scholarly journals Application of the parallelogram mechanism with the effect of quasi-zero stiffness in the vibration protection systems of the operator’s chair of a road construction machine

2021 ◽  
Vol 7 (2) ◽  
pp. 132-140
Author(s):  
M.S. Korytov ◽  
◽  
V.S. Sherbakov ◽  
I.E. Pochekueva ◽  
◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Tensile Force ◽  
Road Construction ◽  
Negative Stiffness ◽  
Force Characteristic ◽  
Straight Line Passing ◽  
Tension Spring ◽  
Vibration Protection ◽  
Protection Systems ◽  
Isolation Systems

For vibration protection of operators of construction and road machines, a promising direction is the use of passive vibration protection systems based on mechanisms with quasi-zero rigidity. Passive vibration isolation systems, being less complex than active ones, require less frequent maintenance, are cheaper to manufacture and more reliable than active ones. The problem of selecting the optimal, most reliable and simple design of the mechanism with the effect of quasi-zero rigidity remains urgent. In this case, the most widespread use of elements that create negative stiffness. This requires elements with positive stiffness in the mechanism, which complicates the design. More promising structures of mechanisms, where elements with negative stiffness are not separated into a separate structure. In mechanisms such as the parallelogram, studied in this work, a section with quasi-zero stiffness can be provided with just one tension spring, which simplifies the design and reduces the cost of the entire vibration protection system. By the method of direct analytical inference for the presented diagram of a parallelogram mechanism with one spring, analytical expressions are obtained for the tensile force of the spring necessary to compensate for the force of gravity of the chair with the operator on the height of the chair and the length of the spring. As an example, the graphical dependences of the spring tensile force on the chair lift and on the spring’s own length are given as an example. It was found that the static force characteristic of the spring is a straight line passing through the origin. That is, the zero force corresponds to the zero spring length, which is not technically feasible. It is proposed to use a mechanism that replaces the tension spring, which will provide a given power characteristic.

Design of a Miniaturized Pneumatic Vibration Isolator With High-Static-Low-Dynamic Stiffness

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Yuhu Shan ◽  
Wenjiang Wu ◽  
Xuedong Chen
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Structure Design ◽  
Negative Stiffness ◽  
Vibration Isolator ◽  
Load Bearing Capacity ◽  
Compact Structure ◽  
Chamber Volume ◽  
Isolation Systems ◽  
Magnetic Rings

In the ultraprecision vibration isolation systems, it is desirable for the isolator to have a larger load bearing capacity and a broader isolation bandwidth simultaneously. Generally, pneumatic spring can bear large load and achieve relatively low natural frequency by enlarging its chamber volume. However, the oversized isolator is inconvenient to use and might cause instability. To reduce the size, a miniaturized pneumatic vibration isolator (MPVI) with high-static-low-dynamic stiffness (HSLDS) is developed in this paper. The volume of proposed isolator is minimized by a compact structure design that combines two magnetic rings in parallel with the pneumatic spring. The two magnetic rings are arranged in the repulsive configuration and can be mounted into the chamber to provide the negative stiffness. Then dynamic model of the developed MPVI is built and the isolation performances are analyzed. Finally, experiments on the isolator with and without the magnetic rings are conducted. The final experimental results are consistent with the dynamical model and verify the effectiveness of the developed vibration isolator.

Mathematical models for evaluating the effectiveness of shock-absorbing fasteners of vibro-active mechanisms of marine objects by vibrational power

2021 ◽  
pp. 13-20
Author(s):  
В.А. Пятакович ◽  
В.Ф. Рычкова ◽  
А.П. Пурденко
Keyword(s):  
Mathematical Models ◽  
Rational Design ◽  
Vibration Isolation ◽  
Vibrational Energy ◽  
Technical Problem ◽  
Vibration Protection ◽  
Protection Systems ◽  
Neural Network System ◽  
Theoretical Mechanics ◽  
Theoretical Developments

Для создания виброакустической защиты судового оборудования необходимо учитывать потоки колебательной энергии, распространяющиеся от источников как через опорные и неопорные связи, так и в виде воздушного шума. В работе представлены математические модели оценки эффективности амортизирующих креплений виброактивных механизмов морских объектов по колебательной мощности, учитываемые при обучении разрабатываемой нейросетевой системы классификации морских целей. Теоретические разработки в области виброзащиты и виброизоляции во многом имеют междисциплинарный характер и опираются на методы теории механизмов и машин, теоретической механики, теории колебаний, теории управления, используются методы инфорьт мационные технологии для оценки, поиска и выбора рациональных проектно-конструкторских решений. Создание амортизирующих устройств, способных защитить объекты от вибраций и ударов и, вместе с тем, обладающих ограниченными размерами, является сложной технической проблемой. В связи с этим первостепенное значение приобретают вопросы теории и расчета адаптивных виброзащитных систем. To create vibro-acoustic protection of ship equipment, it is necessary to take into account the flows of vibrational energy propagating from sources both through support and non-support connections, and in the form of air noise. The paper presents mathematical models for evaluating the effectiveness of shock-absorbing fasteners of vibro-active mechanisms of marine objects by vibrational power, which are taken into account when training the developed neural network system for classifying marine targets. Theoretical developments in the field of vibration protection and vibration isolation are largely interdisciplinary in nature and are based on the methods of the theory of mechanisms and machines, theoretical mechanics, vibration theory, control theory, information technology methods are used to evaluate, search and select rational design solutions. The creation of shock-absorbing devices that can protect objects from vibrations and shocks and, at the same time, have limited dimensions is a complex technical problem. In this regard, the issues of the theory and calculation of adaptive vibration protection systems are of paramount importance.

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

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 ◽  
Vibration Isolation System ◽  
Single Degree ◽  
In Series ◽  
Isolation Systems

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.

Analytical and Experimental Investigation of Buckled Beams as Negative Stiffness Elements for Passive Vibration and Shock Isolation Systems

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Benjamin A. Fulcher ◽  
David W. Shahan ◽  
Michael R. Haberman ◽  
Carolyn Conner Seepersad ◽  
Preston S. Wilson
Keyword(s):  
Resonance Frequency ◽  
Vibration Isolation ◽  
Negative Stiffness ◽  
Peak Acceleration ◽  
Single Beam ◽  
Buckled Beams ◽  
Buckled Beam ◽  
Double Beam ◽  
Shock Isolation ◽  
Isolation Systems

The behavior of a buckled beam mechanism, which exhibits both bistability and negative stiffness, is investigated for the purposes of passive shock and vibration isolation. The vibration and shock isolation systems investigated in this research include linear, positive stiffness springs in parallel with the transverse motion of buckled beams, resulting in quasizero stiffness behavior. For vibration isolation systems, quasizero stiffness lowers the resonance frequency of the system, thereby reducing its transmissibility at frequencies greater than resonance. For shock isolation systems, quasizero stiffness provides constant-force shock isolation at tailored force levels, thereby enabling increased capacity for absorbing shock energy relative to a comparable positive stiffness system. Single- and double-beam configurations that exhibit first-mode buckling are utilized for vibration isolation, and a single beam that exhibits first- and third-mode buckling is used for shock isolation. For all cases, the static and dynamic behavior of each configuration is modeled analytically. The models are then used to design prototype vibration and shock isolation systems that are fabricated using selective laser sintering (SLS). The dynamic behavior of the systems in response to base excitations is determined experimentally, and the results are compared to model-based predictions. The vibration isolation prototypes display isolation levels that are tunable by varying the axial compression of the beams. Double-beam systems are shown to provide greater reductions in resonance frequency than single-beam systems for comparable levels of axial compression. However, low-frequency isolation capabilities are sensitive to the high levels of precision required to obtain low levels of system stiffness. The shock isolation prototype provides isolation at prespecified threshold levels of force or acceleration. In the prototype system, an input shock with a peak acceleration of approximately 7 g is reduced to a peak acceleration of the isolated mass of approximately 1 g. High levels of negative acceleration are observed in models and prototype systems when the buckled beam snaps back to its original position; however, models indicate that large negative accelerations can be mitigated using one-way dampers.

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

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 Isolation System ◽  
Vibration Transmissibility ◽  
Optical Table ◽  
Air Table ◽  
Isolation Systems

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.

scholarly journals Simulation model of a chair vibration protective mechanism with a part of quasi-zero-stiffness for the operator of a road-building machine

2020 ◽  
Vol 6 (4) ◽  
pp. 486-496
Author(s):  
M.S. Korytov ◽  
◽  
V.S. Sherbakov ◽  
I.E. Pochekueva ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Vibration Isolation ◽  
Degree Of Freedom ◽  
Protection System ◽  
Production Factor ◽  
Protective Mechanism ◽  
Static Force ◽  
Vertical Movements ◽  
Vibration Protection ◽  
Protection Systems

Vibrations of construction and road machinery components that occur during their operation are a harmful production factor for machine operators, therefore, their reduction can be considered a very urgent task. The main route of vibration transmission is through vibration isolation systems for the operator’s seat and cab. The easiest and most cost-effective way to isolate the operator from vibration is through his seat by reducing vibration. The simplest and most reliable vibration protection systems with one degree of freedom limited by vertical movements of the chair can be used for the chairs. Vibration protection mechanisms and systems with quasi-zero rigidity are considered promising. They provide constant static force over a certain range of movement of the object. The task of developing mathematical models describing vibration protection systems with quasi-zero rigidity is urgent. In the Matlab software package using the Simscape library for modeling physical elements, a simulation mathematical model of the vibration protection system of a chair with one degree of freedom has been developed. The base of the chair in the developed model performs harmonic sinusoidal movements. The output parameters of the developed mathematical model are the time dependences of the chair coordinates and accelerations. The blocks used in the model are described, the static force characteristics are given, given using the Hermite spline. The model includes a block of hard movement restrictions. An example of using the developed simulation mathematical model of the chair is given. The developed model makes it possible to specify both the dimensions of the quasi-zero stiffness section and the shape of the curves of the force static characteristics of the vibration protection system. It can be integrated into higher level models.

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