Assessment of CALM Buoys Motion Response and Dominant OPB/IPB Inducing Parameters on Fatigue Failure of Offshore Mooring Chains

Chesterton

Butler

et al. 2022

JMSE

Currently, the properties of composites have been harnessed on pipelines in the marine offshore industry. In this study, marine bonded composite hose (MBCH) is presented. It is aimed at understanding the stress/strain distribution on marine bonded hoses using local design pressure under burst and collapse cases. This study also investigates composite material modelling, hose modelling, liner wrinkling, helical spring deformation, and two MBCH models—with and without ovalisation. The ovalized model is considered the simplified model in this research. A mesh study was carried out on meshing the hose layers. In this study, local design pressure was considered and not operational pressure. This finite element model was adopted to predict the deformation and mechanical response behaviour of MBCH. From this study, composites could be considered to improve conventional marine hoses. The study findings include identification of buckled sections on the hose and stressed zones on the helix reinforcement. Highly reinforced hose ends are recommended in ends of the MBCH as they had maximum stress and strain values.

Section: Introductionmentioning

confidence: 99%

Finite Element Modelling on the Mechanical Behaviour of Marine Bonded Composite Hose (MBCH) under Burst and Collapse

Chesterton

Butler

et al. 2022

JMSE

“…The buoy's size is determined by the amount of counter buoyancy needed to keep the anchor chains in place, and the anchor chains are determined by environmental factors and the size of the vessel. Some experimental investigations have been conducted on the CALM buoy by varying the buoy skirts [56][57][58][59][60]. Edward & Dev [60] accessed the motion response of the CALM buoy with some empirical estimation on the viscous damping.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Motion Characterisation of CALM Buoy Hose System under Water Waves

Wang

2022

JMSE

The application of marine bonded hoses has increased in recent times, due to the need for more flexible conduits and flexible applications in the offshore industry. These marine structures include Catenary Anchor Leg Moorings (CALM) buoys and ocean monitoring buoys. Their attachments include floating hoses, submarine hoses and submarine cables. However, the structural performance challenges of a CALM buoy system from its hydrodynamics water waves and other global loadings, have led to the need for this investigation. In this study, a detailed presentation on the motion characterisation of the CALM buoy hose system is presented. The CALM buoy is a structure with six degrees of freedom (6DoF). A well-detailed experimental presentation on the CALM buoy hose model conducted in Lancaster University Wave Tank is presented using three novel techniques, which are: a digital image captured using Imetrum systems, using an Akaso 4K underwater camera, using wave gauges arranged in a unique pattern and using underwater Bluetooth sensors. The buoy model was also found to respond uniquely for each motion investigated under water waves. The results showed that the higher the profile, the higher the response of the buoy. Thus, this study confirms the existence of flow patterns of the CALM buoy while floating on the water body.

“…These successfully approached wave theories have been developed to solve some of these issues. Wave forces can generate stresses due to material complexities, leading to excessive motion predictions, system failures, and material breakdowns [101][102][103]. They could produce substantial deformations, bending, and torsional forces in marine hoses.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Hydrodynamic Characteristics, Wave–Current Interaction and Sensitivity Analysis of Submarine Hoses Attached to a CALM Buoy

Wang

2022

JMSE

There is an increase in the utilization of the floating offshore structure (FOS) called Catenary Anchor Leg Mooring (CALM) buoys and the attached marine hoses due to the increasing demand for oil and gas products. These hoses are flexible and easier to use but have a short service life of about 25 years. They are adaptable in ocean locations of shallow, intermediate and deep waters. In this research, a numerical model was developed using a coupling method modeled by utilizing ANSYS AQWA and Orcaflex (Orcina Ltd., Ulverston, UK) dynamic models of the CALM buoy hoses. Two cases were comparatively studied: Lazy-S and Chinese-lantern configurations, under ocean waves and current. Comparisons were also made between coupled and uncoupled models. This research presents the hydrodynamic characteristics with a sensitivity analysis on the influence of waves, current attack angle, soil gradient, soil stiffness and environmental conditions that influence the performance of marine hoses. The study comparatively looked at the configurations from dynamic amplification factors (DAF) on marine hoses. The results show that marine hoses can be easily configured to suit the designer’s need, seabed soil type, seabed topography and the profiles that are useful for manufacturers. The sensitivity analysis also shows the effect of hose parameters on its hydrodynamic behavior from the wave–current interaction (WCI).