Static and Fatigue Full-Scale Tests on a Lightweight Ship Balcony Overhang with Al/Fe Structural Transition Joints

Abstract

Combination of lightweight and sustainable marine structures represents a crucial step to accomplish weight reduction and improve structural response. A key point when considering the reliability of innovative structural solutions, which should not be neglected, is represented by large-scale experimental investigations and not only by small-scale specimen analysis. The present research activity deals with the experimental assessment of a lightweight ship balcony overhang, which incorporates an aluminium honeycomb sandwich structure and Al/Fe structural transition joints obtained by means of the explosion welding technique. The ship balcony overhang was formerly designed with the aim of proposing the replacement of ordinary marine structures with green and lightweight options. Experimental investigations of a large-scale structure were performed to validate the design procedure and to evaluate the feasibility of the proposed solution. Large-scale bending tests of the ship balcony overhang were performed considering representative configurations of severe loading conditions. The experimental analysis allowed the evaluation of the structure’s strength, stiffness and failure modes. Comparisons with analogous structures reported in the literature were performed with the aim of assessing the benefits and drawbacks of the proposed lightweight structure. Fatigue tests were also performed in order to evaluate the hardening and the hysteresis loops. The collapse modes of the structure were investigated using X-ray radiography. The structural transition joints have experienced no cracks during the static and fatigue tests. The results clearly indicated that the proposed solution can be integrated in new and existing ships, even if made of steel, as the Al/Fe structural transition joints produced by explosion welding can be used to connect the ship structure to the Al honeycomb balcony. The systematic analysis of the experimental results gave valuable data to enhance the design methodology of such structures.

Keywords

• lightweight marine structures
• large-scale testing
• bimetallic joints
• failure modes