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Inter-Rivet Buckling Stress

This page calculates an inter rivet buckling allowable, σir, including plasticity effects per ref 1.

Tests have shown that the boundary conditions at the ends of the column depend on the fastener type. The actual condition will lie between the pinned/pinned (c = 1) and fixed/fixed boundary conditions (c = 4).

Type of attachment End-Fixity Coefficient, c
Bolts (Hi-Loks, Jo-Bolts, etc)4.0
Spot welds*3.5
Universal (solid, protruding-head rivets)3.0
Countersunk (flush, tension-head rivets)1.5
Countersunk (flush, shear-head rivets)1.0
                                                                                 * Not verified by testing

     σir = η·c·π²·Ec·t² / (12·s²)

where the plasticity correction factor, η = Et / Ec

Input Data

fastener pitchs = in  
skin thicknesst = in  
Type of Attachment :c =
Material compression modulusEc = psi  
0.2% yield stresst2 = psi  
Ramberg-Osgood curvature parametern = -  


Press Calculate to run the numbers ...


     σir =


  1. Flabel, Jean-Claude "Practical Stress Analysis for Design Engineers"