Influence of different boundary conditions and strain amplitudes on the structural internal friction of anisotropic laminated damped structures

The seven layer laminated structures which are alternatively laminated by fiber reinforced composite layers and viscoelastic damping layers were prepared for providing experimental evidence for new type damping structural theory analysis and its application of vibration and noise control, and the influence of different strain amplitudes and boundary conditions on the temperature and frequency characteristics of the structural internal friction were investigated with a dynamic mechanical analyzer (DMA Q800)for the first time. The experimental results show that the structural internal friction decreases with the increasing of structural strain amplitudes under different boundary conditions at 25℃, and the temperature corresponding to the structural internal frictions peak moves towards the low-temperature with increasing the strain amplitudes. The internal frictions are maximum and second-maximum values under the single cantilever model and the double cantilever model, respectively, and the internal friction is the lowest under the 3-point bending model with the same structural strain amplitudes.