Applicability of the Southwell Plot to the Interpretation of Test Data Obtained from Stability Studies of Elastic Column and Plate Structures

摘要

Thomas Young derived in 1807 a formula which associated the applied load, the Euler critical load, the initial bow, and the elastic deformation under load for a column. Westergaard in 1922 used the Lagrangian law to derive Young's expression in a much wider context, and in so doing demonstrated its general validity in all linear instability problems. This relationship has great significance in the correlation of experimental data with linear theory. This was realized first by Ayrton and Perry in 1887. In 1932 Southwell independently redeveloped the technique and used it to discuss the classic column tests of von Karman. This report coordinates and extends the research made jin this field during the last century and a half. It demonstrates the powe and versatility of the method of expressing the given hyperbolic equation in a linear form - by change of variables - and determining the classic critical load as the slope of this line. (Author)