multi-material aluminum-to-steel and GFRP-to-steel bonded and bolted/bonded connections

Abstract

Abstract : Through an experimental study, this paper describes the behavior of single-lap bonded, bolted and bolted/bonded connections for configurations with minimum geometric parameters proposed in design references. Two types of multi-material connections are considered: Glass Fiber Reinforced Polymer (GFRP)-to-steel and aluminum-to-steel. At first, the behavior of multi-material bonded connection using methacrylate and epoxy adhesives is evaluated. Then experimental results of bolted connections are presented. Finally, the contribution of adhesive in GFRP-to-steel and aluminum-to-steel bolted connections is investigated. Test results show that on single-lap simply bonded joints, failures mostly occur at the substrate to adhesive interface. Sanding the GFRP plate was found to improve the connection strength. Despite their lower elastic modulus, methacrylate adhesives with larger elongation provides better strength due to their high resistance in peeling. For bolted/bonded joints, the adhesive was found to improve the elastic behavior and the strength of GFRP-steel joints while its effect for aluminum-steel joints was not apparent due to reduce bonded surface and the high strength performance of the bolted plates.