In this paper the characteristics of the P-δ testing curves of a buckling structure are analyzed. A method of deducing the buckling load of the structure by means of the concept of maximum curvature is presented and the corresponding equation is established. The method is proved to be both accurate and simple by comparing the theoretical values with the experimentally measured values of the elastic stability tests of struts and frames. The buckling loads can be calculated directly with the formula when failure experiments of the structures and models are not allowed.
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