Passive Vibration Suppression Research Articles

A novel active and passive integrated vibration isolator based on piezoelectric stack: Characteristic analysis and experimental investigation

Passive vibration isolation has the advantages of simple structure, high reliability, and strong ability to absorb high-frequency vibration. Active vibration isolation has wide application range, strong controllability, and good vibration suppression effect for specific frequency band. Active and passive integrated vibration isolation technology combines the characteristics of both and has obvious advantages in dealing with the complex vibration environment in modern engineering practice. In this work, piezoelectric stack actuator is selected as the active control output source and vulcanized butyl rubber is used as the passive vibration absorber. The dynamic model of the novel active and passive integrated isolator is established, then the effects of different parameters on its vibration transmission performance are studied. Furthermore, a typical two-degree-of-freedom vibration isolation system model is established. By comparing the change of vibration transmissibility under different feedback forms, the design of the feedforward–feedback composite controller is applied. Finally, a double-layer vibration isolation test platform is built to verify the vibration reduction capability of the active and passive integrated isolator. The experimental results show that both the passive vibration absorption and active vibration suppression functions of this novel vibration isolator are particularly effective.

On Integration of Vibration Suppression and Energy Harvesting Through Piezoelectric Shunting With Negative Capacitance

While negative capacitance (NC) element has the potential of increasing the apparent electro-mechanical coupling in various piezoelectric applications, it generally requires a power supply which may negate its benefit. Indeed, there has been no systematic analysis of NC power consumption in piezoelectric circuitry. In this article, we investigate the combinatorial effect of NC circuit on an integrated design of passive vibration suppression and energy harvesting with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> resonant shunt. We first conduct a power consumption analysis of a representative NC circuit and analyze its influence on piezoelectric energy harvesting. We then explore the tradeoff between vibration suppression through <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> shunt with NC element and the net power generation of the energy harvester. It is identified that there exists a range of NC values within which the vibration suppression performance is enhanced while the net power generation remains to be positive. This effectively yields a self-sustainable vibration suppression enhancement scheme with an NC element. Correlated numerical and experimental studies confirm this new finding.

Nonlinear inertia and its effect within an X-shaped mechanism – Part I: Modelling & nonlinear properties

This paper presents new understanding and development related to nonlinear inertia and its influence in coupling with an X-shaped anti-vibration mechanism. The inertia unit is designed with an inspiration from arm swing of human body in walking and integrated within an anti-vibration X-shaped mechanism. The new inertial design mechanism allows larger excitation displacement and more adjustable inertial ratio compared to previous designs, resulting in much more reduced vibration transmissibility and resonant peak and also producing both symmetric and asymmetric nonlinear inertia. The beneficial effects consequently incurred are explored. The results of this study unveil that: (a) There are 3 different typical nonlinear inertia forms while the U-shaped symmetrical nonlinear inertia coupling with X-shaped mechanisms can provide better vibration isolation performance at low frequency, however two other asymmetrical types can have relatively smaller high-frequency transmissibility; (b) High-frequency transmissibility can be tuned to different level, indicating a tunable band-suppress property, which is a unique property discovered in this study; (c) The nonlinear inertia can have stronger and more adjustable nonlinearity and larger inertia range, which lead to very favorite dynamic properties, including (i) lower and adjustable resonant and anti-resonant frequency and peaks, (ii) sharper decay ratio from the peak value to the anti-peak value, and (iii) different levels high-frequency transmissibility (a unique band suppress property). This study provides new insight into application of nonlinear inertia in various engineering systems for better and passive vibration suppression or isolation.

Passive vibration suppression method based on frequency domain analysis in white light vertical scanning interferometer

Vibration in manufacturing environment can significantly affects the accuracy of surface measurements, especially for the white light vertical scanning interferometry (VSI), which requires mechanical scanning for full-field measurements. This paper proposes a passive vibration suppression technique that integrates a second common-path interferometer and uses frequency domain analysis to measure vibration and reconstruct surface topography. The method is feasible for suppressing vibrations with different frequencies and amplitudes, as verified by simulation and signal recovery analysis. An in-house developed interferometer with a common optical path is used to demonstrate the measurement performance experimentally. The mathematical formula relating the vibration amplitude, the vibration frequency, the frame rate of the camera and the scanning interval is presented. The experimental results show that the precision of plane measurement decreases with increasing vibration amplitude and frequency. Moreover, the step sample signals under a maximum vibration condition of 400 nm/5 Hz are recovered, with a standard deviation of 26.07 nm for the step height measurement. As the scanning interval increases, the system can suppress higher-amplitude vibrations.

Integration of triboelectric sensing and electromagnetic energy harvesting for self-adaptive vibration suppression

There has been growing interest in using self-adjusting damping to suppress vibration in precious industrial equipment and transportation. Current vibration suppression strategies focus on improving the transformation mechanism for a specific environment. However, owing to space and power supply limitations, the implementation of energy recovery and adaptive vibration control remains a technical challenge. In this study, a random vibration suppression–energy harvesting coupling system (VS-EHCS) based on self-driven triboelectric sensing is developed. A magnetic-suspension-based energy harvester with a honeycomb structure is designed to enable energy harvesting and passive vibration suppression. Self-powered triboelectric sensors are integrated with the honeycomb to obtain vibration information. The energy harvester output and the sensor output are used as feedback for the adaptive signal tracking control algorithm, allowing a trade-off between active vibration suppression and energy harvesting. The proposed VS-EHCS achieves a vibration suppression efficiency of 96.2 % and peak power exceeding 200 mW under random vibrations of 15.9 g. These are sufficient to charge a 0.1 F super-capacitor to 5 V in 70 s. By combining self-driven monitoring, active-passive control, and energy harvesting, the VS-EHCS provides a new paradigm for efficient vibration suppression and energy recovery in variable-vibration environments.

Fault-tolerant model predictive sliding mode control with fixed-time attitude stabilization and vibration suppression of flexible spacecraft

This brief proposes two novel double-loop fault-tolerant controllers to tackle the problems of stabilizing the attitude and nullifying appendages' vibration of flexible spacecraft by integrating the advantages of model predictive control (MPC) and sliding mode control (SMC). The structure of the first method is as follows: First in the external loop, by using terminal sliding mode (TSM), the attitude of the spacecraft is derived to its reference value, and the proper angular velocity of the interior part is generated. Then, by employing the preciseness and constrained attributes of MPC, an optimal fault-tolerant controller is suggested in the internal part. Constrained fault-tolerant MPC tracks the angular velocity to the set value while guaranteeing appendages' passive vibration suppression. In another method, as opposed to the first technique, in the inner loop fault-tolerant finite-time TSM, and in the outer loop MPC are designed. The unified double-layer nonlinear controller schemes guarantee good dynamics and robustness against external torques and actuator faults. The closed-loop system's stability of the controllers is precisely proved using the Lyapunov theorem in the presence of actuator faults and external disturbances and in the absence of the damping matrix to study the advantages of the proposed methods. The performance of the proposed methods has been compared with each other. Moreover, the simulation results substantiate that the proposed method outperforms faster fixed-time sliding model control significantly.

Active fractional-order sliding mode control of flexible spacecraft under actuators saturation

In this article, a novel multi-objective modified fractional-order nonsingular terminal sliding mode (MFONTSM) controller is designed for the flexible spacecraft attitude control and passive vibration suppression, assuming the control torque saturation in the system dynamics. Then, by considering the effects of flexible components on the appendages modal equation as an external disturbance, an active FONTSM controller is designed separately to suppress any residual vibrations using piezoelectric actuators. The practical fixed-time stability of the closed-loop system is analyzed and proved using the Lyapunov theorem. Finally, the proposed controllers’ performance has been tested in the presence of uncertainties, external disturbances, and the absence of the damping matrix to study the proposed method’s effectiveness. It was observed that the proposed passive and active control strategies were able to achieve fast attitude stabilization while providing substantial vibration suppression under uncertainty and disturbance even in the absence of any damping terms in the system.

Simultaneous Suppression of Translational and Tilt Vibrations in a Superconducting Magnetic Levitation System by a Gyroscopic Damper

In this paper, suppression effect of a gyroscopic damper on vibrations of a body levitated by magnetic force acting from superconductors is investigated by numerical calculations. Because of the low damping property of the superconducting magnetic levitation system, simultaneous suppression of multi-degree-of-freedom vibration due to the coupled translational and tilting motions of the levitating body and suppression of nonlinear vibration are important development issues. A gyroscopic damper has been considered as a passive vibration suppression method that takes advantage of the control-free features of superconducting magnetic levitation systems, and if the design parameters are optimized, it may be possible to simultaneously suppress not only tilt vibration but also translational vibration. In this paper, the governing equations are first derived from the analytical model, and then numerical calculations are performed. As a result, the simultaneous suppression effect of the gyroscopic damper on the translational and tilt vibrations of the levitating body was numerically confirmed. Furthermore, the suppression effect of the gyroscopic damper on the nonlinear vibration of the levitating body was also confirmed numerically.

Passive vibration suppression using 2-degree-of-freedom vibration absorber consisting of a beam and piezoelectric elements

This paper describes a piezoelectric two-degree-of-freedom vibration absorber. The piezoelectric 2 degree-of-freedom (DOF) vibration absorber consists of a beam-type dynamic vibration absorber with piezoelectric elements and an LR circuit. A translational 1-DOF vibration system and a continuous body were used as the host structure, and the governing equations were theoretically derived in this study to accurately estimate the mass ratio of the beam-type dynamic vibration absorber and the equivalent stiffness ratio of the piezoelectric elements. Using modal analysis, an equivalent and discrete 3-DOF vibration model was obtained, and it was proved that a conventional series-type double-mass dynamic vibration absorber can be equivalently transformed into a discrete 3-DOF vibration model of a piezoelectric 2-DOF vibration absorber when the optimum values are used. The optimum values of the proposed piezoelectric 2-DOF vibration absorber were obtained using this equivalent transformation and the exact optimum values of the conventional series-type double-mass dynamic vibration absorber. Because only the exact optimum values of mobility have been formulated in research conducted on a conventional series-type double-mass dynamic vibration absorber, the quasi-optimum values under both compliance and accelerance were additionally obtained in the present study. In terms of optimization, the damping of the beam-type dynamic vibration absorber should be zero; however, it is non-negligible in practice. Therefore, a retuning method considering the damping of the beam-type dynamic vibration absorber was briefly described. Finally, effectiveness of the proposed methods and a theoretical analysis was verified through simulations and experiments.

Vibration suppression of bridges under moving loads using the structure-immittance approach

This paper presents the possibility of suppressing the train-induced vibration on bridges using a linear passive vibration suppression device incorporating inerter. The inerter is a two-terminal mechanical element with the property that the applied force is proportional to the relative acceleration across its terminals. The inerter has been applied to various engineering structures where performance benefits have been identified. However, currently these studies are either limited to simple network configurations with moderate performance improvement, or resulted in complicated configurations with a large number of elements which are impractical for real-life applications. In addition, the potential of using inerter-based absorbers for suppressing the train-induced bridge vibrations has not been taken into consideration. In this paper, a simplified bridge model equipped with a vibration suppression device subjected to series of moving forces is presented. The structure-immittance approach, which can cover all networks with pre-determined numbers of each element type, is adopted for the identification of the optimal absorber configurations. Numerical studies for two bridges, the THSR and the Kum-gang, under three types of railway excitations, the French T.G.V., the German I.C.E. and the Japanese S.K.S. are conducted. It is demonstrated that the overall performance of the bridge can be improved by using the proposed inerter-based configuration. It is also checked that the absorber stroke is much smaller than the inner space of bridge box girder, indicating the practical installation of the absorber. Furthermore, the robustness of the proposed absorber is verified by sensitivity analysis subjected to the change of bridge parameters and the device component values.

Realising embedded stiffness in hydraulic implementations of stiffness-damping-inertance configurations

The performance benefits of passive vibration suppression with network configurations consisting of stiffness, damping and inertance elements have been demonstrated for a wide range of mechanical systems. Considering physical implementations of these beneficial network configurations, hydraulic realisations have the advantages of durability and simplicity for integration with existing hydraulic dampers. Such designs are exemplified by fluid inerters and fluid-inerter-damper devices. However, in contrast to the convenience of realising inertance and damping elements, realising ‘embedded’ stiffness is very challenging. We use ‘embedded’ to refer to a network element, which is not purely in series or in parallel with the remainder of the network but instead lies within the network layout. In this work, a setup using a rubber membrane to realise such embedded stiffness is proposed, together with a procedure for hydraulic implementations of any stiffness-damping-inertance configurations. The nonlinear properties of the embedded stiffness due to rubber membrane properties are then investigated both theoretically and experimentally. In addition, the effectiveness of both the membrane setup and the design procedure are demonstrated via a case study of suspension design for passenger vehicle ride comfort enhancement.

Vibration and damping study of multifunctional grille composite sandwich plates with an IMAS design approach

In the present study, an integrated material and structure (IMAS) design approach is proposed for fabrication of a multifunctional grille composite sandwich plate. It consists of two panels made of carbon fiber/resin polymer (CFRP) and one grille functional core that includes several grid frame beams (GFBs) and grille functional units (GFUs) via falcon riveting connections to achieve vibration sensing and damping control functions. In each GFU, it is composed of a rectangular grille (RG) and several embedded functional materials with 4-layer laminates, including a piezoelectric sensing layer, an upper copper wire layer, a magnetorheological elastomer (MRE) layer and a lower copper wire layer. To investigate the free vibration and damping characteristics of such a highly integrated sandwich structure, an analytical model is proposed that is based on the complex modulus method, the polynomial expansion approach, the improved Rayleigh-Ritz method, etc. After the natural frequencies, modal shapes and damping parameters are successfully solved, with results from literature being employed to roughly validate the model developed. Meanwhile, the dynamic experiments with different internal magnetic field distribution patterns and intensities of MRE are undertaken to give a further validation of the present model. Finally, the parameter analysis is carried out and some important conclusions are summarized to better exert active and passive vibration suppression performance of the CFRP-GFB-GFU plate.

Using an inerter to enhance an active-passive-combined vehicle suspension system

Performance of a passive vehicle suspension can be improved with the help of an active actuator, however, with potentially problematic control requirements, such as high energy consumption and large actuator forces. To maximize performance benefits without requiring significant control efforts, the passive and active parts need to be designed and work synergistically. In this paper, a novel combined passive and active vibration suppression approach of which the passive part is enhanced by an inerter is proposed for improving the trade-off between dynamic performance and control requirements. Via this approach, the optimal passive configuration consisting of inerter(s), spring(s) and damper(s) with pre-determined numbers and the optimal active control parameter can be identified. The approach is demonstrated using a case study where the combined suspension is designed considering a quarter-car model and a typical active controller (i.e., the skyhook control). It will be shown that, compared with a conventional passive part of a spring-damper, adding an inerter in parallel can significantly improve the pareto optimality between the ride comfort and power (or force) requirements. The improvement is further enhanced by systematically exploring all passive network possibilities with a pre-determined complexity via the structure-immittance technique. This approach is also applicable to the vibration suppression of other engineering structures.

Experimental investigation on a new sensitive payload platform with simultaneous positioning and vibration suppression capabilities

Precision positioning and vibration isolation are two main challenges for the sensitive payloads, to realize high quality observation. It means that on the one hand the sensitive payload should keep pace with the changes of target location for achieving alignment; on the other hand, the micro-vibrations from space cabin equipment should be suppressed for avoiding image jitter. A six-degree-of-freedom platform with simultaneous positioning and vibration suppression capabilities is proposed for replacing the original scheme with series connection of a positioning platform and a vibration isolation platform. The theoretical model of the platform with rigid payload is established and then is utilized as a constraint to conduct the passive vibration suppression optimization. Subsequently, a finite element model is constructed to verify the optimization results. Finally, experimental setups are built and tests are carried out to validate the performances. The test results demonstrate that the proposed platform possesses good simultaneous positioning and vibration suppression capabilities.

Passive vibration suppression in a coupled linear–bistable continuous module excited near resonance

Vibration suppression for marine structures has been an important concern for a long time. In this paper, a specifically designed continuous module that consists of an Euler beam, a preloaded bimorph beam and a coupled spring unit produces self-increasing damping and strongly suppresses the steady-state response near resonance. Based on Hamilton’s principle, we derive a two-degree-of-freedom coupled linear–bistable (CLB) model of this module. Utilizing the harmonic balance method and a numerical simulation, we analyze the proposed CLB model under a harmonic excitation. When the preloaded beam moves toward the critical amplitude of the saddle point of the system potential, the unstable equilibrium greatly increases the velocity phase difference between the Euler and preloaded beams and spontaneously enhances the dissipation power of the system. The self-increasing damping decreases the amplitude of the steady-state vibration of the coupled module excited near resonance by an order of magnitude. Numerical results demonstrate the essential roles of the damping ratio and the shape of the potential function in determining how this module can better suppress vibrations. This investigation provides opportunities to suppress dynamical responses using a continuous CLB module.

Enhanced vibration and damping characteristics of novel corrugated sandwich panels with polyurea-metal laminate face sheets

All-metallic sandwich panels with lattice truss cores are typically ultralight, stiff and strong, yet poor in passive vibration damping. Novel laser-welded corrugated-core (LASCOR) sandwich panels with polyurea-metal laminates (PML) as face sheets were proposed and fabricated, and their vibration and damping characteristics were systematically investigated, both experimentally and numerically. Frequency/time response curves, natural frequencies, vibration mode shapes and damping loss factors were measured and compared with LASCOR sandwich panels without embedded polyurea layers. A combined finite element-modal strain energy (FE-MSE) method was proposed to predict the vibration damping performance and explore the underlying enhancement mechanisms, with the frequency-dependent damping behaviors of polyurea considered. Good agreement was achieved between numerical simulations and experimental measurements. The PML face sheets enabled remarkable damping enhancement, due mainly to viscoelastic energy dissipation of the polyurea layers. The capacity of the sandwich panel in passive vibration suppression could be further improved by tailoring the polyurea layer thickness and the distribution of polyurea layers.

Structural design and optimization of a novel shimmy damper for nose landing gears

Passive vibration suppression devices known as shimmy dampers are vital in maintaining stability and safety of certain landing gears. Yet, systematic design, performance analysis, and optimization of such devices are rarely discussed in the literature. This paper presents structural design optimization of a novel shimmy damper for nose landing gears. This new design is a multifunctional mechanism integrating the shimmy damper into the torque link system of the nose landing gear. It features symmetric load distribution, and it can be tailored to existing nose landing gears. Here, the damper design concept is developed in the structural sense and optimized for the nose landing gear of a Piper Cheyenne aircraft. Dynamic loads from a representative shimmy scenario are employed in the analysis and design procedures. Utilizing equivalent static load method, topology optimization with transient loads is performed to obtain optimal material distribution satisfying the objective function and constraints. Flexible multibody dynamics analysis based on a high-fidelity finite element model is utilized in the analysis of design candidates and for validating the final design. To ensure adequate strength under the dynamic torque loads and to offer sufficient damping needed for stabilizing the nose landing gear, a three-piece torque link mechanism emerged through multiple design iterations guided by the topology optimization. Using numerical simulations, the final design is shown to satisfy the strength requirement while providing sufficient damper stroke. The results from the present study signal a vast potential in improving shimmy mitigation strategies by eliminating the need for costly redesigns of landing gears susceptible to shimmy.

Vibration suppression and modal energy transfers in a linear beam with attached vibro-impact nonlinear energy sinks

We present a comprehensive study of nonlinear resonant modal energy scattering and passive vibration suppression in a linear cantilever beam with vibro-impact nonlinear energy sinks (VI NESs) attached to it. It is well-known that vibro-impacts are a strong source of non-smooth nonlinearity, resulting in rapid and intense multi-scale energy scattering from low-to-high frequencies in the modal space of the beam. We present a direct correlation between such low-to-high frequency nonlinear energy scattering induced by vibro-impacts and vibration suppression of the beam vibrations under both sweep- and constant-frequency harmonic excitations. In particular, we study the intensity of the collisions between the tip of the beam and the particles of the VI NESs by means of an event-driven method based on an explicit variable time step integration scheme, and relate the dynamics of the integrated beam-VI-NES system to the induced resonant energy scattering from low beam modes to higher ones. On this basis, the effects of the mass ratio and clearance between the absorber and the beam on the resonant energy scattering are presented. Our aim is to perform predictive design of the VI NESs for effective and robust vibration mitigation of the beam response. To this end we perform optimization studies on the mass ratio and clearance between the absorber and beam for the case of single and multiple VI NESs and identify regions of optimal suppression. Besides, since the single VI NES is only effective in a limited frequency and amplitude range – as its dynamics is energy-dependent – using multiple VI NESs with optimized parameters can extend the frequency range of effective vibration suppression, rendering the resulting vibration mitigation more robust to variations of the applied excitations.

Passive vibration suppression of large space truss structures by viscous damping

Viscous damping methods are commonly employed to suppress the vibration due to their simple design, low cost, and stable damping performance. However, the harsh space environment makes the normal viscous dampers suspicious to various failures. This paper proposes a novel and robust design of viscous damper to provide high damping under low-frequency vibration disturbance in space. The characterisation of the damper at low-frequency and large displacement is first investigated by numerical analysis and then validated by experiments. Based on the results of the damper, this paper presents an optimal design strategy for the damping system of large space truss structures, which is critical for space mission because there is no sufficient damping in such space structures. The design is further optimised by weighted-sum that includes the damping characteristics of dampers and elastic flexibility of space truss structures. The effect of the damping system is demonstrated by the optimal design of a 60-bay truss structure. The results show that the damping ratios of the first three modes of the truss structure can be increased by over 10% with two viscous dampers. Comparisons between the structure with and without dampers demonstrate that significant vibration suppression at low-frequency bandwidth can be achieved satisfactorily.

Passive vibration suppression of large space truss structures by viscous damping

Viscous damping methods are commonly employed to suppress the vibration due to their simple design, low cost, and stable damping performance. However, the harsh space environment makes the normal viscous dampers suspicious to various failures. This paper proposes a novel and robust design of viscous damper to provide high damping under low-frequency vibration disturbance in space. The characterisation of the damper at low-frequency and large displacement is first investigated by numerical analysis and then validated by experiments. Based on the results of the damper, this paper presents an optimal design strategy for the damping system of large space truss structures, which is critical for space mission because there is no sufficient damping in such space structures. The design is further optimised by weighted-sum that includes the damping characteristics of dampers and elastic flexibility of space truss structures. The effect of the damping system is demonstrated by the optimal design of a 60-bay truss structure. The results show that the damping ratios of the first three modes of the truss structure can be increased by over 10% with two viscous dampers. Comparisons between the structure with and without dampers demonstrate that significant vibration suppression at low-frequency bandwidth can be achieved satisfactorily.