Huth Eqn.

[Brian6700]

Hi,

Can the Huth bolt equation be used for double shear when all three plates are different (i.e. top and bottom plates aren't identical)?

Thanks,

 

[rb1957]

FWIW ...

sure, i'd model as two equal plates, the average thickness

or you could model each shear face separately, ie 1/2 the middle plate with either outer plate and add the two single shear stiffnesses together ... not sure if huth has a term to account for the offset loading of a single shear interface.

 

[Brian6700]

Thanks rb1957 for replying, this is very helpful.

I do have one question though, would you pretty much have to go with your second suggestion (i.e. making 2 single shear calcs and adding them), since the sandwich plates are different E's? Or could you average the E's?

Thanks again,

 

[Brian6700]

almost forgot to mention, the core and one of the sandwich plates are laminate, the remaining sandwich plate is metal.

 

[rb1957]

sorry brian but this is unfortunately a typical eng-tips post ... the story evolves with each post, and much time is wasted.

so it sounds like you have a sandwich panel (metal faces, honeycomb core?) joining two other plates (both metal, or one is composite ?)

if the honeycomb core fastener doesn't have a bushing then i'd consider the two faces as separate bearing surfaces. if it does have a bushing you Might consider it as one thick plate.

different Es should be accounted for in Huth, directly ... it's a while since i looked over the equation, but i remember Es all over the place.

if one "plate" is composite ("laminate"?) i'd be careful ... huth was developed from testing metal joints, and composites have a nasty way of not acting like metal.

apologies for the opening rant ...