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2 Copyright 2005 by ASME

is the total linear wear up to the jth wear step, 1jh is the total

linear wear up to thej-1th wear step and js is the increment

of sliding distance for the jth (current) wear step,p is the

contact pressure at each surface node and Dk is the

dimensional wear coefficient.

2.

Simulation of wear in a pin-on-disc set-up

In principle, because of the generality of this method, wear oncomponents for any material combination can be simulated as

far as experiments are available. In this section, for a first

demonstration, the Wear-Processor is applied for simulatingwear on a loaded spherical pin sliding over a disc (pin-on-

disc) as shown in Figure 2.1(a). The FE model is built using a

very small slice of the pin and the disc in the contact region

from that part of the pin-on-disc, which is within the dashed

circle in Figure 2.1(a).

The progress of wear over the number of revolutions(proportional to the sliding distance) on the pin and the discsurfaces is shown in Figure 2.1(b). It can be seen that the slope

of the wear curve for the pin is steadily decreasing, owing tothe fact that the contact conforms and so the pressurecontinuously decreases (running-in).

CONCLUSIONA post processing scheme has been proposed with which

wear in 3D contacting geometries can be simulated. The resultsfrom the wear simulation and the experimental observations arequalitatively in good agreement. Such a simulation tool is thefirst step to develop guidelines for material selection and micro-

machine design. Part of that is to formulate requirements on thematerials and production technology, so that a given life spancan be achieved. The simulation tool determines the loss ofmaterial at the surface. Our goal is to further develop the tool tosolve 2D transient wear problems, like e.g. in a micro gearThis will allow to study the continuous change of thekinematics of micro-machines as well as to obtain a morerealistic stress analysis during their operating life time. Thusthe life span can be predicted more accurately both by thefailure due to kinematics and the breakdown due to drasticallyrisen loads resulting from wear.

ACKNOWLEDGMENTSThe authors would like to thank the German Research

Foundation (DFG) for funding this work within the scope of acollaborative research center named SFB 499 Designproduction and quality assurance of molded micropartsconstructed from metals and ceramics.

REFERENCES[1] V. Hegadekatte, N. Huber, O. Kraft, Chapter 5.4

Development of a Simulation Tool for Wear in Microsystems

of the special edition of Micro-Engineering in Metals and

Ceramics(Ed.: H. Baltes, O. Brand, G. K. Fedder, C. Hierold

J. G. Korvik and O. Tabata:Advanced Micro and Nano System

Volume 3), Wiley-VCH, Weinheim, Germany, in press.

[2] V. Hegadekatte, N. Huber, O. Kraft, Finite elemenbased simulation of dry sliding wear,Modelling and Simuation

in Materials Science and Engineering, 2005, 13, p. 57 75.

(a)

FN

2RD

2RP

FEM

Model

Wear

Track

tD

z

y

x

2RWT

FN

2RD

2RP

FEM

Model

Wear

Track

tD

z

y

x

2RWT

(b)

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0.0016

0 50 100 150 200

No. ofRevolutions *103[ -]

Li

near

Wear

,

h

[mm]

LinearWearon Pin

LinearWearon Disc

Figure 2.1: (a) Model of a spherical loaded pin revolving

over a disc in dry sliding contact. The geometry inside

the dashed line is used for the FE simulation by the

Wear-Processor. (b) Progress of wear.