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Traditional structures adopt a split design with vibration control, energy harvesting and monitoring, which is difficult to meet the needs of technological development. The development of new structure from a single function to a multifunctional integration structure requires that the structure not only has the characteristics of low-frequency vibration control and energy harvesting, but also takes into account functions such as sensing, fault diagnosis and health monitoring. Given the continuously growing trend of multifunctional integration research, this paper presents the latest review on multifunctional integration of nonlinear vibration control, energy harvesting and monitoring. This is an interdisciplinary topic related to structural dynamics, mechanical design and power electronics, which has great prospects in various potential applications. The nonlinear design of new multifunctional integration structure is an essential step in the development of vibration control and energy harvesting, and is one of the most effective technical means to improve performance in low-frequency excitation environments. Therefore, the main implementation methods of nonlinear vibration control are discussed in detail. Subsequently, different strategies for nonlinear vibration energy harvesting and the challenges faced by wireless sensor network monitoring are described. On this basis, the research status, engineering applications and research trends of multifunctional integration structure are introduced in detail.

This paper investigates the forced vibration and dynamic stability of a simply supported axially moving beam coupled to a nonlinear energy sink with the aim of passive vibration control. The equations of motion of the coupled system are solved using harmonic balance and pseudo-arc-length continuation methods. The impacts of the beam velocity, excitation frequency, and magnitude of the external force on the behavior of the system are studied. It is observed that the absorber should be designed in a way that the strongly modulated response (SMR) and weakly modulated response occur in the response of the system when the moving beam is excited near its primary resonances. The results show that the saddle node and Hopf bifurcations boundaries, as well as the absorber performance, would be reduced by increasing the beam velocity. It is also realized that the excitation frequency in which the response of the system enters the SMR region is decreased by enhancing the beam velocity, as well as the magnitude of the external force. Using the results of this paper, one can readily simulate the vibration control of simply supported moving beams utilizing a nonlinear energy sink.

This paper investigates the high-performance attitude control and active vibration suppression problem for flexible spacecraft in the presence of external disturbances. The active vibration control usually depends on additional sensors and actuators, which will highly increase the difficulty of practical application. In order to reduce the implementation complexity, the piezoelectric sensors are not adopted, but instead a modal observer is introduced to estimate the modal information. Based on the observed modal information and the prescribed performance design process, an adaptive attitude controller is developed, which has the capabilities of rejecting disturbances as well as possessing predetermined transient and steady-state control performance. Similarly, an active controller is constructed to deal with the vibrations induced by attitude motions. It can be proved that by constraining the estimations of the modal variables, the actual modal coordinate will also be constrained with expected attenuation characteristics. The stability of the entire closed-loop system is analyzed by the Lyapunov theory. Simulation results in different cases show the effectiveness and performance of the proposed algorithms.

An improved pendulum tuned mass damper with nonlinear cable tension, known as the prestressed tuned mass damper (PSTMD), has been proposed and investigated for mitigating excessive vibrations of offshore wind turbines (OWTs) across a frequency range. Unlike conventional nonlinear TMDs constructed with nonlinearity springs or dampers, the nonlinearity in the PSTMD originates from the geometric properties of its prestressing cables. This study extends the development of the device to a bi-directional PSTMD, considering the distinct nonlinear-memoryless-amplification (NMA) behavior for integrated vibration control in an OWT system, by means of the theoretical analysis and numerical simulation approaches. A mathematical model is derived to describe the nonlinear tensile forces of the cables in the bi-directional PSTMD, and a dynamical nonlinear model of the OWT with proposed PSTMD is established to account for aero-hydrodynamic loadings. NMA dynamic behavior under harmonic loads is examined via using the Newton–Raphson algorithm to explore the integrated vibration control of bi-directional PSTMD under wind–wave loads. Numerical simulations are conducted to demonstrate the effectiveness of the nonlinear bi-directional PSTMD in suppressing vibrations of the OWT system under both harmonic and wind–wave excitations. The analysis results indicate that the bi-directional PSTMD, considering the NMA behavior, effectively mitigates the frequency detuning phenomenon at the natural frequency of the OWT system. Furthermore, the study reveals that this approach offers significant advantages in vibration mitigation compared to a linear system.

This review of MRF (magnetorheological fluids or MR fluids) brings out the challenges in methods of preparation, difficulties encountered in storage and use, and possible solutions to overcome the challenges.Magnetorheological fluid in the rheological fluid domain has found use due to its ability to change its shear strength based on the applied magnetic field. Magnetorheological fluids are composed of magnetizable micron-sized iron particles and a non-magnetizable base or carrier fluid along with additives to counter sedimentation and agglomeration.Magnetorheological fluids can respond to external stimuli by undergoing changes in physical properties thus enabling several improved modifications in the existing technology enhancing their application versatility and utility. Thus, magnetorheological fluid, a rheological material whose viscosity undergoes apparent changes on application of magnetic field, is considered as a smart material. Such materials can be used for active and semi-active control of engineering systems.Many studies on the designs of systems incorporating MR fluids, mainly for vibration control and also for other applications including brakes, clutches, dynamometers, aircraft landing gears, and helicopter lag dampers, have emerged over last couple of decades. However, the preparation as well as the maintenance of magnetorheological fluids involves several challenges. Sedimentation is a major challenge, even when stored for moderate periods of time. A comprehensive review is made on the problems confronted in the preparation of magnetorheological fluids as well as sustenance of the properties, for use, over a long period of time. Other problems encountered include agglomeration and in-use thickening (IUT) as well as rusting and crusting. Of interest is the mitigation of these problems so as to prepare fluids with satisfactory properties, and such solutions are reviewed here. The control of magnetorheological fluids and the applications of interest are also reviewed.The review covers additives for overcoming challenges in the preparation and use of magnetorheological fluids that include incrustation, sedimentation, agglomeration, and also oxidation of the particles. The methodology to prepare the fluid along with the process for adding selected additives was reviewed. The results showed an improvement in the reduction of sedimentation and other problems decreasing comparatively. A set of additives for addressing the specific challenges has been summarized. Experiments were carried out to establish the sedimentation rates for compositions with varying fractions of additives.The review also analyzes briefly the gaps in studies on MR fluids and covers present developments and future application areas such as haptic devices.

Satellite borne flexible structure is a multi-degree-of-freedom system, which contains complex dynamic characteristics such as time-varying parameters, geometric nonlinearity, gap nonlinearity, and so on. Flexible structure suspension typically results in geometric nonlinearity. The oscillation equation with nonlinear term is established according to the law of motion of a nonlinear pendulum and considering the influence of medium swing angle and lateral force. The perturbation approach is used to get the relationship between vibration frequency and the nonlinear term, and the impact of factors on vibration characteristics is investigated. The satellite borne flexible structure’s active vibration control (AVC) system is then established. Considering proportional differential (PD) or fuzzy control adjustment, variable step size least mean square (VSS-LMS) adaptive filtering algorithm is used to calculate the control signal, and considering the influence of geometric nonlinearity, the actuator is used to suppress the vibration of the satellite borne flexible structure. Finally, the vibration response’s amplitude under steady-state excitation significantly decreases as an outcome of the vibration control simulation.

A nonlinear energy sink (NES) passively reduces transient vibration energy of a typically impact loaded mechanical system. It is locally connected to the vibrating system through a nonlinear connecting stiffness. For a NES to perform efficiently, through targeted energy transfer (TET), the vibration levels need to exceed a well-defined threshold, below which the NES performs poorly. This threshold can be lowered by considering a NES with a bi-stable connecting stiffness. A bi-stable NES (BNES) has two stable equilibria. Besides vibrating in TET regime, a BNES can also vibrate chaotically or close to one of its equilibria, called intra-well vibrations. However, during both chaotic and intra-well vibrations, the mitigating performance of the BNES is poor. Here, a novel tuning method is developed, which finds the boundary between chaotic and TET regime, such that the BNES avoids the chaos and operates with the more performant TET. This boundary is found by numerically calculating the Lyapunov exponent, a measure for chaos. To quantify performance, two algebraic expressions, requiring no simulations, are derived in the paper expressing the speed of vibration mitigation and expressing the residual vibration energy left after TET. The result is a generic tuning methodology that not only ensures the BNES operates in the efficient TET regime, but also guarantees optimal speed of vibration mitigation. The developed performances measures in function of the NES’s parameters are to the point and easy to use. The tuned BNES shows a superior robustness w.r.t detuning compared to the linear vibration absorbers.

This paper deals with the active vibration control of composite cantilever beam. Based on the finite element method and Golla–Hughes–McTavish (GHM) model, the system dynamics equation is established. Models are simplified in physical and modal space because of unobservable and uncontrollable. Based on the particle swarm optimization (PSO) algorithm, the linear quadratic regulator (LQR) feedback gain was optimized. The effect of system vibration damping under different controller parameters, piezoelectric-constrained layer position and excitation signal was studied. The study show that the optimal feedback gain of the controller can effectively balance the control effect and the control cost. The closer the piezoelectric layer and viscoelastic layer are to the fixed end, the better the system control effect and the smaller the control cost. The reduced-order model has a good control effect on different excitation signals.

The present paper contributes to the nonlinear vibration control of the composite cantilever beam structures of aeroplanes under base excitation via employment the NiTiNOL–steel wire ropes (NiTi–ST) by means of systematic theoretical and experimental investigations. A polynomial model is introduced to simulate the damping characteristic of NiTi–ST and then the governing equation of motion of laminated composite cantilever beam treated with NiTi–ST has been derived in frame of Hamilton’s principle. The Galerkin Truncation method is employed to discretize the partial differential equations of the system while the frequency response curves are computed with the Harmonic balance method. A series of systematic experimental and numerical research projects are put on schedule to confirm the effectiveness of the proposed analytical procedure and the damping of NiTi–ST. The influence of NiTi–ST on vibration response of the composite beam with various excitations and composite schemes are discussed in detail and several new conclusions are drawn. The results indicate that NiTi–ST is a lightweight and effective method of vibration damping without changing the natural frequency of the construction, providing a new solution for vibration damping in aerospace composite structures.

The series tuned inerter dampers (STID) with distributed inerters are proposed in this paper to suppress seismic response for ground motion excited structures with broadband characteristics. In order to reveal the mechanism of the STID for vibration mitigation, the dimensionless displacement objective function of a single degree of freedom structure equipped with an STID under random Gaussian white noise base excitations is thereupon derived. Based on the principle of the reasonable distribution of inertance, the analytical optimal design parameters of STID are obtained under constraint for total inerter-mass ratio. The vibration mitigation performance of the STID is evaluated and further compared with the tuned inerter damper (TID), tuned mass damper (TMD) and typical series dampers using same mass ratio or inerter-mass ratio when structure is subjected to harmonic and random excitation. Results demonstrate that the performance of structural vibration control and broadband characteristics of STID outperform both the TMD and TID. On the condition of same inerter-mass ratio, the deformation enhancement of damping element can be further increased compared with TID because of dual-tuning effect of series inerters. The higher vibration control performance of STID is realized by using very small nominal damping ratio compared with the TMD and TID. Meanwhile, there exist two grounded inerters in STID compared to other series dampers, and both two subsystems are not affected by base random acceleration excitation which also brings STID a wider VSB and better seismic response mitigation effect. Substantially, due to STID is a type of dual-grounded inerter-based device, for force and base acceleration excited main system, the optimal expressions are identical. Hence, STID can adapt to more complex practical engineering and random and diverse excitations. Hence, the STID can be deemed to be a broadband, high effectiveness and high-performance inerter system. Meanwhile, considering low damping, lightweight and flexible install of STID, it is easier for implementation in practical engineering.