A modular wireless microelectromechanical system (MEMS) inclination sensor system (WMISS) is developed and tested for providing structural health monitoring of large-scale hook structures. The operating principle of a 3-D-MEMS-based dual-axis inclinometer is analyzed. A wireless MEMS sensor is integrated using sensing disposal, wireless communication, and power units. The WMISS is calibrated by using a laser displacement sensor in a pendular structure. The maximal error of the wireless MEMS inclination sensor is about 1%. The resolution is plusmn0.0025^deg. With the new-type tuned mass damper control module, an experiment on a WMISS for the swing monitoring of a Lanjiang hook model is developed. Experimental results indicate that the developed WMISS is highly precise, convenient, stable, and low cost and has long range, and thus, a WMISS can accurately and conveniently monitor the swing of a Lanjiang hook model.

Nonlinear vibration control of structures has attracted much attention in recent years. In this paper, the adaptive fuzzy sliding mode (AFSM) control algorithm is adopted to actively control nonlinear structural vibration. Since the AFSM control algorithm needs the full state feedback of the structure, a dynamic neural network (DNN) observer is proposed, considering the nonlinearity of the structure. The neural network weights are adapted on-line, and no off-line learning is required. Furthermore, no exact knowledge of structural nonlinearities is needed. The weight training algorithm is established based on Lyapunov stability theory in the presence of modeling error. A semi-active control algorithm is used for MR damper to track the active control force, which is computed by the AFSM control algorithm based on the DNN observer. Results of the numerical simulation of semi-active control of a 20-story nonlinear building using MR dampers verify the performance of the DNN observer and the effectiveness of the proposed AFSM control.

Active mass damper (AMD) control of civil structures has attracted much attention in recent years. However, there are few researches on the control of nonlinear structure using AMD under earthquake excitation, especially for high-rise building. In this paper, a fuzzy logic-based control algorithm was developed to control a nonlinear high-rise structure under earthquake excitation using AMD device. For the control of a high-rise building under earthquake excitation, due to the complexity of vibration modes, many inputs are needed for the fuzzy controller, and this may cause the explosion of fuzzy rules. To solve this problem, generalized inputs for fuzzy control were proposed by considering all the states of the structure based on a quadratic performance index. An AMD control system may magnify the interstory drift of a high-rise nonlinear building, which is regarded as Interstory Response Amplification (IRA) phenomenon. To avoid this problem, a control scheme of using both an AMD and interstory dampers was proposed to control the nonlinear vibration of a high-rise structure. We used a 20-story Benchmark nonlinear structure for the numerical studies. Numerical simulations show that the combination of an AMD and interstory dampers can eliminate the IRA phenomenon and achieve better vibration suppression than either an AMD alone or interstory dampers alone, in not only displacements relative to ground but also interstory response. Copyright © 2010 John Wiley & Sons, Ltd.

In the first part of this paper, the theoretical and simulation analyses have been studied to prove the effectiveness of the pounding tuned mass damper (PTMD) to control the vibration of a traffic signal pole. In order to further verify the control effect of the PTMD, an experimental structure was prepared to test the novel approach in the lab. A horizontal and a vertical steel pipe are used to model the traffic signal pole. An L-shaped beam and a pounding collar covered on the interior with viscoelastic materials are used as the PTMD device. Both free and excited vibration tests were performed with and without PTMD control on the structure. It was found that the damping device was very effective in controlling the vibrations of the structure in both out-plane and in-plane vibrations.

Use of a variable stiffness tuned mass damper (VSTMD) is an effective approach to reduce the dynamic responses of a structure with shifting natural frequencies. Magnetorheological elastomer (MRE) isolators can be used to build VSTMD due to their tunable stiffness by applying a magnetic field. However, conventional MRE isolators show deformation limits, huge energy consumption and uneconomic production. Focused on developing a MRE VSTMD system to improve this situation, a conical MRE isolator has been proposed and tested. Compared to conventional MRE isolators, the conical isolator shows much higher efficiency, better overall stability, greater deformability and a larger tunable range. The experimental results indicate that the prototype can provide a 46.29% increase in frequency and a 75 N control force range with a 25 W power source. The quick responding MRE VSTMD system has the potential to accurately provide the desired stiffness in two directions to achieve a better structure control.