adhesive shear allowable under torque

[40818]

I'm having trouble thinking about how to come up with a ballpark allowable value for a bonded attachment under a torque load.
The attachment pad is circular and is bonded to a baseplate. The pad has a direct shear allowable of say 100lb. However, it is subjected to a force which will induce a rotation about the base giving rise to torque-shear in the adhesive.
Any ideas?

 

[SWComposites]

Are you saying the circular pad has a shear allowable of 100 lbs for a "single lap shear" type configuration? Was this value obtained from a test or a calculation?

 

[CoryPad]

Torsion induces non-uniform shear. You can use standard torque-shear stress equations to calculate the maximum stress that occurs at the outer periphery and compare that to the material allowable stress.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[inertia4u]

Have a look at the attached link to get your equations.

Also note that failure of the "test" article may not have been in the elastic region, so your answer may be off as well.

When in doubt, install some fasteners through that puppy



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Nert