Calculation of dynamic stresses in viscoelastic sandwich beams using oma

The mechanical response of sandwich elements with viscoelastic core is time and temperature dependent. Laminated glass is a sandwich element where the mechanical behavior of the glass layers is usually considered linear-elastic material whereas the core is made of an amorphous thermoplastic which is modelled as linear-viscoelastic. Dynamic displacements and stresses can be estimated in structural elements combining the experimental responses measured in a reduced set of DOF's with standard sensors and the mode shapes of a finite element model which has to be correlated and updated using experimental data. In simple structures, analytical mode shapes can be used alternatively to the numerical ones. In this paper, the dynamic stresses on the glass layers of a laminated glass beam have estimated using the experimental acceleration responses measured at 7 points of the beam, and the experimental mode shapes estimated with operational modal analysis which were expanded using an analytical model. The predicted stresses are validated with the experimental strains provided by two strain gages attached to the beam.