Vibration Reduction Mechanism Research Articles

Nonlinear vibration analysis of multi-support oil-tank system in aero-engine based on asymptotic methods

This article is primarily focused on the complicated nonlinear vibration behavior of an aero-engine lubricating oil-tank system with multiple nonlinear pedestals. First, the rubber damping ring’s nonlinear factors are introduced into a cubic nonlinear dynamic model of lubricating oil-tank system. The nonlinear system parameters are identified by testing a simplified aero-engine lubricating oil-tank structure. Then, the nonlinear dynamic model is solved via asymptotic approach, and results are confirmed using Runge-Kutta numerical analysis approach. The system’s vibration responses and amplitude-frequency curves are also acquired, and influence of system parameters on nonlinearity is analyzed. Finally, an experimental investigation on the simplified oil-tank is performed. The nonlinear vibration characteristics of the rubber damping ring and its vibration reduction mechanism are verified using vibration transmissibility. The experimental results are consistent with numerical results. This paper’s recommended analysis approach has engineering significance for vibration and noise reduction design of aero-engine components.

Additively Manufactured Stainless Steel Wind Tunnel Model Support Featuring Honeycomb Structures for Vibration Attenuation

Wind tunnel model support (WTMS) is an indispensable component of wind tunnel testing. However, the presence of vibrations within the model‐support system can compromise the accuracy of data and give rise to significant safety hazards. In this study, an approach for vibration attenuation by incorporating honeycomb structures into the design of the WTMS is proposed. To this end, stainless steel WTMSs with integrated honeycomb structures are fabricated by selective laser melting (SLM). Results showed that stainless steels prepared under optimized SLM processing parameters exhibit high crystallinity and consist of single‐phase Fe–Cr–Ni alloy. The stainless steels exhibited robust mechanical properties, including a tensile strength of ≈1 GPa, an elongation of ≈8%, and a compressive strength of ≈1.4 GPa. These exceptional mechanical properties can be attributed to the formation of a cellular structure and tangled dislocations. The first‐order and the third‐order resonant response of WTMS honeycomb structures can be effectively reduced. The vibration reduction mechanism can be attributed to the occurrence of local resonance when the natural frequency of the internal periodic unit of the WTMS closely matched the vibration frequency of the model. The utilization of honeycomb structures holds significant potential for achieving vibration attenuation in WTMS.

Local resonance metamaterial-based integrated design for suppressing longitudinal and transverse waves in fluid-conveying pipes

To solve the problem of low broadband multi-directional vibration control of fluid-conveying pipes, a novel metamaterial periodic structure with multi-directional wide bandgaps is proposed. First, an integrated design method is proposed for the longitudinal and transverse wave control of fluid-conveying pipes, and a novel periodic structure unit model is constructed for vibration reduction. Based on the bandgap vibration reduction mechanism of the acoustic metamaterial periodic structure, the material parameters, structural parameters, and the arrangement interval of the periodic structure unit are optimized. The finite element method (FEM) is used to predict the vibration transmission characteristics of the fluid-conveying pipe installed with the vibration reduction periodic structure. Then, the wave/spectrum element method (WSEM) and experimental test are used to verify the calculated results above. Lastly, the vibration attenuation characteristics of the structure under different conditions, such as rubber material parameters, mass ring material, and fluid-structure coupling effect, are analyzed. The results show that the structure can produce a complete bandgap of 46 Hz–75 Hz in the low-frequency band below 100 Hz, which can effectively suppress the low broadband vibration of the fluid-conveying pipe. In addition, a high damping rubber material is used in the design of the periodic structure unit, which realizes the effective suppression of each formant peak of the pipe, and improves the vibration reduction effect of the fluid-conveying pipe. Meanwhile, the structure has the effect of suppressing both bending vibration and longitudinal vibration, and effectively inhibits the transmission of transverse waves and longitudinal waves in the pipe. The research results provide a reference for the application of acoustic metamaterials in the multi-directional vibration control of fluid-conveying pipes.

Resonant peak reduction of a rotor system based on gradually variable stiffness of supports with shape memory alloy springs

A novel method for reducing the resonant peak of a flexible rotor at critical speeds based on control of the gradual variable stiffness of supports (GVSS) using shape memory alloy (SMA) springs is presented in this paper. The resonance peaks of a rotor structure can be attenuated through the design of GVSS law. Firstly, the impact of GVSS on the rotor's critical speeds was analyzed, and the mechanical mechanism of vibration reduction based on GVSS was identified. Secondly, a rotor system with a single critical speed was used for simulation analysis and it was founded that the starting time to change support stiffness and the change rate were two critical factors that affect vibration reduction. Then, a further simulation was undertaken on a test rig designed with dynamic similarity of an aeroengine rotor having multiple supports and multiple critical speeds. The range of the variable stiffness with SMA springs’ supports and the control strategy of GVSS were investigated. Afterwards, the test rig was manufactured and assembled for testing and validation. To achieve rapid temperature changes for variation of the support stiffness, an innovative design utilizing the carbon fiber heating tubes and the liquid nitrogen sprays for heating and cooling of shape memory alloy springs was carried out. The test results indicate that using gradually variable stiffness of supports with SMA Springs can effectively reduce the multiple resonance peaks of a rotor, with a maximum suppression rate of 52.3 %. This verifies the feasibility of the method. It also indicates the potential for further engineering applications.

Distributed control of vehicle suspension system based on nonlinear energy sink

Vehicle riding comfort is deteriorated not only by low-order but also by high-order resonance in the suspension system. This paper proposes to arrange the nonlinear energy sink (NES) on the tire to suppress high-order resonance. Two modal resonances can be controlled by a vibration control scheme of the distributed NESs. A dynamic model of a 2-degree-of-freedom quarter-vehicle (2-DOFQV) suspension system integrated with two NESs is established. Then, the model is analyzed approximately analytically by the harmonic balance method (HBM) and verified numerically. Next, the vibration reduction mechanism of the new suspension system is revealed from the perspective of transferred energy. In addition, the vibration reduction effects of the parameters of two NESs are studied. The results of the study show that high-order modal resonance in the suspension system can be effectively controlled by placing an NES of small mass on the tire. Thus, the novelty of this paper is to propose a distributed control strategy for the vehicle suspension system, which can reduce the high-order resonance at the cost of a small mass.

Vibration control mechanisms of plate structures by 1D acoustic black hole dynamic vibration absorber

Due to the advantages of simple structure and effective vibration suppressions, acoustic black hole (ABH) structures attract many scholars’s attention. In this paper, by capitalizing phenomenon of acoustic black hole (ABH), an ABH-featured dynamic vibration absorber (1D-ABH-DVA) is proposed for vibration suppressions, and three improved cases are proposed based on the 1D-ABH-DVA. To achieve broadband vibration suppression, three optimization cases of distribution are designed. Using a plate as primary structure, both numerical simulations and experiments show that multiple resonances of the plate can be significantly reduced by 1D-ABH-DVA. Three types of vibration reduction mechanisms are revealed, manifesting and dominating by different physical process, i.e. peak splitting effect, damping enhancement effect and their combination. The numerical simulations show that an evenly distribution pattern can get better vibration suppressions. This work provides ideas for further application of ABHs in vibration and noise reduction, and has significant engineering significance.

Analysis of steady-state dynamics and stability of particle dampers considering the friction effect

This study analyzes the steady-state dynamics and stability of a structure with a particle damper considering the friction effect between the particle and container, with a focus on whether the system can maintain stable-state motion for an extended period. The determination of friction’s contribution and the maximum allowable gap clearance for steady-state motion is demonstrated through the solution of motion of the primary structure with a particle damper subjected to low-frequency vibration conditions. Additionally, stability analysis is conducted to assess if initial disturbances cause deviations from the original stable state and identify necessary parameters for stability when the system parameters are uncertain. Analytical descriptions for the stability of the system are derived. The effects of friction on the dynamics and stability regions of the particle dampers are systematically revealed, where the theoretical and numerical models are mutually verified and supported by the cases of previous studies. Results show that the inclusion of the rolling friction effect will disrupt the steady-state motion as gap clearance approaches the optimal value. As the coefficient of rolling friction increases, the stability region’s area gradually decreases with a notable leftward shift of its right boundary. This shift ultimately leads to a leftward shift in the optimal vibration reduction curve. In the range of gap clearance variation allowing for steady-state motion with two symmetrical impacts per cycle, the relative velocity of the particle is more effective and intuitive to reveal the vibration reduction mechanism of particle dampers than other perspectives such as momentum, energy, and phase.

Dynamics and vibration reduction performance of asymmetric tristable nonlinear energy sink

With its complex nonlinear dynamic behavior, the tristable system has shown excellent performance in areas such as energy harvesting and vibration suppression, and has attracted a lot of attention. In this paper, an asymmetric tristable design is proposed to improve the vibration suppression efficiency of nonlinear energy sinks (NESs) for the first time. The proposed asymmetric tristable NES (ATNES) is composed of a pair of oblique springs and a vertical spring. Then, the three stable states, symmetric and asymmetric, can be achieved by the adjustment of the distance and stiffness asymmetry of the oblique springs. The governing equations of a linear oscillator (LO) coupled with the ATNES are derived. The approximate analytical solution to the coupled system is obtained by the harmonic balance method (HBM) and verified numerically. The vibration suppression efficiency of three types of ATNES is compared. The results show that the asymmetric design can improve the efficiency of vibration reduction through comparing the chaotic motion of the NES oscillator between asymmetric steady states. In addition, compared with the symmetrical tristable NES (TNES), the ATNES can effectively control smaller structural vibrations. In other words, the ATNES can effectively solve the threshold problem of TNES failure to weak excitation. Therefore, this paper reveals the vibration reduction mechanism of the ATNES, and provides a pathway to expand the effective excitation amplitude range of the NES.

Magnetic-Control Variable Stiffness and Damping Tail Support for a Wind-Tunnel Aircraft Model

To suppress random vibration of aircraft models during wind tunnel tests, a novel magnetorheological elastomer (MRE)-based device with variable stiffness and variable damping (VSVD) is proposed, which is installed on the tail support system. Firstly, the dynamic characteristics of the tail support system are established using finite element model simulation to obtain the vibration mode and stress distribution. Next, the vibration reduction mechanism of the MRE-based tail support system is analyzed by solving a finite element model. Then, the magnetic-controlled VSVD device with an annular sandwich structure is proposed, and the decisive rheology material and structural parameters in relation to the tail support system’s dynamics are determined. Subsequently, the magnetically generated element with multicoils is designed to guarantee a large enough magnetic field, and the optimal structure parameters are obtained. Finally, random wind flow experiments in the wind tunnel and frequency sweep tests in the ground laboratory for the tail support system equipped on the VSVD device are conducted to verify the effectiveness of the proposed device, respectively. The results under 15–200 Hz random excitation indicate the root mean square of acceleration at the centroid of the aircraft model with the VSVD device can be decreased by 46.8% compared to the system without the VSVD device.

Mechanism and Experimental Investigation of Vibration Reduction for Container Cranes Based on Particle Damping Technology

Container cranes have been widely used for port operation. However, the structure of the port container crane is large, which always leads to crane damage under vibration and strong wind. Therefore, a method for vibration reduction of container crane structure based on particle damping technology is proposed. In this investigation, the scale 1:80 crane model is built, and the equivalent mechanical model is also established to preliminarily verify the effect of vibration suppression. Furthermore, the dependence of vibration suppression effect on the key parameters of the damper, i.e., filling material, filling rate, particle size, and installation position of dampers are analyzed through experiments. The results indicate that the vibration peak of the crane structure displayed in the Simulink oscilloscope is weakened and lags behind, the installation of the damper brings the effect of vibration suppression for the crane, and the vibration suppression effect reaches 25%; the crane mode obtains the best vibration suppression effect under the condition that the material filled in the damper has a large density and elastic modulus, sufficient collision space and high collision frequency, and the dampers are installed far away from the crane center of gravity. The optimum parameters of the damper obtained from experiments were 12 mm lead beads, a filling rate of 60%, installed in the distal ends within the strength range of the forearm of the crane. It is thus concluded that particle damping technology has provided an effective way of wind and vibration reduction for container cranes.

Periodic motion and optimization design of non‐stacked particle damper based on the double inert mass equivalent model

AbstractTo promote the application of non‐stacked particle damper (NSPD) in civil engineering, a design methodology was suggested on the basis of the double inert mass equivalent model. NSPD single‐story steel frame model is selected as the research object in this paper. First, the analytical solution for the periodic motion with symmetric two impacts was discussed. The shaking table test was performed to verify the rationality of the analytical solution under harmonic excitation. Subsequently, based on the analytical solution, the influence of equivalent connection stiffness on the vibration reduction effect and mechanism was analysed under resonant and non‐resonant harmonic excitation. The numerical analysis methods of the optimal equivalent connection stiffness were obtained accordingly. Finally, the effectiveness and generalization of the proposed optimal equivalent connection stiffness were discussed numerically under harmonic excitation and seismic ground motion. An optimal design process for the NSPD was proposed accordingly. Based on this, the vibration reduction performance analysis of NSPD under far‐field records, near‐fault pulse‐like records and near‐fault non‐pulse records was further conducted in the end. The results show that the time‐dependent frequency behaviour of the uncontrolled structure has a significant impact on the performance of the NSPD. The proposed optimization method is effective, which can be used as the foundation for the optimization of NSPD under earthquakes.

Lightweight Design for Active Small SAR S-STEP Satellite Using Multilayered High-Damping Carbon Fiber-Reinforced Plastic Patch

In the launch environment, satellites are subjected to severe dynamic loads. These dynamic loads in the launch environment can lead to the malfunction of the payload, or to mission failure. In order to improve the structural stability of satellites and enable the reliable execution of space missions, it is necessary to have a reinforcement structure that reduces structural vibrations. However, for active small SAR satellites, the mass requirements are very strict, and this makes it difficult to apply an additional structure for vibration reduction. Therefore, we have developed a carbon fiber-reinforced plastic (CFRP)-based laminated patch to obtain a vibration reduction structure with a lightweight design for improving the structural stability of an S-STEP satellite. To verify the vibration reduction performance of the CFRP-based patch, sine and random vibration tests were conducted at the specimen level. Finally, the structural stability of the S-STEP satellite with the proposed CFRP-based laminated patch was experimentally verified using sine and random vibration tests. The validation results indicate that the CFRP-based laminated patch is an efficient solution which can effectively reduce the vibration response without the need for major changes to the design of the satellite structure. The lightweight vibration reduction mechanism developed in this study is one of the best solutions for protecting vibration-sensitive components.

Development of an anti-vibration aircraft model support system with magnetorheological annular squeeze dampers for wind tunnel

Sting support is an important equipment in wind tunnel test and is also vulnerable to resonance under the influence of wind flow, which will reduce the accuracy of test data and even pose a hazard to the wind tunnel. To address the vibration problem, an innovative magnetorheological sting support (MRSS) was proposed in this paper. Specifically, the vibration reduction mechanism was explained by using a combination of Euler-Bernoulli beam and Kelvin-Voigt element. Furthermore, the relationship between the stiffness and damping of the magnetorheological damper (MRD) and the natural frequency (NF) and damping ratio (DR) characteristics of the MRSS was illustrated. To provide controllable damping and stiffness for the support system, an MRD with annular squeeze mode was designed, taking into account various factors such as low influence on wind flow, sting shape, and magnetic circuit requirements, and was also optimized by considering target magnetic field and low power consumption as the objectives. Tests on the manufactured MRD demonstrate the effectiveness of the structure design and optimization. Also, the response time characteristic satisfies the system vibration control. Subsequently, the controllability and superior fail-safe property of MRSS were verified through laboratory and wind tunnel tests. Finally, an on–off control logic was developed, and real-time vibration control tests were conducted in various impulse excitation, the resonance peak was significant attenuated by 27.1 dB. Additionally, the resonance peak was attenuated by 17.6 dB in the passive state. The experimental results showed that the MRSS was able to suppress the vibration with efficiency and reliability.

Novel Wood-Based Functional Material with Vibration and Noise Reduction.

As a kind of typical green material, natural materials tend to exhibit excellent performance in the engineering field because of their structure and special functions. The homogeneous vessels of red willow (RW) are potentially unique structures to store lubricants or reinforcing agents to present special functions for engineering applications. A series of novel red willow wood-based composites, which were infused with nano-MoS2 and then reinforced by the epoxy, were developed. Their self-lubricating, mechanical vibration and noise reduction performances were investigated, and the friction, vibration, and noise reduction mechanisms were disclosed. The infusion MoS2 treatment was very beneficial for improving the tribological properties of MoS2-curing epoxy/red willow (MCW), and the coefficient of friction (COF) was reduced by 65.8% under water-lubricated friction after infusing 24 times. Meanwhile, the mechanical performances of MCW were obviously enhanced through the curing treatment of the epoxy. The synergistic effects of the infusion and curing treatments significantly decreased the wear phenomena on the friction surfaces of MCW and weakened the COF and its fluctuation amplitudes, which resulted in the presented excellent vibration and noise reduction performance. The knowledge gained herein could not only develop a novel wood-based composite with low COF and good vibration reduction properties in the engineering field but also provide a new methodology for the design of artificial porous materials with stable and smooth friction processes.

Suppression of axial vibration of satellite antennas using the self-resetting frictional damper

In order to solve the problems of low-profile accuracy and poor control stability of the satellite antenna due to axial coupling vibration, in this paper, a self-resetting friction damper is proposed to suppress axial vibration. Firstly, a self-resetting friction damper, with a lightweight, wide frequency band, and high energy consumption, is designed. The principle of dry friction energy loss of metal rubber (MR) and the effect of self-resetting of shape memory alloy (SMA) are used. Secondly, the vibration reduction mechanism model of the self-resetting friction damper is established, and the principle of damping energy dissipation is analysed. Finally, sinusoidal excitation tests of the components of the satellite antennas with self-resetting friction dampers are carried out. The axial vibration loss factor of the components of the satellite antenna with the self-resetting friction damper is calculated, and the vibration resistance performance of the damper is verified. Theoretical analysis and experimental results show that the self-resetting friction damper has a significant effect on suppressing the axial vibration of the components of the satellite antenna. It is feasible to install a self-resetting friction damper in the components of the satellite antenna to suppress the axial vibration.

Research on the Vibration Reduction Mechanism of a New Tensioning Platform with an Embedded Superstructure

Aiming at the problem of precision driving and vibration suppression for sensitive payloads on-orbit, this paper proposes a new compliant platform based on an embedded superstructure and a smart material actuator. Firstly, the main structure of the platform is designed and optimized to achieve the expected indicators via the response surface method. Then, the vibration reduction mechanism of the platform with the embedded superstructure is studied by establishing an equivalent model. Following that, a four-phase superstructure is matched and designed with a compact space, and the results are verified by finite element modal analysis. Finally, both the tensioning performance and vibration reduction performance under fixed frequency harmonic disturbance are studied via transient dynamic simulation. Based on the obtained results, directions for future improvements are proposed. The relevant conclusions can provide a reference for function integration of precision tensioning and vibration suppression.

Research on vibration reduction performance of metaconcrete based on local resonance theory

Metaconcrete is a newly manufactured construction material designed based on local resonance theory, which can reduce impact shock and structural vibration. The local resonant bandgap generated by metaconcrete cells is the key to effectively attenuating elastic waves. However, there are relatively few studies on the vibration reduction performance of the metaconcrete, and there is currently no method for designing the metaconcrete cell according to the target vibration reduction frequency range. In this study, the generation mechanism and influencing factors of the metaconcrete cell bandgap were first studied, and then the bandgap prediction formula of the metaconcrete cell was deduced based on the bandgap generation mechanism. Secondly, the vibration reduction mechanism of the metaconcrete under different frequency vibration loads was studied. Finally, a metaconcrete cell design method based on the bandgap prediction formula is proposed. The results showed that the bandgap starting frequency of the metaconcrete cell was mainly determined by the translational vibration mode of the resonator, and the resulting vibration energy is strongly coupled with the long-wave traveling energy of the matrix, thereby opening the local resonance bandgap. The cut-off frequency of the bandgap was determined by the opposite vibration mode between the resonator and the matrix, and the coupling between the two weakens, resulting in a closed bandgap. The elastic modulus and Poisson's ratio of the soft coating and the density of the matrix are the main material factors affecting the bandgap. In addition, a larger soft coating radius can obtain a lower frequency bandwidth, and a larger resonator radius and a smaller matrix side length can obtain a larger bandgap width. The metaconcrete has a shielding and attenuating effect on the vibration within the bandgap range, and the vibrational energy is dissipated through multiple conversions between the kinetic energy of the resonator and the elastic strain energy of the soft coating. The proposed method can design metaconcrete cells that meet the target vibration reduction frequency range.

Finite element modeling of straight pipeline with partially attached viscoelastic damping patch based on variable thickness laminated element

To successfully implement the viscoelastic damping patch (VDP) for vibration reduction of the straight pipeline, it is necessary to perform dynamic modeling to guide vibration reduction design. The nonlinear vibration characteristic of the straight pipeline with partially attached VDP is studied by the FEM. A modeling method of laminated shell elements with variable thickness is proposed. Additionally, the local coordinate transformation is executed to facilitate the integration calculation of each layer. The nonlinear dynamic equation of the straight pipeline with VDP is established by considering the frequency dependence of VDP and the non-uniform continuous variable stiffness distribution of the clamp. The Vector Iteration method based on Improved Approximate Eigenvalue (VIM/IAE) is proposed to solve the nonlinear eigenvalues further. The rationality of the FE model is verified by constructing an experimental test system and compared with the ANSYS simulation and references. Finally, the vibration reduction mechanism of the clamp-straight pipeline with partially attached VDP considering frequency dependence is analyzed under different nonlinear iterative algorithms, VDP parameters (thickness, elastic modulus, and loss modulus), and boundary stiffness.

Vibration reduction mechanism of Van der Pol oscillator under low-frequency forced excitation by means of nonlinear energy sink

Van der Pol (VDP) oscillator under forced excitation has complicated vibration modes, and its harm to the system cannot be ignored. The vibration reduction mechanism of VDP oscillator by means of nonlinear energy sink (NES) is explored under low-frequency forced excitation. Firstly, a mechanical model of VDP oscillator coupled NES is established by utilizing Newton’s law. Then the time history diagrams under different excitation amplitudes are compared to measure the vibration reduction effect of the coupled system. Finally, the stability and Hopf bifurcation behavior of the corresponding autonomous system are discussed, and the mechanism of cluster phenomenon and the mechanism of vibration reduction are revealed. It is interesting that, the vibration reduction effect is optimal when cluster phenomenon occurs, which is a typical vibration model in slow–fast system. The real part of eigenvalues and hysteresis time are critical factors affecting vibration reduction. These researches provide a theoretical basis for the vibration reduction of VDP oscillator coupled NES.

The Application of Neural Networks to Modular Arrangements of Predetermined Time Standards

To study the method of reducing the low-frequency vibration noise of tires, a passenger car tire (205/55R16) is taken as the research object. The dynamic grounding characteristics and vibration reduction mechanism of the cat’s paw pad are analysed. The research showed that the swing deformation characteristics of paw pads during the walking process of cats are one of the main ways to reduce the impact from the ground and achieve vibration reduction and silencing. To analyse the influence of tire grounding on noise, tire grounding is divided into five areas, and the characteristics of ten tire grounding areas are analysed through tests. Pearson correlation analysis is used to obtain the characteristics of the eight most relevant grounding parameters with tire noise, and multiple linear regression is conducted between the characteristics of the eight grounding areas. The product of the correlation coefficient and the average value of the characteristics of the ground contact area shows that the central area of the tire tread contributes the most to the tire noise. The swing deformation characteristics of the bionic cat paw pad are realized by setting the staggered side branch pipe groove in the centre of the tire, and the vibration reduction characteristics of the bionic tire are analysed using the finite element method. The results showed that when the tire rolls, the amplitude and fluctuation range of the ground radial excitation force acting on the bionic tire are reduced compared with the original tire, and the vibration and noise characteristics of the tire are improved.