Time dependent behavior of laminated glass

This research deals with the mechanical characterization of laminated glass beams (glass-interlayer-glass) subjected to bending, with the main purpose of evaluating the coupling that the interlayer is able to establish between the glass sheets; in fact, the interlayer provides the glass plies with the ability to work more or less jointly. Four-point-bending tests (constant load) were performed on glass beams laminated with different interlayer plastic sheets. Shear tests (constant load) were performed on laminated glass specimens to determine the viscosity properties of the interlayer, when laminated between glass sheets. The parameters of viscosity, determined by the shear tests, make it possible to reproduce the time-dependent behavior of the composite beam, both numerically and by means of a closed-form procedure. The experimental results were compared with those obtained with the theoretical model and with the numerical simulation. The comparison among the different polymer interlayers shows that they are able to influence differently the mechanical behavior of the laminated composite and that their performance degrades at different rates as a function of time.