TheSwamp
CAD Forums => CAD General => Topic started by: CAB on November 04, 2008, 04:38:12 PM
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This is a engineering problem but thought it would get more views here.
I'm trying to find the formula to solve for the Rod Load in this example.
Anyone have an equation for this?
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What's the rod spacing and length of canopy?
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P = 500/sin(tan-1(2'11.5 / 4'6.5))
This will find you the load, not the stress (ultimate or allowable)..
The 500# is the tributary load right ? (imperial ??)
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The way I calc it:
T=1.83218*W
Where T=rod tension, W=Tributary Load
@W=500, T=916.1
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The way I calc it:
T=1.83218*W
Where T=rod tension, W=Tributary Load
@W=500, T=916.1
Yours is simpler...but we get the same answer :kewl:...... :lmao:
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did he say rod load? :roll:
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Thanks so much for the replies.
Imperial, Yes
500 pounds tributary load, Yes
I would think you needed to consider the angle of the rod.
Thanks PS_port
Atook is the 1.83218 constant for a specific angle?
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PS_Port is there a difference in this situation for the Load & Stress?
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I saw that CAB. :wink: :-D
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I saw that CAB. :wink: :-D
Ditto
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Yes CAB that is for that angle...
1/sin(tan-1(2'11.5 / 4'6.5)) = 1.83218
(tan-1(2'11.5 / 4'6.5)) = your angle
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I saw that CAB. :wink: :-D
Ditto
You're all too quick.
:evil: :evil: :evil:
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Yes CAB that is for that angle...
1/sin(tan-1(2'11.5 / 4'6.5)) = 1.83218
(tan-1(2'11.5 / 4'6.5)) = your angle
Thanks for the clarification.
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Stress will be the tension in lbs divided by the cross sectional area of the rod.
And Port is right, my solution was for the drawing shown. Port's solution can be used for other triangles, just substitute your H & W values.
My solution stayed away from trig (sort of) and is:
T=W*L/H
Where T=tension in lbs, W= load, L=length of hypotenuse, and H=height.
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CAB,
Load is just the load being applied to the rod, the diameter of the rod can vary,
The load will remain the same but the stress developed in the rod will be dependant on the diameter,
stress = load / area of steel.
This is where imperial start to loose me. (here Newtons / millimetres 2 = MPa)
I believe you guys work in KIPs ' (Pounds per square inch) so as long as you keep your units the same you should be ok.
Might have to wait for Bob G. to check..? :oops:
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Stress will be the tension in lbs divided by the cross sectional area of the rod.
And Port is right, my solution was for the drawing shown. Port's solution can be used for other triangles, just substitute your H & W values.
My solution stayed away from trig (sort of) and is:
T=W*L/H
Where T=tension in lbs, W= load, L=length of hypotenuse, and H=height.
Nerd :-D
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I understand now.
I love this stuff :roll:
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I was trying to get the formula in a LISP form but don't know what to do with the -1 power.
(/ load (sin(tan (/ H W))))
Hight & Width
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I'm sticking with my reply :P
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tan-1 is the inverse tan or (arctan)
found this it might help. (note radians)
http://www.afralisp.net/Tips/code20.htm
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CAB
sorry mate a man of your experience would know the (radians) thing....
I didn't need to point that one out.. :oops:
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I was trying to get the formula in a LISP form but don't know what to do with the -1 power.
(/ load (sin(tan (/ H W))))
Hight & Width
just in case - load is a lisp function - ..... :)
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CAB, my equation is the same as Port's, just without any trig functions (you could say they've been evaluated already).
SohCahToa right? :)
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Atook, your right there.
CAB just divide the hypotenuse by the height and multiply by load
(* load (/ (sqrt (+ (* h h) (*w w))) h))
I'm not good at lisp, someone might need to check the syntax :oops:
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Thanks Luis I just threw the load in there at the posting for readability.
PS_Port, Arctan I understand but did not recognize it as tan-1
This works just fine.
_$ (setq l 500 h 35.5 w 54.5)(* l (/ (sqrt (+ (* h h) (* w w))) h))
916.089
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Cool bananas
I get thrown with arctan :-D
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This works as well. 8-)
(/ 500(sin(atan (/ 35.5 54.5))))
916.089
So here is the final test.
Where T=tension in lbs, W= load, L=length of hypotenuse, and H=height.
(setq W 500 H 35.5 L 54.5)
(setq T (/ W (sin (atan (/ L H)))))
916.089
(setq T (* W (/ (sqrt (+ (* H H) (* L L))) H)))
916.089
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My company wouldn't let us use the net today (!?). I'm finally home from a really long day and not presently capable of doing any math at all so I'm worthless. But looks like everyone's covered it well. All day I had that song on my mind, "Whiskey for my horses, champaigne for my men". After reading all your posts, I'm singing, "Whiskey for my horses, Pay raises for the Swampers".
Kips are in units of 1000 pounds or one kip = one thousand pounds. Anybody know who the hell Kip is?
Happy evening all. May your votes work out for you.
Bob
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Bob,
Hope tomorrow is a better one. 8-)
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Anybody know who the hell Kip is?
yes. Kip is that burned-out engineer who needs help with his "engineering" from a guy named Robert that just so happens to be gifted with pointing out all of his mistakes.
Dr. George: "Good catch, Robert, wow! **makes sounds of a crowd screaming**
I need to make a youtube video of the engineer here... y'all would laugh your (_Y_)'s off!
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Anybody know who the hell Kip is?
Like you people don't know.
She's only seventeennnnnn
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:? :?
I am VERY envious of you folks that can figure this out.
It makes me wish I would have gone further in Math & Engineering.
I bow to you....
craigr
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If y'all can find the book, "Simplified Mechanics and Strength of Materials", by Parker, it's a gem for figuring this stuff out. I told a welder about this book recently and he was able to find it. I think the author is now Parker and Ambrose.
Bob
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I usually figgur these brackets graphically since I have to draw them anyway. Attached is such a graphical drawing.
I hope this helps.
Bob G
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Kips are in units of 1000 pounds or one kip = one thousand pounds. Anybody know who the hell Kip is?
Short for kilopound?
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Kips are in units of 1000 pounds or one kip = one thousand pounds. Anybody know who the hell Kip is?
Short for kilopound?
That would be so confusing if it were true.....
S.I. units, 'kilo' surely you guys wouldn't work in anything so logical as a 103 system..
It would be more like a `kappa' which would be 4 & 3/4 of a drizzle which if you times by 67 is a quarter of a delta mile.. :lol: :lmao:
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confusing , but true.
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I like to think of it as "killa-pound" as in; a killer-pound. One bad motha, SHUTCHO MOUF pound... just talkin' bout kips...
Ya know.. wouldn't want to think the metrics are infesting our number system, now would I? :P