Laminate in Shear Cross Pin Bearing Strength

[JD_WTG]

Hello, I am looking to cross pin (using a 10.9 grade stud) a laminate joint loaded in double shear to increase the strength in the joint beyond that given by the adhesive between laminate sections.

Questions I have is related to bearing strength and stress. How is bearing strength of a material typically defined in structural engineering? I have seen comments stating its higher than yield and some saying lower? Is there a standard that defines the bearing strength in regards to yield or UTS.

Also, in terms of stress, for a 10mm stud in a 12mm hole, can the bearing stress be calculated using the simple P/d*t (d being the bolt diameter).

I used the max stress equation for a cylinder in a cylindrical socket (attached) and it gives me crazy high stresses. Much higher than the simplified one above.

 

[desertfox]

Hi
Can you provide a sketch of the actual joint please and how are you intending to increase the strength exactly of the joint above that given By the adhesive between the laminate faces?
The formulae you have provided to me anyway appear to be that of hertzian stresses and whilst that is typical in a bolted joint application like yours I don’t think it’s appropriate for your application, because what will happen in most bolted joints when loaded is that the clamped material yields slightly thus increasing the surface area and reducing the bearing stress between the bolt shank and the bolt hole wall.
For the bearing strength of a material I have always used the yield of the material with a safety factor, again what can happen here is that if the bearing stress is very high say above yield then that material whilst being compressed may work harden and so you can get an increase in yield stress from this process.



“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[SWComposites]

Please don’t double post.

Bearing stress is calculated as P/dt. In your case use diameter of the stud not the hole.

See my other answer re strength values. In composites it is a bad idea to use an oversized hole. Bearing strength will be greatly reduced.