Friction coefficient of Mud and grass

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Discussion Overview

The discussion centers around determining the friction coefficient of mud for a device designed to be pulled through fields of thick grass and mud. Participants explore the implications of this coefficient on calculating maximum frictional forces, torsional, and bending moments on the device's framework.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant inquires about the friction coefficient of mud to aid in the design of a device, specifically a mower unit.
  • Another participant provides links to various resources that list friction coefficients for different materials.
  • Some participants argue that the friction coefficient alone may not adequately estimate the friction force, suggesting that factors such as the nature of contact (skimming vs. plowing) and the size of the skid play significant roles.
  • A participant mentions that testing with a forcemeter to measure the actual force required to pull the device through the mud may be more effective than relying solely on theoretical coefficients.
  • One participant clarifies that their mower unit is designed to skim over the mud, which influences the opposing forces they need to estimate.
  • Another participant raises a concern about the potential impact of gravel or rocks on the material thickness needed for the device, although the original poster states this is not a primary concern for their calculations.
  • The original poster later claims to have found a friction coefficient of approximately 0.57 for mud.

Areas of Agreement / Disagreement

Participants express differing views on the utility of the friction coefficient in this context, with some emphasizing the need for empirical testing rather than relying solely on theoretical values. The discussion does not reach a consensus on the best approach to estimate the opposing forces.

Contextual Notes

Participants note that the friction force is influenced by multiple factors beyond just the friction coefficient, including the nature of the interaction with the mud and grass, which may complicate the calculations.

KentJacobsen10
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Hi Guys,

Just wondering if anyone knows of the friction coefficient of Mud?

i am designing a device that gets pulled through fields of thick grass and mud. And i am wanting to know what the friction coefficient of Mud would be so i can calculate the maximum frictional force on the device, which it turn will help me calculate all the torsional and bending moments on the frame work.

the bottom of my device will mostly be steel.

Cheers
 
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Friction coefficient probably isn't a very useful way of estimating the friction force here. The friction force depends on much more than just the contact normal force. Are you plowing the mud so you have to determine the viscous fluid losses? Or are you skimming over the surface so it's more like a lubricated solid? The force for flattening the grass will also depend on the size of the skid more than the normal force.

Probably easiest to get a forcemeter and pull something through the mud to test it.
 
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I am skimming over it.
Basically its a mower unit with side skids, so points of contact is the mowers rear roller and the skids on either side. i just need to find the opposing force of the mud/thick grass to make a rough estimate of the material thickness needed.
 
If you pull your mower over gravel, or a skid hits a protruding rock, would that factor into your material thickness needed, for wear and dents to the skid/structure?
 
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it would not effect the objective of my calculations. i have beams attached to the mower, that are attached to the tractor. if my mower undergoes a high opposing force the beams will undergo bending and torsion. thus i needed to calculate the possible opposing forces. the mower and skids are made well so rocks won't damage them.

However i found the friction coefficient i was looking for , it is approx. 0.57.

Thanks for all your help though.
 

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