Paper Ahadya Pancasakti

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Laboratorium Metalurgi Fisik - DTMM

The Effect of Wear on Fatigue Characteristics

Wear is a phenomena which shows mechanical failure in which there is loss

of material on the surface. It is also closely related to plastic deformation

phenomena. In tribology terms, wear is classified into surface-related phenomena

where the main cause of this is due to friction. This phenomena happens in almost

every kind of material applications.

On top of that, there is also failure named fatigue. It is a form of failure due

to fluctuated or dynamic stress caused by repeated loading. The stress itself can be

axial, torsional, and flexural. Fatigue is usually catastrophic. In other words, the

indication of failure cannot be noticed clearly whereas the initial cracks are difficult

to detect.

Both of failure explained above, it is agreed by some studies that they have

a correlation to each other. Strictly speaking, wear phenomena has certain effect

regarding to fatigue characteristic of materials.

For example in fretting phenomena, a small amplitude oscillatory

displacement between contacted surfaces, the damage that may happen is wear,

fatigue, but it has high tendency for both of them to happen simultaneously.

Vingsbo and Soderberg studied qualitative approach in regards to how

fretting damage depends on slip amplitude. The result indicates that the increase in

slip regime with increasing slip amplitude will reduce fatigue damage significantly

even though wear continues to increase. Unfortunately, these particular phenomena

are still not clearly explained yet.

Another study states that if combined low frequency torque is said to be the

major cycle, meanwhile axial load and higher frequency rotating ending moment is

said to be the minor cycle, it is predicted that during fluctuating torque, major cycles

load to gross slip whereas minor cycles lead to partial slip. This shows that the effect

Paper Ahadya Pancasakti

1306389045

Group 22

Laboratorium Metalurgi Fisik - DTMM

of gross slip wear is to increase the contact area, therefore it reduces the contact

pressure and reduce the predicted fretting fatigue damage.

However, it should be noted that the experiment applied some assumption

that is necessary to simplify the effect. It is assumed that wear coefficient is to be

constant and no additional surface damage effects are incorporated other than

material removal.

As a conclusion, effect of wear can cause markedly different failure

characteristics, particularly in terms of the failure position, as above example

already explained. On the word of above experiment, the fretting wear is predicted

to reduce fretting fatigue damage, which is considered as an increase in material’s

usage life.

Paper Ahadya Pancasakti

1306389045

Group 22

Laboratorium Metalurgi Fisik - DTMM

Source

Ding, J., & Leen, S. (2008). Finite element simulation of fretting wear-fatigue

interaction in spline couplings. Tribology, 2(1). Retrieved February 28, 2015.

Madge, J. (2008). Numerical Modelling of the Effect of Fretting Wear on Fretting

Fatigue. Retrieved February 28, 2015.