Back


Newsgroup sci.engr.mech 28625

Directory

Subject: Re: Can somebody recommend a handbook? -- From: mwcraig
Subject: Question: Specialize or not to specialize -- From: hippy@acca.nmsu.edu (Hippy The Original)
Subject: Re: Can somebody recommend a handbook? -- From: mwcraig
Subject: Re: Drafting Software Survey -- From: cbonnett@netonecom.net
Subject: testing spring force - how? -- From: atp@kepler.unh.edu (Andrew T Piskorski)
Subject: Re: Question: Specialize or not to specialize -- From: pete-hughes@slb.com (Pete Hughes)

Articles

Subject: Re: Can somebody recommend a handbook?
From: mwcraig
Date: Sat, 16 Nov 1996 21:16:35 +0000
Charles E. Ely wrote:
> 
> I have to predict the resonant frequency of a large passive,
> unpowered vibration indicator that can be seen from far away.
> The indicator is comprised of a fairly stiff, tapered, hollow rod.
> One end is fixed in a bracket.  A mass is attached to the free end.
> The mass is between 4 and 10 times the mass of the rod.
> 
> I thought I would adapt some basic spring equations but nothing
> from my library accounts for the weight distribution and taper of
> the rod.
> 
> Can somebody recommend a handbook that would make a good addition
> to my library?
> 
Try using virtual work to determine the rod tip deflection for a unit load.  
Then take the reciprocal of that to get the spring constant.  Use a varying 
moment of intertia for your virtual work integral.
       d=integral(m*M/(E*I)*ds)
M=moment in rod due to a unit load where the mass is attached
m=moment in rod due to a virtual unit load where the mass is attached
For this problem, M and m are equal but the dimensions of m contain no force 
because the force is virtual.
Most elementary mechanics texts have this derived.
-matt
Return to Top
Subject: Question: Specialize or not to specialize
From: hippy@acca.nmsu.edu (Hippy The Original)
Date: 17 Nov 1996 00:10:23 GMT
	Well after a year searching for a job I have not found one. Yeah
probibly something I did of didn't do. But I am going back to school for
my masters. During my year long search I have come to the conclution that
companies want specialized engineers. Not in the classic sense, but
specialization in a specific process, hardware, or software. Finally the
question: What do you think about this kind of situation? Should one go
against what is taught by ASME and other engineering societies, and pick a
specific area and process to study. Or should young "average" engineers
try to stick with a general background (ie. Jack of all traids, but Master
on none).
Thanks for your input
Rich
-- 
*************************************************************************
*   		      	The Original Hippy on Acca                      *
*			     Rich Murphy BSME				*
*	      		    hippy@acca.nmsu.edu				*
*		     URL: http://rever.nmsu.edu/~hippy			*
*									*
*	The opinions expressed are mine, Who do I have to sleep		*
*		with to get a job in this country?!?!?			*
*									*
*************************************************************************
Return to Top
Subject: Re: Can somebody recommend a handbook?
From: mwcraig
Date: Sat, 16 Nov 1996 21:22:31 +0000
Charles E. Ely wrote:
> 
> I have to predict the resonant frequency of a large passive,
> unpowered vibration indicator that can be seen from far away.
> The indicator is comprised of a fairly stiff, tapered, hollow rod.
> One end is fixed in a bracket.  A mass is attached to the free end.
> The mass is between 4 and 10 times the mass of the rod.
> 
> I thought I would adapt some basic spring equations but nothing
> from my library accounts for the weight distribution and taper of
> the rod.
> 
> Can somebody recommend a handbook that would make a good addition
> to my library?
> 
Another way to do this is to use Rayleigh's method or Dunkerley's method.
There is a vibrations book by Thompson that has some stuff on this.
Rayliegh's method will always give an upper bound solution and Dunkerley's 
will give a lower bound, so you can bracket the actual frequency.  
Also, these methods will allow you to include the mass of the rod as well as 
the mass of the weight at the end.
-matt
Return to Top
Subject: Re: Drafting Software Survey
From: cbonnett@netonecom.net
Date: Sun, 17 Nov 96 03:41:31 GMT
On 11/12/96 4:54PM, in message <3288F228.2CDE@inetdirect.net>, Andrew Kidd 
 wrote:
> Jane, Watson wrote:
> > 
> > >Gary Lynn Kerr said...To whom ever wrote that the term
> > draftsMEN was not correct.  GET A LIFE!
> > >And a female boss has a problem with it she has too much time
> > on her hands....GET A LIFE! ....snip, snip, snip!
> > 
> > Here, here Katarina!
> > 
> > Gary, it's rather sad you feel the way you do, maybe you'll get
> > a life yourself one day.  In the meantime, will you take that
> > attitude with your female boss when she has to reprimand you?
> > (If you don't have a female boss yet, chances are you'll
> > probably have one in the future).  Get rid of your appalling
> > attitude before she gets rid of you!
> 
> I have a female boss already,  and she is open enough to realize that when I 
> say 
> draftsman or designer,   I mean the same thing.  She calls them the same...  
> Why 
> does everything have to be so "politically correct".  Why would you be 
> offended 
> to be called a draftsman if that is what you have studied to be?  What would 
> you 
> rather be called?  A draftswoman?  Geeez....    I agree with Gary,  get a 
> life! 
> 
> IM(not so)HO!!!
> -- 
> Andy Kidd   kidd@inetdirect.net   http://netdirect.net/~kidd
> 
> "He who knows not, and knows not that he knows not, is a fool. Shun him.
> He who knows not, and knows that he knows not, is a child. Teach him.
> He who knows, and knows not that he knows, is asleep. Wake him.
> He who knows, and knows that he knows, is wise. Follow him."---Author unkown
Ok, for all the suppressors out there, language is an ever-changing method of 
communication, e.g. every few years new dictionaries are produced with (what do 
you know NEW WORDS!)  Second, if individuals are affected by the terminology 
used to describe them, then let those people correct the words how they see 
fit.  If it aggravates you that badly, you may need to seek psychiatric help to 
find out why this even bothers you!
Return to Top
Subject: testing spring force - how?
From: atp@kepler.unh.edu (Andrew T Piskorski)
Date: 16 Nov 1996 23:33:10 -0500
I would like a quick, easy, accurate way of measuring the force of
springs, specifically, steel magazine springs.  What's the best way of
doing this?  30 pounds force (133 N) would be plenty for a maximum. 
I could of course simply build some sort of apparatus to sit atop the
spring and pile weights on it, but while sufficiently accurate, that
wouldn't by quick, or easy.  I'm hoping there's a better way.
It would also be nice to be able to get a force vs. spring compression
curve, rather than just measuring a point or two and depending on Hooke's
law, but that's frosting, not really necessary. 
Please Cc: any posts to me, thanks...
-- 
--
Andrew Piskorski
atp@hopper.unh.edu
Return to Top
Subject: Re: Question: Specialize or not to specialize
From: pete-hughes@slb.com (Pete Hughes)
Date: Sun, 17 Nov 1996 04:29:57 GMT
hippy@acca.nmsu.edu (Hippy The Original) wrote:
> Should one go
>against what is taught by ASME and other engineering societies, and pick a
>specific area and process to study. Or should young "average" engineers
>try to stick with a general background 
Hippie,
In the old days, a company hired a reasonably smart looking young
engineer not much caring what she thought she was good at.  Someone at
that age can be expected to adapt or be molded, at the cost of not
knowing much to start off.
My impression is now there's more hiring to target a specific skill 
for a particular project, based on prior experience.  Graduate
school can possibly stand in place of this experience.
Long term, based on observation, an engineer advances faster with
a useful specialization.  Staying general is less risk but also less 
reward.
Regards,
Pete Hughes
Return to Top

Downloaded by WWW Programs
Byron Palmer