Subject: Re: FEA theory needed for FEA software?
From: rizzo@hogpb.ho.att.com (-A.RIZZO)
Date: 8 Dec 1996 03:51:10 GMT
In article <58ca42$1l9@hermes.louisville.edu>,
James M. Scherer wrote:
>
...
>
>How much can you trust this new software to apply the best element to the
>given problem? Can the software tell what accuracy to expect for a given
>problem and will it let the user know?
>
>Mitch
Mitch makes some very good points. His thinking has triggered some
interesting thoughts of my own. I'd like to post them here, for
your consideration.
If (100) the deliberate solution of an engineering problem
requires that the engineering problem be understood,
and if (110) no software can understand anything,
then (120) no software can deliberately solve an engineering problem.
I doubt that anyone is willing to dispute the existence of entity (100).
If anyone is, please let me know. In any case, the key entity is (110).
If we can prove that no software can understand anything,
then the logic cluster is valid.
The entity, "(130) at least one piece of software can understand
one thing," is mutually exclusive with entity (110). Let's assume
that (130) is valid.
If (130) is valid, then we should be able to observe one or more
effects caused by the existence of (130). For example, if
even one piece of software understands even one thing, then we
might expect to see an article or a paper describing the event.
Is anyone aware of such a paper? Is there any evidence that
even one piece of software has ever understood anything?
If we can find no evidence, then we are forced to conclude that
the entity, "(130) at least one piece of software can
understand one thing," does not exist.
If (130) and (110) are mutually exclusive, and if (130) does
not exist, then (110) must exist.
If we accept (100), and if (110) exists, then we must conclude
that no software can deliberately solve an engineering problem.
So why do we keep chasing this golden fleece?
Tony Rizzo
Subject: Advise Urgently Needed! - Portable Multi-Stage Centrifugal Fan/Blower (Mining)
From: Schalk van Niekerk
Date: Mon, 09 Dec 1996 12:47:07 +0200
Background
We have designed a basic single-stage fan for the mining industry
for the purposes of compacting explosives into its blast-hole
The blower/fan operates as follows:
1. Fan generates compressed air of approx. 20kPa (Static)
2. Conveys air through a 3/4" hose, 3 meters in length (12ft)
3. Explosives in the form of furtilizer is then fed into the
hose via a measuring flask
4. The air/fertilizer mix travels 1.5 meters (6ft) through
the hose into the blast-hole
Current Specifications:
Type: Single Stage Fan
Fan Blade Detail: Vane Type with Backing Plate
on one side
Fan speed: 30 000 RPM
Fan Blade Outside Diameter: 145 mm
Static Pressure: 20 kPa
Capacity: 70 CFM
Compressed Air Temperature: 50 Degrees Celsius
(High, but Acceptable Temp)
Needs
There has been a further need for a stronger fan/blower to cope with
the following minimum requirement:
Extension of hose from 1.5 meter (6ft) 3/4",
to 20 meters (60 ft) 3/4" through which mix has to flow
New Specifications:
Type: Multi Stage Fan
Fan speed: 30 000 RPM
Fan Blade Outside Diameter: 145 mm (1st Stage)
Static Pressure: 60 kPa (last stage output)
Capacity: 70 CFM
Compressed Air Temperature: Max. 50 Degrees Celsius
(High, but Acceptable Temp)
Ambient Temp 20 Degrees Celcius
Air Density @ 1000 meters above sea-level
Current Status:
We have developed a 2nd Stage fan/blower and currently have the
following problem:
- After the 1st Stage, no increase in pressure
(20 kPa before/after 2nd Stage)
The stages after 1st Stage need to be re-designed in order to achieve
our objective
Please inform or provide information regarding this problem, or how
you could assist solving this problem
Thank you
Regards
Andre Swart
Hydro Power Engineering
PO Box 1148
Honeydew
2040
Republic of South Africa
Tel +2711 462-1903
Fax +2711 462-7156
Subject: FS Chiller Analysis Manual
From: heatscan@kalama.com (Gerhard N. Thoen)
Date: 8 Dec 96 17:29:12 GMT
Our new manual shows how to set up an analysis program using vibration,
infrared thermography and ultrasonic analysis as well as spectrographic
oil analysis on Chillers and Heat Pumps while they are operating. Several
actual examples are presented with accompaning data/reports. This is a
real "How to" book written in standard, simple terms and should be a must
for those operating or maintanining Chillers and Heat Pumps.
^^^^
How to Analyze Chillers/Heat Pumps Manual
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Table of Contents-
NEED FOR ANALYSIS
Equipment -Types/Systems
Service
Cost of outages/collateral damages
Cost of replacement
NON DESTRUCTIVE TESTING(NDT)
Vibration
Axes of measurements
Ultrasonics
Leaks-air/refrigerant
Infrared Thermography
Heat losses
Electrical systems
COMPUTER ANALYSIS
Mass/Energy Balance/Performance
Spread Sheets
Data Collection/entry
MAINTENENACE SCHEDULES/COSTS
TROUBLESHOOTING SYSTEMS
APPENDIX-Actual cases/results
REFERENCES
Comes in a 3 ring notebook,61 pages-Drawings, Photographs, Charts, Tables
Cost is $65 + $3.80 S/H USA
Information at E mail: heatscan@kalama.com
Tele: 360 423-7167
Subject: communications protocols for process analyzers
From: 7397@mne.net (Mark Weiss)
Date: Mon, 9 Dec 1996 12:18:16 GMT
I am writing an article on process analyzer communications.
The focus of the article is communications between the
analytical instrument (process GCs, mass specs, photodiode
array, FT IR, etc.,), the analyzer data, the plantwide data
highway, system, and the process control computers.
Whether you are a vendor or user, could you share your
experiences with the magazine's readers by answering the
questions below?
1. What is the problem with analyzer communications right
now?
2. How is the analyzer communications issue relate to
standard analyzer outputs, ie, analytical signal and signals
related to instrument operation?
3. What different communications protocols are out there?
4. Why are they different? Is there a standard?
5. What do these protocols do/attemtpt to do?
6. Why choose one over the other?
7. What kinds of devices are necessary to utilize these
protocols?
8. What kinds of analyzers can be interfaced to these
devices?
9. What kinds of output do these devices accept from the
analyzer?
10. What kind of output do they transmit and to where?
11. What benefits can users expect for each
device/protocol? ie, cost savings (where, how), increased
efficiency (where,),better/more accurate data, better
maintenance/uptime,
make something easy to use, other reasons?
12. Are these devices suited for any kind of analyzer, ie,
smart analyzers (with some sort of intelligence like smart
transmitters, self-diagnostics, etc) as opposed to just a
sensor that just provides a reading and that's it?
13. Are these devices replacing older devices or being used
in conjuction with major system upgrades?
14. What are the computing requirements for using t hese
devices, ie, PC/Mac, Unix, or some othe proprietary
architecture?
15. Are these devices/protocols plug and play?
16. Who is using? Names and phone numbers? (Please
provide your name phone and fax numbers, corporate
affiliation, and title so I can contact for more information
or if I have questions. Please let me know if I can quote
you, too.
Thanks for your help.
Mark Weiss
Subject: Research Experience for Undergrads in Nanostructured Materials
From: cmrareu@unlinfo.unl.edu (diandra pelecky)
Date: 9 Dec 1996 13:39:04 GMT
The University of Nebraska is offering a Research Experience for
Undergraduates in Nanostructured Materials Program for summer 1995.
This is an interdisciplinary program involving students in physics,
chemistry, materials science, and chemical, electrical and mechanical
engineering. To be eligible for the program, you must:
1) be a junior or senior in fall, 1997
2) be enrolled in a program leading to a bachelor's degree in a
science or engineering, but not have received a bachelor's degree in
any field
3) be a U.S. citizen or permanent resident.
(NSF's rules)
The program includes a $2800 stipend, room and board, and travel
expenses. For information and an application form, write:
REU Program in Nanostructured Materials
c/o Center for Materials Research and Analysis
University of Nebraska
Lincoln, NE 68588-0113
cmrareu@unlinfo.unl.edu
or see our web site at http://www.unl.edu/physics/REU/reu.html, which
has an on-line form to request an application
Dr. Diandra Leslie-Pelecky
Assistant Professor of Physics
Subject: Re: FEA theory needed for FEA software?
From: trimech@aol.com
Date: 9 Dec 1996 13:51:48 GMT
The FEA world is about to make a major turn-about. A new field is being
broken off from FEA - the new field is DESIGN ANALYSIS. It's basically
Finite Element for those without a PhD. I just received a Beta version of
Cosmos/Works 2.0, the new program from Structural Research & Analysis Corp
(makers of Cosmos/M) designed to run completely inside of SolidWorks 3D
design.
I was completely floored when I saw this, design analysis with
Cosmos/Works is completely pushbutton. The program was written so that
the engineer, at any point in the design, can run a quick analysis on
parts or assemblies without exporting anything, without starting any other
programs, just go down the menu or use their graphical interface to mesh,
add boundaries/loads, and run.
I don't want to ramble on and on about the implications of this, but now
analysis is a part of the design process, totally seamless, with no time
or $$ penalty!! If anyone wants any more details, you can send me e-mail.
Paul Gimbel
Tri-Mech Solutions, Inc.
Subject: Good Technical Books?
From: Christian_Campbell@brown.edu (Christian Campbell)
Date: 9 Dec 1996 14:17:35 GMT
I am a buyer of technical books at Brown University. So, I thought I'd go
to the people who read these books to find out which books are "must
have's!" If you have any suggestions, please e-mail me. I am
particularly interested in recent non-computer titles, but I also stock a
number of technical classics.
Thank you,
--
Christian Eric Campbell
Buyer, Technical Books & Custom Publishing
phone(401)863-2023 fax(401)863-2233
Subject: Re: Ultrasonic Flaw Testing of Materials
From: cmw
Date: Mon, 9 Dec 1996 15:43:52 GMT
lbliao wrote:
>
> I am looking for help on equipment needed for ultrasonic testing, or
> ultrasonic nanoscopes from those who currently have access to such an
> equipment, own it, or have used it.
>
> Thanks a lot!
> lbliao
You may wish to consider several resources.
NDT link (from American Society of Non-destructive testing) has many
useful links relating to ultrasonic inspection. The URL is:
http://www.asnt.org
Another excellent "European" site is:
http://www.ultrasonic.de
Also, there is a much more appropriate newsgroup for this topic
available. In the USE (english) collection it is:
sci.techniques.testing.nondestructive
Also, I have considerable experience with "immersion" flaw detection
practices and equipment and vendors. If you want to chat about it
E-mail me your phone number at cmw@cmwinc.com.
Hope this helps
James Woodruff
Materials Engineer
visit our web site at:
http://www.cmwinc.com/cmw
Subject: Re: Need Source for Alloy C276 Valves and Fittings
From: mgibbons@gpss.com
Date: Mon, 09 Dec 1996 09:38:04 -0500
Greetings Dr. Kane,
Great Plains Stainless, Inc. (Tulsa) is unable to help, but please try
the following C276 sources:
Noble Alloy Valve (Houston) - 800.688.4893
Corralloy (Houston) - 800.262.5569
Corrosion Materials (Baton Rouge) - 800-535-8032
Very Best Regards,
Steven D. Buck
Great Plains Stainless, Inc.
Pipe, fittings, and flanges
(309, 310, 317L, 321, 347, 410 446-2, N08904(904L), S31803(2205))
Tulsa, OK - Perth, Western Australia
800.345.5757
Subject: Re: FEA theory needed for FEA software?
From: "Steven D. Wix"
Date: Mon, 09 Dec 1996 09:17:43 -0700
george wrote:
>
> :it is possible to do FEA analysis with existing software, without ever
> :having studied FE theory, because it is never used as such in the actual
> :analysis and the software does everything. But I'm convinced that you do
> :need some knowledge of what you're doing in order to do the right choices.
> ^^^^^^^^^^^^^^
> some knowlege seems right. It seems that if you came at the subject
> in the right way you could learn the essentials needed for running
> a canned package without knowing much at all about the core theories
> involved.
How does one know if the results are actual or from some artifact within
the code? It seems that a user needs to know a little about the subject
material before one goes charging into an analysis problem. Also, with
all of the packages, the user needs to apply boundary conditions, and
without some experience and knowledge in the analysis area, the boundary
conditions can be applied incorrectly. Then there is the question of
convergence and has the user really gotten an accurate solution or some
divergent artifact of a numerical instability. There is also the choice
of elements in a finite element analysis, like, for example, do I use
triangular elements or quadrilateral elements? Without some FEA theory,
the user would not know that triangular elements can, in some cases,
cause the matrix to be too stiff and cause inaccuracies in the results.
______________________________________________
Steven D. Wix Sandia National Laboratories
505-844-0778
sdwix@sandia.gov
" If you build it, he will come"
______________________________________________
Subject: Flow loss past coupling.
From: Paul Skoczylas
Date: Mon, 09 Dec 1996 11:08:20 -0700
A rod is run through a length of vertical pipe. The rod is not
continuous, but is in discrete sections which are attached together with
couplings which have a larger outside diameter than the rod itself. The
difference in the diameters of the rod and coupling are significant
relative to the pipe's internal diameter.
| | | |
| | | |
| | | |
| | | |
| - - |
| | | |
| | | |
| | | |
| - - |
| | | |
| | | |
| | | |
| | | |
Fluid flows vertically upward in the annular space between the pipe wall
and the rod/coupling. The fluid can range from water (1 cp) to very
viscous fluids (>8000 cp, possibly up to 100,000 cp). What we need to
calculate is:
1. The flow loss (pressure loss) past the coupling. Flow rates are
such that the flow will always be laminar (esp. with viscous fluids).
Right now we are not considering the effects of the change in diameters,
but rather are considering the loss in an annulus of the length of the
coupling. This may or may not be a good approximation. Any
suggestions?
2. The axial force on the rod caused by fluid flowing past the
coupling. Right now we are only using the estimated differential
pressure across the coupling multiplied by the difference in
cross-sectional areas of the rod and coupling. There is presumably some
drag effects, by the flow along the surface of the coupling, plus some
effects caused by the change in direction of the fluid to get around the
coupling, plus the fact there is probably a low pressure wake behind the
coupling. Does anyone have some suggestions for calculating these
effects?
Thanks!
-Paul
Subject: Re: Good Technical Books?
From: "Michael Lindeburg, PE"
Date: Mon, 09 Dec 1996 11:31:00 -0800
Dear Christian -
At the university level, books for the FE (formerly E-I-T) exam are
always popular. In fact, many univ. libraries won't circulate them
because they "walk".
Of course, I'd love to see you buy one of the books I've written,
but there are others out there, as well.
I don't think books for the PE exam are necessary in your collection,
unless you were getting them for professors.
How else can I help?
--
Michael Lindeburg, PE, Publisher
Professional Publications, Inc., http://www.ppi2pass.com
(415) 593-9119 ext. 23
"Your comments, suggestions, and (ugh!) criticisms are always welcome."
Subject: Re: Good Technical Books?
From: blosskf@apci.com (Karl F. Bloss)
Date: Mon, 09 Dec 1996 20:01:14 GMT
Christian_Campbell@brown.edu (Christian Campbell) wrote:
>I am a buyer of technical books at Brown University. So, I thought I'd go
>to the people who read these books to find out which books are "must
>have's!" If you have any suggestions, please e-mail me. I am
>particularly interested in recent non-computer titles, but I also stock a
>number of technical classics.
Here's a start, IMHO, for Chem E topics:
* CRC Handbook of Chemistry and Physics
* Merck Index
* Perry's Chemical Engineers' Handbook
* McCabe & Smith "Unit Operations of Chermical Engineering"
* Luyben "Process Modeling Simulation and Control for Chemical
Engineers" (BTW, I hear that Luyben and son have a new book... is that
out yet?)
* Numerical Recipes in C/FORTRAN
* Bird, Stewart, & Lightfoot "Transport Phenomena"
As far as Thermo, I have Balzhiser, but I didn't really like it. I
hear Smith and VanNess is better.
-Karl
+=========================================+
| Karl F. Bloss, Sr. Systems Engineer |
| Air Products & Chemicals, Inc. |
| blosskf@ttown.apci.com |
| http://www.airproducts.com/ |
| PGP key: http://wwww.enter.net/~bloss |
+=========================================+
#include
Subject: Re: Good Technical Books?
From: Jerry Bukley
Date: Mon, 09 Dec 1996 14:27:32 -0600
Christian Campbell wrote:
>
> I am a buyer of technical books at Brown University. So, I thought
> I'd go to the people who read these books to find out which books
> are "must have's!" If you have any suggestions, please e-mail me.
> I am particularly interested in recent non-computer titles, but I
> also stock a number of technical classics.
In astrodynamics I really enjoy using "Fundamentals of Astrodynamics" by
Bate, Mueller and White. This is an excellent soft cover book. For
designing satellite missions try "Space Mission Analysis and Design" by
Wertz and Larson. For the numerical analysis I really use "Numberical
Recipes in FORTRAN (or C, or Pascal)" by Press, Teukolsky, Vetterling
and Flannery. Recently I have read criticism about some of the
algorithms presented in this book. Usually for not being the most
robust or the best answer for specific cases. However, in general I
believe it is an excellent book. The authors explain the theory and the
basis for their selection and provide ample other references if the user
needs further guidance.
Jerry Bukley
jwbukley@tasc.com
Subject: US-Midwest-Director Tech Transfer & Business Dev-Analytical Instrumentation
From: "Adam Zak"
Date: 9 Dec 1996 21:14:39 GMT
Position Description
Director, Technology & New Business Development
Analytical Instrumentation Products
Company Background
Our client is a highly successful international manufacturer of sensory
instrumentation products utilized for measurement in all types of liquid
process applications. These products, recognized world-wide for
outstanding performance and reliability, employ state-of-the-art
electrochemical and optical sensing technologies, coupled with high-quality
electronic instrumentation (microprocessor-based with embedded software).
The company, a subsidiary of a well-respected international technology
organization, is located in modern research & manufacturing facilities in a
major Midwestern metro area.
Position
The Director of Technology & New Business Development will provide
leadership and direction to the company's engineering resources in the
areas of new product development, manufacturing engineering and applied
research. Primary disciplines involved are electronic, software,
mechanical and sensor engineering. The Director chairs the New Product
Committee (NPC) and coordinates, with the International Marketing
Director, the planning and execution of global product development. The
Director will also fulfill the strategic business development function, and
in this capacity will seek out and investigate other potential sources of
new business: acquisitions, partnerships, strategic alliances, etc. The
Director will manage a Technology Department of 35 individuals (full
budgetary and capital spending responsibility) and will also manage
contract development activities with outside vendors. Reports to company
President.
Requirements
We seek a highly motivated, creative and entrepreneurial individual, with
outstanding technical expertise in analytical/sensory instrumentation.
Ideal candidate will be hands-on, with demonstrated track record of getting
things done, an individual who can translate ideas into profitable,
value-added business initiatives. Must have: outstanding interpersonal and
communications skills; strong understanding of electronics, mechanics &
software (and progressive utilization of current technologies in these
areas); strong project management skills; expertise in managing a
concurrent, team-based cradle-to-grave engineering environment
(development, production, QA); and, a decision-making style that
effectively balances the need for speedy execution against highest quality
standards. Candidate will also be sensitive to budgetary issues,
intimately familiar with TQM philosophies and ISO 9001 certification, and
the CIP processes involved. Minimum BSEE, BSME, BSChE or BS software
development required.
Compensation
Package includes base salary, bonus, benefits. Moving & relocation as
appropriate.
If responding via e-mail, please incorporate resume into your message using
ASCII characters only. Please e-mail to azak@Executive-Search.com for
prompt reply.
--
Adams & Associates International
Executive Search Consultants
463-D W. Russell St.
Barrington (Chicago) IL 60010 USA
847-304-5300 FAX 847-381-2215
Internet: azak@Executive-Search.com
(use for reply -ASCII only- to all postings)
Subject: US-Midwest VP & General Manager, Industrial Factory Automation Product Mfg.
From: "Adam Zak"
Date: 9 Dec 1996 21:31:10 GMT
Position Description
Vice President & General Manager
Factory Automation Products & Components
Company
Our client is a highly successful manufacturer of engineered industrial
products which are utilized in manufacturing, assembly & test, and
material handling environments. The company serves customers world-wide in
a number of diverse markets, among them the machine tool, automotive,
electronics and telecommunications industries. The company is highly
successful because of it's unique marketing approach, investment in and
application of leading-edge technologies, and strong commitment to
delivering a total quality solution. Sales volume is between $50 - $60
million annually and the company is well-positioned for continued growth
from this excellent foundation.
Position
The individual we seek for the position of Vice President & General Manager
will have full responsibility for the company's P&L.; He will continue to
develop the company's strategic direction and will implement his strategies
through the effective management of people, technology and financial
resources at his disposal. The company employs under 200 total staff;
direct reports include the individuals responsible for engineering,
manufacturing, sales, marketing, financial and personnel functions. The
Vice President & General Manager reports to the company's President & CEO;
attractive central Michigan resort area location.
Requirements
We seek a highly motivated, creative general manager with the ability to
innovate, motivate and lead. Our ideal candidate will be a hands-on
individual with a demonstrated track record of getting things done in a
complex engineered product, manufacturing environment. Previous industry
background should ideally include electrical or mechanical products and
well-rounded experience in all functional areas. Our VP & GM must be
equally effective at managing sensitive customer negotiations, nurturing
vendor partnerships, and building those inter-departmental bridges
critical to improved productivity, quality and profitability. Our
candidate will be intimately familiar with TQM/CIP philosophies, ISO 9001,
team-building and self-directed work group processes, and the application
of advanced management technologies to engineering, manufacturing and sales
functions. Excellent analytical and organizational skills are a must, as
are solid communications and leadership abilities. Since the company
sells its products through multiple distribution channels, strong
experience in managing a direct sales force and distributor organizations
is important. Due to the company's continually increasing emphasis on
international markets, previous international experience and Western
European language skills are a strong plus. Minimum BSME or BSEE required;
MBA a plus.
Compensation
Excellent, performance-based, compensation package; comprehensive employee
benefits.
If replying via e-mail please incorporate resume into your message using
ASCII text only. Please reply to azak@Executive-Search.com only.
--
Adam Zak, Managing Director
Adams & Associates International
Executive Search Consultants
463-D W. Russell St.
Barrington (Chicago) IL 60010 USA
847-304-5300 FAX 847-381-2215
Internet: azak@Executive-Search.com
(use for reply - ASCII only)
Subject: Re: Slipping Hub on Shaft!!!
From: Glenn Capone
Date: Mon, 09 Dec 1996 17:10:00 -0500
What are the materials of the impeller hub and shaft? Check the Youngs
Modulus for both materials and treat the hub as a thick walled cylinder,
ie; the interference will be the result of the difference between the
decrease in the shaft diameter, and the increase in the hub diameter.
Then check to make sure that the stresses in both are less than the
proportional limit of their respective materials.
Good Luck,
Glenn Capone
Jon Kerr wrote:
>
> We are struggling with a design of a water pump hub which is pushed onto a
> shaft with an interference fit. The hub is then torque tested to 50Nm. If
> it slips, it fails.
>
> After running fine for 5 years we have suddenly had a slippage problem.
> Even hub made especially undersize slip. I am trying to get to the bottom
> of the mechanism in this assembly. I assume it is related to coefficient of
> friction and force between the two parts. Are there any other factors
> involved? What about hardness, Youngs modulus, surface finish etc.
>
> Any help would be appreciated.
>
> Thanks
> Jon Kerr
Subject: Re: Good Technical Books?
From: Glenn Capone
Date: Mon, 09 Dec 1996 17:19:49 -0500
On my desk you will find;
Mechanical Engineers Handbook, aka "Marks", Beaumeister/McGraw-Hill
Standard Handbook of Machine Design, Shigley&Micshke;/McGraw-Hill
Roark's Formulas for Stress and Strain, Young/McGraw-Hill
Mechanical Engineering Design, Shigley&Mischke;/McGraw-Hill
Design of Machine Elements, Spotts/Prentice-Hall
Christian Campbell wrote:
>
> I am a buyer of technical books at Brown University. So, I thought I'd go
> to the people who read these books to find out which books are "must
> have's!" If you have any suggestions, please e-mail me. I am
> particularly interested in recent non-computer titles, but I also stock a
> number of technical classics.
>
> Thank you,
>
> --
> Christian Eric Campbell
> Buyer, Technical Books & Custom Publishing
> phone(401)863-2023 fax(401)863-2233
Subject: Re: toothpick bridge
From: Ron Williams
Date: 9 Dec 1996 16:19:05 -0800
Dan Evens wrote:
> David W.Fisher wrote:
> >
> > I'm a high school Physics student in search of information concerning
> > the design/specifications for building a "toothpick" bridge. Does anyone
> > have expertise or advise on the process?
We've been hosting a toothpick bridge competition at Moorhead State University
for the last 23 years. It's a joint effort with the FM Engineers Club - local
chapter of NSPE, and is usually held the Thursday of E-week.
We set constriants on the minimum span (currently 56 cm) and maximum mass (now
85 grams). The students can use only round wooden toothpicks and white glue
(like Elmers) or woodworking glue. The students place their bridge in a test
frame that provides abutment support, and then place 9" lead weights on the top
until failure. We judge the winner based on "capacity" - mass supported before
failure/mass of the bridge.
Since the load is applied at the top of the structure, rather than on a traffic
deck, and the weights stack up on top rather than being suspended below, as
in other competitions, one major concern is providing a flat, level surface to
support the weights. An out-of-level stack soon tips, and when the bridge leans
over, all the load is carried on one side.
We've considered changing our process, but the students seem to get a kick out
of watching the toothpicks fly. A simpler, and more realistic design problem
might be to define a minimum load to be carried - 20, 50, or 100 lbs. (Yes, our
bridges often carry 100 lbs - the strogest I've seen held over 300 lbs). The
winner would be the lightest bridge to carry the design load without failing.
As for design, most of our bridges are made up of pairs of trusses set one or
two toothpicks apart. Many of the more successful bridges use built-up members
with overlapping glue joints. Some have built up columns the diameter of
pencils by gluing toothpicks side-by-side. One side note - we don't let them
trim off the toothpicks, or fray the ends to get better glue contact, except at
the top, where they must support the load, and at the ends to meet the
abutments.
If you'd like to know more, please post or e-mail
Ron Williams
Director, Pre-engineering
Moorhead State University
Moorhead, MN 56563
Subject: Re: Slipping Hub on Shaft!!!
From: hobdbcgv@aol.com
Date: 10 Dec 1996 02:19:11 GMT
I had a similar problem a few years ago, I think it was a steel brake
face. Drove me nuts-checked everything-load, unloader, calc'ed mass
moments and frictions and fits ad nauseum. Went three sizes bigger on the
brakes.
Turns out my hot rolled had been subbed with cold-rolled, and even
though the surfaces were machined, it appeared that the lube from cold
rolling had penetrated deep enough that we were not machining it off. So
I baked the lot.
That group worked just fine after that. Purchasing returned to hot
rolled, and the problem no longer appeared.
Good luck, and let me know what you find.
Subject: Re: What's in a Job Title ?
From: "G. Shane J. Lafreniere"
Date: Mon, 09 Dec 1996 20:03:23 -0500
Nägel wrote:
>
> John H. wrote:
>
> > One who does Drafting via CAD is a CAD Technician. A person on a
> > Survey Crew is a Survey Crewman (composed of an Instrument man, a
> > Rodman and sometimes a Chainman - NOTE: replace person in place of
> > MAN to be politically correct!)
>
> I don't like the sound of technician, it makes me feel like I have a
> headset on and saying "can I take your order, and would you like me to
> include our free catalog" I've also heard the term CAD Operator but
> that's even worse.
>
> Looking at my collage diploma (which was only a 2 year course) it
> clearnly states "Commercial Engineer". I've been calling myself that
> for years and nobody has gave me a hard time about it,...... yet....
Nagel,
Well, good thing you not in Ontario, Canada, or any other province for
that matter.
Within Canada, it is a provincial and federal offence to use the term
'engineer' in your job title unless you are a licenced practioner.
Canada passed the Professional Engineers Act in 1990, and along with the
Ritual Calling of an Engineer, (if you notice a Canadian engineer with a
battered Iron ring on their working hand...) the job title, whether
working for a company, or on your own private business card will not
allow you or your company to use those terms.
As well, being a self-governing, self regulated (within provincial
boundaries), there are also different levels of 'Service' or licences
that can be obtained. These range from a Temp Licence, to a "Consulting
Engineer" title.
There is a rather lengthy, formal process to be followed to obtain a
licence (which I'm currently doing) and be able to practice within
Canada as a Professional Engineer.
With this extra work, comes extra responsibility. All practicing
Engineers have special Certificates and Liability insurance either at
the personal level, or at the employer-company level.
Hence, not only can a skilled person who may do a similiar job in
Canada NOT use an Engineering title, but those who do need special
Licences to practice.
Subject: Re: FEA theory needed for FEA software?
From: Julie Hofer
Date: Mon, 09 Dec 1996 23:24:46 +0000
-A.RIZZO wrote:
>
> In article <58ca42$1l9@hermes.louisville.edu>,
> James M. Scherer wrote:
> >
> ...
> >
> >How much can you trust this new software to apply the best element to the
> >given problem? Can the software tell what accuracy to expect for a given
> >problem and will it let the user know?
> >
> >Mitch
>
> Mitch makes some very good points. His thinking has triggered some
> interesting thoughts of my own. I'd like to post them here, for
> your consideration.
>
> If (100) the deliberate solution of an engineering problem
> requires that the engineering problem be understood,
>
> and if (110) no software can understand anything,
>
> then (120) no software can deliberately solve an engineering problem.
>
> I doubt that anyone is willing to dispute the existence of entity (100).
> If anyone is, please let me know. In any case, the key entity is (110).
> If we can prove that no software can understand anything,
> then the logic cluster is valid.
>
> The entity, "(130) at least one piece of software can understand
> one thing," is mutually exclusive with entity (110). Let's assume
> that (130) is valid.
>
> If (130) is valid, then we should be able to observe one or more
> effects caused by the existence of (130). For example, if
> even one piece of software understands even one thing, then we
> might expect to see an article or a paper describing the event.
> Is anyone aware of such a paper? Is there any evidence that
> even one piece of software has ever understood anything?
>
> If we can find no evidence, then we are forced to conclude that
> the entity, "(130) at least one piece of software can
> understand one thing," does not exist.
>
> If (130) and (110) are mutually exclusive, and if (130) does
> not exist, then (110) must exist.
>
This does not logically follow by my definition of mutually exclusive.
It is possible that (110) exists or that neither (110) or (130) exist.
That said, I agree with Tony's conclusion that an engineer must
understand and interpret a problem for the analysis software before
the software may be employed to aid in the solution of a problem.
> If we accept (100), and if (110) exists, then we must conclude
> that no software can deliberately solve an engineering problem.
>
> So why do we keep chasing this golden fleece?
>
My guess is that many managers and engineers do not look at the whole
process of solving an engineering problem; instead they focus on the
tools and processes of analysis. It is only when one looks at the
bigger picture, that of how to solve an engineering problem, that one
can readily see that software alone is insufficient.
> Tony Rizzo
Douglas Hofer
hoferja@digital.net
Subject: Re: In automobiles...
From: inet@intellisys.net (brian whatcott)
Date: 10 Dec 1996 02:58:43 GMT
>On Tue, 3 Dec 1996, Assefa A. wrote:
>
>> regarding vehicle suspension. ... what mechanical member is
>> supposed to transmit lateral and
>> longuitudinal forces between the body and the axles?...
Racing & Sports Car Chassis Design, Costin & Phipps, 1965,
Batsford, London is a classic in this area.
brian whatcott
Altus OK
Subject: Neet Coriolis Flowmeter Advice?
From: "B.R.H."
Date: 10 Dec 1996 06:36:11 GMT
Multivariable measurement and control is gaining in importance. On-line
measurement and control of product mass flow, density, temperature, %
solids, and viscosity improves product quality. Coriolis flowmeters are
being successfully applied for the measurement of these process parameters.
I have more than 15 years experience applying this technology for the
development of new processes. If you have questions on the use of these
instruments, contact me by e-mail at masster1@ix.netcom.com.
BRH
