Static Friction for wheels
Static Friction for wheels
(OP)
Hello,
I am an electrical engineer but need to do a quick calculation for a new builidng that will have anchors installed in order to move large transformers and gear around in it. However I am not quite certain as to what coefficient of resistance I should use for a wheel between concrete and metal (ie: will be using trolley wheels on rollers skates to move) in order to determine the maximum force these anchors need to be withstand. If you could help me out I would really appreciate it. Thanks in advance.
I am an electrical engineer but need to do a quick calculation for a new builidng that will have anchors installed in order to move large transformers and gear around in it. However I am not quite certain as to what coefficient of resistance I should use for a wheel between concrete and metal (ie: will be using trolley wheels on rollers skates to move) in order to determine the maximum force these anchors need to be withstand. If you could help me out I would really appreciate it. Thanks in advance.






RE: Static Friction for wheels
RE: Static Friction for wheels
Look at this site for values of rolling friction.
http
desertfox
RE: Static Friction for wheels
Thanks for the website desertfox. I just have one more question though regarding the rolling friction. I was trying to remember back in my first year of school when we had to take a statics and dynamics class. There is a difference between rolling friction and the static friction before you start to get a wheel to move is there not? As I want to to make sure I will be calculating the maximum load (ie: around 100,000lbs). Thanks again.
RE: Static Friction for wheels
There is a formula for rolling friction on the link I gave you.
ht
Yes rolling friction is a lot less than the static friction coefficient.
desertfox
RE: Static Friction for wheels
RE: Static Friction for wheels
Google "Hilman Rollers" or whoever is furnishing your 'roller skates,' they will have both rolling friction and starting friction data for their particular equipment, on different surfaces. Yes, the starting force will be higher than the pulling force required once the system is in motion. The starting force has more to do with a localized bearing stress and deformation situation at the rollers, where you are almost pulling the rollers, up hill, out of a bit of a depression in the surface below. Is the 100k the weight of the load you're moving or the approx. pulling force applied to the bldg. column. You should clear this with the structural engineer on the bldg. because he won't have included this kind of loading in his column design; and he may care where you drill holes in his columns for your anchors. That is, load height and orientation, steel column web or flange; or reinf'g. stl. locations in conc. columns or are anchors cast-in-place? Many times, for heavy loads, riggers run steel rollers on steel plates or rails rather directly on concrete slabs, or they beat the hell out of the conc. slab.
RE: Static Friction for wheels
RE: Static Friction for wheels
htt
RE: Static Friction for wheels
The formula I gave you would be the force to get one wheel or roller moving, therefore you have to multiply that force by the number of rollers in your system assuming the total load is equally divided across the rollers.
Any additional force will be dependent on how fast you wish to move this load ie is there any acceleration? If there is acceleration then you could use the formula f=m*a where f = force, m = mass of object to be moved and a = acceleration.
Once the load is moving at constant velocity you only need sufficient force to balance the friction and to prevent the trolley from slowing down.
Finally, once the trolley is moving the dynamic friction of the trolley is usually less than the static friction.
desertfox
RE: Static Friction for wheels
RE: Static Friction for wheels
RE: Static Friction for wheels
RE: Static Friction for wheels
Regarding your steel rollers on concrete, you probably won't find any meaningful coefficients of friction, either static or dynamic, for these units and heavy loads. The roller bearing stresses are very large and the units are no longer called heavy load skates, as you call them. At these loads they are called concrete pulverizes or crushers.
RE: Static Friction for wheels