Buckling behaviour of constructions occurs at a critical load. Until Professor Koiter did, no one ever described which factors influence this critical load,often leading to large deviations between theoretical and experimental results.

Koiter described how small imperfections such as undulations and thickness variations influenced the critical load. He found that this was especially relevant for thin-walled shell structures such as those found in aeronautics, aerospace, and civil works.

Building on the first fundamental work on the stability of structures by Euler (in 1744), Koiter received his doctorate in 1945 for his thesis ‘On the stability of elastic equilibrium’. It took until 1970 before it was published in English.