Newsgroup sci.engr.mech 29483

cpollard@csn.net (Chris Pollard) wrote:
>A review of the new Audi Quattro A8 in the local paper sounds as though
>Audi engineers have learnt some lessons from GM.
>The car is supposed to have an Aluminum body thats got "40 patents" "took
>10 years to develope with ALCOA" "is 40 % lighter thatn competitive designs"
>Only one slight problem the curb weight is listed at 3900 pounds (sorry
>couldn't figure out how to shout in numbers)
>Do they mean to say it would have weighed 6000 pounds otherwise - that's
>not a car it's a tank.
>Come on guys - you are disgracing the profession.  
Anyone interested in this thread might want to read the article "A
Practical Road to Light Weight Cars" in the latest issue of Technology
Review (published by MIT). The url is:
http://web.mit.edu/afs/athena/org/t/techreview/www/articles/jan97/clark..html
Jim Bonvouloir    ||
Nashua, NH USA    ||

"p3dlab"  previously wrote...
>We are Amsat, The Amateur Radio Satellite Corporation. We are currently
>doing the final integration of our next spacecraft, Phase 3D.  [...]
>If you have ever wanted to help build a spacecraft this is your chance.
>What we need is a computer simulation of our solar array deployment
system.
>The requirements are listed below [...]
>You will need the following skills. A solid understanding of double
>pendulum mechanics. Experience modeling complex mechanical 
>systems using an iterative approach. Some knowledge of torsion 
>spring energy equations and related formulas.  You must also have 
>the time and be willing to make a commitment to this project.  [...]
>We can not offer any financial compensation for this work. You will 
>however be able one day to look up and point to a spacecraft in orbit 
>around our planet that you helped design.
Let me understand you correctly.  You are asking for the equivalent
of several hundred hours of engineering effort, with some strong skills,
and offer NOTHING IN RETURN for it save the ability to "point to a 
spacecraft?"  With all due respect, you are being silly.
Maybe you have no money.  Then you jolly well had better consider
other ways you can come to the table with satisfaction for those who
want to help you, or I'm afraid I can't tell which is worse: that you'd
get
no offers at all, or that you'd actually get some.
You might start by offering letters of recommendation and public 
acknowledgments of help received.
Dr. Ron Graham
Project Engineer for Robotics, GreyPilgrim LLC, Washington DC
founder of Usenet newsgroup sci.engr and editor of the sci.engr.* FAQs
EMMA Robotic Manipulator online -- http://www.greypilgrim.com/

In article ,
groddy@iol.ie (Gary Roddy) wrote:
>I'm trying to calculate the force produced when a vehicle, moving at
>constant velocity, strikes a hollow metal tube that is, itself, welded
>between two posts.
I'm not surprised you're having trouble looking it up. It's a tough
problem under real world circumstances. In its simplest and least
realistic form assume no permanent deformation anywhere and that the
energy of elastic deformation of the beam equals the kinetic energy of the
auto. When you run the numbers you'll probably find that the beam
deformation produces yielding and the force is high enough to dent the
automobile. 
The energy approach is correct except that you'll have to assume some
(usually most) of the energy goes into yielding. So figure the ultimate
load of the beam (load to form plastic hinges appropriate to the boundary
conditions and ignore the yielding in the car. The ultimate load in the
beam times the beam deflection plus the little bit of elastic energy at
the beginning of the collision equals the car kinetic energy. That's the
second shot. 
But an estimate of what it takes to crush auto sheet metal or collapse a
bumper, probably shows too much energy involved to ignore. So you estimate
the energy needed to bash the car in and add that to the balance. By now
it's pretty much physics-based guess work, so if you want a better answer
it's time to get into a computer program like DYNA or some such software.
Christopher Wright P.E.    |"They couldn't hit an elephant from
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/subscribers/chrisw

ASME Y14.5M describes concentricity as, "a cylindrical (or spherical) tolerance 
zone whose axis (or center point) coincides with the axis (or center point) of 
the datum feature(s).  The median points of all correspondingly-located elements 
of the feature(s) being controlled, regardless of feature size, must lie within 
the cylindrical (or spherical) tolerance zones."
To verify a concentricity tolerance as described would require that the part be 
loaded into some type of indexing device so that mid points could be derived for 
each random cross-section. (An inspection set-up using opposed indicators could 
also be used) When a number of mid point measurements are made, we would end up 
with a "cloud" of points for the single cross-section, all which must lie within 
the concentricity tolerance zone. We then move on to check another cross-section, 
...and another, .... and another.  
My question is, does anyone ever have a design consideration where we would need 
to verify the location of feature in this manner?  
In my own experiences, I am usually interested in locating the axis of the actual 
mating envelope (i.e.- largest inscribed cylincer for a hole; smallest 
circumscribed cylinder for a pin) or providing a clearance boundary for the 
feature (virtual condition). These would be defined on the drawing using a 
positional tolerance.  Where I have an interest in the feature surface, runout or 
profile typically are used to define the requirements.
In observing numerous inspectors verifying a concentricity tolerance, I have yet 
to see any that verified the tolerance according to the description in ASME 
Y14.5M. Most verify the Full Indicator Movement (FIM) of the feature, which is a 
runout tolerance.  The remainder usually verify the callout as a positional 
tolerance applied on an RFS basis.  I have also yet to see tolerance analysis 
software which correctly analyzes a concentricity tolerance according to the 
Standard.  
Older versions of Y14.5 stated that concentricity is used to control dynamic 
balance for high speed rotating parts.  However, mid-point distribution does not 
ensure dynamic balance since other factors, such as material density, also affect 
balance.  Therefore, the 1994 version removed the reference to dynamic balance.
I would be most interested in hearing from others on their use of a concentricity 
tolerance as defined by ASME Y14.5M-1994.  Do you ever use this tolerance?  If 
so, in what types of applications?  How is it typically verified in your 
inspection shop?  Your comments are appreciated.
Marty Wright

murli srini  wrote:
>Hello folks,
>              I am planning to take my EIT exam and later the PE exam..
>I left school 15 years ago but did manage to keep in touch with books in 
>a small way.  How difficult is EIT exam going to be for guys like me ?
>Did anyone experience this situation before ? 
>    thanx in advance           murli
I took the EIT 17 years after graduating.  I took an EIT/PE 5 month
prep course offered in the Washington DC area, and spent a lot ot time
studying and working the problems.  I passed the EIT first time, and
then took the PE the following year and passed it to.
BTW, the EIT is now a closed book exam.  You can bring nothing into
the exam with you except pencils and a calculator.  You will be given
a handbook with most of the formulas you may need.  I highly recommend
that you purchase this for your studying so you are familiar with how
it is laid out and where specific formulae are.  It costs about $5.
Also, the EIT is converting to SI units.  For me that  was the most
difficult since all my studies were in English units.
Lots of luck,
Bob Van Jones, PE

I don't know if anyone out here has already compiled a list of all the
commercial FEA software for different platforms, but I thought it would be
a good idea to prepare one for everyone's benefit. 
In case no one has already prepared such a list, I would be happy to
prepare one and post it here. Does anyone know of the any FEA software
besides Abaqus, Algor, Ansys, MSC Nastran, and Marc? What are the
prices/seat? What are their features and good/bad points?
Any gurus wanna share their first hand experience w/ different FEA
software?

Follow up question though, 
1. Does anyone REALLY know how the grading is done 
   for the PE? 
   There's a total of 80 points raw, but you need only 48
   raw to pass. Percentage to pass is 70%. But, 48 raw 
   is not 70%, it's ~68%. And to boot, you're never 
   given your raw. They only release your percentage.
   On what is the percentage based? 
   A colleage of mine suspects that in addition to the NCEES 
   grading raw scores, they pass the raw scores out to the 
   states and that the states determine a breakpoint 
   percentage score for passing the PE. 
   Comments?
2. Since there seems to be alot of positive stuff to 
   say about Lindeburg for mechanical. What do others 
   have to say about Yarborough for EE?

In article <19970102150700.KAA14210@ladder01.news.aol.com>,
   rongraham1@aol.com wrote:
>"p3dlab"  previously wrote...
>
>>We are Amsat, The Amateur Radio Satellite Corporation. We are currently
>>doing the final integration of our next spacecraft, Phase 3D.  [...]
>>If you have ever wanted to help build a spacecraft this is your chance.
>>What we need is a computer simulation of our solar array deployment
>system.
>>The requirements are listed below [...]
SNIP
>Let me understand you correctly.  You are asking for the equivalent
>of several hundred hours of engineering effort, with some strong skills,
>and offer NOTHING IN RETURN for it save the ability to "point to a 
>spacecraft?"  With all due respect, you are being silly.
>
>Maybe you have no money.  Then you jolly well had better consider
>other ways you can come to the table with satisfaction for those who
>want to help you, or I'm afraid I can't tell which is worse: that you'd
>get
>no offers at all, or that you'd actually get some.
>
>You might start by offering letters of recommendation and public 
>acknowledgments of help received.
>
>Dr. Ron Graham
>Project Engineer for Robotics, GreyPilgrim LLC, Washington DC
>founder of Usenet newsgroup sci.engr and editor of the sci.engr.* FAQs
>EMMA Robotic Manipulator online -- http://www.greypilgrim.com/
Ron,
I believe these folks are hobbyists; at least there is a similar group of 
people which is composed of hobbyists.  Some people will do the strangest 
things as a hobby.  I know one person who takes unpaid days off work to help 
run motorcycle races, and another who voluntarily ( I think ) maintains the 
sci.engr FAQS :).
It looks like an interesting way to pass the time ( for someone with the 
time! ).
Cheers,
Glenn
glenn.thomson@comdev.ca

I also was in a similar situation a number of years ago. I took a study
course put on by the University of Illinois, and worked in several study
guides. At the time that I took the test, it was important to have a
general background in several disciplines, (don't neglect engineering
economics, and chemistry). The class taught me exactly what to expect from
the exams, and the format used (this is important). With this backgroung I
passed the EIT with ease, and the PE exam at the next opportunity. My only
wish is that I had taken them both in the same session. Hope this helps.
Kevin Brown Robert H. Penoyer (rpenoyer@pacbell.net) wrote: : >Hello
folks, : > I am planning to take my EIT exam and later the PE exam.. : >I
left school 15 years ago but did manage to keep in touch with books in :
>a small way.  How difficult is EIT exam going to be for guys like me ? :
>Did anyone experience this situation before ?  : > thanx in advance murli

For a comprehensive text on this subject, pick up a copy of "Design of
Structures and Foundations for Vibrating Machines" by Suresh Arya, Michael
O'Neill, and George Pincus.  It is published by Gulf Publishing Company,
Houston, Texas, and is/has been available through the McGraw-Hill civil
engineering Book Club.
David Duerr, P.E.
http://members.aol.com/twodm

Anonymous wrote:
> level positions.  The reality is that the supply far outstrips the
> demand.  Maybe if you tried to enter the field 10 or so years ago, you
> might have been able to enter it, and work continuously and successfully
> Sorry, -X
Hmm. That's odd. What's your degree in. I am getting offers on 2/3 of
my interviews, most in the midwest. The headhunters I've talked to 
say that it is the best job market in years.

doug_mckean@paragon-networks.com (Doug) wrote:
> Follow up question though, 
> 1. Does anyone REALLY know how the grading is done 
>    for the PE? 
>    There's a total of 80 points raw, but you need only 48
>    raw to pass. Percentage to pass is 70%. But, 48 raw 
>    is not 70%, it's ~68%. And to boot, you're never 
>    given your raw. They only release your percentage.
>    
>    On what is the percentage based? 
>    A colleage of mine suspects that in addition to the NCEES 
>    grading raw scores, they pass the raw scores out to the 
>    states and that the states determine a breakpoint 
>    percentage score for passing the PE. 
>    Comments?
-----
I think the PE Exam structure is just another Oliver Stone plot.
-----
> 2. Since there seems to be alot of positive stuff to 
>    say about Lindeburg for mechanical. What do others 
>    have to say about Yarborough for EE?
-----
The electrical Pro Pubs books suck!!!!!!  Look into PERC.
--------------
M. H. Lyle, PE
Don't_Spam_Me@I_Hate_Spam.com
"Of course that's just my opinion, I could be wrong."  Dennis Miller

	I'm just starting my second semester as a sophomore at South Dakota School
of Mines and Technology.  I never used to have any trouble in high school,
and even freshman year at SDSM&T; wasn't too bad, but it is definetely
getting harder.  I was wondering what other people have experienced as
their hardest year in engineering school.  I've heard a lot of people say
it's the junior year, but it seems to me that in the junior year is just
when it gets more interesting because you actually start working on things
strongly related to your major, instead of building your knowledge for
later classes with basics (if you can call calculus and physics basics!).  
							Thanks for your responses,
								Joshua Willhite

Samurai929 (samurai929@aol.com) wrote:
: In case no one has already prepared such a list, I would be happy to
: prepare one and post it here. Does anyone know of the any FEA software
: besides Abaqus, Algor, Ansys, MSC Nastran, and Marc?
 lists many more programs, but it's
not "complete".

In article <32CAF095.12B0@pacbell.net>, murli srini  writes:
>Hello folks,
>              I am planning to take my EIT exam and later the PE exam..
>I left school 15 years ago but did manage to keep in touch with books in 
>a small way.  How difficult is EIT exam going to be for guys like me ?
>Did anyone experience this situation before ? 
>    thanx in advance           murli
Good Luck!  After being out of school for 15 years I took the PE test and then took
the EIT test the next day.  That was last October and I'm still waiting for the
results.  The new system for the EIT has you indicate a preferred engineering
field for the questions in the afternoon.  They come in a separate book.  I selected
electrical engineering.  I was surprised at the lack of power questions in the EIT
especially in light of the number of power questions in the PE exam I took the day
before.
I don't know what I would have done without the review class for the EIT.  I hadn't
even thought of chemistry for all those 15 years and would have been lost without the
formal review.  My local library had some good review materials.
Study hard!
Kevin Donahoe
ComEd

>When I sat for the exams in Illinois (quite a few years ago) with the 
>proper number of years experience, and a degree from an accredited 
>university a person could sit for both the Fundementals of Engineering 
>(EIT) and the PE exam in the same session. Obtaining the PE license was 
>dependent on passing both exams. I don't remember if the PE exam was on 
>the first or second day of the session. I do remember as I stated in an 
>earlier post that my regret was not taking both tests at the same time. 
>As a practicing engineer, I found the PE exam much easier than the EIT 
>exam, even though I received the same score on both. I also spent more 
>time preparing for the EIT exam.
>Later
>Kevin Brown
An acquaintence in California told me he also took both exams at the
same time. I don't know if that's still possible.

Sean Tracey wrote:
> 
> randall williams wrote:
> >
> > Is there a source for charts or a program that will
> > give the metric limits and fits from 0 to 3500mm
> > with all the letter and number combinations?
> > Even formulas would be a help or pointers to references
> > where they can be found.
> >
> 
snip
> 
> Machinery's Handbook has all the metric fits with all the letter and
> number combos.  If it doesn't have a particular combo, I think there is
snip
Another source for the limits and fits is :
"Mechanical Engineer's Reference Book", 11th Edition, edited by
A.Parrish, ISBN:0-408-00083-X
Published by Butterworth & Co (They have offices in USA, UK, Australia,
Canada, New Zealand and South Africa)
The information can be found in section 3-33. Page 36 also gives
equation, which, when combined with basic tabular data will allow you to
calculate the values instead of using the tables (but why not use them).
I do agree that if the intent is to provide a drawing to manufacturing,
it is prefferable to give the dimensionnal information (± tolerances) on
the drawing rather than giving a code which needs interpretation and
processing before being usable by the shop floor.
Hope this helps.
Eric Marcotte

At one time (at least in 1978), Maryland allowed people to sit for
both PE and EIT over 2 consecutive days.  Three of my friends did it
that way.  By time I got around to taking my EIT and PE, this was no
longer allowed in Maryland.  I wish it were.  As a matter of fact, the
minimum waiting time between exams is one year, because your
application for PE is due 4 months ahead of time and you must have
passed you EIT.  However, they dont even notify you that you've passed
the EIT until 3 months after the exam.
Bob Van Jones, PE
kdonahoe@ceco.ceco.com (Kevin E. Donahoe) wrote:
>In article <5agumt$s3r@camel0.mindspring.com>, Don't_Spam_Me@I_Hate_Spam.com (M. Lyle, PE) writes:
>>kdonahoe@ceco.ceco.com (Kevin E. Donahoe) wrote:
>>
>>> Good Luck!  After being out of school for 15 years I took the PE test and then took
>>> the EIT test the next day.  That was last October and I'm still waiting for the
>>> results.  The new system for the EIT has you indicate a preferred engineering
>>> field for the questions in the afternoon.  They come in a separate book.  I selected
>>> electrical engineering.  I was surprised at the lack of power questions in the EIT
>>> especially in light of the number of power questions in the PE exam I took the day
>>> before.
>>
>>  (Some snippage)
>>> Kevin Donahoe
>>> ComEd
>>
>I took the exams in Illinois.
>
>On October 25, 1996 I TOOK THE PE EXAM at the Dolton Expo Center in Dolton, Il.  And on
>October 26, 1996 I (along with about 20 of the people from the PE exam) TOOK THE EIT
>EXAM.  This was one of the options offered.
>

Immediate employment opportunities:
Rapid growing Livermore California manufacturer of custom automation
and robotic systems for material handling requirements serving the disk
drive, wafer fab and flat panel display industries is seeking
experienced Machine Designers and Engineers, both Mechanical and
Electrical.  We are also seeking Software Engineers with experience
with one or more of the following: PLC, Adept V+, Borland C++, and PC
Windows applications development.  We offer competitive compensation
and benefit packages as well as a small company atmosphere.  We are
part of a $200M multi-national corporation yet operate completely
autonomous.
E-mail resume to SShifman@afsc.com

Kurt Jaeger wrote:
> 
> Anonymous wrote:
> 
> > level positions.  The reality is that the supply far outstrips the
> > demand.  Maybe if you tried to enter the field 10 or so years ago, you
> > might have been able to enter it, and work continuously and successfully
> 
> > Sorry, -X
> 
> Hmm. That's odd. What's your degree in. I am getting offers on 2/3 of
> my interviews, most in the midwest. The headhunters I've talked to
> say that it is the best job market in years.
I guess I should have gotten my degree in Chemical Engineering, or some
other form of engineering, rather thant a B.S. in Chemistry.  Every one
that I have talked to have acted as if it is no better than flipping
burgers.

bmurray@bbn.com wrote:
> 
> We are looking for accurate method(s) of measuring the moisture content of
> soil which has been compacted.
> 
> The method should be non invasive as far as possible and suitable for in-field
> testing.
> 
> We do not wish to remove a sample for laboratory testing.
> 
> We are looking to buy systems rather than develop them.
> 
> So, two questions
> 
> a) can anyone suggest suitable methods of measurement and
> 
> b) can anyone suggest US manufacturers of suitable equipment?
The most common means for measuring the moisture content of compacted 
soil (at least in my experience) is the nuclear density gauge.  I can't recall 
the theoretical details of how they work but they essentially measure the 
amount of hydrogen in the soil and then correlate this to moisture content.  
The same devices are used to measure soil density.  The devices are only 
useful near the soil surface so measurements must be taken as the fill is 
placed.  They are essentially non-intrusive in that it is only necessary to 
drive a small hole into the soil approximately 12 inches deep.
It is necessary to calibrate readings with other measurements (typically 
oven dried samples are best).   In addition, the measurements can be 
extremely erroneous if there are other sources of hydrogen in the soil (not 
too common of a problem).   Despite there limitations, they are very 
widely used since they are capable of being used to take a large number of 
measurements very quickly (the results are essentially immediate as 
opposed to waiting a day or so to get results for oven dried samples).  If you 
want to do numerous tests with reasonable accuracy, this is the device for 
you.
There are several manufacturers of these devices.  I don't have any direct 
contact information but the "Troxler" gauge comes to mind.  For others you 
might check out some civil engineering or earthwork periodicals for 
advertisements.  You might also post a message to both "sci.engr.civil" and 
"sci.engr.geomechanics".  I'm sure someone there will have more 
information for you.
Hope this helps.
Erik Loehr
> 
> If possible, please e-mail me directly  bmurray@bbn.com
> 
> Thankyou
> 
> Bruce S Murray
> 
> BBN Systems and Technologies
> Cambridge, MA
> 
> 617 873-3356