Investigating the performance of laminated glass panels under windborne debris impact

Abstract

Glass façades, a prominent feature in modern buildings, have garnered widespread popularity despite the inherent brittleness of glass due to its non-crystalline molecular structure. While glass is commonly utilised as a structural material following quality and performance enhancement measures, its susceptibility to extreme loads, particularly impact loads, is higher compared to other structural elements. Past investigations into windstorms have revealed that the generation of various debris poses a significant threat to glass façades during extreme wind conditions. This research addresses the imperative need to comprehensively study the response of Laminated Glass (LG) panels to windborne debris impact, emphasising the potential consequences of damage during windstorms. LG, known for its safety features and higher post-crack load carrying capacity, is employed in buildings. The study focuses on fully framed LG window panels and employs a finite element (FE) based numerical modelling approach to assess their impact performance. The FE models are validated using results from past experiments, and subsequent examinations explore the impact performance of LG panels and their constituent components under various critical impact locations. Key findings suggest that support conditions and impact locations significantly influence the LG panel's impact performance. The Polyvinyl Butyral (PVB) interlayer plays a crucial role in resisting penetration by absorbing substantial impact energy. The study advocates purposeful design of LG window panels as sacrificial elements to enhance impact resistance, rather than relying solely on thicker glass panes. Energy absorption is found to be highest for mid-impacts, diminishing for long-span mid-impacts, short-span mid-impacts, and corner impacts, respectively. The research highlights the importance of an iterative design process for impact-resistant glazing, emphasising the need for designers to propose suitable layer thicknesses and configurations. Failure to do so may result in additional material costs without achieving satisfactory impact resistance. Hence, the findings of this research encourage manufacturers to create innovative materials with strong energy absorption, enabling engineers to implement impact-resistant glazing for safe, optimised, and aesthetically pleasing glass façades in cyclone-prone areas. Keywords: Windborne debris impact; Impact-resistant glazing; Laminated glass; Finite element modelling; Material failure