Ice-breaking Cone Research Articles

Optimum design of ice-resistant offshore jacket platforms in the Bohai Gulf in consideration of fatigue life of tubular joints

Economy and ice-resistance are two factors that must be considered in the design of offshore oil platforms in the Bohai Gulf. This paper focuses on the optimal design of ice-resistant offshore jacket platforms in the Bohai Gulf in consideration of fatigue life of tubular joints, with the minimum initial weight and satisfying dynamic properties. An efficient fatigue analysis procedure based on spectral analysis is proposed, in which a hybrid finite element model is adopted to simulate the jacket platform and the tubular joints, and the pseudo-excitation method is used to calculate the power spectral density of the hot spot stress. Finally, a practical jacket platform with an ice-breaking cone in the Bohai Gulf is optimized, and the results demonstrate that the fatigue life of tubular joints could be improved and the weight of jackets decreased simultaneously.

A random ice force model for narrow conical structures

This paper describes a time-varying random ice force model for narrow conical structures. The model concerns a situation where a uniform ice sheet acts on a narrow cone and fails by bending in a mode where the broken ice pieces are cleared away. The ice force is simplified as a series of impulses with random magnitudes and periods, which are based on a statistical analysis of the load panel data obtained in full scale tests. It was found that normal distributions can be used as approximations to the statistical characteristics of the force amplitudes and periods. This paper addresses the determination of the distribution parameters. The random ice load function that is derived in this paper can be used in the dynamic analysis of compliant offshore structures with narrow ice breaking cones that are subjected to ice actions. Further limitations are discussed in the paper.

Ice-Induced Jacket Structure Vibrations in Bohai Sea

Full-scale tests of ice-structure interaction were conducted on three multileg jacket platforms in Bohai Sea. Two of them were installed with ice-breaking cones on each of their four legs to reduce...