Performance Of Damper Research Articles

Research on the Sensing Properties and Vibration Reduction Performance of Self-Sensing Self-Tuning Magnetic Fluid Damper

Abstract The semi-active control damping system has gained popularity due to its quick response time and versatility. However, external sensors are susceptible to environmental interference, affecting system reliability and increasing complexity and maintenance costs, restricting their use. To address this, a self-sensing self-tuning magnetic fluid damper is proposed. The vibration-measuring induction coil is wound on the damper to sense the magnetic fluid vibration information in real time, and the vibration signal is communicated to the self-tuning control circuit. The control circuit calculates and determines the dominant frequency of structural vibration, then outputs the relevant current signal to set the damper's natural frequency to track the excitation frequency, resulting in self-tuning vibration reduction. First, the self-sensing unit's output induced electromotive force model is created, followed by an expression of the damper's natural frequency, indicating that the self-sensing unit can achieve self-tuning vibration reduction by tracking the excitation frequency. The multi-field coupling simulation model of the magnetic fluid damper is generated, and the induction coil coupling mode and damper excitation angle are defined to obtain the maximum induced voltage.
Finally, an experimental platform was developed to assess the damper's self-sensing and self-tuning vibration reduction performance. The experimental results demonstrate that the suggested self-tuning magnetic fluid damper exhibits excellent self-sensing capabilities and effectively reduces vibrations. This offers an innovative research concept for using magnetic fluid in self-sensing technology and vibration reduction domains.

Double Low‐Yield‐Point Steel Corrugated Plates as an Innovative Damper to Improve the Behavior of CBF Braces

ABSTRACTIn this paper, an innovative damper made of low yield point (LYP) steel compound of double corrugated plate and flange plates to form an I‐shaped damper was considered parametrically and numerically. This damper pertain to easy fabrication and replacement after a severe earthquake. The proposed damper is expected to yield while elements outside the damper remain elastic. Consequently, it acts as a ductile fuse that was confirmed in this study. Results indicated that changing the damper from conventional steel to LYP steel improves the damper's performance. Because dampers with the same exhibited different responses, classification of the damper response based on the is not approritae. Of course, considering the fact that it has shear behavior with can be used in the initial design, but it is an incomplete criterion. Also, for dampers with , the ultimate strength is increased related to the from 2.64 to 4.50 times whereas for and is reached 1.35 to 3.84 times and 1.34 to 3.80 times, respectively. It confirms that on the , the most effective on the ultimate strength is obtained by changing the A36 steel to LYP steel. It should be noted that by increasing the by two to four times, the energy dissipation is enhanced 1.44 to 5.64 times for LYP dampers and 1.15 to 2.02 times for A36 dampers.

Largely enhanced damping performance of nitrile rubber/ethylene–vinyl acetate blends via phenolic resin-induced phase separation

The low glass transition temperature (Tg) and narrow effective damping temperature range (EDTR) greatly restrict the application of common vulcanized rubbers in fields relating to high temperature environmental condition due to the greatly reduced damping performances. In this work, phenolic resin (PR) was incorporated into nitrile rubber/ethylene–vinyl acetate (NBR/EVM) blends through melt-compounding processing, and the microstructure and damping performance changes induced by PR were comparatively investigated. The results show that PR induces the phase separation of the blends and most of PR particles selectively locate in the NBR component. Molecular dynamics simulation confirms that more hydrogen bonds form in the ternary blends, and reduced free volume fraction is also achieved. The ternary blends show good high-temperature damping performances, and apparently enhanced Tg (up to 17.7 °C) and EDTR (82.6 °C, from −2.6 to 80 °C) are also achieved. Additionally, the ternary blends exhibit good mechanical properties, including higher ductility and larger fracture energy, and better energy dissipation ability. This work provides an alternative resolution way to enhance the damping performances of the common vulcanized rubbers at high temperatures.

Optimal replicator dynamic controller for semi active control of long span cable stayed bridge with considering special variability of seismic excitations

Cable-stayed bridges are lifeline infrastructures. However, due to their design and structural characteristics, they are sensitive to the vibrations. Thus, vibration control in these structures is essential. Semi-active control systems have gained significant attention due to their high performance and adaptability. However, the implementation of these systems has always faced serious challenges particularly when it comes to developing appropriate control algorithms because semi active devices have complex and non-linear characteristics. Inspired by evolutionary game theory, the author utilizes the replicator dynamic controller concept to optimize the performance of MR dampers to improve the vibration reduction of cable-stayed bridges. Two key parameters in the proposed control methodologies using replicator dynamics are the total population (total available resources or the sum of actuator forces) and the growth rate. Instead of using the sensitivity analysis that has been done in previous studies for vibration reduction of highway bridges using a replicator controller, the author used an evolutionary algorithm named the nondominated sorting genetic algorithm (NSGA-II) to create an optimal replicator dynamic controller for more effective vibration reduction. The proposed methodology is evaluated through its numerical application to a second-generation benchmark example based on the Bill Emerson Memorial Bridge, which considers a more realistic behavior of the cable-stayed bridge by accounting for multiple support excitations. The study indicates that the optimal replicator dynamic controller improves the vibration reduction performance of MR dampers. Specifically, deck displacement is reduced by 46 % compared to passive control system and shear forces at the tower base are reduced by 33 % compared to active control systems for the El Centro earthquake. The results indicate that the proposed Replicator Dynamic Controller optimized through NSGA-II provides a robust and effective solution for improving seismic resilience of cable-stayed bridges.

Cyclic functional degradation of NiTi shape memory alloy wires in wide ranges of strain rate and ambient temperature

Shape memory alloy (SMA) dampers frequently experience cyclic loading over a broad spectrum of strain rates and ambient temperatures, resulting in a significant thermo-mechanical coupling effect during cyclic deformation. Nevertheless, the impact of this coupling effect on the functional degradation of SMAs has not been thoroughly examined, particularly in scenarios involving severe deformation. In this study, a series of strain-controlled cyclic loading–unloading tests were conducted on NiTi SMA wires utilizing various combinations of strain rates ranging from 5 × 10−4 6 × 10−2/s and different ambient temperatures (313–393 K). The functional degradation was exacerbated by increasing ambient temperature and loading rate due to the complex interactions among the inelastic deformation mechanisms and thermo-mechanical coupling effects. Furthermore, although the cyclic deformation behavior of NiTi SMA wires varied with the loading rate, this rate dependence diminished with increasing ambient temperature. The synergistic effect of elevated strain rates and high temperatures markedly accelerated the fatigue failure of NiTi SMA wires and substantially altered the underlying microstructural morphology. These findings can provide valuable support for evaluating the service performance of NiTi SMA dampers under various engineering conditions and contribute to developing a cyclic constitutive model for NiTi SMAs.

Review of Surface Treatment Technology for Improving Wear Resistance of Magnesium Alloys

Background: As the lightest metal structural material in engineering, magnesium alloy has excellent mechanical properties, such as high specific strength, high specific stiffness, good damping performance, and good machinability. It is widely used in the fields of precision parts, automobiles, aerospace, and military. However, poor friction and wear performance are significant magnesium defects of the alloys, which make its use limited in some areas with high working conditions, so it is essential to improve the wear resistance of the magnesium alloy surface. Objective: The aim of this study was to summarize the technology of improving the wear resistance of magnesium alloy in recent year. The influence of different surface treatment technology for enhancing friction and wear properties was also analyzed, which could provide a reference for related scholars and researchers. Method: In this paper, the literature related to friction and wear properties of magnesium alloys in recent years were reviewed, the principles of various surface treatment technology of magnesium alloys were explained, and the advantages and disadvantages of each technology were analyzed. Results: Based on the literature analyses related to the wear resistance of magnesium alloys, the problems existing in the surface treatment technology for improving the wear resistance of magnesium alloys are summarized, and future development directions are put forward. Conclusion: Among the technologies to improve the wear resistance of magnesium alloys, the combination of various techniques can better meet the working demands. The environmentally friendly and efficient manner has a good prospect for development.

Experimental and numerical study on the cyclic behavior of web dumbbell-shaped damper fabricated of low-yield-point steel

Current double-conical steel dampers, mainly made from low-carbon steel, stainless steel or high-strength steel, do not perform well in terms of fatigue, energy dissipation, and plastic deformation. To address these limitations, this study proposes a web dumbbell-shaped damper fabricated of LYP225 low-yield-point steel (LYP-WDP). This innovation aims to significantly improve the hysteretic behavior and fatigue performance of double-conical steel dampers. Given the limited experimental research on the hysteretic behavior of LYP-WDP under cyclic loading, this study conducts tests to evaluate its performance. Seven full-scale LYP-WDP specimens with different structural parameters were designed using LYP225 steel and subjected to low-cycle loading tests to assess their behavior under shear deformation. The effects of various design parameters on the performance of LYP-WDP were thoroughly analyzed. Finite element models of the specimens were created, and the simulation results were compared with experimental data. Additionally, formulas for calculating the elastic stiffness and yield strength of the LYP-WDP were proposed. The findings reveal that LYP-WDP has high ductility and stable energy dissipation capacity. The elastic stiffness and load-carrying capacity of LYP-WDP increase with the internal shrinkage ratio when the inner diameter and length of the energy dissipation segment are constant, while a negative correlation is found when the outer diameter and length are fixed. Increasing the length of the straight segment greatly enhances the energy dissipation capacity of LYP-WDP. The test results validate the accuracy of the proposed formulas and provide valuable insights for the design and application of LYP-WDP, marking a significant advancement in the field of damping technology.

Multimodal shunt damping of monolithic bladed drums using multiple digital vibration absorbers

Abstract Based on a digital realization of piezoelectric shunt circuits, this works presents a proof-of-concept damping approach tailored to address the complex dynamics of monolithic bladed drums (BluMs) and attenuate their vibrations. This approach comprises the simultaneous use of multiple digital vibration absorbers (DVAs) together with a mean shunt strategy, taking advantage of the fact that multiple absorbers act simultaneously on the structure and that the blade modes of BluMs appear closely-spaced. In order to target multiple groups of modes, this strategy is incorporated in a multi-staged shunt circuit. The damping concept is numerically and experimentally demonstrated on a BluM with multiple piezoelectric patches, proving its ability to achieve excellent damping performance on multiple groups of modes. This performance is shown to be relatively insensitive to the spatial distribution of the shunted patches. Based on a robustness study, it was also found that the shunts are robust to changes in the host structure which could, e.g., be due to mistuning. Owing their digital nature, DVAs are easily adjustable making them highly attractive in practical applications.

Experimental study on seismically isolated systems using a novel roller-type bearing with energy dissipation capacity

The roller-type isolation bearing is highly effective in limiting the transmission of lateral seismic forces to the superstructure. This paper introduces a novel roller-type bearing with energy dissipation capacity (RB-EDC), which includes flat bearing seats, rollers, limit plates with energy dissipation capability, and limit rings. The RB-EDC is characterized by its excellent energy dissipation capacity, simple manufacturing process, low cost, vertical tensile bearing capacity and stable performance in extremely cold regions due to its specific configuration and materials. The design procedure for the RB-EDC is detailed herein. Subsequently, pseudo-dynamic comparison tests were conducted on both a seismic isolation system specimen and a RC column specimen under frequent and rare earthquake conditions to validate the damping performance of the RB-EDC. The seismic isolation system consists of the RB-EDC and an RC column identical to the RC column specimen. The results indicate that, compared to the RC column specimen, the column in the seismic isolation system specimen significantly reduces crack distribution ranges, rebar strain, concrete strain, and displacement at the column top under seismic actions. The RB-EDC exhibits significant energy dissipation capacity even during frequent earthquakes, demonstrating effective damping performance. However, the residual displacement of the RB-EDC increases with seismic intensity, which may impact the damping performance of the bearing in future potential earthquakes, indicating the need for further redesign to incorporate self-centering capacity.

CO2-based polyurethane elastomers with enhanced mechanical and tunable room-temperature damping performances

Elastomers provide excellent damping performance owing to their unique viscoelasticity, which are widely used as vibration and noise reduction materials. However, conventional rubber-based elastomers with a low glass transition temperature (Tg) and narrow damping range are difficult to adapt to room-temperature conditions. Additionally, most of petroleum-based elastomers hinder the sustainable development. In this work, a series of novel polyurethane elastomers was synthesized using carbon-fixed CO2-based polycarbonate propylene diol (PPCD). The impact of hard segment (HS) content on the thermal, mechanical, and damping properties of CO2-based polyurethane (PU) was comprehensively investigated. Increasing the HS content from 16 % to 44 % increased the Tg from −3.8 °C to 21.7 °C, covering the entire damping range at room temperature with an adjustable damping performance. Furthermore, the tensile strength increased from 7.2 MPa to 27.0 MPa. The synthesis of CO2-based PU can propel the utilization of PU in damping applications, enabling sustainable advancement of the PU industry.

Theoretical and experimental investigation of flexible air spring stiffness in a tuned liquid column gas damper for vertical vibration control

This study investigates the effectiveness of equivalent linear air spring stiffness in a Vertical Tuned Liquid Column Gas Damper (VTLCGD) for reducing vertical structural vibrations, particularly considering different sealing conditions. The VTLCGD system, designed with a single sealed vertical air column, allows flexible frequency tuning by adjusting the air spring stiffness. It aims to be used in low-frequency structures where conventional VTLCGD designs with two sealed ends are less efficient. The geometric configuration and working principle of the VTLCGD are first described. The equation of motion is derived using liquid dynamic equilibrium and the pressure-volume relationship, with expressions for natural frequency and control force validated through shaking table tests conducted with varying VTLCGD lengths. Experimental investigations are conducted to examine the parameters affecting damper performance using pressure data. The system's vibration reduction performance is then numerically evaluated on a cantilevered floor subjected to human walking. The numerical results, based on the equation of motion for liquid displacement and natural frequency, show good agreement with experimental data, which confirms the effectiveness of using linearized air spring stiffness for frequency tuning. The effects of total liquid length and height difference on control force are further investigated, and a polytropic index of 1.2 is determined for the VTLCGD frequency formula. The VTLCGD system achieves a maximum vibration reduction of 52.63 % in acceleration response on the cantilevered floor compared to the uncontrolled case. Moreover, the variation in stiffness due to changes in the sealing condition is presented to validate the damper's adaptability over a wide frequency range.

Thermal/vibration characteristics of additional damping structures with entangled metallic wire material under high temperature environment

In modern engineering practice, the simultaneous exposure to high temperatures and vibrations can threaten the security of the structure. In this paper, a novel additional damping structures with entangled metallic wire material (EMWM) are proposed and its vibration characteristics at high temperature are investigated. Firstly, a thermal/vibration coupling test platform of additional damping structures is designed and constructed, and a high-temperature vibration pickup method is adopted to extract the response signals. On this basis, the 5–400Hz frequency sweep tests are carried out under the unilateral constraint condition. The effects of excitation magnitude, ambient temperature and EMWM thickness on the vibration parameters are analyzed. The vibration performance is evaluated by modal identification and loss factor by half-power method. The results show that the damping performance of the constrained damping structure and insertion damping structure is better than that of the free damping structure under different excitation levels; the increase of the ambient temperature generates a greater influence on the vibration damping performance of the structure, but it still has a good stability; the amplitude change of the structure is more apparent through the increase of EMWM thickness, and the vibration damping performance is more superior. Under extreme engineering environments, a new approach to plate damping structures is provided that still maintains excellent performance.

Numerical study of the vibration control performance of Kelvin foam

Vibration control in microsystems is an important challenge. Because of the space limitation, structures that consume minimal space but provide effective performance need to be identified. In this research, we evaluate the vibration damping performance of various Kelvin-cell structures in microsystems using the Finite Element Method. Nine types of unit cells are designed based on the tetrakaidecahedron with different geometric parameters. The lattices are composed of the aforementioned unit cells, and two types of boundary condition are set according to the actual application scenarios. The results of the simulation include dissipated energy , isolation efficiency, etc. The results are compared with each other and two types of non-Kelvin-cell structures. This comparative analysis aims to inform the development of space-efficient vibration absorbers for microsystems.

A self-damping triboelectric tactile patch for self-powered wearable electronics

Wearable tactile sensing systems with bionic designs holds significant promise for environmental interactions and human–machine communication. Triboelectric sensing technology plays a vital role in acquiring and quantifying tactile signals. Conventional elastic sensing materials, however, lack damping performance and are easily damaged by vibrations, leading to sensor failure. To address this challenge, our study proposes a highly damping triboelectric gel based on a hydrogen bonding assisted microphase separation strategy. In microphase separation, the soft phase provides the viscoelasticity needed for the gel, while the hard phase dissipates shock energy. This energy dissipation mechanism enables the gel to achieve excellent damping performance (tan δ = 0.68 at 1Hz), skin-like softness (Young’s modulus of 130 kPa), and stretchability (> 900%). The resulting self-damping tactile patch effectively absorbs and dissipates external vibrations, ensuring a stable and reliable wearable tactile sensing device. This work provides new insights into the application of triboelectric gels in wearable electronics.

Performance evaluation of vibration-damping bucking bar in human-robot collaboration

Abstract The riveting process in aircraft manufacturing generates large vibrations, and if it is exposed to vibration for a long period of time, riveting workers may suffer from Hand-Arm Vibration Syndrome causing irreversible damage to the robot. In this study, firstly, the vibration mechanical model of human-robot collaboration was established, and then the vibration characteristics of human-robot collaboration under squeezing force were deduced. Finally, an experiment was performed to evaluate the vibration damping performance of vibration-damping bucking bars by evaluating the mean peak squeezing force with different rivet guns and input pneumatic pressure. Compared with the conventional stainless steel bucking bar, the PU-cylinder bucking bar has a lower mean peak squeezing force. The results show that the utilization of the PU-cylinder bucking bar in human-robot collaborative riveting operations can considerably reduce the vibration transmitted from the rivet gun to the robot and the operator.

Research on Protective Effect of Lead Buffer Device under Explosion Load

In modern society, the frequency of explosion accidents is gradually increasing, which brings a great threat to the safety of people's lives and property and social stability. Explosive loads are extremely destructive, with huge energy and powerful impact force released in an instant, capable of causing serious damage to buildings and infrastructure. Therefore, it is of great practical significance to study explosion protection measures in depth and improve the damage resistance of buildings and infrastructure under explosion loads. The traditional underground dispersed layer can reduce the impact of blast load on the structure to a certain extent, but with the continuous improvement of protection requirements, its limitations are gradually revealed. For example, the protection of underground dispersed layers may be less than ideal in some complex explosion situations, and their performance is susceptible to environmental factors such as salinity, consolidation, precipitation and ice, resulting in reduced protection effectiveness. In order to find a more effective solution for explosion protection, the idea of replacing the underground dispersion layer with lead dampers was proposed. As a new type of protective device, lead damper has unique advantages. Lead has good plastic deformation ability, and can absorb a large amount of energy through its own deformation under the action of explosion load, so as to effectively reduce the impact of explosion on the structure. In addition, lead dampers can be customized to meet specific engineering needs, allowing them to better adapt to different explosion scenarios and structural types. The purpose of this study is to further investigate the protective effect of lead dampers instead of underground dispersed layers under blast loads. Through a combination of theoretical analysis, numerical simulation and experimental research, the performance of the lead damper is comprehensively evaluated, and its response mechanism under blast load is analyzed, as well as the advantages and disadvantages compared with the underground dispersed layer. At the same time, the influence of the design parameters of the lead damper on the protection effect will be studied, so as to provide scientific basis and guidance for its application in practical engineering. Through this study, it is expected to provide a new and more effective means of protection for explosion protection engineering, and improve the safety and reliability of buildings and infrastructure under explosion loads. This will not only help reduce the losses caused by explosion accidents and ensure the safety of people's lives and property, but also contribute to the stability and sustainable development of society.

Linear equivalence for motion amplification devices in earthquake engineering

AbstractMotion amplification devices utilized to amplify the motion of dampers can effectively improve the energy dissipation performance of dampers to reduce seismic responses of engineering structures. This study systematically develops a linear equivalence theory for motion amplification devices based on the proposed equivalent Maxwell model. This equivalent model accurately predicts the supplemental damping effect provided by motion amplification devices without approximation. Also, the equivalent model is capable of quantifying the amplification effect of motion amplification devices by means of deriving the analytical expressions of the equivalent damping and stiffness coefficients, which reveal that motion amplification devices simultaneously enhance the original damping and stiffness coefficients by , where is the proposed rigidity motion amplification factor. The representative value of member stiffness is developed to comprehensively evaluate the supporting stiffness of motion amplification devices. All the achieved results strongly support that the proposed linear equivalence theory provides a generic paradigm to explain, measure and compare different types of motion amplification devices in terms of their supplemental damping effects, and hence helps researchers and engineers gain valuable insight into the dynamic properties of motion amplification devices.

Mechanical properties and damping ratio of gradient polymer concrete for damping beam structure

AbstractDue to its higher overall performance than ordinary concrete, polymer concrete (PC) beam has been widely used in the field of structural engineering. However, it is widely recognized that PC cannot simultaneously achieve the highest mechanical strength and optimal damping performance to reduce vibration during its long‐term service lifetime. To address this contradiction, the effect of various diluents contents on the overall performance of PC was investigated first in this investigation. Experimental findings revealed that the bending strength of PC exhibits an initial increase followed by a decrease with an increment of diluents, while its damping ratio displays an inverse trend. To obtain excellent overall performance (higher flexural strength and damping ratio) of PC, gradient PC has been manufactured by horizontal partition casting process (HPCP) and stereoscopic layered casting process (SLCP). Experimental results demonstrated that the gradient PC manufactured by HPCP exhibited better overall performance compared to SLCP. Furthermore, the graphite and carbon fiber were incorporated into the above gradient PC, and experimental results revealed that the incorporated graphite and carbon fiber can further increase the overall performance of the above gradient PC. Similarly, the incorporation of glass fiber cloth and carbon fiber cloth, along with surface treatment, significantly enhanced the overall performance of PC. The significance of this study lies in enhancing the comprehensive performance of PC beam structures, thus broadening its utilization scope within structural engineering.

Electromagnetic Field and Variable Inertia Analysis of a Dual Mass Flywheel Based on Electromagnetic Control

The moment of inertia of the primary flywheel and the secondary flywheel in a dual mass flywheel (DMF) directly affects the vibration damping performance in an automotive driveline. To enable better minimization of vibration and noise by changing the moment of inertia of the DMF to adjust the frequency characteristics of the automotive driveline, a new variable inertia DMF structure is proposed by introducing electromagnetic devices. The finite element simulation model of the electromagnetic field of an electromagnetic device is established, the electromagnetic field characteristics in the structure are analyzed, and the variation in the electromagnetic force under different air gaps and current conditions is obtained. The electromagnetic force test system of the electromagnetic device is constructed, and the validity of the finite element simulation analysis of the electromagnetic field of the electromagnetic device is verified. A mechanical model of the electromagnetic device is established to analyze the characteristics of the displacement of the moving mass in the structure as well as the variation in the moment of inertia of the DMF at different rotational speeds and currents. The maximum adjustable proportion of its moment of inertia can reach 15.07%. A torsional model of the automotive driveline is established to analyze the effect of variable inertia DMF on the resonance frequency of the system under different currents. The results show that the electromagnetic device introduced in the DMF can realize the active adjustment of the moment of inertia and enable the resonance frequency to decrease with increasing rotational speed, which expands the idea of optimizing the vibration damping performance of the DMF and provides a reference for better control of the torsional vibration of the automobile or other mechanical transmission systems.

A novel optimal design method for tuned mass dampers with elastic motion‐limiting stoppers

AbstractTuned Mass Dampers (TMDs) are commonly used passive control devices in practical engineering applications. However, motion‐limiting stoppers are usually installed to control the excessive TMD displacement due to the building space limitation, resulting in piecewise nonlinearity and detuning of TMD. This paper studies the influence of elastic motion‐limiting stoppers on the optimal design of TMDs through a piecewise stiffness TMD (PSTMD) model. Performance of a PSTMD with classical design is first investigated and proven to be ineffective. To optimize the PSTMD parameters, the motion of PSTMD is decoupled from the controlled structure, and the frequency response equation of PSTMD is obtained analytically through the averaging method. Subsequently, the solution of the optimal design frequency for PSTMD is transformed into the solution of the jump frequency in the frequency response equation. With the optimal frequency of PSTMDs, the optimal damping and control performance of PSTMDs are discussed and analyzed compared with classical linear design, which fully showcases the effectiveness of the novel design method. Finally, the effectiveness of the novel design method is verified using a nine‐story benchmark frame structure, and the results demonstrate that the control performance of the optimal PSTMD can be improved by nearly under specific seismic excitation, compared to the PSTMD with classical linear method. In summary, the novel design method can effectively take into account the influence of piecewise nonlinearity caused by elastic motion‐limiting stoppers and improve the optimal control performance of TMD in a more realistic engineering environment.