Experimental study and multi-scale refinement model of high damping acrylic polymer matrix VEDs for civil structural seismic retrofit

The viscoelastic dampers (VEDs), which can provide both stiffness and damping, have been recently introduced into the field of structural vibration control for seismic enhancement of civil engineering structures. In this study, a kind of high damping acrylic polymer matrix VEDs (HDPVED) is developed independently, and this innovative HDPVED can solve the significant problem of service performance under medium-high temperature environments, as well as low-frequency vibration control under earthquake actions for civil engineering structures. To systematically investigate the influencing rules of frequency, temperature, and displacement amplitude on the mechanical properties and damping dissipation performance of HDPVEDs, a series of dynamic mechanical performance tests of the developed HDPVEDs are carried out at different frequencies, temperatures, and displacement amplitudes. The research results show that HDPVED exhibits excellent damping dissipation capability and adaptability under medium-high temperature environments and low-frequency excitations. The mechanical properties and energy dissipation performance present a strong correlation with frequency, temperature and displacement amplitude, and there is an obvious coupling effect between the three influencing factors. Based on the macroscopic mechanical property research of HDPVED, the microscopic damping mechanism and microscopic mechanical properties of HDPVED are then investigated. High-order fractional derivative fraction Voigt and Maxwell model in parallel (FVMP) models are preferred to characterize the combined hyper-elasticity and viscoelasticity owned by networked molecular chains and free molecular chains. The breaking and reconstruction theory of microphysical bonds is used to assess the effect of packing particles, and the time-temperature equivalence principle is introduced to assess the effect of temperature. The multi-scale refinement model is proposed, and the validity and accuracy of this model are verified by testing data of HDPVED. The study results show that the proposed model can accurately describe the effects of frequency, temperature, displacement amplitude, and microstructure on the multi-scale mechanical properties of HDPVED. It provides a theoretical basis for the multi-scale design and development of high damping VEDs.