A simplified approach to the dynamic effective thickness of laminated glass for ships and passenger yachts

Abstract

In the last years, after the economic crisis that modified the super and megayacht market and construction, the project focus of shipyards and owners has been moved from the research of higher performances and whimsical exteriors to more classic aesthetics and higher level of onboard comfort. This first aspect has led to the use of larger openings on superstructures’ sides in order to enlarge windows and bring more natural light onboard vessels. The request of more comfortable units has granted a strong effort to find new solutions in order to reduce the noise and vibration level, dealing in particular to the structural elements with higher noise radiations, such as dampers, pillars and windows. The aforementioned trends is reflected on a more intensive use of glazed windows onboard, that have led to non-trivial problem of both structural response (since the structural component are reduced in order to enlarge opening) and NVH assessment, considering that glued glass panes act as an harmonic speakers, having natural frequencies closed to ones of the main superyacht excitations. In this paper, a simplified interactive design procedure for laminated glass used onboard super and megayacht is provided; in particular, authors developed a model for the calculation of a simplified dynamic effective thickness of laminated glasses, in order to increase the reliability of the modelling of glazed panes, with the same dynamic properties, in global numerical models of vessels.