# In shear or...?

• posted

So I'm not an engineer or a student, but I fabricate some things for various jobs I need done. Recently I pondered two things and was wondering about them, if anyone could enlighten me that'd be wonderful as I can reason out both a yes and no to 'A' as well as either end result for 'B', but I don't know which is correct.

A) If there's two plates standing on end with force pulling them down, a third fit in between them being pulled up, and a shaft running through concentric holes in all 3 plates, the shaft is in shear. Now lets spread those two plates being pulled down further apart so there's a good amount of space between them, to throw some numbers at it, .5" plates with the outer two being 8" apart from inside face to inside face and the third centered between them. Is this still shear even though the shaft will bend when it yields rather than flat out shearing if the force is great enough?

B) I have a pipe that fits inside another pipe, I slide the one halfway in the other and drill a hole through both putting a pin in there to hold them together. I apply compression to the ends of the tubes putting the pin in shear. Is this considered double shear or is each side of the pipe treated individually?

• posted

Dear joshya...:

On May 16, 12:44=A0pm, snipped-for-privacy@gmail.com wrote: =2E..

Yes. If the line of action of each force is not "coaxial" with all the others, a bending moment is produced, and the material under stress is forced to provide / transmit this bending moment, which produces non-zero shear in the member.

I wouldn't spend a great deal of time worrying about names. *If* the pin is inserted normal to the line of action of the forces, and the holes are all the same diameter, you can treat the pipe example as you do the "tongue and groove" example in A).

David A. Smith

• posted

Thanks a bunch :)

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.