Dynamic Load Analysis of Sealing Mechanisms in Floating Offshore Structures

The primary focus is to develop a test bench specification that evaluates the durability and effectiveness of various sealing systems subjected to dynamic forces.

Floating offshore structures rely on mooring systems such as flexible cables, anchors, or lines that secure them to the seabed. These installations must withstand external accelerations caused by waves and wind, making seal integrity a critical factor in their design. The report examines two primary sealing systems—the excess rubber system and the excess groove system—both of which serve as crucial mechanisms to prevent oil leaks between bolted components.

Understanding their performance under dynamic conditions is essential due to the potential risks of oil leakage, environmental hazards, and fire outbreaks.

The excess rubber system utilizes an O-ring with a cross-section 15-30% larger than its groove, creating a tight seal upon compression. In contrast, the excess groove system features a groove larger than the sealing element, filling approximately 85-90% of its volume, with a compression rate of about 30-35%. Both systems are analysed through Finite Element Method (FEM) simulations, which evaluate their response to hydrostatic pressure and tilting forces. The simulations apply sinusoidal load variations with angular amplitude changes of 16° and frequencies ranging from 0.1 to 0.3 Hz. Results indicate that both sealing systems withstand the dynamic loading conditions without exhibiting leaks or fatigue-related damage. While the bolted components experience pressure variations, these do not compromise their structural integrity. However, further empirical validation is necessary to confirm long-term performance and resilience under real-world offshore conditions.

To verify the analytical results, a scaled mock-up is constructed and subjected to rigorous testing under environmental conditions, including corrosive and dynamic factors, to simulate real service exposure conditions acting on the sealing systems. The test setup features different configurations for the rubber and groove systems, with accessories and sensors to assess their efficiency under mechanical wave conditions.

In summary, the article provides valuable insights into the design and optimization of sealing systems for offshore applications. By integrating numerical simulations with experimental testing, the study establishes foundational criteria for the development of robust sealing mechanisms capable of enduring the harsh offshore environment. The findings contribute to advancing offshore engineering, ensuring improved safety and reliability in floating installations.