Damping in beams using viscoelastic layers

Abstract

Various types of sandwich beams with viscoelastic cores are currently used in aerospace and automotive industries, indicating the need for simple methods describing the dynamics of these complex structures. In order to understand the effectiveness of the sandwich structures, the dynamics of bare beam with unconstrained and constrained viscoelastic layers are investigated in this study. The viscoelastic layer is bonded uniformly on the beam. The effects of distributed viscoelastic layer treatment on the loss factors are studied. From the experiments it is observed that beams with constrained viscoelastic layer provide higher loss factors than those with unconstrained layer. The dynamics of sandwich beams is modeled using Euler and Bernoulli beam theory. Frequency-dependent Young’s modulus and loss factors are considered in the model of viscoelastic material. The predicted Eigen frequencies obtained from the model are compared with the experimental results for two viscoelastic materials with aluminum base material. Frequency response functions are obtained from the finite element model and compared with experimental results for harmonic input. Reductions in vibration amplitudes for two viscoelastic materials (EAP-2 and EAP-43) are also compared. Based on the experimental results, it has been observed that the loss factors of EAP-43 are higher than that of EAP-2.