Variationally-Based Effective Dynamic Thickness for Laminated Glass Beams

Abstract

Abstract. Laminated glass, consisting of glass layers connected with transparent foils, has found its applications in civil, automotive, or marine engineering. Due to a high contrast in layer properties, mechanical response of laminated glass structures cannot be predicted using classical laminate theories. On the other hand, engineering applications demand easy-to-use formulas of acceptable accuracy. This contribution addresses such simplified models for free vibrations of laminated glass beams, with the goal to determine their natural frequencies and modal damping properties. Our strategy is to approximate the complex behavior of a laminated structure with that of an equivalent monolithic beam. Its effective thickness is determined by the variational method proposed by Galuppi and Royer-Carfagni for static problems, which we extended for modal analysis. We show that this new approach overcomes inaccuracies of the currently used dynamic effective thickness model by López-Aenlle and Pelayo.

Early-Detection of EVA Encapsulant Degradation in PV Modules Based on Vibration Frequency Analysis

“…On the other side, it is experimentally proved that high vibration frequencies for EVA films -like for viscoelastic interlayers in general -typically have a stiffening effect, and this can be positively quantified in a possible moderate increase in shear bond efficiency(Knight et al 2022, Hána et al 2019). However, it is also experimentally observed that repeated mechanical loads (even at high strain rate) induce a marked reduction in the material stiffness, with deterioration of shear bond rigidity(Schmidt et al 2017). In such a variable and uncertain scenario, both the metal frame at the edges (Fig.3 (c)) and the fixing brackets (Fig.3 (d)) -that can be efficiently characterized by numerical analysisfurther contribute to modify the vibration response of the PV system, compared to ideal simplified restraints.5 / 12 Article 10.47982/cgc.9.614 Challenging Glass Conference Proceedings -Volume 9 -June 2024…”