Subject: Re: Young's Modulus vs. Temperature
From: Vicen=?iso-8859-1?Q?=E7 Marqu=E8?=s
Date: Thu, 19 Sep 1996 19:59:23 -0700
Robert Paynter wrote:
> =
> Does anyone know relationships between Young's Modulus and Temperature
> for typical "Engineering Materials", eg Steel, G.R.P. I'm sure the
> general effect is: "As temperature increases stiffness reduces" but
> can anyone quantify it. I'm not looking for extremes, of stress
> or temperature.
> =
> Any leads will be appreciated
> =
> Robert Paynter
> =
> Dept. Aeronautics, .... ... \_/
> Imperial College, / ( (. ) -.( ).(_)--
> / (...).) ( (.. ).\
> c/o Energy Research Unit ----O=3D< (......)..)\
> Rutherford Lab, Chilton |\ / | \
> DIDCOT, Oxon OX11 0QX -| \ -,-,-,-, |
> United Kingdom ,-,| -,-,-,-, Tel:+44 (0)1235 445304
> email: R.Paynter@rl.ac.uk -,-,-|,-,-,-,-, Fax:+44 (0)1235 446863
Indeed. As T increases, E decreases, but this is just a thumb rule, valid =
for most materials. The particular behaviour of each alloy is a function =
of a number of parameters and needs to be determined experimentally. =
I suggest to take a look at the "Atlas of Stress-Strain curves" published =
by ASM. =
Good luck!
-- =
Vicen=E7 Marqu=E8s - Laboratori General d'Assaigs i Investigacions - LGAI
Subject: Re: Which engineers are more in demand?
From: pjtemes@ix.netcom.com(Peter Temesvary )
Date: 19 Sep 1996 20:27:58 GMT
>
>>Somebody asked:
>> Of mechanical, electrical, and aerospace, which engineer is more in
>> demand? And which would you do if you were interested in all 3?
>>(or all 8 for that matter) Thank-you kindly.
>
>snip
>
>Today, I would advise any engineering student to strive to do much
>more than simply learn engineering. The tunnel-vision perspective
>is a dangerous one, because it prevents one from seeing the complete
>corporate system of which we, engineers, are mere components.
>The engineers that are in greatest demand are the ones who can
>see what their companies need and can adapt to provide it. For
>these, there are always jobs.
:
:The above cannot be stated enough I think.
:
To that end, I would suggest to the student (I presume) that asked the
question: look into undergrad programs which are "general" engineering
(commonly called "Engineering and Applied Science," e.g., at Caltech &
Stanford). You will take a variety of engineering classes covering
everyting from circuits to fluid dynamics, and you can usually tailor
your focus somewhat in your last 1 to 1-1/2 years. There are two huge
advantages to such a course of study: (1) you don't tie yourself into a
certain field before you know if it really interests you or not, and
(2) you have a relatively broad technical background. I did such a
degree at Harvey Mudd College here in L.A.; as a freshman I was
convinced I wanted to go into aerospace, but at the beginning of my
senior year I realized that wasn't for me and "switched" to
environmental engineering, which really didn't amount to much of a
switch except probably dropping a compressible flow class for organic
chemistry. When I went for my Master's, I may not have known as much
as some of my civil engineer classmates about road grading and
excavation shoring, but at least I had a basic concept of things like
wiring design and control logic, which they didn't have.
Good Luck!
Peter Temesvary, P.E.
Santa Monica, CA
Subject: Re: Young's Modulus vs. Temperature
From: "Chris Rogers"
Date: Thu, 19 Sep 1996 20:22:11 GMT
Ken Irving wrote in article
<9127cc$9161c.1e3@PolarNet>...
> In article <51onsq$juu@newton.cc.rl.ac.uk>, R.Paynter@rl.ac.uk says...
> >
> >Does anyone know relationships between Young's Modulus and Temperature
> >for typical "Engineering Materials", eg Steel, G.R.P. I'm sure the
> >general effect is: "As temperature increases stiffness reduces" but
> >can anyone quantify it. I'm not looking for extremes, of stress
> >or temperature.
>
> No, but the thought occurs that you could use such an effect to have a
> structure resist resonating: a forcing function causes some vibration,
> which heats the material, changing the modulus and shifting the resonant
> frequency, reducing the vibration...
>
>
Dream on, dream on!! The change in Young's modulus is insignificant until
well over 100 degrees Centigrade, hence your not having to consider it for
normal design. In addition, the frequencies would have to be so high that
only a few very special structures would be able to benefit from such a
process, and they will have other more important design aspects.
--
==+==+==+==+==+==+=[ http:\\www.cprsys1.demon.co.uk ]+==+==+==+==+==+==+==
Chris Rogers - Technical Director
CR Engineering Analysis & Computing Engineering Solution Providers
cr-ea@cprsys1.demon.co.uk Commited To Excellence
Subject: STEAM-LIST, A Mailing List About Industrial Steam
From: miles@mail.utexas.edu (Miles Abernathy)
Date: Thu, 19 Sep 1996 21:03:42 -0500
The STEAM-LIST is a free e-mail mailing list intended for discussion of
steam generators, piping, boilers, boiler feed pumps, water treatment,
corrosion and scaling, valves, PRV's, traps, turbines, flow metering,
heating coils, condensate pumps, district heating, system modeling, etc.
Practical discussions, rather than theoretical or academic ones, are the
intent of this list.
The list has a membership of about 250, spread all over the world.
To subscribe to the list, send the request
subscribe STEAM-LIST YourFirstName YourLastName
in the body of a mail message to
listproc@mcfeeley.cc.utexas.edu
Railroad steam locomotives are not included in this list.
--
Miles Abernathy, miles@mail.utexas.edu, http://klingon.util.utexas.edu/
Subject: Re: Young's Modulus vs. Temperature
From: Jim Papadopoulos
Date: Fri, 20 Sep 96 01:18:23 -0500
Robert Paynter writes:
>Does anyone know relationships between Young's Modulus and Temperature
>for typical "Engineering Materials", eg Steel, G.R.P. I'm sure the
>general effect is: "As temperature increases stiffness reduces" but
>can anyone quantify it. I'm not looking for extremes, of stress
>or temperature.
>
I suspect it's far more complicated than most
people imagine.
I'm looking at a paper called"the dimensional behaviour of materials"
by L. M. Schetky, and he shows (for example) a complicated
curve for modulus change (of order 5%) for Aluminum,
as a function of working stress.
His table 5 gives "modulus change" over the -50F -- +150F
range, all the (fairly exotic) engineering metals
increased by about 3% to 6%.
I do remember a book on precision mechanisms, where the
author averred that change ov modulus was
at least as important as thermal expansion, for
dimensional stability.
Doesn't "elinvar" show an "S"-shaped
curve of modulus with temp??
Cheers
Jim
Subject: Re: Need heat transfer material
From: Mark Thornton
Date: Fri, 20 Sep 1996 09:32:37 +0100
Wayne S. Hill wrote:
> On 17 Sep 1996 16:18:28 -0400, Jon Wilder (jonwilder@aol.com) said...
> >
> >Searching for a thermally conductive medium to place between a curved
> >aluminum heater and a round stainless steel boiler/chamber. The two are
> >fastened tightly with four stainless steel bands. Hoping to find something
> >with very high thermal conductivity. Would be open to paste, or powder,
> >or sheet forms if anyone knows of something that might be suitable. This
> >substance must survive up to at least 300 C
The Cambridge Materials Selector (see http://www.granta.co.uk
for more details) suggests that you use either
Beryllia or Copper-Zirconium alloys, in sheet form. Apart from
diamond (ruled out for obvious reasons), these look the 2 best
solid materials for your application.
The Copper alloys are cheaper, but look slightly borderline on the
300 C service temp. criterion. Beryllia is more expensive, but will
pass that criterion with ease.
Hope this helps,
Mark Thornton
--
Mark Thornton Tel: +44 1223 332760
Cambridge University Eng. Dept. Fax: +44 1223 332662
Trumpington Street E-mail: mht11@eng.cam.ac.uk
CAMBRIDGE CB2 1PZ, UK
http://www2.eng.cam.ac.uk/~mht11/
Subject: Re: Cost indexes
From: Robert Davis
Date: Fri, 20 Sep 1996 00:18:18 -0700
Richard Mateles wrote:
>
> David Gionet wrote:
>
> > Also, I was wondering where I could get a flowsheet for a typical
> > brewery to better understand the industrial beer making process.
> >
> > Thanks
>
> Flow sheets appear in a number of books, e.g. "Industrial Microbiology"
> by C.G. Dunn; "Industrial Microbiology," A.H. Rose, and others. These
> books are ca. 30 years old, but the general processes haven't changed,
> and some more up-to-date books lack process flow sheets.
>
> Rich Mateles
> --
> Candida Corporation
> Suite A-1706
> 175 W. Jackson Blvd.
> Chicago, IL. 60604
> U.S.A.
Check out the September issue of Chemical Engineering mag, page 45 there
it is.
Later,
Rob
Subject: Re: Tecplot, etc.
From: Polyhedron Software
Date: Fri, 20 Sep 1996 09:28:15 +0100
In article <51sg3m$jf6@itnews.sc.intel.com>, Surinder Singh
writes
>In article <323EFF92.41C6@flow.mit.edu>, Joe Curran
>writes:
>|> Does anyone out there know of a good site for information about
>|> linking Tecplot to Fortran 77 programs, or how to create binary
>
>Hey what is Tecplot ?
>Is it as good as idl ?
>
>
>
>
>|> data files directly by F77 to be read real-time into Tecplot during
>|> a run?
>|> If anyone has any personal information/experience, that would be
>|> appreciated as well.
>|> Thank you.
>|>
>|> Joe Curran
>|> curran@flow.mit.edu
>|> Vortical Flow Research Lab
>|> Massachusetts Institute of Technology
>|> (617) 252-1635
Tecplot is a stand alone data visualization package available from
Polyhedron Software Ltd (Europe) or directly from Amtec Inc 1-800 676
7568 or 206 827 3304 (USA and Canada).
It is particularly good at modeling curvilinear grids and is ideal for
finite element and fluid dynamics problems, as well as graphing and
charting. Version 7 for UNIX has just been released and the Windows
version is due for release soon.
Sue Taylor
--
Sales Dept. Sales@polyhdrn.demon.co.uk
Polyhedron Software Ltd.
Programs for Programmers - QA, Compilers, Graphics
************ Visit our Web site on http://www.polyhedron.co.uk/ ************
Subject: Re: Human Powered Vehicles - looking for a news group
From: Doug Milliken
Date: Mon, 16 Sep 1996 04:43:13 GMT
Hi,
On 15 Sep 1996, cruberg wrote:
> I'm interested in human powered vehicles (planes, bikes, cars, etc).
> Are there any active groups on this topic...thanks in advance..Chris.
Check out the International Human Powered Vehicle Assn. web site:
http://www.ihpva.com , or some such address (search on the web
if my memory is wrong)
This should tell you how to join the hpv mail-list which I believe is
carried as part of the "cyclery.com" group.
The signal-to-noise ratio may be poor, since we (I'm an ex-IHPVA officer)
are undergoing management problems at this time... which is why I'm not
signed-on to the newsgroup.
You can also check on rec.bicycles.tech which has some good contributors.
-- Doug
Subject: Re: PE Liability
From: Eric Mieczkowski
Date: Fri, 20 Sep 1996 09:16:16 -0700
pvincent@execpc.com wrote:
>
> < SNIP >
>
> You are held personally responsible for any errors that occurs in your work
> or that done under your supervision, _if you sign the plans as the registered
> engineer in charge of the work_.
>
Does this hold true for an engineer working withing a corporation, or just an
independant consultant? In other words, if I sign of on a design at my
employer and that design fails catastrophically and injures someone, who will be named
in the lawsuit my employer, myself, or both? And would that be any different if I did
not hold a PE?
>
> < SNIP >
>
> What this boils down to is: If you want to do consulting work, get it.
> Consultants tend to work in fields which require PE's. If not, in my
> experience, it's not a requirement. In my case, I don't need it, don't use it,
> but I am proud to have "P.E." after my signiture on the letters I send.
> It may (and I mean _may_) be worth a buck or two if you are job seeking.
>
> < SNIP >
Yup. I'm pursuing registration for the same reasons. I do not have a perticular
"NEED" for it right now. Perhaps some day I will get involved in consulting, but not
for at leas several years. I just want the satisfaction of the achievement and
recognition.
Thanks for the reply,
Eric Mieczkowski
Subject: Re: high pressure coolant retrofit
From: klwasson@aol.com (Klwasson)
Date: 20 Sep 1996 09:35:19 -0400
>Does anyone have any info on retrofitting high pressure coolant systems
>on Mazak HMC's? I'd like to get to approx 1000 - 1500 psi on a H630
>machining center. Any vendor info, personal experience or suggestions
>would be greatly appreciated.
>TIA
>--
>Joe Smolen - Tooling
>Engineer
>Plesh Industries, Inc.
>One River Rock Drive
>Buffalo, NY 14207
>(716)873-4916 voice
>(716)876-8370 fax
That's a good question. It is hard to find good pumps that can handle
1,000-1500 psi of coolant at rates over 10 gpm. Oil is easy because it
has a lubricity, but coolant doesn't. Piston pumps (sold to car washes)
are inexpensive and can handle the requirement, but they are
overwhelmingly loud. They also have substantial pressure pulsations.
Gear pumps wear out. The lubricity problem.
We recently tried a screw pump sold by Knoll, a German company. It was
designed for oil, but they said coolant is no problem. Uh uh. It
vibrated itself to death within an hour. They said it must have been our
fault (!) and refuse to give our money back. They sent us a smaller
version and although it is working it is also loud. There are just
sliding contact bushings in there, so it is no wonder.
If you find a good high-pressure coolant pump that is inexpensive and
quiet please give me an email (klwasson@aol.com), I would appreciate it.
I'll do the same.