Laminated glass (LG) is largely used in buildings for facades, windows, balustrades, stairs, under various loading and boundary configurations. The typical application consists of minimum two glass plates bonded by polymeric interlayers, which are expected to keep together glass fragments in case of failure, and thus enhance safety / minimize risk for people.
Compared to other constructional materials, however, glass is rather new and still highly vulnerable. For this reason, simplified (and limited in generalization) calculation models are used for structural design and assessment, with often severely conservative design assumptions.
Sustainable and recyclable, glass has several positive motivations for its use in building but rather scarce knowledge about complex fracture mechanics and uncertain post-breakage residual capacity in case of damage, due ageing, unfavorable operational conditions, accidental glass breakage. This suggests the urgent need of research towards in-depth analysis and holistic / harmonized discussion on LG members in the post-breakage stage.
HOPgLAz (2024-2029) will be mostly carried out at the Host Institution (University of Trieste, Department of Engineering and Architecture) and spans over 60 months, with a total budget of 910k€.
HOPgLAz will explore with multi-scale extended experiments and parametric numerical analyses the post-breakage mechanical parameters of LG components variably composed and loaded, including ageing, to derive holistic damage characterization, in support of design of novel structures / retrofit – maintenance of in-service structures. HOPgLAZ will propose a novel fail safe holistic description of LG damage parameters. This will manifest in optimized, safe design of glass in buildings, sustainable constructions, added user’s comfort. Benefits will also result in minimized risk for people, minimized weight, thickness, maintenance, enhanced architectural impact, improved day life, sustainable buildings.
Traditional experimental destructive methods (quasi-static bending, cyclic loading, impact, vibrations) and simultaneous non-destructive testing (NDT) protocols (like Operational Modal Analysis) on i) small- and ii) full-scale laboratory samples (with similar properties for correlation purposes). Further support will derive from observations on iii) similar small-scale sample based on synchrotron light (Elettra Sincrotrone), given its potential for degradation analysis. The target is the definition of multi-scale correlation parameters and find predictability of damaged residual characteristics from small- to full-scale.
Possible non-invasive retrofit solutions will be also studied. The efficient use of anti-shatter films to catch fragments will be mechanically quantified under cyclic loading and unfavorable conditions. The use of embedded micro sensors / optical fibers in LG sections will be addressed as early damage detectors of “smart” in-service LG structures. This will result in monitoring optimization of in-service systems (for example based on deformation or stress levels in operational conditions, or vibration frequencies), where major uncertainty arises from difficult estimation of actual mechanical properties of bonding layers, glass fracture, boundaries.