SIZE EFFECTS ON MODE I AND MODE II FRACTURE BEHAVIOUR OF COMPOSITE-STEEL BONDED INTERFACE

Wrapped composite joints offer an innovative alternative to conventional welded joints in steel circular hollow sections (CHS), demonstrating superior performance in ultimate and fatigue limit states. This study experimentally investigates interfacial fracture behaviour between composite and steel in upscaled wrapped composite joints for practical applications. Different-scale composite-steel interface specimens were prepared for Double Cantilever Beam (DCB) and Four-point End Notched Flexure (4ENF) tests to analyze mode I (opening) and mode II (in-plane shear) interfacial behaviour and fracture properties. The findings provide insights into the size effects on composite-steel interfacial behaviour and enhance the modelling of upscaled wrapped composite joints.