Stress in Adhesive

[EngDM]

How would one approach calculating the stress induced in an adhesive being used to secure two members for a shear or torque? Think two disks adhered together, where one disk is spun and the other is fixed. How would you calculate the stress experienced by the adhesive to determine if there would be a failure in the adhesive.

There are several wood-wood connections that I've seen in residential construction that are just glued together and call it a day, but how would you actually check this?

 

[SWComposites]

Well, if this was the aerospace world, I would say "you need specific test data for the structural and joint configuration using the particular adhesive and adhered materials."

If its a purely shear joint, some people would just blindly use a 500 psi shear strength allowable and go merrily on their way.

The analysis approach really depends a lot on the particular configuration. And be very careful if there are any sorts of peel stresses introduced into the joint.

 

[EngDM]

If its a purely shear joint, some people would just blindly use a 500 psi shear strength allowable and go merrily on their way.

It's for a 2' outrigger from a wall stud with a particularly high snow load. Client insists on using wood, but getting nails to work in this connection to a 2x6 wall stud just doesn't have the room required for nails to satisfy my spacing requirements. Was hoping to nail whatever I could fit code wise, but also glue the entire face. So I basically have a rectangle that is sliding against another, in a T joint.

Practically speaking I can't see this thing going anywhere, but getting the numbers to work is proving difficult.

 

[SWComposites]

First, the nails won't pick up much if any load until the adhesive fails ......
Second, adhesives tend to degrade over time, as do the interfaces between the adhesive and adherends.
Adhesive works well for things like LVLs, GlueLams, long scarf joints in wood members, etc.
No way would I count on the adhesive for the situation you describe. Use some sort of hanger bracket.

 

[EngDM]

Use some sort of hanger bracket.

Have you ever specc'd something like this before? I checked with some suppliers and they don't appear to have any moment brackets for a simple outrigger like this.

 

[XR250]

Get a "T" fabricated.

 

[EngDM]

Get a "T" fabricated.

Steel T's and through bolts it is.

Thanks guys.