Columns: Static and Dynamic Interactive Buckling

Abstract

The interaction of local and overall buckling in thin‐walled columns is considered. A finite strip method in conjunction with the theory of mode interaction is developed to study the problem. The method is applicable to doubly symmetric cross sections carrying uniform stress or monosymmetric cross sections subjected to uniform end compression. Imperfection‐sensitivity surfaces are presented for stiffened panels and I‐section columns. A brief parametric study on I‐section columns is presented to illustrate the effect of flange slenderness and the ratio of local to Euler critical load on the maximum load carried. The effect of dynamic loads in the form of suddenly applied end compression is also investigated. It is found that in the presence of overall imperfections likely to occur in practice, the suddenness of load application can cause a reduction of about 10% of the maximum static load carrying capacity. A test program on I‐section columns carried out in Cornell University is cited for an evaluation of the present theory. There exists fair agreement between the theoretical predicted and experimentally observed collapse loads.