# Formula to assess wear due to friction in sheaves/pulleys

• Antonius Robertus
In summary, the conversation is about estimating wear due to friction on a rope passing through a pulley. The participants discuss the need for data from previous experience or lab tests to accurately determine wear rate. They also mention that handbooks can provide formulas and data for common material combinations, but they are not a substitute for solid data. The conversation also touches on the question of whether the traction force on a winch rope depends on the length of the rope spooled on the drum.

#### Antonius Robertus

Hi everyone and greetings from a new member.

I'm looking for informations about how to estimate the wear due to friction of a rope as it passes through a pulley. Couldn't find anything really consistent about the subject. I looked at the capstan and Archard equations but didn't manage to link one to the other.

Does anyone have any ideas ?

Thanks a lot

A. R.

Search on ' tribology friction wear ' .

To solve actual problems of wear rate you generally need data from previous experience or lab tests or from tests on a prototype of the device being worked on .

There are handbooks which give wear rate formulas and a selection of wear data for common material combinations but they are no substitute for solid data from tests .

At least one high tech company I know of conducted extensive experiments to determine wear characteristics of many materials running against each other under a range of loading and lubrication conditions .

Generally most effort in practical design goes on selecting known material combinations and running conditions that will minimise wear during service life .

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I search on tribology and found some interesting stuff. But as you said, it depends a lot on material combinations and tests results. Anyway, thanks for your help.

Now here's another question, not directly linked to friction wear on pulleys. Does the traction force on a winch rope depend on how many times the rope is spooled on the winch drum ? In other terms, is it necessary to have a minimum length (or minimum contact area) of rope spooled on the drum to avoid sliding ? If so, I would like to know how to determine this required length of spooled rope to get a given traction force.

Thanks

## 1. What is the formula to assess wear due to friction in sheaves/pulleys?

The formula to assess wear due to friction in sheaves/pulleys is F = μW, where F is the force of friction, μ is the coefficient of friction, and W is the weight or load.

## 2. How do I calculate the coefficient of friction?

The coefficient of friction can be calculated by dividing the force of friction by the normal force. In the formula for assessing wear due to friction, μ would be the ratio F/W.

## 3. What is the significance of assessing wear due to friction in sheaves/pulleys?

Assessing wear due to friction in sheaves/pulleys is important because it helps to determine the amount of damage or wear that has occurred over time. This information can be used to predict when maintenance or replacement is needed to prevent failure.

## 4. Are there any other factors that can affect wear due to friction in sheaves/pulleys?

Yes, there are other factors that can affect wear due to friction in sheaves/pulleys, such as the speed of rotation, the type and condition of the materials, and the presence of lubricants. These factors should also be considered when assessing wear due to friction.

## 5. Can this formula be applied to all types of sheaves/pulleys?

The formula for assessing wear due to friction can be applied to most types of sheaves/pulleys. However, it is important to consider the specific design and materials of the sheaves/pulleys in question to ensure accuracy. In some cases, specialized formulas may be needed for more complex systems.