scholarly journals Protection of precision spacecraft equipment from internal sources of vibration

2021 ◽  
Vol 5 (4) ◽  
pp. 217-226
Author(s):  
Yu. A. Zhukov ◽  
E. B. Korotkov ◽  
S. A. Matveev ◽  
N. S. Slobodzyan ◽  
O. V. Shirobokov
Keyword(s):  
Vibration Isolation ◽  
Vibration Suppression ◽  
Thermal Control ◽  
Vibration Source ◽  
Electric Pump ◽  
Pump Unit ◽  
Isolation System ◽  
Vibration Isolators ◽  
Vibration Protection ◽  
Vibration Dampers

The work is devoted to the protection of a spacecraft from the influence of unacceptable internal vibration sources. The urgency of reducing the vibration activity on board the spacecraft to improve the accuracy of the target equipment is indicated. A particular problem of vibration protection of the spacecraft platform from a vibration source – an electric pump unit of a liquid thermal control system – is being solved. The basic requirements for electric pump unit vibration protection have been determined. Possible ways to reduce the level of vibration excited by the electric pump unit on the surface of the spacecraft fixation are considered. Particular attention is paid to such vibration protection methods as damping and vibration isolation, implemented by installing special vibration protection devices between the source (electric pump unit) and the object (spacecraft) – vibration isolators and vibration dampers. The principles of operation of vibration dampers and vibration isolators, the most common materials for vibration dampers are described. Examples of constructive solutions for linear single-axial vibration isolators are considered, recommendations for the use of promising products are developed. Particularemphasis is placed on the use of metal rubber as a material for vibration isolators. With regard to a specific design of electric pump unit, a diagram of the spatial structure of vibration isolation is proposed. Formulas for calculation are given in detail, a mathematical model of the vibration isolation system is developed. The procedure for calculating the parameters of the system has been formed. Based on the model, the maximum possible level of vibration suppression in the mid-frequency region was determined. Minimum required number of operable pixels was identified for monitoring the water surface with sufficient accuracy and reliability.

scholarly journals Vibration Protection of Sensitive Components of Infrared Equipment in Harsh Environments

2001 ◽  
Vol 8 (1) ◽  
pp. 55-69 ◽  
Author(s):  
A.M. Veprik ◽  
V.I. Babitsky ◽  
N. Pundak ◽  
S.V. Riabzev
Keyword(s):  
Vibration Isolation ◽  
Harsh Environments ◽  
Line Of Sight ◽  
Infrared Sensor ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Vibration Protection ◽  
Electro Optic ◽  
Environmental Vibration

This article addresses the principles of optimal vibration protection of the internal sensitive components of infrared equipment from harsh environmental vibration. The authors have developed an approach to the design of external vibration isolators with properties to minimise the vibration-induced line-of-sight jitter which is caused by the relative deflection of the infrared sensor and the optic system, subject to strict constraints on the allowable sway space of the entire electro-optic package. In this approach, the package itself is used as the first-level vibration isolation stage relative to the internal highly responsive components.It was predicted analytically, and confirmed experimentally, that the proposed vibration isolation system would be capable of a sixfold reduction of the dynamic response of the infrared sensor as compared to the case of rigid mounting of the entire package.

A Variable Stiffness Vibration Isolation System Based on Magneto-Rheological Elastomer

2012 ◽  
Vol 452-453 ◽  
pp. 659-662
Author(s):  
Wei Wang ◽  
Yi Min Deng
Keyword(s):  
Shear Modulus ◽  
Vibration Isolation ◽  
Variable Stiffness ◽  
Control Area ◽  
Frequency Range ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Magneto Rheological ◽  
Conventional Type

Vibration isolation is a most widely used vibration protection method.The stiffness of vibration isolators in existing conventional type of vibration isolation system is usually of fixed value. This limits the system in exhibiting its vibration isolation effect in that, it has poor results for lower frequency vibration, especially for resonance frequency. Magneto-rheological elastomer is a new branch of Magneto-rheological materials. It’s an intelligent materials in that it’s shear modulus can be controlled by a magnetic field. It has wide application prospects in the vibration control area. This paper proposes using adjustable stiffness of magneto-rheological elastomer vibration isolation in vibration isolation system. By changing the current of vibration isolators coil to control the shear modulus of magneto-rheological elastomer, it can adjust the stiffness of the isolation system, making the system obtain wider vibration isolation frequency range. By exploying SimuLink software to analyze the vibration isolation system, it is found that such a design is effective and applicable.

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.

Choosing Damping Parameters for the Inertial Orientation System

2021 ◽  
pp. 113-128
Author(s):  
V.P. Podchezertsev ◽  
S.V. Topilskaya
Keyword(s):  
Natural Frequency ◽  
Vibration Suppression ◽  
Outer Space ◽  
Protection System ◽  
Dynamic Vibration ◽  
Shock Absorbers ◽  
Vibration Protection ◽  
Orientation System ◽  
Vibration Impact ◽  
Vibration Dampers

The article discusses criteria for selecting the vibration protection for the spacecraft inertial orientation system. The considered vibration protection system allows providing acceptable amplitude acceleration for the gyroscopic device sensitive elements under vibration impact on the device body during the spacecraft launching and high angular stability of the position of the sensitive elements relative to the inertial coordinate system during a long period of operation (15 years) in orbit. The proposed vibration protection system consists of shock absorbers (springs) with stable high elastic characteristics under all factors of operation in the outer space and dynamic vibration dampers. The article presents a method for determining the parameters of dynamic vibration dampers taking into account the characteristics of the shock absorber, critical for the damping system of an inertial device. The proposed method for adjusting dynamic vibration dampers consists in suppressing vibrations at the natural frequency f1 of the shock absorption system and providing acceptable values of the gain coefficients of the structure resonant vibration amplitudes near the natural frequency f1. Certain characteristics of the damping system allow realizing the permissible vibration amplification coefficients at resonance, without significantly affecting the level of vibration suppression in the natural frequency zone of the vibration protection object

scholarly journals STUDY OF THE EFFECTIVENESS OF VIBRATION ISOLATION OF UNCONVENTIONAL TOROIDAL ROPE VIBRATION ISOLATORS IN DIESEL UNITS VIBRATION ISOLATION SYSTEM

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 110-114
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Aung Thant
Keyword(s):  
Power Plants ◽  
Vibration Isolation ◽  
Steel Wire ◽  
Experimental Studies ◽  
Wire Rope ◽  
Diesel Generator ◽  
Isolation System ◽  
Vibration Isolators ◽  
Before And After ◽  
Materials Used

The paper notes that the structure of the wire rope is one of the most suitable materials used as a fire-resistant elastic element of vibration-insulating structures and fasteners (vibration isolators). To solve the problems of vibration isolation of marine diesel power plants in the framework of development and improvement of the shock absorption system, the original patented elastic supports with elastic elements made of steel wire rope in the form of a torus are presented. When commercially available vibration isolators do not meet the relevant requirements of vibration protection of a particular object, the solution to the existing problem can be achieved by using the proposed wire rope vibration isolators. The technical results of the original patented inventions are: - equal stiffness in the horizontal plane - ensuring the reliability and high vibration efficiency of protection against impacts and shocks. The proposed designs of vibration isolators are easy (technological in manufacturing) to manufacture and assemble, reliable and durable - the service life is 10 years or more. Vibration efficiency is confirmed by the vibration acceleration spectra before and after the vibration isolator of the damping system of the ship diesel-generator DGA-500 and the diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame. The three-year trial life of the DGA-500 and experimental studies on a diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame confirms their efficiency and effectiveness.

scholarly journals Reconstruction of Input Excitation Acting on Vibration Isolation System

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Pan Zhou ◽  
Wen L. Li ◽  
Wanyou Li ◽  
Zhijun Shuai
Keyword(s):  
Vibration Isolation ◽  
Mechanical Design ◽  
Spectral Density Function ◽  
Dynamic Responses ◽  
Accurate Estimation ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Vibration Isolators ◽  
Supporting Structure ◽  
Vibration Prediction

Vibration isolation systems are widely employed in automotive, marine, aerospace, and other engineering fields. Accurate input forces are of great significance for mechanical design, vibration prediction, and structure modification and optimization. One-stage vibration isolation system including engine, vibration isolators, and flexible supporting structure is modeled theoretically in this paper. Input excitation acting on the vibration isolation system is reconstructed using dynamic responses measured on engine and supporting structure under in-suit condition. The reconstructed forces reveal that dynamic responses on rigid body are likely to provide more accurate estimation results. Moreover, in order to improve the accuracy of excitation reconstructed by dynamic responses on flexible supporting structure, auto/cross-power spectral density function is utilized to reduce measurement noise.

scholarly journals Performance study of electric pump unit bearings of spacecraft thermal control systems

2020 ◽  
Vol 747 ◽  
pp. 012043
Author(s):  
N I Smirnov ◽  
N N Smirnov ◽  
M V Prozhega ◽  
S A Matveev ◽  
O V Shirobokov ◽  
...  
Keyword(s):  
Control Systems ◽  
Thermal Control ◽  
Electric Pump ◽  
Performance Study ◽  
Pump Unit ◽  
Spacecraft Thermal Control

scholarly journals Numerical Analysis on the Ground Vibration Isolation of Duxseal

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
M. Gao ◽  
S. P. Tian ◽  
R. He ◽  
Y. Wang ◽  
Q. S. Chen
Keyword(s):  
Vibration Isolation ◽  
Damping Ratio ◽  
Free Field ◽  
Three Dimensional ◽  
Ground Vibration ◽  
Vibration Source ◽  
Isolation System ◽  
Vertical Excitation ◽  
Thin Layer Method ◽  
Active Vibration

A new kind of vibration screening material, Duxseal, with a high damping ratio is proposed to be used as an active vibration barrier in the free field. To investigate the influence of width, thickness, and embedded depth of using Duxseal on vibration reduction, numerical studies are performed using a three-dimensional (3D) semianalytical boundary element method (BEM) combined with a thin-layer method (TLM). The isolation effectiveness of Duxseal in ground vibration is also compared with the traditional wave impeding block (WIB). The numerical results show that Duxseal performed exceedingly well in screening ground vibrations in the free field. The effectiveness of the vibration isolation increases with the increase in the width, thickness, and embedded depth of the Duxseal material, within a certain range, under harmonic vertical excitation. In addition, Duxseal is much more effective for isolating ground vibration than the traditional WIB. The performance of Duxseal in isolating ground vibration is relatively stable along the distance away from the vibration source, while the amplitude attenuation ratio bounces upward when the distance away from the vibration source increases for the WIB isolation system.

scholarly journals Overview of electric pump units for spacecraft thermal control systems

2021 ◽  
Vol 5 (4) ◽  
pp. 198-207
Author(s):  
E. B. Korotkov ◽  
O. V. Shirobokov ◽  
S. A. Matveev ◽  
Z. A. Yudina
Keyword(s):  
Control Systems ◽  
Operating Experience ◽  
Thermal Control ◽  
Technical Condition ◽  
Operating Conditions ◽  
Electric Pump ◽  
Pump Unit ◽  
Brushless Dc ◽  
Long Lifetime ◽  
Pumping Units

The paper reports a brief description of spacecraft operating conditions, the main reasons of heating and thermal gradient appearance and need to reassign the thermal energy. Active thermal control systems and their advantages are considered, spacecraft for which the use of this type of thermal control systems is a priority. The electric pumping unit is pointed as a key unit of active thermal control systems. The electric pump unit is considered from the as the electromechanical system, its key elements are pointed. A description of the preferred pump types is reported and the types of active thermal control systems are briefly discussed. The foreign and domestic operating experience of spacecraft electric pumping units, the features of their designs are considered, the most common types of key elements are determined. Based on the results of the review, it is concluded that the most relevant layout of the electric pump unit is a centrifugal electrical pump with a brushless DC motor and hydrodynamic bearings. It is also indicated that the electric pump unit is a product with a long lifetime, which complicates the task of monitoring the technical condition in order to prevent failure.

scholarly journals Assessment of vibration isolation in «Flexible connector–pipeline–vibration isolators Pendants» mechanical system

2020 ◽  
pp. 9-14
Author(s):  
Yu. A. Burian ◽  
◽  
A. V. Zubarev ◽  
S. N. Polyakov ◽  
◽  
...  
Keyword(s):  
Mechanical System ◽  
Vibration Isolation ◽  
Mechanical Resistance ◽  
Vibration Source ◽  
Vibration Isolators ◽  
Vibration Load ◽  
System Parameters ◽  
Radiated Power ◽  
Pipeline Vibration ◽  
Pumping Units

When designing pipeline systems, the question of reducing the vibration load transmitted from vibroactive elements (pumping units, compressors, etc.) through the pipelines to the base almost always arises. In this case, as a rule, when laying pipes, one end is connected to a vibration source through flexible elements (bellows, elastic compensators, pipes). The pipeline is installed on hangers with vibration dampers. The paper considers the issues of calculating the mechanical resistance of flexible connectors, pipelines and vibration isolators of suspensions, as well as analytical dependences and the results of numerical calculation of the forces transmitted to the base and the radiated power depending on the frequency. The graphic materials show the frequency characteristics of the forces on the base and vibration power, depending on the considered mechanical system parameters

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