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Based on the low cost and superior damping performance of viscoelastic dampers, the new structural system strengthened with viscoelastic energy dissipation braces (VEDB) is proposed to upgrade the reinforced concrete frame structures with insufficient seismic capability. For the dynamic performance researches and damage evolution predictions of this structure system during earthquakes, the dynamic performance of six RCFs (reinforced concrete frames) and six VEFs (another six special reinforced concrete frames with VEDB) are studied under sinusoidal wide frequency range loading excitation horizontally. On this basis, the qualitative and quantitative relations on the damage growing at the material-level and the member-level performance deteriorating about the frame structures are conducted. Furthermore, the empirical calculation model on the cross-level damage evolution of VEFs are established and verified. Finally, a set of useful and robust cross-level judgment criteria for damage performance rates is proposed. The research found that, the installation of VEDB can significantly improve the load bearing capacity, the lateral stiffness and the energy dissipation capacity of the structures. The damage pattern of the structures is improved by VEDB, and it ensures the design criteria of "strong joints and weak members." The empirical calculation model on the cross-level damage evolution and judgment criteria for damage performance rates proposed in this paper are useful and stable in practical engineering. [ABSTRACT FROM AUTHOR]

To expand the inclusiveness of hybrid test platform research, enhance the flexibility of hybrid test platforms using various control strategies, and promote the development of hybrid test techniques, a low-cost user-configurable electric actuator hybrid test platform is established in this paper. This platform can be transferred to other medium or large electric actuator hybrid test platform, the research applications of this platform cannot be limited by their proposed setup. Firstly, the hardware system design including hybrid test facility integrated control system core architecture and all related signal routings are carried out. Then, the improved equivalent force control feedback method based on force-loading control is proposed, and the software system development including hybrid test process control system software and user-configurable STM32 microcontroller (UCSM) software are conducted. Next, the mechanical performance of viscoelastic damper is tested, and the mechanical model parameters of viscoelastic damper are regressed. The accuracy of electric actuator force control (inner control loop), of which the control tasks get executed on the UCSM is verified using the experimental substructure of viscoelastic damper. The hybrid test of viscoelastic damping system verifies the reliability and robustness of hybrid test platform (outer control loop). Finally, the developed hybrid test platform implements various hybrid tests of viscoelastic damping system under broad temperature range and different seismic intensities. The test results reveal the influence of temperature and seismic intensities on the seismic control effect of viscoelastic damper. [ABSTRACT FROM AUTHOR]

The earthquake usually causes multi-dimensional vibration for the large span grid structure, how to effectively isolate and mitigate the vibration response of structure is an important problem in engineering. In this paper, a novel viscoelastic bio-inspired multi-dimensional vibration isolation (VBM-VI) device is proposed under the inspiration of bionic design of the bird legs, which possesses multi-dimensional vibration isolation performance by constituting of viscoelastic core pad and VE-LLS device together. The property experiment of the VBM-VI device is performed to explore the mechanical performance at vertical and horizonal directions, the hysteretic curves and characteristic parameters are discussed to reveal the influence of the excitation frequency and amplitude on the mechanical properties of the VBM-VI device, the experimental results show that the mechanical properties express significant frequency and amplitude dependence at vertical and horizontal directions. To further describe the mechanical proprieties of the VBM-VI device, the mathematical models are established at vertical and horizontal directions respectively, and the comparison analysis between experimental and theoretical results indicates that the established mathematical models can precisely describe mechanical performance of the VBM-VI device. [ABSTRACT FROM AUTHOR]

The bionics design method has been proverbially applied at vibration control field, and how to make bionic vibration control device possess excellent mechanical property and stable energy dissipation capacity is an important subject. In this paper, a bionic viscoelastic limb-like-structure (VE-LLS) device is proposed in conjunction with the viscoelastic (VE) damper and the limb-like-structure (LLS) device together, and the proposed device simultaneously possesses excellent mechanical propriety and energy dissipation capacity. Firstly, the mechanical property test of the VE-LLS device is conducted to investigate the effect of ambient temperature, excitation amplitude and frequency on its dynamic mechanical property and energy dissipation capacity. The energy dissipation contribution caused by the LLS joint friction for the VE-LLS device is discussed. Then, the energy dissipation model of the VE-LLS device is established by simultaneously considering the viscoelastic and friction factors, and the comparison result indicates that the established energy dissipation model can accurately describe the energy dissipation capacity of the VE-LLS device under different ambient temperature, exaction amplitude and frequency. Finally, to further promote the stability of energy dissipation capacity of the VE-LLS device at different temperature and frequency, an energy dissipation compensation strategy is proposed by increasing the energy dissipation of the LLS joint friction to compensate for the energy dissipation attenuation of the VE damper caused by high temperature and low frequency, and the results shows that the compensation strategy expresses excellent effect for the energy dissipation stability of the VE-LLS device. [ABSTRACT FROM AUTHOR]