Dynamic Energy Dissipation Performance of Nonlinear Large-Deformation Viscoelastic Joint Damper under Strong Dynamic Load.

Large-displacement corner deformation often occurs at the joints of towering structures and long-span space structures subjected to strong earthquake. In order to improve the energy dissipation capacity of structural joints, the Nitrile Butadiene Rubber/High Abrasion Furnace Black (NBR/HAF) high damping composite was fabricated by formulation optimization in this paper, where a nonlinear large-deformation viscoelastic joint damper was proposed. The damper consists of five layers of restrained steel plates and four layers of shear energy dissipating material, which can reach 60 mm shear displacement. In this paper, dynamic mechanical performance tests and static mechanical tests were firstly conducted on the core energy dissipating media of the damper. The loss factor of NBR/HAF composite reached a peak of 1.51 at about 8.2°C, while its wide damping temperature range was 27°C. Second, the accuracy of the simulation method was verified by comparing the simulated and experimental hysteresis curves. Then, the refined numerical simulation of this damper was carried out using ABAQUS finite element software with the high damping material as its core energy dissipating media. Finally, the magnitude and type of energy dissipation of each part of the viscoelastic joint damper under different loads were investigated. It was found that the large-deformation viscoelastic joint damper based on the composite had good damping capacity. Its dynamic characteristics were affected by the displacement amplitude and excitation frequency, which exhibited hardening nonlinear characteristics. As the frequency and load amplitude increased, the peak displacement in the loading direction gradually decreased, whereas the total energy input to the damper and the energy dissipated by the viscoelastic material increased monotonically. The input energy was only dissipated by the viscoelastic material, and no plastic loss occurred in the steel plate during the entire loading stage. Under high frequency and large loads, the damper can also have good energy dissipation characteristics. Because of the negative strain energy caused by plastic dilatancy, the energy dissipated by the material was gradually greater than the input energy with the load increasing. [ABSTRACT FROM AUTHOR]