Elastic-plastic behaviour of offshore steel structures under impact loads

✍ Scribed by Yong Bai; Preben Terndrup Pedersen

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 843 KB
• Volume: 13
• Category: Article
• ISSN: 0734-743X
• DOI: 10.1016/0734-743x(93)90110-s

✦ Synopsis

This paper presents an accurate and efficient method for the collision analysis of offshore steel structures. A nonlinear force-displacement relationship is derived for the simulation of the local indentation in a hit tubular member and a three-dimensional beam-column element is developed for the modelling of the global behaviour of the struck structure. Large deformations, plasticity and strain-hardening of the beam-column elements are accounted for by combining an elastic large displacement analysis theory with the plastic node method. The dynamic elastic-plastic response of offshore platforms in typical ship collision situations is investigated. It is shown that strain-hardening plays an important role in the impact response. A large part of the impact energy is transformed into plastic deformation energy of the struck structure in a severe ship--platform collision. Therefore, a rational collision analysis should take into account the effects of large deformations, plasticity and strain-hardening. The presented procedure has the advantage that the number of elements in the analysis model need not be larger than the number of elements used in normal linear analysis procedures. Furthermore, the elastic-plastic stiffness matrices are derived without numerical integrations over the cross-sections.