Generalised nonlinear modeling of unstable stick-slip force reduction effects in friction energy dissipation devices

2014 ◽  
Vol 47 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Geoffrey W Rodgers ◽  
Oliver Mesnil ◽  
Jose Chanchi ◽  
Gregory A. MacRae ◽  
Charles Clifton ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Structural Damage ◽  
Dynamic Behaviour ◽  
Nonlinear Modeling ◽  
Hysteretic Model ◽  
Stick Slip ◽  
Hysteretic Behaviour ◽  
Slip Mechanism ◽  
Variable Friction ◽  
Energy Dissipation Devices

The Sliding Hinge Joint (SHJ) is an Asymmetric Friction Connection (AFC) developed to create a repeatable, efficient means of dissipating seismic response energy and reducing structural damage without yielding of the structural frame elements. Testing has demonstrated stable efficient hysteretic behaviour. However, it is necessary to fully characterise their dynamic behaviour including any less stable aspects observed in the response of these devices for selected materials. This observed behaviour may reduce device force and energy dissipation, creating an influence on the overall structure that should be fully understood and accounted for in design. This research models the hysteretic behaviour of a SHJ with a zinc anti-corrosion coating that demonstrates less than fully stable experimental dynamic behaviour in contrast to many other SHJ material choices. The model developed uses a stick-slip mechanism based on a variable friction coefficient to capture the observed dynamics with an overall Menegotto-Pinto dynamic hysteretic model. The overall results show how the model may be realistically extended to a more general model that captures observed non-linear dynamics in these and similar friction devices, and yield new insight and design tools for use with these devices.

scholarly journals Modeling, analysis and seismic design of structures using energy dissipators SLB

2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Luis Miguel Bozzo
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Structural Damage ◽  
Structural Response ◽  
Reinforced Concrete Building ◽  
Seismic Code ◽  
Wide Range ◽  
Concrete Building ◽  
Energy Dissipators ◽  
Energy Dissipation Devices

This paper initially describes aspects of the modeling of structures equipped with energy dissipators Shear Link Bozzo (SLB) and develops two iterative design procedures to select these devices. This methodology is applied to a precast 5-story reinforced concrete building. The SLB energy dissipation devices are initially stiff, but ductile with a range of yielding forces from 36 kN to 900 kN characterized by 52 + 52 standard devices. Moreover, these devices can be combined in parallel giving a very wide range of possibilities for selection and corresponding structural response. Therefore, to simplify its automatic selection, this article presents two procedures: (1) direct iteration and (2) inverse or fixed force iteration. Both procedures were implemented in an automatic application or “plugin” for the ETABS program that automates its selection for a specific structural system or architectural configuration of these elements. Using these devices, the energy introduced by an earthquake into the structure can be dissipated, protecting other structural elements that suffer damage. The SLB energy dissipation devices are affordable to get a significant performance improvement in the overall structural response. This work presents a five-story precast reinforced concrete building frame, called SLB Building, that provides 4 departments per level all with a diaphanous interior floor. The building is made up of 11 columns with a constant 40x40cm section and all its beams have hinges at the ends. This building was equipped with 120 small SLB devices showing its performance for the maximum earthquake of Peruvian seismic code without ductility reduction (R = 1) by means of nonlinear time history with ten seismic records compatible with the S1 soil spectrum. In this structure, all seismic energy dissipation was concentrated in these devices so there would be no structural damage. In addition, the levels of non-structural damage were controlled with initial stiffness of these devices since lateral displacements were reduced to levels below the Peruvian seismic code (or even immediate occupancy for devices greater than those provided in this example). At the same time, the levels of acceleration decrease in height to only 0.3g and the base shear coefficient is reduced from almost 1.2 to only 0.12-0.2 (this means an R factor between 6 and 10 without structural damage).

scholarly journals Effect of Pressure Distribution on the Energy Dissipation of Lap Joints under Equal Pre-tension Force

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 320-328
Author(s):  
Delin Sun ◽  
Minggao Zhu
Keyword(s):  
Energy Dissipation ◽  
Pressure Distribution ◽  
Theoretical Basis ◽  
Lap Joints ◽  
Power Exponent ◽  
Lap Joint ◽  
Stick Slip ◽  
Pressure Distributions ◽  
Hysteretic Characteristics ◽  
Effective Use

Abstract In this paper, the energy dissipation in a bolted lap joint is studied using a continuum microslip model. Five contact pressure distributions compliant with the power law are considered, and all of them have equal pretension forces. The effects of different pressure distributions on the interface stick-slip transitions and hysteretic characteristics are presented. The calculation formulation of the energy dissipation is introduced. The energy dissipation results are plotted on linear and log-log coordinates to investigate the effect of the pressure distribution on the energy distribution. It is shown that the energy dissipations of the lap joints are related to the minimum pressure in the overlapped area, the size of the contact area and the value of the power exponent. The work provides a theoretical basis for further effective use of the joint energy dissipation.

Low-Cycle Fatigue Performance of Buckling Restrained Braces and Assessment of Cumulative Damage under Severe Earthquakes

2018 ◽  
Vol 763 ◽  
pp. 867-874
Author(s):  
Yu Shu Liu ◽  
Ke Peng Chen ◽  
Guo Qiang Li ◽  
Fei Fei Sun
Keyword(s):  
Fatigue Life ◽  
Energy Dissipation ◽  
Structural Reliability ◽  
Low Cycle Fatigue ◽  
Engineering Application ◽  
Fatigue Performance ◽  
Cycle Fatigue ◽  
Variable Amplitude ◽  
Buckling Restrained Braces ◽  
Energy Dissipation Devices

Buckling Restrained Braces (BRBs) are effective energy dissipation devices. The key advantages of BRB are its comparable tensile and compressive behavior and stable energy dissipation capacity. In this paper, low-cycle fatigue performance of domestic BRBs is obtained based on collected experimental data under constant and variable amplitude loadings. The results show that the relationship between fatigue life and strain amplitude satisfies the Mason-Coffin equation. By adopting theory of structural reliability, this paper presents several allowable fatigue life curves with different confidential levels. Besides, Palmgren-Miner method was used for calculating BRB cumulative damages. An allowable damage factor with 95% confidential level is put forward for assessing damage under variable amplitude fatigue. In addition, this paper presents an empirical criterion with rain flow algorithm, which may be used to predict the fracture of BRBs under severe earthquakes and provide theory and method for their engineering application. Finally, the conclusions of the paper were vilified through precise yet conservative prediction of the fatigue failure of BRB.

Active Control Comparison of Vibration in Flexible Spacecraft Using Different Active Friction Joints

2013 ◽  
Vol 446-447 ◽  
pp. 1160-1164
Author(s):  
Sahar Bakhtiari Mojaz ◽  
Hamed Kashani
Keyword(s):  
Energy Dissipation ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Excitation Amplitude ◽  
Step Function ◽  
Flexible Spacecraft ◽  
Control Effort ◽  
Stick Slip ◽  
Control Comparison ◽  
Frictional Joints

Vibration properties of most assembled mechanical systems depend on frictional damping in joints. The nonlinear transfer behavior of the frictional interfaces often provides the dominant damping mechanism in structure and plays an important role in the vibratory response of it. For improving the performance of systems, many studies have been carried out to predict measure and enhance the energy dissipation of friction. This paper presents a new approach to vibration reduction of flexible spacecraft with enhancing the energy dissipation of frictional dampers. Spacecraft is modeled as a 3 degree of freedom mass-spring system which is controlled by a lead compensator and System responses to step function evaluated. Coulomb and Jenkins element has been used as vibration suppression mechanisms in joints and sensitivity of their performance to variations of spacecraft excitation amplitude and damper properties is analyzed. The relation between frictional force and displacement derived and used in optimization of control performance. Responses of system and control effort needed for the vibration control are compared for these two frictional joints. It is shown that attitude control effort reduces, significantly with coulomb dampers and response of system improves. On the other hand, due to stick-slip phenomena in Jenkins element, we couldn’t expect the same performance from Jenkins damper.

A Study of Effect of Various Normal Force Loading Forms on Frictional Stick-Slip Vibration

2021 ◽  
Author(s):  
Xiaocui Wang ◽  
◽  
Runlan Wang ◽  
Bo Huang ◽  
Jiliang Mo ◽  
...  
Keyword(s):  
Dynamic Behaviour ◽  
Normal Force ◽  
Time Varying ◽  
Stick Slip ◽  
Vibration Signals ◽  
Theoretical Methods ◽  
Normal Forces ◽  
Frequency Domains ◽  
Amplitude Vibration ◽  
Fourier Spectra

In this work, a comparative study is performed to investigate the influence of time-varying normal forces on the friction properties and friction-induced stick-slip vibration by experimental and theoretical methods. In the experiments, constant and harmonic-varying normal forces are applied, respectively. The measured vibration signals under two loading forms are compared in both time and frequency domains. In addition, mathematical tools such as phase space reconstruction and Fourier spectra are used to reveal the science behind the complicated dynamic behaviour. It can be found that the friction system shows steady stick-slip vibration, and the main frequency does not vary with the magnitude of the constant normal force, but the size of limit cycle increases with the magnitude of the constant normal force. In contrast, the friction system harmonic normal force shows complicated behaviour, for example, higher-frequency larger-amplitude vibration occurs as the frequency of the normal force increases. The interesting findings offer a new way for controlling friction-induced stick-slip vibration in engineering applications.

Dynamic Behaviour of Plain Slideways

1966 ◽  
Vol 181 (1) ◽  
pp. 169-184 ◽  
Author(s):  
R. Bell ◽  
M. Burdekin
Keyword(s):  
Machine Tool ◽  
Dynamic Behaviour ◽  
Damping Capacity ◽  
Friction Characteristic ◽  
Stick Slip ◽  
Friction Characteristics ◽  
Physical Systems ◽  
Major Emphasis

The friction characteristics resulting from the motion of one surface over another form a very important facet of the behaviour of many physical systems. This statement is particularly valid when considering the behaviour of machine tool slideways. Most slideway elements consist of two plain surfaces whose friction characteristic is modified by the addition of a lubricant. In many cases the complete slideway consists of many mating surfaces and the choice of slideway material, slideway machining and lubricant is often influenced by the long term problem of wear. The aim of this paper is to present results of experiments on a test rig designed to be representative of machine tool slideway conditions; the experiments were wholly concerned with the behaviour of the bearing under dynamic conditions. The major emphasis is on results obtained with a polar additive lubricant which appears to exclude the possibility of ‘stick-slip’ oscillations. A parallel series of tests are reported where a normal hydraulic oil was used as lubricant. The use of this second lubricant allowed some study of the ‘stick-slip’ process. The dynamic friction characteristics, cyclic friction characteristics and damping capacity of several slideway surface combinations have been obtained and are discussed in the context of earlier work in the field and the role of slideways in machine tool behaviour.

Hysteresis Identification of Carbon Nanotube Composite Beams

2018 ◽  
Author(s):  
Michela Taló ◽  
Walter Lacarbonara ◽  
Giovanni Formica ◽  
Giulia Lanzara
Keyword(s):  
Phenomenological Model ◽  
Differential Evolution Algorithm ◽  
Hysteresis Loops ◽  
Hysteretic Behavior ◽  
Damping Capacity ◽  
Stick Slip ◽  
Slip Mechanism ◽  
Material Optimization ◽  
Constitutive Parameters ◽  
Mean Square Errors

Nanocomposites made of a hosting polymer matrix integrated with carbon nanotubes as nanofillers exhibit an inherent hysteretic behavior arising from the CNT/matrix frictional sliding. Such stick-slip mechanism is responsible for the high damping capacity of CNT nanocomposites. A full 3D nonlinear constitutive model, framed in the context of the Eshelby-Mori-Tanaka theory, reduced to a 1D phenomenological model is shown to describe accurately the CNT/polymer stick-slip hysteresis. The nonlinear hysteretic response of CNT nanocomposite beams is experimentally characterized via displacement-driven tests in bending mode. The force-displacement cycles are identified via the phenomenological model featuring five independent constitutive parameters. A preliminary parametric study highlights the importance of some key parameters in determining the shape of the hysteresis loops. The parameter identification is performed via one of the variants of a genetic-type differential evolution algorithm. The nanocomposites hysteresis loops are identified with reasonably low mean square errors. Such outcome confirms that the 1D phenomenological model may serve as an effective tool to describe and predict the nanocomposite nonlinear hysteretic behavior towards unprecedented material optimization and design.

Stick-slip mechanism in a granular medium

2010 ◽  
Vol 46 (6) ◽  
pp. 600-605 ◽  
Author(s):  
A. P. Bobryakov
Keyword(s):  
Granular Medium ◽  
Stick Slip ◽  
Slip Mechanism
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