Marine Structures 6 (1993) 485-507 Collapse Analysis of Ship Hulls Y. Bai, E, Bendiksen & P. Terndrup Pedersen* Department of Ocean Engineering, The Technical University of Denmark, Building 101 E, DK-2800 Lyngby, Denmark ABSTRACT This paper presents an efficient finite element procedure for the collapse analysis of ship hulls under complicated loads. A set of finite elements, such as beam-column elements, stiffened plate elements, and shear panel elements are developed, directly accounting for the geometrical and material non-linearities and initial imperfections. Elastic-plastic stiffness matrices for elements have been derived by combining elastic large displacement analysis theories with a plastic hinge model. The buckling and post-buckling behaviour of plates is included using an effective width concept. The procedure is effective, since .few node-points are necessary and numerical integration for evaluating stiffness matrices is avoided. Fracture mechanics criteria are introduced in order to account for tension tearing rupture and brittle failure of the material. Practical applications to ultimate longitudinal strength analysis of ship hulls and tanker collision analysis are presented. The procedure can also be used for collapse analysis of offshore and onshore structures. Key words: collapse, collision, longitudinal strength, ship hull. 1 INTRODUCTION In order to carry out limit state design of ship hulls, it is necessary to know the ultimate longitudinal strength of hull girders. Furthermore, in order to estimate oil spills due to tanker collisions and groundings, it is necessary to *To whom correspondence should be addressed. 485 Marine Structures 0951-8339/93/$06.00 © 1993 Elsevier Science Publishers Ltd, England. Printed in Great Britain.