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Bolted Joint Minimum Interface Area

Bolted Joint Minimum Interface Area

Bolted Joint Minimum Interface Area

The requirement for minimum interface area of a Bolted joint could be as follows,
•The pressure frustum determined for a bolted joint will suggest the minimum area required for clamp load distribution.
•The edge distance minimum requirement from the bolt hole center to avoid tearing of the member, in case of bolt contact occurs with hole and bearing load cause this tearing.
What other criteria are taken into consideration to design a bolted joint focusing on the interface area, in addition to other design parameters.
Do the more interface area add more friction to resist the slippage of the joint and adds more member’s stiffness to resist joint separation also.
What design calculations are used to determine the optimum interface area required for a robust bolted joint?
Thanks for your valuable comments.

RE: Bolted Joint Minimum Interface Area

I've only ever considered minimum edge distances as being important or as otherwise determined to resist bearing and tearout under in plane shear. I've never heard of a pressure check presumably you mean under bolt pretension?), it's just implied as working, the bolt will fail in tension before you squash the plies in any way.

The friction for slip critical connections is dependant on the clamping load and roughness of the plies in my opinion and not the area or total plate sizes.

There are maximum edge distances to ensure you don't get gaps that might become a trap for corrosion.

Design for the load if it works its optimal.

RE: Bolted Joint Minimum Interface Area

The equation for friction force does not depend on area of contact. F = mu * N


RE: Bolted Joint Minimum Interface Area

Without pictures and annotated drawings in the OP much time will likely end up wasted on posts getting details.

Here is a bolted joint that evolved to reduce several undesireable side effects.


Bolt prying. Flange deflection. And lots more.

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