The paper by Dr. A. H. Chilver (October 1955 Journal) purposed “ to present alternative theoretical approaches to the problem of local instability of a simple type of panel with unflanged stiffeners.”

Examination of these alternative approaches reveals that they are in fact identical and are based on the same approximate representation of the buckled form of the plate by sinusoidally varying lengthwise and transverse deflection, and of the stiffener by sinusoidally varying twist. The difference in the results obtained by Dr. Chilver is explained by the fact that whereas in the first analysis he uses plate theory correctly to express the strain energy in the stiffener, in his second analysis he omits entirely the torsion-bending energy.