Want to know what is the best in terms of friction

[victor2006]

i want to use a 100 cm diameter piston witch will have 4000 kg of pressure on it.
Questions
-how thick does the piston have to be to hold that much weight if it is made of metal?
-what material should i use to make a seal to the cylinder wall and should the cylinder wall be another material then metal?
-what is the static friction on the cylinder wall and seal if lubricated?

thank you for your time

 

[mfb]

4000kg is not a pressure, it is a mass.

-how thick does the piston have to be to hold that much weight if it is made of metal?

Which metal?

-what material should i use to make a seal to the cylinder wall and should the cylinder wall be another material then metal?

Without any special requirements, steel is probably a good choice for the cylinder wall. The next question: which type of steel.

-what is the static friction on the cylinder wall and seal if lubricated?

Hard to tell without more details about the setup.

 

[fedaykin]

http://en.wikipedia.org/wiki/Friction#Approximate_coefficients_of_friction has some static friction coefficient values for lubricated steel on steel. I would not trust these values for any serious work though.

The coefficient of static friction gives you an approximation of static friction as a portion of the normal force. The normal force is basically how hard your surfaces are pressing against each other.

 

[victor2006]

What i want to do is have a cylinder that is made of steel (don't know what types there are but i guess regular)
with a height of 20 ft or so, filled with water. for the bottom of the cylinder i want a piston that would move 6 inches.

the volume of the water on top of the piston is about 4000 liters
i was wandering if you could tell me how thick the steel would have to be so that it would support that weight.

 

[PJC01]

I can provide some information and recommendations regarding the best friction for your specific scenario. First, the thickness of the piston will depend on the type of metal you use and its strength. A thicker piston will be able to withstand more weight, but it also means more weight and potentially slower movement. It is important to determine the optimal balance between strength and movement for your specific application.

In terms of materials for the seal and cylinder wall, it is important to consider the pressure and temperature requirements for your system. Generally, materials such as rubber, silicone, and Teflon are commonly used for seals due to their flexibility and resistance to high pressure. For the cylinder wall, metals such as steel or aluminum are commonly used due to their strength and durability. However, it is important to ensure that the materials used are compatible with each other to prevent any chemical reactions or degradation.

The static friction on the cylinder wall and seal will depend on the type of lubricant used. Different lubricants have different coefficients of friction, which can affect the overall friction in your system. It is important to choose a lubricant that is suitable for your specific application and can withstand the pressure and temperature conditions.

Overall, it is important to carefully consider the materials and lubricants used in your system to achieve the best friction for your specific needs. It may also be beneficial to conduct experiments or simulations to determine the optimal combination of materials and lubricants for your 100 cm diameter piston with 4000 kg of pressure.