Posted: 13 Apr 2011 06:54 PM PDT

Hello everybody.
I would appreciate your help in something I have been thinking all day (and now I am doing an allnighter, without result )

Please take a look at the pic at the end. It is a bycicle crankset. Now

1) There is a force sensor in the center. It can sense Fx, Fy and Fz and also Mx, My and Mz. (where F are forces and M moments (or torques))

2) The rider applies a Total force (Ftot) in the pedal. This Total Force can be decomposed as (F"x, F"y, F"z)-> just a notation.

My problem is that I have to find Ftot and the only data I have is the force and moments measured at the sensor.
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Now, I have done this so far:

1) I can see that Mz and Mx　are generated ONLY by F"y. So I guess I can find F"y quite easily:

||F"y||= ||Mz||/(radius of crank)

2) I can see that Mｙ is generated by BOTH F"x and F"z.

----------------------

Now how can I get F"x and F"z from My (torque data)???

On related notes what is the relationship between the forces at the pedal(F"x, F"y, F"z) and the forces at the sensor? (Fx, Fy, Fz)
THIS is KEY I think!

So far I am thinking that Fx and Fz are proportional (if not equal!??) to F"x and F"z. If that is the case I can find both by geomety from My only.

Any help would be greatly appreciated. I am running late on a deadline, so I will be infintely grateful for your comments and help

Thanks
Kansai

Posted: 13 Apr 2011 08:57 AM PDT

OK,I'm new here and this is my very 1st post;.
.I want some ideas from you guys about a project with wireless sensor networks..And it has already begun with a solar power source (which has the solar tracking ability ),,furthermore another arrangement to measure the voltage and current (developed by solar panels) send those data to a computer using a wireless method.
my professor said that this whole system can be used as a sensor node in a application where normal current supply is not possible like in a large paddy -field to collect data
The case is I don't have a idea where to use it...But I think you have :rolleyes:
like railway gate control..like traffic control i don't know
THANK YOU;

Definitions Of Terms Used In Mechanical Industry

Posted: 12 Apr 2011 07:22 PM PDT

Let us start something like defining terms of hard core mechanical industry. I will set the ball rolling.

Reynolds number: It is defined as the ratio of inertia force of a flowing fluid and the viscous force of the fluid.

Inertia force= Mass*Acceleration of the flowing fluid.= ρ*V*velocity.

where ρ=density of fluid and V is volume.

Viscous force= Shear stress*Area= τ*a

By definition of Reynolds number R=VL/ν.

Where ν=μ/ρ. Or

R=ρVd/μ

Then there is also Reynolds model law It is a law in which models are based on Reynolds number. These models include
1.Pipe flow problems
2.Resistance experienced by submarines, airplanes, fully immersed bodies etc.

Crazy Engineers .CoM

Wednesday, April 13, 2011

CrazyEngineers Forum - Mechanical & Civil Engineering

CrazyEngineers Forum - Mechanical & Civil Engineering

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