Investigations on the viscoelastic material behaviour and linearity limits of PVB

The consideration of the shear bond via the intermediate layer in the design of laminated glass is of great interest, as this can lead to a considerable reduction of the maximum stresses in the glass, depending on the load and static system. Polyvinyl butyral based interlayers show a typical polymeric thermo‐viscoelastic material behaviour, which means that the shear coupling depends on the load (duration and magnitude) and the prevailing temperature. With small distortions below the linearity limit, the time‐dependent material behaviour of the intermediate layer can be mapped using the Prony‐Series. However, the linear viscoelastic range is exceeded at latest in the post‐fracture behaviour and hence the Prony‐Series can no longer be used straightforwardly. This article shows the experimentally determined limits of the linear viscoelastic range using the example of PVB. In addition, the Prony parameters for the linear viscoelastic range are determined.