Design Load Measures for Vapor Cloud Explosion on Complex Systems: Review and Recommendations

Author(s):  
Maryam Mortazavi ◽  
YeongAe Heo ◽  
Yue Li

A hydrocarbon Vapor Cloud Explosion (VCE) is one of critical hazardous events in offshore installations. Once VCE occurs in the ocean, it results in tremendous economic loss, casualties, and environmental impact. The combustion mechanism of VCE differs from HE in particular in complex geometries (e.g. offshore oil and gas production facilities) as there exist many objects which can trigger severe turbulences. Although many research efforts have been made to develop design provisions for blast resistant structures, most of those provisions are based on high-order explosives (HE) such as TNT (TriNiTrotoluene) in a free field. Therefore, typical blast resistant structural design standards were examined to address the weaknesses of standards in this study. Existing blast wave models which provide key design load parameters were also reviewed to address limitations of each approach. Finally, essential recommendations are discussed in this paper for future studies to improve blast resistant structural design provisions with the ultimate aim of protecting our lives, assets and environment from VCE in the ocean.

Author(s):  
Inge Lotsberg

Conical connections are important structural members for the integrity of most types of welded tubular structures. They are for example used in traditional jacket structures for oil and gas production and in monopiles for support of wind turbines where an optimal design is aimed for. From contact with the industry, it is noted that there is uncertainty about the basis for the stress concentration factors (SCF) for conical connections in design standards for fatigue assessment. This is related to how fabrication tolerances are accounted for and how a transition in thickness from the cone to the tubular or the cylinder should be made to minimize stresses due to thickness transitions and fabrication tolerances. Analytical expressions for stress concentrations at conical transitions are outlined in this paper to get a better understanding of the effect of thickness of the cone and the cylinder. By a proper basis for fatigue design, it is possible to control additional stresses from thickness transitions and fabrication tolerances at these connections.


Author(s):  
Inge Lotsberg

Conical connections are important structural members for the integrity of most types of welded tubular structures. They are for example used in traditional jacket structures for oil and gas production and in monopiles for support of wind turbines where an optimal design is aimed for. From contact with the industry it is noted that there is uncertainty about the basis for the stress concentration factors for conical connections in design standards for fatigue assessment. This is related to how fabrication tolerances are accounted for and how a transition in thickness from the cone to the tubular or the cylinder should be made to minimise stresses due to thickness transitions and fabrication tolerances. Analytical expressions for stress concentrations at conical transitions are outlined in this paper to get a better understanding of the thickness of the cone and the cylinder. By a proper basis for fatigue design it is possible to control additional stresses from thickness transitions and fabrication tolerances at these connections.


1994 ◽  
Author(s):  
Richard F. Mast ◽  
D.H. Root ◽  
L.P. Williams ◽  
W.R. Beeman

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