7.2.6 Main Takeaways on Failure of Mechanically Fastened Joints
Course subject(s)
Module 7. Joining of Structures and Manufacturing
Failure modes
Failure in mechanically fastened joints is a complex competition between different possible failure modes. We examined the major failure modes illustrated below and looked at which design variables are dominant in each failure mode.
Accompanying Failure Load Formulas
Net Section Failure: 𝐹𝑁 𝑆𝑇=𝑡(𝑊−𝑛⋅𝑑)⋅𝜎𝑡𝑢, with n the number of fasteners along net section, d the diameter of the fastener, and t the plate thickness of the section.
Bearing Failure: 𝐹𝑏𝑟=𝑑⋅𝑡⋅𝜎𝑏𝑟, with d the diameter of the bolt and t the thickness of the sheet
Shear Out Failure: 𝐹𝑆𝑇𝑂=2⋅𝑏⋅𝑡⋅𝜏𝑠𝑢, with b the distance to the edge and t the thickness of the sheet.
Fastener Shear Failure:
,with d the diameter of the bolt and n the number of shear plains (n = 1 for 2 plates, n = 2 for 3 plates etc.)
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