STUDY OF VIBRATION ISOLATION SYSTEM OF AGRICULTURAL POWER UNITS WITH HYDRAULIC VIBRATION MOUNTS

Existing Structures ◽

Suspension Systems ◽

Urgent Task ◽

Fixed Base ◽

Isolation Systems ◽

Agricultural Machines

At the present, the improvement of vibration isolation systems for equipment, machines and units remains an urgent task. The ways to solve this problem are based on the optimization of existing structures, the development and application of new vibration-insulating elements as well as the improvement of design methods. In particular, to ensure the reliable functioning of agricultural machines, units, working elements and other mechanization means for the technological processes of agricultural production one of the perspective areas is the use of hydraulic vibra-tion mounts in suspension systems for units. This type of mounts is used to mount engines, cabins of agricultural vehicles, and power units. This paper discusses the simu-lation of the dynamic behavior of a power unit attached to a fixed base by the hydraulic mounts. It is proposed to use approximating functions modelling real stiffness character-istics of the mounts. A comparative analysis with a similar design using rubber-metal mounts as vibration-insulating elements is presented.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

Journal of Vibration and Control ◽

10.1177/10775463211000516 ◽

2021 ◽

pp. 107754632110005

Author(s):

Yonglei Zhang ◽

Guo Wei ◽

Hao Wen ◽

Dongping Jin ◽

Haiyan Hu

Keyword(s):

Vibration Isolation ◽

Dynamic Stiffness ◽

Experimental Studies ◽

Excitation Amplitude ◽

Isolation System ◽

Stiffness Characteristic ◽

Negative Stiffness Mechanism ◽

Isolation Systems ◽

Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

Recent Advances in Quasi-Zero-Stiffness Vibration Isolation Systems

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.397-400.295 ◽

2013 ◽

Vol 397-400 ◽

pp. 295-303 ◽

Cited By ~ 9

Author(s):

Fu Niu ◽

Ling Shuai Meng ◽

Wen Juan Wu ◽

Jing Gong Sun ◽

Wei Hua Su ◽

...

Keyword(s):

Vibration Isolation ◽

Low Frequency ◽

Future Research ◽

Isolation System ◽

Significant Development ◽

Recent Advances ◽

Low Frequency Vibration ◽

Future Research Directions ◽

The quasi-zero-stiffness vibration isolation system has witnessed significant development due to the pressing demands for low frequency and ultra-low frequency vibration isolation. In this study, the isolation theory and the characteristic of the quasi-zero-stiffness vibration isolation system are illustrated. Based on its implementation mechanics, a comprehensive assessment of recent advances of the quasi-zero-stiffness vibration isolation system is presented. The future research directions are finally prospected.

A Modular-Type Three-Axis Vibration Isolation System Using Negative Stiffness

ASME 2010 Dynamic Systems and Control Conference, Volume 2 ◽

10.1115/dscc2010-4128 ◽

2010 ◽

Author(s):

Md. Emdadul Hoque ◽

Takeshi Mizuno ◽

Yuji Ishino ◽

Masaya Takasaki

Keyword(s):

Vibration Isolation ◽

Degree Of Freedom ◽

Experimental Results ◽

Negative Stiffness ◽

Isolation System ◽

Single Degree Of Freedom ◽

Single Degree ◽

In Series ◽

A vibration isolation system is presented in this paper which is developed by the combination of multiple vibration isolation modules. Each module is fabricated by connecting a positive stiffness suspension in series with a negative stiffness suspension. Each vibration isolation module can be considered as a self-sufficient single-degree-of-freedom vibration isolation system. 3-DOF vibration isolation system can be developed by combining three modules. As the number of motions to be controlled and the number of actuators are equal, there is no redundancy in actuators in such vibration isolation systems. Experimental results are presented to verify the proposed concept of the development of MDOF vibration isolation system using vibration isolation modules.

RESEARCH ON VIBRATION ISOLATION SYSTEMS USED IN LASER AND NANOTECHNOLOGIES / VIBROIZOLIACINIŲ SISTEMŲ, NAUDOJAMŲ LAZERINĖSE IR NANOTECHNOLOGIJOSE, TYRIMAI

Mokslas - Lietuvos ateitis ◽

10.3846/mla.2012.92 ◽

2013 ◽

Vol 6 (4) ◽

pp. 559-563

Author(s):

Justinas Kuncė ◽

Mindaugas Jurevičius

Keyword(s):

Vibration Isolation ◽

Composite System ◽

Experimental Tests ◽

Negative Stiffness ◽

Isolation System ◽

Vibration Transmissibility ◽

Optical Table ◽

Air Table ◽

The paper discusses the efficiency of a vibration isolation system made of the optical table and two negative-stiffness tables and considers excitation referring to harmonic and nonharmonic methods in the frequency range of 0,2–110 Hz. The article reviews the types and sources of vibrations and types of vibration isolation systems, including those of negative-stiffness. The paper also presents the methodology of experimental tests and proposes research on vibration transmissibility. A composite system consisting of two vibration isolation table having negative stiffness and an air table has been tested. The results and conclusions of experimental analysis are suggested at the end of the article. Santrauka Nagrinėjama vibroizoliacinės sistemos, sudarytos iš optinio stalo ir dviejų neigiamo standumo staliukų, efektyvumas žadinant harmoniniu ir neharmoniniais būdais 0,2–110 Hz diapazone. Aprašyta eksperimentinių tyrimų atlikimo metodika ir atlikti virpesių perduodamumo tyrimai. Ištirta sudėtinė sistema, sudaryta iš dviejų neigiamo standumo virpesių izoliavimo staliukų ir optinio stalo. Nustatytos vibracijų slopinimo charakteristikos. Pateikti eksperimentų metu gauti rezultatai ir išvados.

Performance Enhancement of Spaceborne Cooler Passive Launch and On-Orbit Vibration Isolation System

International Journal of Aerospace Engineering ◽

10.1155/2020/6017957 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Yeon-Hyeok Park ◽

Mun-Shin Jo ◽

Eung-Shik Lee ◽

Hyun-Ung Oh

Keyword(s):

Vibration Isolation ◽

Performance Enhancement ◽

Coil Spring ◽

Isolation System ◽

Resolution Observation ◽

Position Sensitivity ◽

Spring Type ◽

Isolation Systems ◽

Cryogenic Cooler

A spaceborne cryogenic cooler induces undesirable microvibration disturbances during its on-orbit operation, which is one of the main sources that degrades the image quality of submeter-level high-resolution observation satellites. Several types of vibration isolation systems based on passive approaches have been developed for reducing the microvibration of the cooler. A coil-spring-type passive vibration isolation system developed in a previous study has shown excellent performance in both launch vibration and on-orbit microvibration isolation. To improve the capability of the conventional cooler isolator, including the position sensitivity and launch vibration reduction, we propose a new version of a dual coil-spring-type passive vibration isolator system. The effectiveness of the newly proposed design was validated through a microjitter measurement test, position sensitivity test, and qualification-level launch vibration test of the isolator.

Probability Analysis of Precision Equipment Vibration Isolation System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.467.410 ◽

2013 ◽

Vol 467 ◽

pp. 410-415 ◽

Cited By ~ 3

Author(s):

Vladimir Smirnov ◽

Vladimir Mondrus

Keyword(s):

Vibration Isolation ◽

Dimensional Space ◽

Three Dimensional ◽

Relative Displacement ◽

Probability Analysis ◽

Isolation System ◽

Isolation Systems ◽

Gauss Distribution ◽

Three Dimensional Space

The article deals with probability analysis for a vibration isolation system of sensitive equipment. Vibration isolation system is subjected to external base vibrations due to ambient oscillations (background noise). Considering Gauss distribution for ambient vibrations, we estimate the probability when the relative displacement of isolated mass will still be lower than the vibration criteria. The problem is solved in three-dimensional space, evolved by the system parameters damping and natural frequency. According to this probability distribution, the chance of exceeding vibration criteria for a vibration isolation system is evaluated and different vibration isolation systems are compared.

Novel Double-Parallelogram Motion Constraining Mechanisms for Vibration Isolation Systems

Volume 8: 31st Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2007-34880 ◽

2007 ◽

Author(s):

Jahangir Rastegar ◽

Farshad Khorrami

Keyword(s):

Relative Motion ◽

Vibration Isolation ◽

Translational Motion ◽

Linkage Mechanism ◽

Isolation System ◽

Rocking Motion ◽

Isolation Systems ◽

Isolation Device ◽

Base Structure

Vibration isolation devices are used to attach various systems to their base structure to reduce the transmission of vibration from and/or to the base structure. Vibration isolation devices allow relative motion between the isolated system and the base platform. This relative motion is critical to the effective operation of vibration isolation devices and is used to absorb or divert vibration energy using spring and viscous damping or dry friction elements. In general, larger the allowed relative motion, more effective will be the performance of the isolation system. In certain applications, the introduced relative motion by the vibration isolation device introduces unavoidable and unwanted motion of the isolated system and can significantly degrade its performance, particularly in terms of positioning precision, or limit the range of allowable relative motion, thereby reducing the effectiveness of the isolation system. In this paper, a novel method is presented that uses appropriate linkage mechanisms to constrain relative motions that are introduced by the vibration isolation system that are not necessary for the proper operation of the vibration isolation system but their presence would degrade the performance of the entire system. As an example, a novel double-parallelogram based motion constraining mechanism is presented, which is used to constrain rotational (rocking) motion of an isolation system without hindering its relative translational motion used for vibration isolation. The design of a prototype of such a linkage mechanism used to isolate payloads from launch vehicles during the launch and the results of its successful testing are presented. Other applications of the present method are discussed.

Investigation of the dynamic efficiency of complex passive low-frequency vibration isolation systems

Journal of Low Frequency Noise Vibration and Active Control ◽

10.1177/1461348418822230 ◽

2019 ◽

Vol 38 (2) ◽

pp. 608-614 ◽

Cited By ~ 1

Author(s):

M Jurevicius ◽

V Vekteris ◽

V Turla ◽

A Kilikevicius ◽

G Viselga

Keyword(s):

Vibration Isolation ◽

Low Frequency ◽

Experimental Investigations ◽

Isolation System ◽

Low Frequency Vibration ◽

Vibrating Platform ◽

Optical Table ◽

Narrow Frequency Range ◽

In this study, the theoretical and experimental investigations of the dynamics of complex passive low-frequency vibration systems are described. It is shown that a complex system consisting of a vibrating platform, an optical table and a vibration isolation system of quasi-zero stiffness loaded by a certain mass may isolate low-frequency vibrations in a narrow frequency range only. In another case, the system does not isolate vibrations; it even operates as an amplifier. The frequencies that ensure the top efficiency of the vibration damping system of quasi-zero stiffness were established.

Displacement transmissibility evaluation of vibration isolation system employing nonlinear-damping and nonlinear-stiffness elements

Journal of Vibration and Control ◽

10.1177/1077546317722702 ◽

2017 ◽

Vol 24 (18) ◽

pp. 4247-4259 ◽

Cited By ~ 12

Author(s):

S M Mahdi Mofidian ◽

Hamzeh Bardaweel

Keyword(s):

Numerical Simulation ◽

Vibration Isolation ◽

Harmonic Balance Method ◽

Nonlinear Damping ◽

Resonant Peak ◽

Engineering Practice ◽

Nonlinear Stiffness ◽

Isolation System ◽

Undesired oscillations commonly encountered in engineering practice can be harmful to structures and machinery. Vibration isolation systems are used to attenuate undesired oscillations. Recently, there has been growing interest in nonlinear approaches towards vibration isolation systems design. This work is focused on investigating the effect of nonlinear cubic viscous damping in a vibration isolation system consisting of a magnetic spring with a positive nonlinear stiffness, and a mechanical oblique spring with geometric nonlinear negative stiffness. Dynamic model of the vibration isolation system is obtained and the harmonic balance method (HBM) is used to solve the governing dynamic equation. Additionally, fourth order Runge–Kutta numerical simulation is used to obtain displacement transmissibility of the system under investigation. Results obtained from numerical simulation are in good agreement with those obtained using HBM. Results show that introducing nonlinear damping improves the performance of the vibration isolation system. Nonlinear damping purposefully introduced into the described vibration isolation system appears to eliminate undesired frequency jump phenomena traditionally encountered in quasi-zero-stiffness vibration isolation systems. Compared to its rival linear vibration isolation system, the described nonlinear system transmits less vibrations around resonant peak. At lower frequencies, both nonlinear and linear isolation systems show comparable transmissibility characteristics.

Design and Analysis of Shock and Random Vibration Isolation of Operating Hard Disk Drive in Harsh Environment

Shock and Vibration ◽

10.1155/2009/959714 ◽

2009 ◽

Vol 16 (2) ◽

pp. 143-154 ◽

Cited By ~ 12

Author(s):

Hendri Harmoko ◽

Fook Fah Yap ◽

Nader Vahdati ◽

Chuan Li

Keyword(s):

Random Vibration ◽

Vibration Isolation ◽

Hard Disk Drives ◽

Evaluation Criteria ◽

Hard Disk ◽

Disk Drive ◽

Isolation System ◽

Severe Shock ◽

An effective vibration isolation system is important for hard disk drives (HDD) used in a harsh mechanical environment. This paper describes how to design, simulate, test and evaluate vibration isolation systems for operating HDD subjected to severe shock and random vibrations based on military specifications MIL-STD-810E. The well-defined evaluation criteria proposed in this paper can be used to effectively assess the performance of HDD vibration isolation system. Design concepts on how to achieve satisfactory shock and vibration isolation for HDD are described. The concepts are tested and further enhanced by the two design case studies presented here. It is shown that an effective vibration isolation system, that will allow a HDD to operate well when subjected to severe shock and random vibration, is feasible.