Experimental and Theoretical Study on Nonlinear Behavior of Compression-Mode Viscoelastic Dampers under Different Excitations and Temperatures

This work designs a new compression-mode viscoelastic (VE) damper to avoid bonding interface failure in classical shear-mode VE dampers. However, most existing mathematical models based on the shear deformation at the macroscopic scale cannot fully characterize the damper due to the limitations in describing strong nonlinear behavior. Therefore, a new model is proposed from the microscopic perspective to predict the nonlinear characteristics of compression-mode VE dampers. First, a series of dynamic experiments were conducted to investigate the damper's performance under different excitation conditions and temperatures. The results indicate that the damper exhibits strong energy dissipation characteristics and good deformation capacity in wide temperature and frequency ranges. Besides, the damper also shows obvious nonlinear behavior because the hysteresis loops and mechanical properties are significantly affected by excitation frequencies, displacement amplitudes, and ambient temperatures. Then, the new model is proposed by combining the fractional derivative theory and the micromolecular structure of VE material. The model can reflect the influence of material microstructure on the damper's macroscopic mechanical properties, and each parameter of the model has a clear physical meaning. Finally, the accuracy of the model is verified by experiments. The results suggest that the model can effectively describe the nonlinear behavior of the new damper, both in terms of hysteresis loops and mechanical properties. Furthermore, since the derivation of the model does not depend on a specific damper form, the model is also suitable for analyzing other VE dampers that have similar nonlinear characteristics as the new damper. In future studies, to further improve the applicability of the new model, it is significant to optimize the model to reflect more nonlinear factors and study a structural dynamic analysis method based on the model.