Where in the world is Greg Locock? 3

[Dinosaur]

Greg,

I developed a solution to a highway paving problem and now my collegue asked me to write a paper on it. Well, I wrote a bunch of stuff on my model and some others added a few things and submitted it for publication. a reviewer asked me to "cite" my source for a statement that automobile suspension systems have a natural frequency from 1.2 to 2.0 Hz, which I learned from you. My collegue says I can use that calling the comment "Professional Correspondence." But I need your contact information to complete the citation. How can we get that without violating your privacy, etc.?

dinosaur

 

[SomptingGuy]

He's on some kind of 10-year honeymoon.

- Steve

 

[MiketheEngineer]

Lucky guy.. maybe

 

[Denial]

I was wondering the same thing myself just the other day (purely out of idle curiosity).

 

[FeX32]

Here is a reputable source that I found. (in case you are interested)
Page 1790 "heave mode resonant frequencies 1-1.5 Hz.
There is also much more information about nat. frequencies of automotive vehicles in there. pg. 1785 has some nat. info.

Cheers.




Fe

 

[FeX32]

Of course. I as you do trust Greg completely. I just thought in case you wanted something you could reference


Fe

 

[telecomguy]

Might try contacting thru LinkedIn...

http://au.linkedin.com/pub/greg-locock/2/540/16

<tg>

 

[Dinosaur]

Thanks Greg. I can't tell you how shocked I was to open this thread and see 7 responses. I was wondering, "How many times does Greg have to tell me his address?" It is clear you're a popular guy 'round these parts, which says alot about you, Greg. Thanks for the help. I'm looking forward to the extra information on Monday.

FeX - That is a lot of math in that paper. I printed it off and I'll read it for a couple years. Actually, that is a sophisticated model that I hope to emulate with my study in the future. Right now I just used a 1-DOF model, but I want to get to a 2-DOF dampened model before I am done. To do that though, I will need the rotational moment of inertia of the vehicle (I'm thinking Concrete mixer) to have a coherent model and that would be a heck of a project by itself.

Dinosaur

 

[FeX32]

Dinosaur,
I agree that paper seems like a good one for your situation. Usually 1DOF models are used for fundamental methodology and theory verification. A short while ago I did some work with vibration control theory, mostly non-linear 1DOF models. I later expanded it to 2DOF. Although, my models were of a vibration absorber, not a vehicle like yours.
And yea you are right, you would need the mass-moment of inertia of the vehicle lateral axis for the 2DOF model. However, if I were you I would certainly build the mathematical model first and assume a value for parameters, and then later determine them.
I'm glad I could help.
Best of luck


Fe

 

[GregLocock]

Bah, Dixon doesn't have it. Gillespie Fundamentals of Vehicle Dynamics says 1 to 1.5 Hz for most cars, and performance cars 2 to 2.5 Hz. Page 155 in ISBN 1-56091-199-9

Note that this is a crude corner frequency calculation, the actual whole vehicle bounce and pitch modes are different.






Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[Dinosaur]

That's OK. I used 1.2 Hz for the calculations because it yielded the highest amplitude. This fits well with 1-1.5 since it is in the middle of the range. It is only a 1DOF undampened vibration model. There is no need to fine tune something with such limited response in the model.

But someday I may get to a 3 DOF model and that will be another animal altogether.

 

[FeX32]

Best of luck.


Fe