If some one can clarify as to what formulae is best for calculating wear rate in case of composites.
Dear sanjay mohan,
A common used equation to compute the wear rate is (Archard,1953).
Vi =ki F s
where F is the normal load, s the sliding distance, Vi the wear volume and ki the specific wear rate coefficient. Index i identifies the surface considered.
The k-value is given in m3/Nm or m2/N, sometimes in mm3/Nm. From design view the wear displacement h is more convenient than V. With hi =Vi /A, the contact pressure P=F/A where A is the area subjected to wear then:
hi =ki P S
The sliding distance S can be replaced by S=V.t where V is the mean value for the slide rate and t the running time.
Because the k-value depends just like the friction coefficient on a lot of parameters this factor is to be find experimentally.
Regards,
Hi sanjay mohan Sharma,
The wear rate is calculated by measuring the mass loss, density and known sliding distance and load. The specific wear rate (Ks) is then expressed on volume loss basis
Regards,
Dear Walid,
In some research papers I found wear rate expressed as wear volume/sliding distance.
will i do
Dear sanjay mohan,
A common used equation to compute the wear rate is (Archard,1953).
Vi =ki F s
where F is the normal load, s the sliding distance, Vi the wear volume and ki the specific wear rate coefficient. Index i identifies the surface considered.
The k-value is given in m3/Nm or m2/N, sometimes in mm3/Nm. From design view the wear displacement h is more convenient than V. With hi =Vi /A, the contact pressure P=F/A where A is the area subjected to wear then:
hi =ki P S
The sliding distance S can be replaced by S=V.t where V is the mean value for the slide rate and t the running time.
Because the k-value depends just like the friction coefficient on a lot of parameters this factor is to be find experimentally.
Regards,
Hi sanjay mohan,
yes I know we talk the mass loss just to explain that the Archard's law is not true for many tribological systems and therefore dividing the wear volume by normal load is not approppriate anymore.wear rate is a topic still object of discussion in the tribology community. In my opinion the furmulae/methods here illustrated are valid depending on the degree of accuracy you need. Furthermore, it should be highlighted that if we talk about composite, things changes drastically.
My suggestion is to use the wear specific energy (Ew) calculation method for comparing different tests:
Ew=E/Dm
E = friction work spent at the interface (frictional energy)
Dm = total mass loss (in milligrams, for example)
In particular, E is function of the mean relative sliding velocity, the applied normal load and the coefficient of friction integrated between the initial and final time. Unfortunately, also wear specific energy is not univocally determined, therefore, representation of frictional energy vs mass loss is a good way for comparing tribological characteristics. In the graph, simply calculating the distance between the point and the origin give you an easy way to compare different tests.
Regards,
Dear Sanjay,
The wear rate is calculated as the specific wear rate (Wsp), which is given as follows,
Wsp=V/LD mm3/N-m
where V, L and D are the total wear volume, normal load and the total sliding distance, respectively.
What is relation between sliding distance and stroke length? If one of them is given, how can we calculate other?
A common used equation to compute the wear rate is (Archard,1953).
Vi =ki F s
where F is the normal load, s the sliding distance, Vi the wear volume and ki the specific wear rate coefficient. Index i identifies the surface considered.
The k-value is given in m3/Nm or m2/N, sometimes in mm3/Nm. From design view the wear displacement h is more convenient than V. With hi =Vi /A, the contact pressure p=F/A where A is the area subjected to wear then:
hi =ki p s
The sliding distance s can be replaced by s=v.t where v is the mean value for the slide rate and t the running time.
Because the k-value depends just like the friction coefficient on a lot of parameters this factor is to be find experimentally.
For k value plz find attached file
Sliding speed v = 1 m s−1, Time to reach the total load t∗ = 36 s, Coefficient of friction μ = 0.3. The specific wear rate (equivalent to the wear coefficient) for a PEEK pin sliding on a steel disc was measured as k = 7 × 10−6 mm3 Nm−1 for the operating conditions of v = 1 m s−1 and p = 1 MPa
A common used equation to compute the wear rate is.
Vi =ki F s
where F is the normal load, s the sliding distance, Vi the wear volume and ki the specific wear rate coefficient. Index i identifies the surface considered.
Hello,
I think the following website maybe useful for you:
https://en.wikipedia.org/wiki/Wear_coefficient
Regard,
can someone help me to know what is PV factor and its significance in tribology testing?
Thankyou.
- You cannot directly calculate the wear rate from the wear volume v/s time curve. While measuring a slope, you will get a different wear rate at a different time interval. So instead of this, we can calculate the specific wear rate and wear coefficient. In the case of composite, you can calculate a specific wear rate, which shows the relationship between normal applied load and wear volume defined as K=(V/(PL)); where V: wear volume; P: normal load; L: sliding distance. This formulation does not include the term hardness. If we are multiplying specific wear rate to hardness value, then one constant term will come, which is known as Wear coefficient. This shows the probability of debris formation. If it is in the range of 10^(-8)(mild) to 10^(-2)(Severe), than wear is known as mild wear and in this region dominated by the oxidation wear mechanism.
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