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Load bearing structure made of matchsticks

  • Thread starter grey
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  • #1
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Homework Statement


Ok, i have a small (optional) project, to design a load bearing structure made of matchsticks. The structure must be able to withstand the load a computer monitor (i have a 17" one).

Homework Equations


Now, the problem i am facing is how would the force (of gravity due to the mass of the monitor be distributed across the matchstick structure?
Note that, i intend to make use of 'matchstick trusses' (only two force members), with 'pin joints' (actually strings binding the match sticks).

The Attempt at a Solution


I am actually totally clueless about this, as the problems i had encountered in high school assumed that all the weight acted through the centre of mass, which i don't think would be a valid assumption given the apparent non uniform distribution in the monitor.
 

Answers and Replies

  • #2
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ok...i know i wasn't much specific, but anyone???

maybe to elaborate a little, i want to find the transmission of forces at the monitor-structure interface.
Am i right to assume that the weight actually does act thru the centre of mass (approx) and then find the reaction of supports thru moments at each point of contact?
 
  • #3
PhanthomJay
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I don't know what your monitor (or truss) looks like, but my monitor is a flat 17 " screen supported on a round base about 9" in diameter, and it's load is supported pretty much uniformly at the base. In any case, in determining support reactions on your truss, you can do this by placing the monitor weight at the center of mass of the monitor, and determine the reactions by the static equiilibrium equations. However, in determining member forces, you should distribute the weight to the top joints beneath the monitor support as concentrated loads at those joints. You probably don't have to worry about truss member bending in between the joints since the monitor base is much more rigid than any individual truss member, so you still will only get axial loads in your members.
 
  • #4
70
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thanks a lot!!!
actually mines not a LCD, or any of the new types...its big and heavy, but i do get your point!

Thanks again!
 

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