Stability determination of structures under groups of loads by using the principle of critical energy

Starting from the principle of critical energy, this paper determines the load groups whose joint action might cause buckling or stability loss in any structure (as bars, plates or shells).

The relationships obtained for the critical load groupings depend on the behaviour of the structure material (linear-elastic, nonlinear-elastic, or rigid body), as well as on how the load is applied (slowly or suddenly). The relations deduced closely agree with the experimental results obtained by other authors.

By applying the general relations established in this paper to particular cases, 31 relationships are determined which, broadly speaking, have been established empirically or semi-empirically by previous authors.

Each part of this paper is concluded with examples of actual uses for the relations acquired. Thus one is able to solve problems involving any load groups with varying actions: the results cover many cases for which there previously have been no solutions.