Column Buckling - Inelastic A long topic

Effects of geometric imperfection Leads to bifurcation buckling of perfect doubly-symmetric columns P v v vovo P MxMx

Effects of Geometric Imperfection

Geometric Imperfection A F = amplification factor

Geometric Imperfection Increases exponentially Limit A F for design Limit P/P E for design Value used in the code is This will give A F = 8.13 Have to live with it.

Residual Stress Effects

Consider a rectangular section with a simple residual stress distribution Assume that the steel material has elastic-plastic stress-strain  curve. Assume simply supported end conditions Assume triangular distribution for residual stresses x y b d  rc  rt E yy    y  y

Residual Stress Effects One major constrain on residual stresses is that they must be such that Residual stresses are produced by uneven cooling but no load is present

Residual Stress Effects Response will be such that - elastic behavior when x y b d x y bb bb YY YY  Y /b

Residual Stress Effects