conversion of angular acceleration

[ovalmech]

I am using software that gives angular acceleration in deg/deg^2. How do I convert this to deg/sec^2?

 

[BobM3]

It may just be a typo in the software. Can you put in a known value for acceleration and see what results you get?

 

[GregLocock]

Unless it is something like a cam or gear profile, in which case deg/deg^2 makes some sense, to me




Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GregLocock]

Sorry, if so then multiply the acceleration by the speed of the shaft (in deg/s) squared.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[FrenchCAD]

Smart & simple. Good answer Greg!

Cyril Guichard
Mechanical Engineer Consultant
France

 

[zekeman]

Looks to me that the conversion would require multiplying the deg/deg^2 by (deg/sec)^2 {(angular velocity)^2} which would imply that the mechanism input angular velocity squared must be the multiplier.

 

[FrenchCAD]

that's what Greg said...or I don't read well

Cyril Guichard
Mechanical Engineer Consultant
France

 

[blackwed]

Could you pass along an example application where the units of deg/deg^2 would be used? I don't get it. I see deg/sec^2 as the time rate of change of angular velocity (deg/sec)/sec. I'm electrical in discipline and just can't seem to tie a ribbon around the meaning of (deg/deg)/deg.

Thanks,
Dan Blackwell

 

[GregLocock]

That's because it is deg/sec^2/(deg/sec)^2!

If you are looking at the error created in a gear (say) then the torsional acceleration of the gear wheel would be naturally measured in deg/sec^2, for a given rotation speed

BUT, the acceleration is actually caused by geometrical considerations, so if the gear spins twice as fast the accelerations double. So the intrinsic measure of the acceleration is deg/deg^2




Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[ovalmech]

Thanks to everyone for all the input.

The result comes form cam design software using an oscillating follower. There is no input for the speed of the cam and I believe that is why the follower angular acceleration is given in deg/deg^2. I agee that the solution is most likly multiplying by the speed of the cam squared to change the units to deg/sec^2.

Thanks again to all