The influence of microslip on vibratory response, part I: A new microslip model
TL;DR: In this paper, a physically motivated, continuous microslip model of friction is developed for analyzing the dynamic response of frictionally damped structures in which the friction interface is subjected to high normal loads.
About: This article is published in Journal of Sound and Vibration.The article was published on 1986-06-08. It has received 185 citations till now. The article focuses on the topics: Slip (materials science).
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TL;DR: It is clear that multi-scale effects can dominate performance of friction contacts, and as a result more research is needed into computational tools and approaches capable of resolving the diverse length scales present in many practical problems.
Abstract: Friction is a very complicated phenomenon arising at the contact of surfaces. Experiments indicate a functional dependence upon a large variety of parameters, including sliding speed, acceleration, critical sliding distance, temperature, normal load, humidity, surface preparation, and, of course, material combination. In many engineering applications, the success of models in predicting experimental results remains strongly sensitive to the friction model. Furthermore, a broad cross section of engineering and science disciplines have developed interesting ways of representing friction, with models originating from the fundamental mechanics areas, the system dynamics and controls fields, as well as many others. A fundamental unresolved question in system simulation remains: what is the most appropriate way to include friction in an analytical or numerical model, and what are the implications of friction model choice? This review article draws upon the vast body of literature from many diverse engineering fields and critically examines the use of various friction models under different circumstances. Special focus is given to specific topics: lumped-parameter system models !usually of low order"—use of various types of parameter dependence of friction; continuum system models—continuous interface models and their discretization; self-excited system response—steady-sliding stability, stick/slip, and friction model requirements; and forced system response—stick/slip, partial slip, and friction model requirements. The conclusion from this broad survey is that the system model and friction model are fundamentally coupled, and they cannot be chosen independently. Furthermore, the usefulness of friction model and the success of the system dynamic model rely strongly on each other. Across disciplines, it is clear that multi-scale effects can dominate performance of friction contacts, and as a result more research is needed into computational tools and approaches capable of resolving the diverse length scales present in many practical problems. There are 196 references cited in this review-article. #DOI: 10.1115/1.1501080$
395 citations
TL;DR: In this paper, an adjusted Iwan beam element (AIBE) is proposed for dynamic response analysis of beam structures containing joints, which consists of a combination of springs and frictional sliders that exhibits nonlinear behavior due to the stick-slip characteristic of the latter.
201 citations
TL;DR: In this paper, a theoretical model for analyzing the dynamic characteristics of wedge-shaped under-platform dampers for turbine blades is presented, with the objective to minimize the need for conducting expensive experiments for optimizing such dampers.
Abstract: This paper describes a theoretical model for analyzing the dynamic characteristics of wedge-shaped underplatform dampers for turbine blades, with the objective that this model can be used to minimize the need for conducting expensive experiments for optimizing such dampers. The theoretical model presented in the paper has several distinct features to achieve this objective including: (i) it makes use of experimentally measured contact characteristics (hysteresis loops) for description of the basic contact behavior of a given material combination with representative surface finish, (ii) the damper motion between the blade platform locations is determined according to the motion of the platforms, (iii) three-dimensional damper motion is included in the model, and (iv) normal load variation across the contact surfaces during vibration is included, thereby accommodating contact opening and closing during vibration. A dedicated nonlinear vibration analysis program has been developed for this study and predictions have been verified against experimental data obtained from two test rigs. Two cantilever beams were used to simulate turbine blades with real underplatform dampers in the first experiment. The second experiment comprised real turbine blades with real underplatform damper. Correlation of the predictions and the experimental results revealed that the analysis can predict (i) the optimum damping condition, (ii) the amount of response reduction, and (iii) the natural frequency shift caused by friction dampers, all with acceptable accuracy. It has also been shown that the most commonly used underplatform dampers in practice are prone to rolling motion, an effect which reduces the damping in certain modes of vibration usually described as the lower nodal diameter bladed-disk modes.
127 citations
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TL;DR: In this paper, the dynamic Lagrangian mixed frequency-time method (DLFT) is proposed to calculate the non-linear steady state response to periodic excitation of structural systems subject to dry friction damping.
125 citations
TL;DR: A survey of the literature on the use of dry friction in passive damping and vibration isolation can be found in this article, where several analytical techniques are presented followed by applications from various areas.
Abstract: This paper surveys the literature on the use of dry friction in passive damping and vibration isolation. Several analytical techniques are presented followed by applications from various areas. Despite difficulties in the analytical and experimental treatment of friction damped systems, numerous studies have endeavored to predict, measure, and/or enhance the energy dissipation and vibration isolation properties of dry friction in order to improve system performance. Undoubtedly, friction damping will continue to play an important role in many mechanical and structural systems.
125 citations
References
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Book•
01 Jan 1954
TL;DR: Tabor and Bowden as mentioned in this paper reviewed the many advances made in this field during the past 36 years and outlined the achievements of Frank Philip Bowden, and reviewed the behavior of non-metals, especially elastomers; elastohydrodynamic lubrication; and the wear of sliding surfaces.
Abstract: Originally published in 1950, this classic book was a landmark in the development of the subject of tribology. For this edition, David Tabor has written a new preface, reviewing the many advances made in this field during the past 36 years and outlining the achievements of Frank Philip Bowden. The book covers the behavior of non-metals, especially elastomers; elastohydrodynamic lubrication; and the wear of sliding surfaces, which has gradually replaced the earlier concentration on the mechanism of friction. It remains one of the most interesting and comprehensive works available on a single branch of physics.
5,834 citations
01 Jul 1943
TL;DR: In this paper, a simple formula is suggested for describing the stress-strain curve in terms of three parameters; namely, Young's modulus and two secant yield strengths.
Abstract: A simple formula is suggested for describing the stress-strain curve in terms of three parameters; namely, Young's modulus and two secant yield strengths. Dimensionless charts are derived from this formula for determining the stress-strain curve, the tangent modulus, and the reduced modulus of a material for which these three parameters are given. Comparison with the tensile and compressive data on aluminum-alloy, stainless-steel, and carbon-steel sheet in NACA Technical Note No. 840 indicates that the formula is adequate for most of these materials. The formula does not describe the behavior of alclad sheet, which shows a marked change in slope at low stress. It seems probable that more than three parameters will be necessary to represent such stress-strain curves adequately.
2,473 citations
TL;DR: In this paper, a new method of modeling and solution of a large class of hysteretic systems (softening or hardening, narrow or wideband) under random excitation is proposed.
Abstract: Based on a Markov-vector formulation and a Galerkin solution procedure, a new method of modeling and solution of a large class of hysteretic systems (softening or hardening, narrow or wide-band) under random excitation is proposed. The excitation is modeled as a filtered Gaussian shot noise allowing one to take the nonstationarity and spectral content of the excitation into consideration. The solutions include time histories of joint density, moments of all order, and threshold crossing rate; for the stationary case, autocorrelation, spectral density, and first passage time probability are also obtained. Comparison of results of numerical example with Monte-Carlo solutions indicates that the proposed method is a powerful and efficient tool.
2,377 citations