"Predictions of buckling loads by the Euler formula is only reasonable for very long and slender
struts that have very small geometrical imperfections. In practice, however, most struts suffer
plastic knockdown and the experimentally obtained buckling loads are much less than the Euler
predictions. For struts in this category, a suitable formula is the Rankine4ordon formula which
is a semi-empirical formula, and takes into account"
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