Tensile Yielding,tensile Rupture 1

[arefinmahadi]

hi,

it would be a great help if somebody helps me understanding the following thing,

why tensile yielding is considered as a limiting state when a hot rolled plate is under tensile force where as bolts are only checked for tensile rupture ?

Thanks
Arefin

 

[KootK]

It has to do with the length of the element being strained.

For a very short element, like a bolt, yielding isn't detrimental. The strain that accumulates over the length of the element at yield just doesn't add up to anything appreciable. So the only concern is rupture.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[arefinmahadi]

Thanks a lot KootK.

"The strain that accumulates over the length of the element at yield just doesn't add up to anything appreciable."
Can u just make it a little simpler for me. Just for my understanding better....or any reference link will be world of help.

Thanks a lot in advance..

Thanks
Arefin

 

[KootK]

I'll try. Consider two cases:

1) A bolt in tension connecting two half inch plate. The strain length is very short. At rupture, the bolt might elongate 1/100th of an inch. That's probably not an issue for the structure of which the bolt is a part.

2) An angle used as a 20' cross brace in tension. The strain length is much longer. At rupture the brace might elongate 4". That probably is a problem for the structure of with the brace is a part. Therefore yield is a more relevant limit state for the simple reason that it limits elongation to something much more reasonable.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[arefinmahadi]

Thanks a lot sir. clear as crystal. I was thinking about the full bolt length. actually it is the plates that it is supported between.

 

[ajh1]

The other thing to point out is that bolts don't generally have a well-defined yield point. They are specified strictly by their tensile strength.