The Design, Experimentation, and Simulation of a Novel Coulomb Friction Device for Automotive Valve Spring Damping

1993 ◽  
Vol 115 (4) ◽  
pp. 871-876 ◽  
Author(s):  
J. F. Sefler ◽  
A. P. Pisano
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Wave Equation ◽  
Computer Modeling ◽  
Coulomb Friction ◽  
Damping Term ◽  
Interference Fit ◽  
Valve Spring ◽  
Coulomb Damping ◽  
Elastomeric Dampers

This investigation contains experimental and computer modeling results of an alternative method for damping automotive valve springs, in which a nondestructive elastomeric sleeve that slides over the spring with an interference fit is used to provide coulomb damping on the outside of the valve spring coils. The damper and valve spring dynamics are modeled using the wave equation with a damping term composed of both viscous and coulomb components. Although the damper is very simple and inexpensive, the reduction in residual spring vibrations are shown to be significant without loss of valve spring performance. Experimental data taken from a 1983 Pontiac family-II, 1.8 liter, four cylinder, single overhead cam engine equipped both with and without the new elastomeric dampers is used to verify the results of the computer simulation and demonstrate the effectiveness of the damper.

Dynamic Analysis of a Valve Spring With a Coulomb-Friction Damper

1990 ◽  
Vol 112 (4) ◽  
pp. 509-513 ◽  
Author(s):  
R. S. Paranjpe
Keyword(s):  
Finite Difference ◽  
Difference Scheme ◽  
Finite Difference Scheme ◽  
Coulomb Friction ◽  
Distributed Parameter ◽  
Friction Damper ◽  
Equivalent Viscous Damping ◽  
Valve Spring ◽  
Coulomb Damping ◽  
Explicit Finite Difference

The dynamic behavior of a distributed parameter valve spring with Coulomb damping has been modeled. Such a spring is described by a nonlinear, nonhomogeneous wave equation. This equation is solved using an explicit finite difference scheme. Some sample results are presented. The results of the finite difference scheme are compared with the results of an analytical solution for zero damping. The two compare very well. The spring is also modeled using an equivalent viscous damping coefficient. The results of this analysis are compared with those of the Coulomb damping analysis.

Dynamics of a Coulomb Damped Helical Spring: A Finite Element Approach

2004 ◽  
Author(s):  
Majid Rashidi ◽  
Sachin P. Budhabhatti ◽  
John L. Frater
Keyword(s):  
Finite Element ◽  
Wave Equation ◽  
Friction Force ◽  
Coulomb Friction ◽  
Helical Spring ◽  
Radial Expansion ◽  
Damping Force ◽  
Coulomb Damping ◽  
Constant Friction ◽  
Coulomb Friction Force

This work presents the results of a mathematical modeling to study the dynamic behavior of a helical spring under a periodic excitation induced by a rotating cam. The spring is sleeved over a mandrel; thereby it is further subjected to a Coulomb damping force as it oscillates. Helical springs expand radially when they are compressed. The effect of this radial expansion is included in the mathematical model. Standard wave equation that includes variable Coulomb damping was used to examine the vibratory behavior of the spring. Numerical solution to the no-friction, constant-friction, and varying-friction forces were obtained from the wave equation, using Explicit Finite Difference method. Finite Element was used to model the radial expansion of the spring to determine the variations of the Coulomb friction force. The spring response to the prescribed cam excitation, under the variable Coulomb friction force, was found not to be significantly different from that of a previously assumed constant friction force, for the cases that were studied in this work. In case of postulating a variable damping force the residual vibrations of spring loops are slightly higher than of the constant damping force.

scholarly journals Simulative investigation of ring creep on a planetary bearing of a wind turbine gearbox

2021 ◽  
Author(s):  
Jonas Gnauert ◽  
Felix Schlüter ◽  
Georg Jacobs ◽  
Dennis Bosse ◽  
Stefan Witter
Keyword(s):  
Experimental Data ◽  
Finite Element Method ◽  
Sensitivity Analysis ◽  
Planetary Gear ◽  
The Finite Element Method ◽  
Relative Movement ◽  
Wind Turbine Gearbox ◽  
Interference Fit ◽  
Planetary Gears ◽  
Module Coefficient

AbstractWind turbines (WT) must be further optimized concerning availability and reliability. One of the major reasons of WT downtime is the failure of gearbox bearings. Some of these failures occur, due to the ring creep phenomenon, which is mostly detected in the planetary bearings. The ring creep phenomenon describes a relative movement of the outer ring to the planetary gear. In order to improve the understanding of ring creep, the finite element method (FEM) is used to simulate ring creep in planetary gears. First, a sensitivity analysis is carried out on a small bearing size (NU205), to characterize relevant influence parameters for ring creep—considered parameters are teeth module, coefficient of friction, interference fit and normal tooth forces. Secondly, a full-scale planetary bearing (SL185030) of a 1MW WT is simulated and verified with experimental data.

Robotic Assembly Cell Simulation

1992 ◽  
Author(s):  
Jian Liu ◽  
J. P. Sadler
Keyword(s):  
Computer Simulation ◽  
Computer Modeling ◽  
Collision Detection ◽  
Robotic Assembly ◽  
Research Activities ◽  
Assembly Cell ◽  
Cell Simulation ◽  
Manufacturing Environments

Abstract A flexible robotic assembly cell is described, and some of the research activities involving the cell and robot applications in manufacturing environments are presented. This research relies heavily on computer simulation. Assembly cell computer modeling, cell calibration, robot collision detection, and off-line programming are described in this paper.

scholarly journals Numerical and experimental investigations of steel-concrete beams with thin-walled section

Vestnik MGSU ◽  
2019 ◽  
pp. 22-32
Author(s):  
Farit S. Zamaliev
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Strain State ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Stress Strain ◽  
Stress Strain State ◽  
Numerical Studies ◽  
Field Samples ◽  
Thin Walled

Introduction. Conducted is to the evaluation of the stress-strain state of the steel-concrete beams with thin-walled section. In recent times, steel-reinforced concrete structures have become widely used in civilian buildings (beams, slabs, columns). Thin-walled section have not found wide application in steel concrete structures, unlike steel structures. Presents the results of numerical studies of beams consisting of concrete, anchors and steel beams. Two investigating of the location of anchors are given. Numerical investigations are presented of steel-concrete beams with thin-walled section based on numerical studies. Testing procedure and test result are given. Results of calculations, comparison of numerical and experimental studies are presented. Materials and methods. For full-scale experiments, steel I-beams with filling of side cavities with concrete were adopted, screws are used as anchor ties, with varied both the lengths and their location (vertically and obliquely). As steel curved C-shaped steel profiles were used steel profiles from the range of the company “Steel Faces”. ANSYS software package was used for computer modeling. A total of 16 steel concrete beams were considered, for which the results of strength and stiffness evaluation were obtained in ANSYS. Results. The data of the stress-strain state of beams on the basis of computer simulation are obtained. The results are used for the production of field samples. Data of computer simulation are compared with the indicators of field experiments. Conclusions. The stress-strain state of steel-concrete structures was studied on the basis of numerical and experimental data. The proposed calculation method gives good convergence with the experimental data. Anchor connections made from self-tapping screws can be used in studies for modeling in steel-concrete beams structures and other anchor devices, ensuring the joint operation of concrete and steel profiles in structures.

scholarly journals The Differential Transform Method for n1 - dimensional Equal Width Wave equation with damping term

2018 ◽  
Vol Volume-2 (Issue-4) ◽  
pp. 1586-1593
Author(s):  
T. Siva Subramania Raja ◽  
K. Sathya ◽  
R. Asokan | M. Janani ◽  
Keyword(s):  
Wave Equation ◽  
Differential Transform Method ◽  
Damping Term ◽  
Transform Method ◽  
Differential Transform

Simulation of an On-Off Pneumatic Servomechanism

1967 ◽  
Vol 182 (1) ◽  
pp. 631-642 ◽  
Author(s):  
C. R. Burrows ◽  
C. R. Webb
Keyword(s):  
Computer Simulation ◽  
Coulomb Friction ◽  
Dead Zone ◽  
Analogue Computer ◽  
Viscous Damping ◽  
Acceleration Feedback ◽  
Spool Valve

This paper describes an analogue computer simulation of an on-off pneumatic servomechanism comprising a polarized relay with dead zone and hysteresis, power relays, and an on-off four-way spool valve supplying air to a cylinder driving an inertia load acted upon by viscous damping and Coulomb friction. The effect of varying the amount of friction and of position, velocity, and acceleration feedback is studied. The effect of the addition of stabilizing tanks is also considered.

Rule of Thumb Modelling of Biofilm Reactors

1990 ◽  
Vol 22 (1-2) ◽  
pp. 405-418 ◽  
Author(s):  
S. Elmaleh
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Complex Systems ◽  
Flow Pattern ◽  
Zero Order ◽  
Design Tool ◽  
Rule Of Thumb ◽  
Biofilm Reactors ◽  
Number Of Species ◽  
Operational Variables

Biofilm reactors are very complex systems, the modelling of which requires sophisticated kinetic relationships concerning the highest number of species in reaction and computer simulation. In fact, the process engineer needs a rule of thumb method able to predict the output variables after modification of the operational variables. Such a “simplissime” model is derived by considering a plate reactor coated with a biofilm through which the substrates are diffusion transported and eliminated with a zero order intrinsic reaction. When the liquid-biofilm resistance is neglected, conversion depends on one parameter only, the meaning of which can be displayed. Moreover, in many cases, the flow pattern influence can be neglected. This “simplissime” model was shown accurate enough in fitting various experimental data and it can even be used as a design tool.

Analysis of the interaction mechanisms in dynamic mode SFM by means of experimental data and computer simulation

1998 ◽  
Vol 66 (7) ◽  
pp. S885-S889 ◽  
Author(s):  
B. Anczykowski ◽  
J.P. Cleveland ◽  
D. Krüger ◽  
V. Elings ◽  
H. Fuchs
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Dynamic Mode ◽  
Interaction Mechanisms
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