scholarly journals Effect of adding mass to rotor on in-plane squeal in automotive disc brake

2018 ◽  
Vol 211 ◽  
pp. 13006
Author(s):  
Takashi Nakae ◽  
Takahiro Ryu ◽  
Hiroki Goto ◽  
Daisuke Sato
Keyword(s):  
Dry Friction ◽  
Coulomb Friction ◽  
Disc Brake ◽  
Vibration Modes ◽  
Concentrated Mass ◽  
Mass Model ◽  
Out Of Plane ◽  
The Relationship

This study experimentally examined disc brake-generated inplane squeal by looking at vibration modes. The in-plane squeal was determined to be closely related to both the out-of-plane squeal that has directionality caused by Coulomb friction and the in-plane squeal caused by dry friction. The characteristics of in-plane squeal were also analytically investigated using a concentrated mass model formed by connected massless beams, and the relationship between mass added to the rotor and squeal suppression was clarified.

The Elastic-Dynamic Modeling of a Press Feed Mechanism

1994 ◽  
Vol 116 (1) ◽  
pp. 238-247 ◽  
Author(s):  
C. Chassapis ◽  
G. G. Lowen
Keyword(s):  
Mathematical Model ◽  
Free Vibration ◽  
Equations Of Motion ◽  
Metal Strip ◽  
Disc Brake ◽  
Vibration Modes ◽  
Subsequent Application ◽  
Out Of Plane ◽  
The Masses ◽  
Intermittent Motion

The development of a mathematical model, describing the elastic-dynamic response of an industrial lever type roll feed mechanism, is presented. This device, which is used in all manner of powerpress work, consists of an RSSR linkage with a bent coupler, an indexing-type sprag clutch, a set of feed and pressure rollers, which move a metal strip into a die, and a disc brake. Its intermittent motion has been characterized by four motion regimes. While the spatial coupler link is considered to have distributed mass and electricity, the clutch model neglects the masses of the sprags and represents the total clutch elasticity by way of a single, nonlinear, massless torsional spring. The derivation of the equations of motion of the coupler and the feed-roller driven metal strip, for the various regimes, is based on Hamilton’s principle. The subsequent application of the method of Kantorovich, wherein the space portions of the coupler motion are expressed in terms of its in and out-of-plane free-vibration modes, makes it possible to obtain coupled ordinary differential equations for the feed-roller motion, as well as the time portions of the coupler deflections.

Grain separation enhanced magnetic coercivity in Pt/Co multilayers.

1993 ◽  
Vol 51 ◽  
pp. 1038-1039 ◽  
Author(s):  
G.A. Bertero ◽  
R. Sinclair
Keyword(s):  
Remanent Magnetization ◽  
Strong Influence ◽  
Uniaxial Anisotropy ◽  
Magnetic Coupling ◽  
Recording Media ◽  
Magnetic Media ◽  
Signal To Noise ◽  
Out Of Plane ◽  
Longitudinal Recording ◽  
The Relationship

Pt/Co multilayers displaying perpendicular (out-of-plane) magnetic anisotropy and 100% perpendicular remanent magnetization are strong candidates as magnetic media for the next generation of magneto-optic recording devices. The magnetic coercivity, Hc, and uniaxial anisotropy energy, Ku, are two important materials parameters, among others, in the quest to achieving higher recording densities with acceptable signal to noise ratios (SNR). The relationship between Ku and Hc in these films is not a simple one since features such as grain boundaries, for example, can have a strong influence on Hc but affect Ku only in a secondary manner. In this regard grain boundary separation provides a way to minimize the grain-to-grain magnetic coupling which is known to result in larger coercivities and improved SNR as has been discussed extensively in the literature for conventional longitudinal recording media.We present here results from the deposition of two Pt/Co/Tb multilayers (A and B) which show significant differences in their coercive fields.

A New Method to Find the Forced Response of Nonlinear Systems with Dry Friction

2021 ◽  
Author(s):  
Gregory L. Altamirano ◽  
Meng-Hsuan Tien ◽  
Kiran D'Souza
Keyword(s):  
Dry Friction ◽  
Coulomb Friction ◽  
Nonlinear Response ◽  
Piecewise Linear ◽  
Time Integration ◽  
Nonlinear Behavior ◽  
Forced Response ◽  
New Method ◽  
Analysis Tools ◽  
Compatibility Constraint

Abstract Coulomb friction has an influence on the behavior of numerous mechanical systems. Coulomb friction systems or dry friction systems are nonlinear in nature. This nonlinear behavior requires complex and time demanding analysis tools to capture the dynamics of these systems. Recently, efforts have been made to develop efficient analysis tools able to approximate the forced response of systems with dry friction. The objective of this paper is to introduce a methodology that assists in these efforts. In this method, the piecewise-linear nonlinear response is separated into individual linear responses that are coupled together through compatibility constraint equations. The new method is demonstrated on a number of systems of varying complexity. The results obtained by the new method are validated through the comparison with results obtained by time integration. The computational savings of the new method is also discussed.

scholarly journals Influence of the flexibility of beams and slabs in static response and dynamic properties

2016 ◽  
Vol 9 (6) ◽  
pp. 842-855 ◽  
Author(s):  
J. R. BUENO ◽  
◽  
D. D. LORIGGIO ◽  
Keyword(s):  
Finite Element Method ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Vibration Modes ◽  
Linear Regime ◽  
Static Response ◽  
The Finite Element Method ◽  
Standard Code ◽  
The Relationship ◽  
Brazilian Standard

Abstract This article examines numerically the flexibility influence of support beams in static response and dynamic properties of a symmetric plate formed by massive slabs of reinforced concrete in elastic linear regime, using the Finite Element Method. In the static response the variation of bending mo-ments and displacements are evaluated, which depend on the relationship between the flexibility of the slab and the beam. The evaluation of dynamic properties is held in undamped free vibration, through which the vibration modes and the values of the natural frequencies is obtained, which are compared with the limits of the Brazilian standard code for design of concrete structures. Results show that the response may show great variation due to the change in the relationship between bending stiffness of the slabs and the beams.

scholarly journals Derivation of a finite-element model of lingual deformation during swallowing from the mechanics of mesoscale myofiber tracts obtained by MRI

2010 ◽  
Vol 109 (5) ◽  
pp. 1500-1514 ◽  
Author(s):  
Srboljub M. Mijailovich ◽  
Boban Stojanovic ◽  
Milos Kojic ◽  
Alvin Liang ◽  
Van J. Wedeen ◽  
...  
Keyword(s):  
Finite Element ◽  
Connective Tissue ◽  
Diffusion Tensor ◽  
Element Model ◽  
Out Of Plane ◽  
Posterior Direction ◽  
Elastic Constraints ◽  
The Relationship ◽  
Passive Muscle ◽  
Anterior Posterior

To demonstrate the relationship between lingual myoarchitecture and mechanics during swallowing, we performed a finite-element (FE) simulation of lingual deformation employing mesh aligned with the vector coordinates of myofiber tracts obtained by diffusion tensor imaging with tractography in humans. Material properties of individual elements were depicted in terms of Hill's three-component phenomenological model, assuming that the FE mesh was composed of anisotropic muscle and isotropic connective tissue. Moreover, the mechanical model accounted for elastic constraints by passive and active elements from the superior and inferior directions and the effect of out-of-plane muscles and connective tissue. Passive bolus effects were negligible. Myofiber tract activation was simulated over 500 ms in 1-ms steps following lingual tip association with the hard palate and incorporated specifically the accommodative and propulsive phases of the swallow. Examining the displacement field, active and passive muscle stress, elemental stretch, and strain rate relative to changes of global shape, we demonstrate that lingual reconfiguration during these swallow phases is characterized by (in sequence) the following: 1) lingual tip elevation and shortening in the anterior-posterior direction; 2) inferior displacement related to hyoglossus contraction at its inferior-most position; and 3) dominant clockwise rotation related to regional contraction of the genioglossus and contraction of the hyoglossus following anterior displacement. These simulations demonstrate that lingual deformation during the indicated phases of swallowing requires temporally patterned activation of intrinsic and extrinsic muscles and delineate a method to ascertain the mechanics of normal and pathological swallowing.

In-Plane Vibration Modes of Arbitrarily Thick Disks

1997 ◽  
Author(s):  
Kevin I. Tzou ◽  
Jonathan A. Wickert ◽  
Adnan Akay
Keyword(s):  
Natural Frequencies ◽  
Arbitrary Dimension ◽  
Three Dimensional ◽  
Mode Shapes ◽  
Vibration Modes ◽  
Three Dimensional Model ◽  
Bending Vibration ◽  
Annular Disk ◽  
Out Of Plane ◽  
Plane Bending

Abstract The three-dimensional vibration of an arbitrarily thick annular disk is investigated for two classes of boundary conditions: all surfaces traction-free, and all free except for the clamped inner radius. These two models represent limiting cases of such common engineering components as automotive and aircraft disk brakes, for which existing models focus on out-of-plane bending vibration. For a disk of significant thickness, vibration modes in which motion occurs within the disk’s equilibrium plane can play a substantial role in setting its dynamic response. Laboratory experiments demonstrate that in-plane modes exist at frequencies comparable to those of out-of-plane bending even for thickness-to-diameter ratios as small as 10−1. The equations for three-dimensional motion are discretized through the Ritz technique, yielding natural frequencies and mode shapes for coupled axial, radial, and circumferential deformations. This treatment is applicable to “disks” of arbitrary dimension, and encompasses classical models for plates, bars, cylinders, rings, and shells. The solutions so obtained converge in the limiting cases to the values expected from the classical theories, and to ones that account for shear deformation and rotary inertia. The three-dimensional model demonstrates that for geometries within the technologically-important range, the natural frequencies of certain in- and out-of-plane modes can be close to one another, or even identically repeated.

Squeal Analysis of a Disc Brake Considering Damping between a Disc and a Pad Lining

2012 ◽  
Vol 157-158 ◽  
pp. 1000-1003
Author(s):  
Ke Wei Zhou ◽  
Cheol Kim ◽  
Min Ok Yun ◽  
Ju Young Kim
Keyword(s):  
Finite Element ◽  
Equations Of Motion ◽  
Element Model ◽  
Disc Brake ◽  
Vibration Modes ◽  
Assumed Mode Method ◽  
Frictional Damping ◽  
System Components ◽  
Mode Method ◽  
Assumed Mode

The improved equations of motion for a friction-engaged brake system have been newly derived on the basis of the assumed mode method and frictional damping. The equations of motion with a finite element model were constructed by a set of vibration modes found from FE modal analysis on all system components. Consequently, the modal information of system components are combined with equations of motion derived from the analytical model. Numerical analysis showed the mode which was unstable in an undamped case became stable in a damped case.

LIMIT CYCLES OF A DOUBLE OSCILLATOR EXCITED BY DRY FRICTION

2011 ◽  
Vol 21 (10) ◽  
pp. 3043-3046 ◽  
Author(s):  
SERGEY STEPANOV
Keyword(s):  
Fixed Points ◽  
Numerical Method ◽  
Limit Cycles ◽  
Dry Friction ◽  
Coulomb Friction ◽  
Three Dimensional ◽  
Slip Mode ◽  
Two Dimensional ◽  
Parametric Investigation ◽  
Friction Laws

A two-mass oscillator with one mass lying on the driving belt with dry Coulomb friction is considered. A numerical method for finding all limit cycles and their parametric investigation, based on the analysis of fixed points of a two-dimensional map, is suggested. As successive points for the map we chose points of friction transferred from stick mode to slip mode. These transfers are defined by two equalities and yield a two-dimensional map, in contrast to three-dimensional maps that we can construct for regularized continuous dry friction laws.

Modal Analysis of a Utility Bicycle From the Perspective of Riding Comfort

2019 ◽  
Author(s):  
Alberto Doria ◽  
Edoardo Marconi ◽  
Pierluca Cialoni
Keyword(s):  
Modal Testing ◽  
Vibration Modes ◽  
Response Functions ◽  
The Road ◽  
Power Spectral ◽  
Vehicle Structure ◽  
Power Spectral Densities ◽  
On The Road ◽  
The Relationship ◽  
Insight Into

Abstract The correlation between the modal properties and the comfort characteristics of a utility, step-through frame bicycle are investigated. In-plane modal testing of the vehicle is carried out both without and with the rider, and the major differences between the results obtained with the two conditions are highlighted. In order to have an insight into the contribution of the various bicycle components to the transmission of vibrations, the frequency response functions (FRFs) between the main interface points in the vehicle structure are measured and studied. Finally, the modal characteristics are compared with road tests data, emphasizing the relationship between the in-plane vibration modes and the main peaks in the acceleration power spectral densities (PSDs) measured on the road.

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