///Mechanical behaviour of laminated glass under time-dependent and explosion loading
The mechanical behaviour of laminated glass depends, inter alia, on the time history of the applied load. As this relation has not been sufficiently investigated yet, the present work discusses different aspects of the structural behaviour of laminated glass under timedependent loading and particularly under explosion loading. In this context, the material glass and different interlayer materials as well as the interaction of both components were investigated.
The strength of glass depends on load duration due to the subcritical crack growth.
On the basis of experimental and theoretical investigations, strength values for short-term dynamic loads were determined. Compared to quasi-static loading, a significant increase of the strength was ascertained.
Dynamic Mechanical Thermal Analyses were performed on the interlayers to investigate the effect of load duration and temperature on the stiffness at small strains. Subsequently, an optimization method was developed to identify parameters for the applied material models. The results were validated by creep tests on laminated glass specimens.
Thus, the mechanical behaviour of laminated glass can be fully described until glass breakage occurs.
Under explosion loading, a linear elastic modelling of the interlayer is sufficient as long as the glass is unbroken. This was shown by experimental studies in a shock tube and associated numerical simulations.
After glass breakage occurs, the structural behaviour changes: The interlayer suffers large strains and delaminates locally from the glass. On the basis of uniaxial tensile tests at different loading rates, the mechanical behaviour of different interlayers was investigated up to large strains. The influence of stiffness and adhesion on the post-breakage behaviour under explosion loading was demonstrated experimentally in small-scale experiments and shock tube tests. Accordingly, an optimized interlayer should have low adhesion, low stiffness and high failure strain. The experimental results were compared to numerical simulations, which also capture the post-breakage behaviour.