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Ocean Systems Engineering
  Volume 7, Number 3, September 2017 , pages 225-246
DOI: https://doi.org/10.12989/ose.2017.7.3.225
 

Suppression of tension variations in hydro-pneumatic riser tensioner by using force compensation control
Hooi-Siang Kang, Moo-Hyun Kim, Shankar S. Bhat Aramanadka, Heon-Yong Kang and Kee-Quen Lee

 
Abstract
    Excessive dynamic-tension variations on the top-tensioned risers (TTRs) deteriorate the structural integrity and cause potential safety hazards. This phenomenon has become more remarkable in the development of deep-water fields with harsher environmental loads. The conventional prediction method of tension variations in hydro-pneumatic tensioner (HPT) has the disadvantage to underestimate the magnitude of cyclic loads. The actual excessive dynamic tension variations are larger when considering the viscous frictional fluid effects. In this paper, a suppression method of tension variations in HPT is modeled by incorporating the magneto-rheological (MR) damper and linear-force actuator. The mathematical models of the combined HPT and MR damper are developed and a force-control scheme is introduced to compensate the excessive tension variations on the riser tensioner ring. Numerical simulations and analyses are conducted to evaluate the suppression of tension variations in HPT under both regular- and irregular-wave conditions for a drilling riser of a tensioned-leg platform (TLP). The results show that significant reduction of tension variations can be achieved by introducing the proposed system. This research has provided a theoretical foundation for the HPT tension control and related structural protection.
 
Key Words
    top-tensioned riser; hydro-pneumatic tensioner; tension variations; tension control; force compensation; magneto-rheological damper
 
Address
Hooi-Siang Kang: Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Johor, Malaysia;
Institute for Vehicle Systems and Engineering (IVeSE), Universiti Teknologi Malaysia, Johor Bahru, Malaysia
Moo-Hyun Kim and Heon-Yong Kang: Department of Ocean Engineering, Texas A&M University, College Station, Texas, USA
Shankar S. Bhat Aramanadka: Sabah Shell Petroleum Co. Ltd., Kuala Lumpur, Malaysia
Kee-Quen Lee: Department of Mechanical Precision Engineering, Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia Kuala Lumpur, Wilayah Persekutuan Kuala Lumpur, Malaysia
 

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