PSI - Issue 82

Chiara Bedon et al. / Procedia Structural Integrity 82 (2026) 65–71 Chiara Bedon et al. / Structural Integrity Procedia 00 (2026) 000–000

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mathematical models, as well as the derivation of robust simplified empirical strategies in support of structural design (Biolzi et al., 2022; Bedon et al., 2025).

Nomenclature A cr

cross-section area of the cracked glass layer cross-section area of the intact glass layer

A g

AN

annealed glass

E g

modulus of elasticity of intact glass

E g,cr G int

equivalent modulus of elasticity of cracked glass secant shear modulus of the interlayer

Γ I g

shear transfer coefficient moment of inertia of intact glass

I g,cr

equivalent moment of inertia of cracked glass out-of-plane bending stiffness of the 2-ply LG section

EI

EI cr

equivalent out-of-plane bending stiffness of the partially cracked 2-ply LG section

L

length of glass specimens

LG

laminated glass

t cr t int

thickness of cracked glass thickness of interlayer thickness of intact glass width of glass specimens

t g

W

Four different stages can be detected to describe the bending performance of LG members, including (Fig. 1): • Stage 1: fully elastic response; • Stage 2: partially cracked stage (target of this study), in which the intact glass layer has to provide appropriate residual capacity and the cracked glass ply, which is no longer transfers bending normal stresses; • Stage 3: the cracks propagate inside the thickness, and the interlayer can still prevent it; • Stage 4: the LG section is affected by a progressive increase in the severity of damage, with gradual necking of the interlayer, up to the final collapse.

Stage 1

Stage 2

Stage 3

Stage 4

Fig. 1. Reference pre- and post-breakage stages for a 2-ply LG element.

For Stage 1, structural design principles are based on the use of equivalent thicknesses that capture the effective mechanical bond offered by the interlayer (CNR-DT 210/2013). As far as damage propagates in glass, however, major issues derive from fragments and their possible debonding. The idea of present study (as a part of a more extended and elaborated investigation) is hence to assess the partially fractured bending response of 2-ply LG elements in Stage 2, and to quantify their residual mechanical capacity. Annealed (AN) glass layers are taken into account, since characterized by large shards that can offer a relatively high residual stiffness to the fractured LG section, compared to prestressed glass types (Galuppi & Royer-Carfagni, 2018). In particular, the issue is explored at the small-scale