angular deflection/torsional deflection question please help

[kazste]

i have been trying to find out how to answer a question for three dyas now and have come no closer, so am asking the good people of pistonheads for help!

i have a solid circular shaft of which i have the diameter and length so should be able to work out the second moment of inertia from this.

i have the shear stree value

and i have the shear modulus value

i need to find the angular (torsional?) deflection value of the shaft.

any ideas greatly appreciated

[_rubinho_]

Ask your lecturer for help at the next tutorial?

[kazste]

the only problem with that is that in true man style i figured i had it all sorted as only had two questions left on the paper and the next time i see the lecturer is the day i should of handed the paper in (i know i know im an idiot)

needs to be handed in this tuesday, i am on nights tonight so could go in on monday if he is free but wouldnt be the easiest thing in the world for me to do.

[Poledriver]

kazste said:

the only problem with that is that in true man style i figured i had it all sorted as only had two questions left on the paper and the next time i see the lecturer is the day i should of handed the paper in (i know i know im an idiot)

needs to be handed in this tuesday, i am on nights tonight so could go in on monday if he is free but wouldnt be the easiest thing in the world for me to do.

You'll also get marked down for lack of capitalisation, lack of punctuation and using 'of' instead of 'have'!

HTH

[kazste]

cheers fo' thee advice poledriver, innit

[Poledriver]

This any use?

Torsional Deflection of Shaft
The angular deflection of a torsion solid shaft can be expressed as
θ = 584 L T / (G D4)
where
θ = angular shaft deflection (degrees)
L = length of shaft (mm, in)
G = modulus of rigidity (Mpa, psi)
The angular deflection of a torsion hollow shaft can be expressed as
θ = 584 L T / (G (D4- d4))

[kazste]

that is what i keep findingbut cannot find what the 584 figure relates too, as want to understand it as well as do it, any ideas?

[WorAl]

If that is the formula (which, does look familiar), it is a constant, derived from else where, dont remember how to find, or what it comes from, would have to go into garage to find out in my uni stuff - dont worry about it, just remember it.

[kazste]

cheers for that woral and poledriver if that is the constant then thats cool.

i knew i could reply on the ph'ers not only to answer my question but also to provide as an added bonus some grammer assistance

[working class]

I presume you are studying engineering?

[kazste]

yes, it is for an electrical engineering HNC but one of the core modules is in mechanical engineering, i guess to balance knowledge.

[working class]

kazste said:

yes, it is for an electrical engineering HNC but one of the core modules is in mechanical engineering, i guess to balance knowledge.

Ah i mentioned on your other thread the other day i was thinking of studying this in sepmtember next year, however some fo your questions are starting to fighten me a little!

[holmzy]

Hopefully this will help
http://en.wikipedia.org/wiki/Torsion_%28mechanics%...

Has all the equations I think you need to work it out.

[kazste]

go for it mate, i was really poor at maths (almost number dyslexic) and took me three attempts at gcse maths to get a grade c. but i am finding that due to a more measured approach i am able to work my way through to the answers. it helps that i have some really good lecturers who are aware of my shortcomings and have a lot of patience with me.

if you dont do it you may regret it, if you do do it then at least you'll know.

[working class]

kazste said:

go for it mate, i was really poor at maths (almost number dyslexic) and took me three attempts at gcse maths to get a grade c. but i am finding that due to a more measured approach i am able to work my way through to the answers. it helps that i have some really good lecturers who are aware of my shortcomings and have a lot of patience with me.

if you dont do it you may regret it, if you do do it then at least you'll know.

I need to ask you a couple of questions, can i pm you?

[kazste]

You have mail. Hope it helps

[Would You]

Best thread title, since that guy asked for help importing a domesticated elephant...

[kazste]

thankyou very much and how's the elephant?

;_

[_rubinho_]

You should download a program called MDSolids ( http://www.mdsolids.com/index.html). It's a great help with these sorts of Mechanics questions.

[kazste]

thanks a lot downloading the program now.

thanks to everyone who's helped, paper now completed and will be handed in, in 2 hours time.

thanks again.