Free Body Diagram of a Tire in Steady state motion
Free Body Diagram of a Tire in Steady state motion
(OP)
Along the lines of discussion thread108-192670 ...
I have been puzzled by the question of how a single tire on a moving vehicle maintains steady state motion. Both the torque acting on the center, and the resistive moment of the ground (weak assumption I know) seem to cause an unbalanced force sum.
What other force, ie. compression of the rubber material, am I missing to complete the free-body diagram? If this was kept a 2D problem, that would be appreciated.
Thanks,
I have been puzzled by the question of how a single tire on a moving vehicle maintains steady state motion. Both the torque acting on the center, and the resistive moment of the ground (weak assumption I know) seem to cause an unbalanced force sum.
What other force, ie. compression of the rubber material, am I missing to complete the free-body diagram? If this was kept a 2D problem, that would be appreciated.
Thanks,





RE: Free Body Diagram of a Tire in Steady state motion
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Free Body Diagram of a Tire in Steady state motion
Of course, torque is transfered through the sidewalls of the tire as well. It gets pretty complicated and there are several different ways you can analyze the loads which are all correct.
RE: Free Body Diagram of a Tire in Steady state motion
RE: Free Body Diagram of a Tire in Steady state motion
RE: Free Body Diagram of a Tire in Steady state motion
Ted
RE: Free Body Diagram of a Tire in Steady state motion
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Free Body Diagram of a Tire in Steady state motion
Can the friction force be considered of the static type, since relative motion of tire contact patch and road is null? I think that was the hurdle there, trying to classify the type of friction force.
RE: Free Body Diagram of a Tire in Steady state motion
RE: Free Body Diagram of a Tire in Steady state motion
Well, I think he means the static friction force between tire and road, from which traction is derived.
RE: Free Body Diagram of a Tire in Steady state motion
RE: Free Body Diagram of a Tire in Steady state motion
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RE: Free Body Diagram of a Tire in Steady state motion
RE: Free Body Diagram of a Tire in Steady state motion
Regards
Pat
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RE: Free Body Diagram of a Tire in Steady state motion
I inadvertantly left out the horizontal force acting through the axle. That force is the driving torque divided by the tire radius. The flatting of the tire contact patch adds a complication. It reduces the effective tire radius and adds a rolling resistance term.
Ted