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General control line discussion => Open Forum => Topic started by: James Mills on February 13, 2011, 11:54:39 AM

Title: Tension/Sheer
Post by: James Mills on February 13, 2011, 11:54:39 AM

I have read a couple of time (most recently Dave Fitzgerald's article on the Thundergazer) about something being under sheer/tension.  What does this mean?

James

Title: Re: Tension/Sheer
Post by: Howard Rush on February 13, 2011, 12:02:50 PM

http://en.wikipedia.org/wiki/Strength_of_materials  Look at the "stress terms" paragraph.  There's a cartoon that explains them.

Title: Re: Tension/Sheer
Post by: Tim Wescott on February 13, 2011, 01:17:52 PM

He probably means that the member in question is under both shear and tension.  Shear is not independent of tension, so if something is being both pulled and put in shear, then it'll break sooner than if it's just being pulled.

Title: Re: Tension/Sheer
Post by: rustler on February 13, 2011, 04:32:56 PM

Tension is when something is subject to a straight pulling apart force.
Those notches at the side of a pair of pliers for cutting wire, cut the wire by shearing it. It cuts by making the ends slide across each other, ultimately separating the two new ends.
Hope this makes sense.

Title: Re: Tension/Sheer
Post by: Randy Ryan on February 13, 2011, 06:23:29 PM

Shear tension is stress that trys to separate laterally. As the name implies, "shear" as in scissors, (shears)

Compressive stress, squeezing something

Tensile stress is as it implies, pulling apart

In a spar with sheer webbs, under positive G loading, the upper member of the spar is under compression, the lower under tension, the webbs are in shear, resisting the opposed lateral loads of the upper and lower spar members.


Randy Ryan <><
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Title: Re: Tension/Sheer
Post by: PJ Rowland on February 13, 2011, 06:30:06 PM

Does anyone have a link or a copy of the article in question they could email me ?

I must have missed that one.

Title: Re: Tension/Sheer
Post by: Randy Heydon on February 13, 2011, 09:38:58 PM

I hope will help.

Title: Re: Tension/Sheer
Post by: M Spencer on February 14, 2011, 12:48:34 AM

If you put a six foot two by four one end in a bench vise ,
and stand on the other end , it'll bee in both SHEAR and
tension ,on the top.And Compession on the bottom .

Unless it slips , when you might be in hospital. or
you fall of , where it may spring around a bit .

Best to call for voulenteers whilst you film it then . <=