Design, Make and Test a Warren Girder - Revision history

DT Online at 10:15, 1 March 2017

2017-03-01T10:15:29Z

← Older revision		Revision as of 10:15, 1 March 2017
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	===== What to Make: =====		===== What to Make: =====
	Design Make and Test a [~~https~~://en.wikipedia.org/wiki/Girder '''Warren Girder'''] truss frame 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg		Design Make and Test a [http://en.wikipedia.org/wiki/Girder '''Warren Girder'''] truss frame 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg


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	=====What to Use:=====		=====What to Use:=====

	* Material available is restricted to 3mm thick medium density [~~https~~://en.wikipedia.org/wiki/Ochroma_pyramidale '''Balsa Wood'''].		* Material available is restricted to 3mm thick medium density [http://en.wikipedia.org/wiki/Ochroma_pyramidale '''Balsa Wood'''].
	* Use any suitable '''[[Adhesive Types\|adhesive]]''' to make connections but '''[[Adhesive Tapes\|adhesive tape]]''' is not allowed.		* Use any suitable '''[[Adhesive Types\|adhesive]]''' to make connections but '''[[Adhesive Tapes\|adhesive tape]]''' is not allowed.

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2016-11-23T09:12:37Z

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			[[Category:Topics, Projects and Tasks]]
	[[Category:Structures Projects]]		[[Category:Structures Projects]]
	[[Category:Bridges]]		[[Category:Bridges]]

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	[[Category:Structures Projects]]		[[Category:Structures Projects]]
			[[Category:Bridges]]

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2016-05-31T09:30:12Z

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← Older revision		Revision as of 09:30, 31 May 2016
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	==== What to Make: ====		===== What to Make: =====
	Design Make and Test a [https://en.wikipedia.org/wiki/Girder '''Warren Girder'''] truss frame 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg		Design Make and Test a [https://en.wikipedia.org/wiki/Girder '''Warren Girder'''] truss frame 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg

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	====What to Use:====		=====What to Use:=====

	* Material available is restricted to 3mm thick medium density [https://en.wikipedia.org/wiki/Ochroma_pyramidale '''Balsa Wood'''].		* Material available is restricted to 3mm thick medium density [https://en.wikipedia.org/wiki/Ochroma_pyramidale '''Balsa Wood'''].
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	====Things to find out and think about:====		=====Things to find out and think about:=====

	* Draw full-size a Warren Girder exactly 450mm wide		* Draw full-size a Warren Girder exactly 450mm wide
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	====Some ideas:====		=====Some ideas:=====

	[[File:FramePlan.png\|400px]][[File:WarrenFrame.png\|400px]]		[[File:FramePlan.png\|400px]][[File:WarrenFrame.png\|400px]]


	~~<div style~~=~~"clear: both;"></div>~~		=====Ways of Making:=====
	====Ways of Making:====


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	[[File:FrameTestRig.png\|400px\|right]]		[[File:FrameTestRig.png\|400px\|right]]
	====Testing:====		=====Testing:=====

	* Carefully weigh the completed truss frame ''(ideally to 1/10<sup>th</sup> of a gram)''.		* Carefully weigh the completed truss frame ''(ideally to 1/10<sup>th</sup> of a gram)''.
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	====Further Work:====		=====Further Work:=====


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	* Divide the maximum load before failure by self-weight to gain a revised measure of the frame's efficiency.		* Divide the maximum load before failure by self-weight to gain a revised measure of the frame's efficiency.
	* Observe how the frame failed : which '''[[Structural Member\|Member]]''' failed first? Was it a '''[[Strut]]''' or a '''[[Tie]]'''? Did just one '''[[Structural Member\|Member]]''' fail or several all at once - and what would this indicate?		* Observe how the frame failed : which '''[[Structural Member\|Member]]''' failed first? Was it a '''[[Strut]]''' or a '''[[Tie]]'''? Did just one '''[[Structural Member\|Member]]''' fail or several all at once - and what would this indicate?


			{{Stripwood Frames Buyers Guide}}


	[[Category:Structures Projects]]		[[Category:Structures Projects]]

DT Online at 23:01, 17 February 2016

2016-02-17T23:01:17Z

← Older revision		Revision as of 23:01, 17 February 2016
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	* Continue to load the ~~fram~~ until it fails and record the maximum load before failure.		* Continue to load the frame until it fails and record the maximum load before failure.
	* Divide the maximum load before failure by self-weight to gain a revised measure of the frame's efficiency.		* Divide the maximum load before failure by self-weight to gain a revised measure of the frame's efficiency.
	* Observe how the frame failed : which '''[[Structural Member\|Member]]''' failed first? Was it a '''[[Strut]]''' or a '''[[Tie]]'''? Did just one '''[[Structural Member\|Member]]''' fail or several all at once - and what would this indicate?		* Observe how the frame failed : which '''[[Structural Member\|Member]]''' failed first? Was it a '''[[Strut]]''' or a '''[[Tie]]'''? Did just one '''[[Structural Member\|Member]]''' fail or several all at once - and what would this indicate?

DT Online: Added links

2016-01-12T18:03:01Z

Added links

← Older revision		Revision as of 18:03, 12 January 2016
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	==== What to Make: ====		==== What to Make: ====
	Design Make and Test a Warren Girder ~~Truss Frame~~ 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg		Design Make and Test a [https://en.wikipedia.org/wiki/Girder '''Warren Girder'''] truss frame 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg


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	====What to Use:====		====What to Use:====

	* Material available is restricted to 3mm thick medium density Balsa Wood.		* Material available is restricted to 3mm thick medium density [https://en.wikipedia.org/wiki/Ochroma_pyramidale '''Balsa Wood'''].
	* Use any suitable adhesive to make connections but adhesive tape is not allowed		* Use any suitable '''[[Adhesive Types\|adhesive]]''' to make connections but '''[[Adhesive Tapes\|adhesive tape]]''' is not allowed.

DT Online: Created article

2016-01-12T16:09:33Z

Created article

New page

==== What to Make: ====
Design Make and Test a Warren Girder Truss Frame 450mm wide to span a 400mm wide gap and support a centrally applied load of 1kg

[[File:BrinningtonBridge.png |400px|right|link=http://www.ipernity.com/doc/302581/30372307]]
__TOC__

====What to Use:====

* Material available is restricted to 3mm thick medium density Balsa Wood.
* Use any suitable adhesive to make connections but adhesive tape is not allowed

====Things to find out and think about:====

* Draw full-size a Warren Girder exactly 450mm wide
* Analyse the forces acting within a Warren Girder and determine which '''[[Structural Member|Members]]''' will be '''[[Strut|Struts]]''' and which will be '''[[Tie|Ties]]'''.
* Apply '''[[Bow's Notation]]''' and use '''[[Force Diagrams]]''' to determine the '''[[Forces in Frames|Forces in the Frame]]''' when the 1kg load is applied.
* Determine the '''[[Tensile Strength]]''' of medium density Balsa Wood either by testing or looking up in tables and from this establish how wide to cut '''[[Tie|Ties]]''' from 3mm thick sheet Balsa ''(e.g. U.T.S. should be around 15Nmm<sup>2</sup> - use this figure if in doubt or to check magnitude of test results)''.
* Apply '''[[Buckling|Euler's Buckling Equation]]''' to inform an estimate of how wide to cut the '''[[Strut|Struts]]''' from 3mm thick sheet Balsa ''(e.g. assume a figure for '''[[Young's Modulus]]''' (E) of 4000Nmm<sup>2</sup> or determine by experiment by measuring the '''[[Beam Deflection|Deflection]]''' of a balsa sample beam for example)''.

====Some ideas:====

[[File:FramePlan.png|400px]][[File:WarrenFrame.png|400px]]

<div style="clear: both;"></div>
====Ways of Making:====

* Conduct some tests to establish which is the most effective adhesive and consider how each joint can be provided with an adequate gluing surface area.
* Take care when shaping and finishing the '''[[Structural Member|Structural Members]]''' to avoid any ''nicks'' or sharp indentations which might cause a '''[[Stress Concentration]]'''.
* Use the full-size drawing to position the '''[[Structural Member|Structural Members]]''' accurately and glue them in place.
----
<span style="color: green">'''Note:'''
Cover the drawing with tracing paper to enable the truss frame to release after gluing.
</span>
----

[[File:FrameTestRig.png|400px|right]]
====Testing:====

* Carefully weigh the completed truss frame ''(ideally to 1/10<sup>th</sup> of a gram)''.
* Mount the completed truss frame in the testing rig as shown
* Suspend a mass set hanger from the centre as shown
* Add masses carefully to avoid generating a '''[[Live Load|Dynamic Load]]''' until the specified load of 1kg is reached.
* Divide 1kg by the truss frame self-weight to gain a measure of the frame's efficiency ''(i.e. high numbers win!)''

====Further Work:====

* Continue to load the fram until it fails and record the maximum load before failure.
* Divide the maximum load before failure by self-weight to gain a revised measure of the frame's efficiency.
* Observe how the frame failed : which '''[[Structural Member|Member]]''' failed first? Was it a '''[[Strut]]''' or a '''[[Tie]]'''? Did just one '''[[Structural Member|Member]]''' fail or several all at once - and what would this indicate?

[[Category:Structures Projects]]