Session: 06-05-02 Marine Hydrodynamics

Submission Number: 155338

Statistical ULS Evaluation of Tension Leg Slackline for Lightweight TLP Platforms in Unidirectional Long Crest Wave Using Linear and Second-Order Potential Flow Solvers 

Lightweight tension leg platforms whose ratio of mass to buoyancy is lower than 0.75 on average have been used commonly for supporting wind turbines or exchange power stations. The outstanding difference between mass and buoyancy leads to a massive pretension load endured by the tendons. The massive pretension loads cause notable acceleration at fairleads when the structure is exposed to the range of high-crest wave frequency and correspondingly the slackline may occur in tendons. Hence, the ultimate limit state is dictated by the regulations and standards along with the basic design, which imposes load factors for evaluating slackline. Accordingly, the environmental loads such as the 100-year wave record must be taken into account while obtaining 3-hour elapsed tension loads along tendons for statistical analysis and determining the extreme tension loads. Therefore, an opportunity is taken in the present study to compare the numerical results of linear and second-order potential flow solutions for slackline evaluation in long crest unidirectional incident waves. The second-order potential model uses the full quadratic transfer function to consider the second-order wave components derived by the interference of frequency pairs. Moreover, the steady drift force is involved in the pretension load estimation where the linear stiffness of tendons is assumed.

Presenting Author: Arash Abbasnia University of Rostock

Presenting Author Biography: Arash Abbasnia holds a PhD in Ocean Engineering. His expertise focuses on the computational marine hydrodynamic and numerical solutions of wave-body interaction problems. He has developed extensive numerical models to compute the response of floating structures in different environmental conditions. He has served as a researcher in research projects in scopes of ship hydrodynamics, offshore renewable energy and offshore structures. Moreover, he has been appointed as an editorial member in pioneering scientific journals.