shear stress

samtrix

attached is my problem.

any help will be appreciated!

thanks!

Attached Thumbnails

 

TVP45

Do you have a formula?
How many cross-sections must be sheared in order for any to be sheared?
Please start and show your work.

Pyrrhus

What do you know about planes of shears?

In your example each bolt will have 2 planes of shears, making the bolt in a double shear state. Which means each of the shear forces will be equal to the half of the total load transmitted per bolt.

With this in mind you know the total load is simply 80 kilonewtons, and for a bolt the average shear stress will be equal to the shear force divided by the cross section of the area where it acts. You have the total load, you have the allowed shear stress, and the only unknown is the diameter, so simply by using the equation you have stated, you can solve for the diameter of the bolts.

Remember: you have 2 cross section areas, because you have two bolts (which should be accounted in A).

ToSucc

I am a metal shears professional, I would like to help you if you need.