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Subject: 
Re: New Civil Engineer letter
Newsgroups: 
lugnet.technic
Date: 
Tue, 3 Jul 2001 13:12:53 GMT
Viewed: 
1387 times
  
In lugnet.technic, Thomas (T. J.) Avery writes:
In lugnet.technic, Simon Bennett writes:
that steel structures are generally welded or riveted together

Large steel structures (i.e. buildings and bridges) are welded and BOLTED
together. Rivets are rarely used anymore in these structures.

Noted.  You're absolutely right.  It's been a while since my degree and I'm
a railway engineer now, sorry about that slip up.  I must go back and review
my notes on egg-sucking too!!

friction pin system is a better analogue for this than Meccano’s bolts.

Friction pins are an excellent connector because they are easy and
convenient to use, but they lack the ability to provide any axial
compression (i.e. tightening of a bolt "squeezes" the parts together). While
this may not be necessary for most applications, it can be a problem.

So should I leave the part about Lego being no worse for modelling steel
out?  Actually I need to research Meccano but I think it only consists of
plates so if you want to form a member (I-beam or box section) you have to
bolt it together first.  A technic beam is already a decent member.  Should
I make this point instead?

Although Lego does make (or has made) threaded axles, they are rare and it
is unfeasible to plan a large structure using many of these axles.

I wouldn't leave out using axles as connectors. They are much stronger in
shear than pins are. If you're creating a structure like a truss and have
eccentric connections, axles can be better.

Okay, I'll add that.

Pictures of Lego structures can be found at
www.lugnet.com/~469/projects/archbr (Ross Crawford’s arch truss bridge) and

Large impressive structure, yes; truss, no. This bridge is technically not a
truss and therefore doesn't have the strength that a true truss would.
Without going into too much detail, the members in a truss must intersect at
a common point. <snip-ment>

Blame that on my not looking at it properly.  I do remember what I was
taught about trusses!

In recent times, the trend in bridge building is moving towards large plate
girders and box girder sections. I'm not familiar with Meccano at all, but
Lego is excellent for building these structures. It can take a lot of
plates, but it works well:
http://tanyatj.home.texas.net/tjscreations/ideas/beam/

Hmm, I think Meccano may work better for this.  I need to check it out
properly before I send the letter.

As far as mechanical engineering is concerned Meccano may have had an
advantage prior to the late 1970s but these days Lego has a much wider range
of gears and other mechanical elements than Meccano, including
differentials, shock absorbers, pneumatic pumps and cylinders, gearboxes,
cams and flexible drive shafts.  Examples of models which show good use of
mechanical principles are Jennifer Clark’s trucks and construction machinery
(www.telepresence.strath.ac.uk/jen/lego/) and Dennis Bosman’s mobile cranes:
(www.geocities.com/MotorCity/Highway/2290/bmnr04.html).

Yes, excellent, good!!! Examples are the best way to defend our argument
that Lego is far superior. There are many other sites out there with good
MOC's that are worthy of mentioning.

Really good examples welcome (I don't want to overload it).

Also, if you're going to present the benefits of Lego and Technic to someone
who is not familiar with Lego, mention Jim Hughes' site: Technica,

http://w3.one.net/~hughesj/technica/technica.html

it is an excellent reference for Technic parts.

I had a big section giving references to various elements in Technica and
going on to cover the online support that Lego builders give each other but
I cut it due to length.  If others think it's really relevant I'll put
something in.

Lego also has an educational theme called Dacta, which is only available to
educational establishments (though if anyone is interested it can be bought
at Legoland or by mail order from www.pitsco-legodacta.com).  Dacta includes
solar cells, capacitors and other electronic and mechanical parts along with
teaching guides and other support to use Lego in the classroom.  I do not
believe anything so comprehensive has ever been provided by Meccano.

Don't forget about Mindstorms and all the Lego robotics stuff. How does
Meccano compare against that? (if at all)

It doesn't but I thought that was widening the point a bit and I didn't have
the space.  Also if, as Steve Lane suggests (and I also suspect) we are
replying to an older engineer he may dismiss the more modern stuff as just
'playing with computers'.

Thanks for the input.

Psi



Message has 2 Replies:
  Re: New Civil Engineer letter
 
(...) I think for ease of use, Lego parts (like a Technic beam) are certainly better. You'd still have to build-up a Technic beam to get an "I" or box section, but the Technic beam by itself is relatively strong and as you say, is "a decent member". (...) (23 years ago, 3-Jul-01, to lugnet.technic)
  Re: New Civil Engineer letter
 
"Simon Bennett" <simon.bennett@ntlworld.com> skrev i meddelandet news:GFwFDH.8JM@lugnet.com... (...) As far as I know, Meccano has 'L'-beams, and perhaps 'U' too? At least there are large plates, with folded sides, which is effectively a 'U'. (I (...) (23 years ago, 3-Jul-01, to lugnet.technic)

Message is in Reply To:
  Re: New Civil Engineer letter
 
(...) Large steel structures (i.e. buildings and bridges) are welded and BOLTED together. Rivets are rarely used anymore in these structures. (...) Friction pins are an excellent connector because they are easy and convenient to use, but they lack (...) (23 years ago, 3-Jul-01, to lugnet.technic)

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