  Laminated glass achieves improved post-critical response through the
composite effect of stiff glass layers and more compliant polymer films,
manifested in progressive layer failure by multiple localized cracks. As a
result, laminated glass exhibits greater ductility than non-laminated glass,
making structures made with it suitable for safety-critical applications while
maintaining their aesthetic qualities. However, such post-critical response is
challenging to reproduce using deterministic failure models, which mostly
predict failure through a single through-thickness crack localized
simultaneously in all layers. This numerical-experimental study explores the
extent to which progressive failure can be predicted by a simple randomized
model, where layer-wise tensile strength is modeled by independent, identically
distributed Weibull variables. On the numerical side, we employ a
computationally efficient, dimensionally-reduced phase field formulation --
with each layer considered to be a Timoshenko beam -- to study progressive
failure through combinatorial analysis and detailed Monte Carlo simulations.
The reference experimental data were obtained from displacement-controlled
four-point bending tests performed on multi-layer laminated glass beams. For
certain combinations of the glass layer strengths, results show that the
randomized model can reproduce progressive structural failure and the formation
of multiple localized cracks in the glass layers. However, the predicted
response was less ductile than that observed in experiments, and the model
could not reproduce the most frequent glass layer failure sequence. These
findings highlight the need to consider strength variability along the length
of a beam and to include it in phase-field formulations.
