Steel reinforced bonded vulcanized rubber loading hoses are frequently used in offshore oil loading systems. The hoses are used as offloading system between platforms and shuttle tankers and represent a flexible economical feasible solution for hydrocarbon transfer. The reliability of these hoses throughout the service life is an important issue both with respect to operational availability and with respect to environmental safety. Hence, the load bearing capacity of these hoses and the fatigue endurance become matters of concern and important design topics. Due to the large deformation of these hoses and the complicated composite structure in the hose wall, the hoses are difficult to analyze with respect to the strain and stress response when subjected to the various load cases.
The present paper presents extreme load capacity assessments and a fatigue life prediction methodology for bonded loading hoses subjected to high pressure, tension and bending in a catenary configuration and in repeated reeling under high hose tension. The load effects on the hose during the reeling operations and the fatigue life predictions methodology for both steel components and rubber are emphasized in the present work. A combination of advanced finite element modeling and full scale testing to corroborate the analyses results has been carried out to qualify the hoses to be fit for service and to fulfill the API17K requirements. The present paper presents results from advanced finite element models and full scale testing for a 20″ bonded hose with steel end fittings. The investigation brings new knowledge in the field of hose design methodology and the results are discussed in light of current requirements and regulations such as OCIMF and API 17K.
A consequence of the comprehensive testing and analysis work is that the requirement for testing in future projects is reduced, and calibrated analysis models can be used to predict hose capacities.