The Historical Development of the Strength of Ships

摘要

Timber from oaks and soft wood was hundreds of years the only material for building ocean going ships. Sufficient strength of wooden ships based only on the practical experience of their builders. The strength of iron ships has been estimated first by William Fairbairn 1860. His method based on a very modern ultimate load concept. A couple of years later John Macquorn Rankin first published the physically correct formulation of the longitudinal bending moment of the whole ship hull structure including a quasi-static wave effect. On occasion of the sinking of the torpedo boat H.M.S. Cobra 1901 the bending test of a similar ship H.M.S. Wolf in a dry-dock has been prepared. The test results were found not in line with the classical bending theory. After a lot of research work Georg Schnadel found 1929 a proper explanation by taking the post buckling behavior of the thin deck plating under consideration. It needs nearly hundred years to consider the probabilistic nature of the seaway into the design formula of the longitudinal strength of ships. Nowadays almost all structural members of the steel design of ships like the stiffened plates of the shell, bulkheads and decks has be calculated by the classical theory of elasticity, including post buckling effects following the rules of the classification societies. Since the end of the last century the Finite Element Method is used not only for structural details but also for the whole hull structure, including the dynamic loads of the seaway.