Offshore Structure Response due to Ship Collision on Jacket Legs

Abstract

This paper discusses graded and collision velocity supply vessel influence to local and global structure damage subject to collision. This case study for CONOCO BELANAK wellhead platform that approaching with of 2500 tonnes of supply vessel with tidal variation for each collision scenario. Deformation of the jacket leg occurs causes by material inability to proof against pressure. This paper uses 2 software are ANSYS LS-DYNA 9.0 to acquire local deformation and GT-STRUDL 27.0 version to acquire global deformation included dynamic transient analysis. Outside diameter of Jacket Leg is 1.651 m with wall thickness is 0.0381 m. Normal velocity in each sideway, stern; manoeuvring collision and extreme velocity is 0.28 m/s, 0.39 m/s and 0.74. Extreme velocity in each sideway and stern collision is and 10% exceedance velocity is 0.54 m/s, 0.73 m/s and 1.29 m/s. The result of this paper is dent of the landing platform for each normal and extreme is 0.2725 m, 0.2352 m, and 0. 3241 m/s it must be repaired or changed because of it is 30% larger than spacing frame. Maximum displacement x, y, z direction is 0.2423 m on 0.38 s, 0. 0559 m on 0.39 s, 0.7492 m on 0.41 s. The deformation in landing platform, jacket leg and jacket structure is smaller than research result indeed.