BEHAVIOUR OF SANDWICH BEAMS WITH CONVENTIONAL AND MODIFIED CORE JUNCTIONS UNDER FATIGUE LOADING CONDITIONS

摘要

The paper considers local effects occuring near junctions between different cores in sandwich structures. Two groups of sandwich beams, with conventional "butt" and reinforced "butt" core junctions, respectively, were manufactured and examined experimentally. The reinforcement of the "butt" junctions was achieved via a local introduction of small reinforcing patches of resin or adhesive agent in grooves machined along the core junctions. The technology of producing such reinforcements with the purpose of faster redistribution of the resin/adhesive is well known, but being applied locally at the junctions, it effectively suppresses local stress concentrations. The sandwich beams with the conventional and modified core junctions were tested in three-point bending under static and fatigue loadings. A rigorous statistical treatment of the obtained data has unambiguously shown that sandwich beams with reinforced "butt" junctions display superior structural performance compared with sandwich beams with traditional core junctions.