Application of a dynamic antiresonant vibration isolator to minimize the vibration transmission in underwater vehicles

2017 ◽  
Vol 24 (17) ◽  
pp. 3819-3829 ◽  
Author(s):  
Niuniu Liu ◽  
Chenyang Li ◽  
Caiyu Yin ◽  
Xingjian Dong ◽  
Hongxing Hua
Keyword(s):  
Power Flow ◽  
Thrust Bearing ◽  
Vibration Mode ◽  
Underwater Vehicle ◽  
Vibration Isolator ◽  
Harmonic Force ◽  
Vibration Transmission ◽  
Force Transmissibility ◽  
Isolation Performance ◽  
Analytical Dynamic

Harmonic axial force resulting from a propeller’s first vibration mode is a major cause of tonal sound radiation of an underwater vehicle. To reduce the harmonic force, we employ a dynamic antiresonant vibration isolator (DAVI) in parallel with thrust bearing of the shafting system to attenuate vibration transmitted to the hull. The methods of transfer matrices and substructure synthesis are used to create a semi-analytical dynamic model of the propeller–shaft–hull system with DAVI. In this model, the elastic properties of the propeller and foundation are taken into consideration. The force transmissibility and power flow are then used to evaluate the isolation performance of the DAVI. For the purpose of comparison, a resonance changer (RC) proposed in the published literature is also used to reduce the axial vibration transmission. It is demonstrated numerically that by using DAVI, the vibration and power flow of the underwater vehicle are greatly attenuated at the designed frequency without obviously changing the axial fundamental resonance frequency of the shafting system, which is superior to the RC isolator.

Beneficial performance of a quasi-zero stiffness vibration isolator with generalized geometric nonlinear damping

2020 ◽  
pp. 095745652097238
Author(s):  
Chun Cheng ◽  
Ran Ma ◽  
Yan Hu
Keyword(s):  
Damping Ratio ◽  
Nonlinear Damping ◽  
Vibration Isolator ◽  
Equivalent Damping ◽  
Frequency Responses ◽  
Geometric Nonlinear ◽  
Resonant Region ◽  
Force Transmissibility ◽  
Isolation Performance ◽  
Force And Displacement Transmissibility

Generalized geometric nonlinear damping based on the viscous damper with a non-negative velocity exponent is proposed to improve the isolation performance of a quasi-zero stiffness (QZS) vibration isolator in this paper. Firstly, the generalized geometric nonlinear damping characteristic is derived. Then, the amplitude-frequency responses of the QZS vibration isolator under force and base excitations are obtained, respectively, using the averaging method. Parametric analysis of the force and displacement transmissibility is conducted subsequently. At last, two phenomena are explained from the viewpoint of the equivalent damping ratio. The results show that decreasing the velocity exponent of the horizontal damper is beneficial to reduce the force transmissibility in the resonant region. For the case of base excitation, it is beneficial to select a smaller velocity exponent only when the nonlinear damping ratio is relatively large.

Energy flow and performance evaluation of inerter-based vibration isolators mounted on finite and infinite flexible foundation structures

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110704
Author(s):  
Zhuang Dong ◽  
Jian Yang ◽  
Chendi Zhu ◽  
Dimitrios Chronopoulos ◽  
Tianyun Li
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Flow Behavior ◽  
Flexible Beam ◽  
Vibration Isolators ◽  
Force Transmissibility ◽  
And Performance ◽  
Flexible Foundation ◽  
Isolation Performance

This study investigates the vibration power flow behavior and performance of inerter-based vibration isolators mounted on finite and infinite flexible beam structures. Two configurations of vibration isolators with spring, damper, and inerter as well as different rigidities of finite and infinite foundation structures are considered. Both the time-averaged power flow transmission and the force transmissibility are studied and used as indices to evaluate the isolation performance. Comparisons are made between the two proposed configurations of inerter-based isolators and the conventional spring-damper isolators to show potential performance benefits of including inerter for effective vibration isolation. It is shown that by configuring the inerter, spring, and damper in parallel in the isolator, anti-peaks are introduced in the time-averaged transmitted power and force transmissibility at specific frequencies such that the vibration transmission to the foundation can be greatly suppressed. When the inerter is connected in series with a spring-damper unit and then in-parallel with a spring, considerable improvement in vibration isolation can be achieved near the original peak frequency while maintaining good high-frequency isolation performance. The study provides better understanding of the effects of adding inerters to vibration isolators mounted on a flexible foundation, and benefits enhanced designs of inerter-based vibration suppression systems.

scholarly journals Dynamic Modeling and Characteristic Analysis of Floating Raft System with Attached Pipes

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Longlong Ren ◽  
Yang Li ◽  
Xiuchang Huang ◽  
Hongxing Hua
Keyword(s):  
Power Flow ◽  
Vibration Isolation ◽  
Transmission Performance ◽  
Characteristic Analysis ◽  
Vibration Transmission ◽  
Floating Raft ◽  
Flow Through ◽  
The Mean ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration transmission performance of a floating raft system with attached pipes is investigated in this paper. The frequency response function-based (FRF-based) substructure synthesizing method whose accuracy has been verified by numerical simulations and experiment is applied for modeling the system. The power flow through the transmission paths is used for exploring the additional vibration transmission path provided by the attached pipes. The results show that the existence of the additional transmission paths caused by the pipes breaks the symmetries of the system, which leads to the enhancement of the coupling between each substructure. Consequently, it degrades the vibration isolation performance of the raft system. Moreover, a parametric study is performed to investigate the effects on the mean-square velocity of the hull of the attached pipes, which gives a brief guideline for designing the attached pipes.

Vibration transmission path analysis of underwater vehicle power plant based on TPA power flow

2021 ◽  
pp. 147509022110240
Author(s):  
Yang Yang ◽  
Guang Pan ◽  
Shaoping Yin ◽  
Ying Yuan
Keyword(s):  
Power Plant ◽  
Path Analysis ◽  
Power Flow ◽  
Sea Water ◽  
Low Frequency ◽  
Underwater Vehicle ◽  
Vibration Energy ◽  
Vibration Transmission ◽  
Transmission Path ◽  
Transfer Path

In order to obtain the energy contribution of all paths transmitting vibration from the underwater vehicle power plant to the outer shell, a new method named TPA (Transfer Path Analysis) power flow which combines classical TPA and power flow theory was proposed. Calculation results showed that isolators were the critical paths for transmitting vibration energy to the shell in low frequency band. In addition the main engine and sea water pump were critical vibration sources, which provided directions for reducing the vibration energy transmitted from vibration sources to the target body. To the best of our knowledge, this was the first time to assess the vibration transmission path of the underwater vehicle by TPA power flow method. This method can be employed in other works that need to evaluate the contribution of vibration energy.

A nonlinear stiffness and nonlinear inertial vibration isolator

2020 ◽  
pp. 107754632094092
Author(s):  
Yong Wang ◽  
Hao-Xuan Li ◽  
Chun Cheng ◽  
Hu Ding ◽  
Li-Qun Chen
Keyword(s):  
Dynamic Response ◽  
High Frequency ◽  
Nonlinear Stiffness ◽  
Vibration Isolator ◽  
Dynamic Displacement ◽  
Isolation Frequency ◽  
Inertial Characteristic ◽  
Force Transmissibility ◽  
Isolation Performance ◽  
Displacement Peak

A nonlinear stiffness and nonlinear inertial vibration isolator is proposed in this article. It consists of an inerter, a damper, and spring elements. The nonlinear stiffness characteristic is achieved through a negative stiffness structure based on the diamond-shaped structure that generates nonlinear displacement terms. The nonlinear inertial characteristic is implemented via a geometrical nonlinear inerter that produces a nonlinear acceleration term and a nonlinear quadratic velocity term. An averaging method is developed to analyze approximately the dynamic response. The isolation performance is evaluated using four performance criteria: dynamic displacement peak, force transmissibility peak, isolation frequency band, and high-frequency force transmissibility. The effects of the nonlinear inertial characteristic on the dynamic response and isolation performance are examined. The results show that the backbone curve of the nonlinear stiffness and nonlinear inertial vibration isolator has two changing trends: bending first to the right and then to the left and bending directly to the left. The corresponding frequency response curve displays linear, hardening, and softening characteristics. The isolation performance of the nonlinear stiffness and nonlinear inertial vibration isolator is compared with that of the nonlinear stiffness and nonlinear stiffness and linear inertial ones. It could achieve a smaller force transmissibility peak, lower resonant frequency, and larger isolation frequency band than the nonlinear stiffness one and could have smaller dynamic displacement peak and smaller high-frequency force transmissibility than the nonlinear stiffness and linear inertial one. The proposed nonlinear stiffness and nonlinear inertial vibration isolator achieves a better integrated isolation performance among the three vibration isolators.

Vibration control of an unbalanced system using a quasi-zero stiffness vibration isolator with fluidic actuators and composite material: An experimental study

2022 ◽  
pp. 107754632110514
Author(s):  
Sivakumar Solaiachari ◽  
Jayakumar Lakshmipathy
Keyword(s):  
Composite Material ◽  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Basalt Fiber ◽  
Experimental Investigations ◽  
Vibration Isolator ◽  
Coil Spring ◽  
Linear Type ◽  
Fluidic Actuators ◽  
Isolation Performance

In this study, a new type of vibration isolator based on fluidic actuators and a composite slab was tested experimentally with an unbalanced disturbance. Quasi-zero stiffness vibration isolation techniques are advanced and provide effective isolation performance for non-nominal loads. The isolation performance of the proposed isolator was compared to that of a nonlinear vibration isolator equipped with fluidic actuators and a mechanical coil spring (NLVIFA). The NLVIFA system is better suited to non-nominal loads; however, the mechanical spring axial deflection leads to limited amplitude reduction in the system. To address this issue, a cross buckled slab was developed to replace a mechanical coil spring for absorbing vertical deflection by transverse bending, which is made of a specially developed composite material of Basalt fiber reinforced with epoxy resin and enhanced with graphene nano pellets. This current study was concerned with the theoretical analysis and experimental investigations of the proposed nonlinear vibration isolator with fluidic actuators and composite material (NLVIFA-CM), which performs under quasi-zero stiffness characteristics. Because of its reduced axial deflection, the theoretical and experimental results show that the NLVIFA-CM system outperforms the NLVIFA system and other linear type vibration isolators in terms of isolation performance. Furthermore, the proposed vibration isolator makes a significant contribution to low-frequency vibration.

Design and Experimental Analysis of Origami-Inspired Vibration Isolator With Quasi-Zero-Stiffness Characteristic

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Sachiko Ishida ◽  
Kohki Suzuki ◽  
Haruo Shimosaka
Keyword(s):  
Pacific Ocean ◽  
Experimental Analysis ◽  
Frequency Region ◽  
Vibration Isolator ◽  
Spring Stiffness ◽  
Torsional Buckling ◽  
Harmonic Oscillations ◽  
Stiffness Characteristic ◽  
Current Specification ◽  
Isolation Performance

We present a prototype vibration isolator whose design is inspired by origami-based foldable cylinders with torsional buckling patterns. The vibration isolator works as a nonlinear spring that has quasi-zero spring stiffness in a given frequency region, where it does not transmit vibration in theory. We evaluate the performance of the prototype vibration isolator through excitation experiments via the use of harmonic oscillations and seismic-wave simulations of the Tohoku-Pacific Ocean and Kobe earthquakes. The results indicate that the isolator with the current specification is able to suppress the transmission of vibrations with frequencies of over 6 Hz. The functionality and constraints of the isolator are also clarified. It has been known that origami-based foldable cylinders with torsional buckling patterns provide bistable folding motions under given conditions. In a previous study, we proposed a vibration isolator utilizing the bistability characteristics and numerically confirmed the device's validity as a vibration isolator. Here, we attempt prototyping the isolator with the use of versatile metallic components and experimentally evaluate the isolation performance.

scholarly journals Analysis and design of the power law damping based on the nonlinear vessel isolation system

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881719 ◽  
Author(s):  
You Wang ◽  
Xinghua Zhu ◽  
Rong Zheng ◽  
Zhe Tang ◽  
Bingbing Chen
Keyword(s):  
Resonant Frequency ◽  
Working Conditions ◽  
Power Law ◽  
Nonlinear Damping ◽  
Frequency Region ◽  
Isolation System ◽  
Analysis And Design ◽  
Force Transmissibility ◽  
Isolation Systems ◽  
Isolation Performance

In this study, the applications of the cubic power law damping in vessel isolation systems are investigated. The isolation performance is assessed using the force transmissibility of the vessel isolation system, which is simplified as a multiple-degree-of-freedom system with two parallel freedoms. The force transmissibilities of different working conditions faced in practice are discussed by applying the cubic power law damping on different positions of the vessel isolation system. Numerical results indicate that by adding the cubic power law damping to an appropriate position, the isolation system can not only suppress the force transmissibility over the resonant frequency region but also keep the force transmissibility unaffected at the nonresonant frequency region. Moreover, the design of the nonlinear vessel isolation system is discussed by finding the optimal nonlinear damping of the isolation system.

Shock isolation characteristics of a bistable vibration isolator with tunable magnetic controlled stiffness

2021 ◽  
pp. 1-28
Author(s):  
Bo Yan ◽  
Peng Ling ◽  
Yanlin Zhou ◽  
Chuan-yu Wu ◽  
Wen-Ming Zhang
Keyword(s):  
Damping Ratio ◽  
Excitation Amplitude ◽  
Relative Displacement ◽  
Vibration Isolator ◽  
Maximum Acceleration ◽  
Vibration Isolators ◽  
Displacement Ratio ◽  
Shock Isolation ◽  
Maximum Relative Displacement ◽  
Isolation Performance

Abstract This paper investigates the shock isolation characteristics of an electromagnetic bistable vibration isolator (BVI) with tunable magnetic controlled stiffness. The theoretical model of the BVI is established. The maximum acceleration ratio (MAR), maximum absolute displacement ratio (MADR) and maximum relative displacement ratio (MRDR) are introduced to evaluate the shock isolation performance of the BVI. The kinetic and potential energy are observed to further explore the performance of the BVI. The effects of the potential barrier, shape of potential well, damping ratio on the BVI are discussed compared to the linear vibration isolators (LVI). The results demonstrate that the intrawell oscillations and snap-through oscillations are determined by the excitation amplitude and duration time of main pulse. MADR and MRDR of the BVI are smaller than those of the LVI. The maximum acceleration peak amplitude of the BVI is far below that of the LVI, especially when the snap-through oscillation occurs. In brief, the proposed BVI has a better shock isolation performance than the LVI and has the potential to suppress the shock of space structures during the launch and on-orbit deploying process.

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