Damped Vibration Absorbers Applied to Lateral Modes of Rotating Machinery

1999 ◽  
Author(s):  
Lyn M. Greenhill ◽  
Linda F. Raven
Keyword(s):  
Detailed Analysis ◽  
Optimum Design ◽  
Test Data ◽  
Design Methodology ◽  
Rotating Machinery ◽  
Vibration Absorbers ◽  
Mass Ratio ◽  
Rotating Machine ◽  
Lateral Modes ◽  
Tuning Frequency

Abstract Damped vibration absorbers can significantly reduce the amplitude of resonant motion. Normally, these devices are used on machinery that is non-rotating (stationary). However, as this paper demonstrates both analytically and experimentally, a damped absorber can be successfully applied on rotating equipment, particularly on vertical machines, to attenuate lateral resonances. To illustrate this application, a detailed analysis of the damped absorber is presented, focusing on mass ratio, tuning frequency, amount of damping, and speed effects. It is shown that an optimum design can be obtained for use on a rotating machine that parametrically differs from a non-rotating application. Test data is also given illustrating the effectiveness of the concept and design methodology on an actual machine. Recommendations are provided to guide the application of this technology on other rotating machines.

OPTIMUM DESIGN PROCESS OF VIBRATION ABSORBER VIA IMPERIALIST COMPETITIVE ALGORITHM

2012 ◽  
Vol 12 (03) ◽  
pp. 1250019 ◽  
Author(s):  
ROUHOLLAH HOSEINI ◽  
HAMZE SALEHIPOOR
Keyword(s):  
Optimum Design ◽  
Seismic Design ◽  
Design Methodology ◽  
Imperialist Competitive Algorithm ◽  
Design Solution ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Structural Vibrations ◽  
Multi Objective ◽  
Analytical Expressions

This paper deals with the optimum design of vibration absorbers utilized to reduce undesirable random vibrational effects that are originated in linear structures. Analytical expressions, for the case of nonstationary white-noise accelerations, are derived. The criterion is different from most conventional optimum design criteria, since it is based on minimizing the displacement or the acceleration variance of the main structure responses, without considering performances required against failure. In this study, in order to control the structural vibrations induced on a mechanical structure excited by nonstationary based acceleration random process, the MOO (multi-objective optimum) design of a vibration absorber has been developed in a typical seismic design problem. This has been performed using the modern imperialist competitive optimization algorithm for multi-objective optimization. Results demonstrate the importance of this method and show that the multi-objective design methodology provides a significant improvement in performance stability, giving a better control of the design solution choice. A numerical example of a vibration absorber for a multi degree of freedom (DOF) system is developed and the results are generated and compared for higher (DOF) systems using two types of modeling. Finally, the results of each of the two types are discussed.

scholarly journals A proposal to determine the distribution of lateral forces from loaded recycled plastic drainage kerbs

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Fin O’Flaherty ◽  
Fathi Al-Shawi
Keyword(s):  
Laboratory Test ◽  
Detailed Analysis ◽  
Test Data ◽  
Lateral Force ◽  
Measuring Device ◽  
Test Methodology ◽  
Lateral Forces ◽  
Test Conditions ◽  
Fit For Purpose ◽  
Construction Product

AbstractThis study presents a detailed analysis of the lateral forces generated as a result of vertically applied loads to recycled plastic drainage kerbs. These kerbs are a relatively new addition to road infrastructure projects. When concrete is used to form road drainage kerbs, its deformation is minimum when stressed under heavy axle loads. Although recycled plastic kerbs are more environmentally friendly as a construction product, they are less stiff than concrete and tend to deform more under loading leading to a bursting type, lateral force being applied to the haunch materials, the magnitude of which is unknown. A method is proposed for establishing the distribution of these lateral forces resulting from deformation under laboratory test conditions. A load of 400 kN is applied onto a total of six typical kerbs in the laboratory in accordance with the test standard. The drainage kerbs are surrounded with 150 mm of concrete to the front and rear haunch and underneath as is normal during installation. The lateral forces exerted on the concrete surround as a result of deformation of the plastic kerbs are determined via a strain measuring device. Analysis of the test data allows the magnitude of the lateral forces to the surrounding media to be determined and, thereby, ensuring the haunch materials are not over-stressed as a result. The proposed test methodology and subsequent analysis allows for an important laboratory-based assessment of any typical recycled plastic drainage kerbs to be conducted to ensure they are fit-for-purpose in the field.

Optimization and Standardization of Flanged and Flued Expansion Joint Design

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Kamlesh M. Chikhaliya ◽  
Bhaveshkumar P. Patel
Keyword(s):  
Heat Exchanger ◽  
Optimum Design ◽  
Design Methodology ◽  
Thick Wall ◽  
Process Conditions ◽  
Expansion Joint ◽  
Standard Requirement ◽  
Spring Rate ◽  
Tube Heat Exchanger ◽  
Heat Exchanger Design

Flanged and flued type expansion joint (thick wall expansion bellow) used as an integral part of many shell and tube heat exchanger where process conditions produce differential expansion between shell and tubes. It provides flexibility for thermal expansion and also functions as a pressure retaining part. Design of expansion joints is usually based on trial and error method in which initial geometry must be assumed, and accordingly maximum stresses and spring rate are be calculated. Inadequate selection of geometry leads to higher tubesheet and bellow thickness, which increases cost of equipment. This paper presents standardization and optimum design approach of flange and flued expansion bellow fulfilling ASME VIII-1 and TEMA standard requirement. Methodology to define expansion bellow geometry is developed, and geometry dimensions are tabulated for expansion bellow diameter from 300 to 2000 mm and thickness from 6 to 30 mm. Each defined geometry is analyzed using finite element method, and maximum von Mises stresses are calculated for bellow axial displacement from 0.5 to 1.5 mm and internal pressure from 0.1 to 6.5 MPa. Spring rate is also calculated for each defined geometry for consideration in tubesheet calculation. Accordingly, optimum design methodology is developed, tested, and compared with existing design. Results depicted that proposed standardization approach and design methodology will optimize expansion bellow and tubesheet thickness and will also save considerable time in finalization of heat exchanger design.

An Optimum Design Methodology for Planar-Type Coaxial Probes Applicable to Broad Temperature Permittivity Measurements

2008 ◽  
Vol 56 (3) ◽  
pp. 684-692 ◽  
Author(s):  
Namgon Kim ◽  
Jeonghoon Yoon ◽  
Sungjoon Cho ◽  
Jeiwon Cho ◽  
Changyul Cheon ◽  
...  
Keyword(s):  
Optimum Design ◽  
Design Methodology ◽  
Coaxial Probes ◽  
Permittivity Measurements

scholarly journals Investigation On The Optimal Tunable Bi-Stable Clustered Energy Conversion Inspired Dynamic Vibration Absorbers: A Theoretical Study

2021 ◽  
Author(s):  
Xingbao Huang ◽  
Xiao Zhang ◽  
Bintang Yang
Keyword(s):  
Energy Conversion ◽  
Vibration Control ◽  
Conversion Efficiency ◽  
Energy Conversion Efficiency ◽  
Vibration Absorbers ◽  
Input Energy ◽  
Mass Ratio ◽  
Vibration Absorption ◽  
Dynamic Vibration Absorbers ◽  
Conversion Performance

Abstract This paper introduces an energy conversion inspired vibration control methodology and presents a representative prototype of tunable bi-stable energy converters. This work is concerned on improving the vibration absorption and energy conversion performance of tunable bi-stable clustered energy conversion inspired dynamic vibration absorbers (EC-DVAs). The deterministic parametric analysis of the energy transfer performance of clustered EC-DVAs is conducted. Firstly, nonlinear vibration behaviors including transient energy transfer and snap-through motions are studied, and then effects of EC-DVA number on vibration control is investigated. Furthermore, the optimal computation based on adjusting the length ratio (namely bi-stable potential barrier height) is developed to obtain the maximum energy conversion efficiency of clustered EC-DVAs and the minimum residual kinetic energy of the primary system considering different number of clustered EC-DVAs. Moreover, the optimal calculation based on optimal EC-DVA number is also developed to achieve the most excellent vibration absorption and energy conversion performance. Finally, the optimal calculation based on optimal mass ratio is conducted. Numerical simulations show that when the total mass ratio is constant the snap-through motions of each EC-DVA depend remarkably on EC-DVA number; the energy conversion efficiency and residual kinetic energy after dynamic length ratio optimization is independent on ambient input energy and EC-DVA number; The energy conversion efficiency and vibration absorption performance based on optimal EC-DVA number maintain high efficiency and stable when the ambient input energy or the potential energy of clustered EC-DVAs varies. The optimal mass ratio is large when the system’s potential barrier is too large and the ambient input energy is small. Therefore, the presented tunable bi-stable system of clustered EC-DVAs with appropriate bi-stable potential function and proposed optimization strategies is a potential alternative for vibration control of mechanical components exposed to varying impulses.

scholarly journals RELIABILITY BASED DESIGN OF RUBBLE-MOUND BREAKWATER

1988 ◽  
Vol 1 (21) ◽  
pp. 153
Author(s):  
Masato Yamamoto ◽  
Kazumasa Mizumura ◽  
Taiji Endo ◽  
Naofumi Shiraishi
Keyword(s):  
Water Level ◽  
Optimum Design ◽  
Failure Probability ◽  
Design Methodology ◽  
Construction Cost ◽  
Probabilistic Design ◽  
Reliability Based Design ◽  
Rubble Mound ◽  
Reduced Risk

The object of this present research is to study probabilistic design of armor blocks protecting composite breakwaters and to produce optimum design methodology for S-shaped breakwaters in terms of failure probability and construction cost. Failure probability in the vicinity of the still water level is greatest in the case of uniform sloped breakwaters. Therefore,S-shaped breakwaters of which the slope near the still water level is milder have a reduced risk of damage compared to uniform sloped ones. The optimum design index presents good economics and reliability in rubble-mound breakwater design.

Shape Optimum Design of Robotic Manipulators With Static Performance Criteria

1987 ◽  
Author(s):  
D. A. Saravanos ◽  
J. S. Lamancusa ◽  
H. J. Sommer
Keyword(s):  
Finite Element ◽  
Optimum Design ◽  
Robotic Manipulators ◽  
Performance Criterion ◽  
Performance Criteria ◽  
Robotic Arm ◽  
Mass Ratio ◽  
End Effector ◽  
Vibrational Response ◽  
Static Performance

Abstract The end effector deflections of robotic manipulators may be minimized by optimizing the geometric shape and the dimensions of their links. A multiple posture static performance criterion for the prediction of the shape optimum design is presented. An efficient optimization algorithm is developed for the solution of the problem using finite element modeling to predict the compliance of the robotic arm. The method is applied to an existing robotic arm, and the results demonstrate that simple alterations to the dimensions and the shape of the links can greatly improve, not only the stiffness, but also the stiffness/mass ratio and consequently the vibrational response of the manipulator structure.

Analysis of memristor-based differentiating circuit

2020 ◽  
Vol 39 (3) ◽  
pp. 683-690
Author(s):  
Stoyan Kirilov ◽  
Ivan Zaykov
Keyword(s):  
Detailed Analysis ◽  
Computer Simulations ◽  
Input Signal ◽  
Operational Amplifier ◽  
Design Methodology ◽  
Pulse Sequence ◽  
Rectangular Pulse ◽  
Classical Analog ◽  
Content Type ◽  
Radio Electronics

Purpose The purpose of this paper is to propose a detailed analysis of a memristor-based differentiating circuit with buffering amplifier, a capacitor and a memristor. Design/methodology/approach The analyzed circuit is based on a resistor–capacitor differentiating scheme together with a buffering operational amplifier. In the proposed circuit, the resistor is replaced by a memristor element. Findings The considered circuit and its classical analog are investigated using a rectangular pulse sequence as input signal. A comparison between the derived results is made. An advantage of the proposed memristor circuit is the shortened duration, i.e. higher localization, of the output pulses of rectangular input pulses to be derived. Originality/value Differentiating circuits are important modules in radio-electronics. Because of their widespread usage, it is of higher interest that their new potential schematic realizations are analyzed. For the computer simulations, a previously proposed modified nonlinear memristor model is used. Several of the best and widely used basic memristor models are applied as well.

Analysis of Parallel Damped Dynamic Vibration Absorbers

1969 ◽  
Vol 91 (1) ◽  
pp. 282-287 ◽  
Author(s):  
A. V. Srinivasan
Keyword(s):  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Dynamic Vibration Absorber ◽  
Main Mass ◽  
Dynamic Vibration ◽  
Frequency Comparison ◽  
Dynamic Vibration Absorbers ◽  
Tuning Frequency ◽  
Comparison Of The Results ◽  
Operational Range

The analysis of parallel damped dynamic vibration absorbers is presented. The system considered is essentially a modification of the conventional damped vibration absorber and consists of adding, in parallel, a subsidiary undamped absorber mass in addition to the damped absorber mass. The analysis clearly shows that it is possible to obtain an undamped antiresonance in a dynamic absorber system which exhibits a well-damped resonance. While the bandwidth of frequencies between the damped peaks is not significantly increased, the amplitudes of the main mass are considerably smaller within the operational range of the absorber. The damped absorber mass and the main mass attain null simultaneously so that the vibratory force is transmitted directly to the undamped absorber. Numerical results are presented for the special case when the absorber masses have the same magnitude. Two cases of tuning have been considered: (a) when the absorber masses are tuned to the frequency of the main mass, and (b) when the absorber masses are tuned to the so-called favorable tuning frequency. Comparison of the results with those of the conventional absorber indicates that the parallel damped dynamic vibration absorber has definite advantages over the conventional damped vibration absorber.

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