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Wave endurance time: A new concept for structural assessment under extreme waves Dastan, Jahanmard, Tabeshpour, Seif and Mehdigholi Abstract The wave endurance time method is a novel dynamic approach to conveniently estimate structural performance under various extreme wave conditions. In this method, offshore structures are subjected to a gradually intensifying sea surface profile called wave function, and their performance is assessed in different sea state conditions by a single time history analysis. From a wave endurance time analysis perspective, structural behavior is judged based on the maximum time duration that a structure can withstand the wave function. In this study, a description of the wave endurance time concept is presented, and generation of the initial type of wave functions is thoroughly addressed. In addition, the evaluation of a simplified model of a realistic jacket platform under extreme wave conditions is viewed through the lens of a wave endurance time study. The accuracy of this approach is investigated by a comparative study between the wave endurance time approach and typical 3-h time history analyses. The results indicate that the wave endurance time approach is capable of estimating the results of 3-h simulations with acceptable accuracy and less computational effort. منبع دانلود Tabeshpour_Wave.endurance.2015-first&end.Pages.pdf

Modification of endurance wave analysis based on New-wave theory Saeed Mohajernassab, Mohammad Ali Dastan Diznab, Hamid Mehdigholi, Mohammad Saeed Seif∗ and Mohammad Reza Tabeshpour Department of Mechanical Engineering, Center of Excellence in Hydrodynamics and Dynamics of Marine Vehicles, Sharif University of Technology, Tehran, Iran (Received 30 June 2014; accepted 28 January 2016) The main objective of this investigation is to modify endurance wave analysis (EWA) based on New-wave theory for convenient assessment of offshore structures under extreme waves. EWA is a novel time history based approach to evaluate structural performance in various excitation levels of wave loading by intensifying wave records. In this article, modifications are proposed to determine appropriate time duration and intensifying trend for reliable and practical assessment of offshore structures. In this way, a simplified model of a real jacket platform is utilised to investigate the application of this approach under extreme wave conditions in the Persian Gulf and results are compared with typical three hour random wave simulations. It is shown that in extreme waves, except resonance states, proposed method can estimate the structural response with acceptable accuracy and very low computational costs. Keywords: New-wave theory; endurance wave analysis; jacket platform; extreme waves; assessment منبع دانلود Tabeshpour_Modification-of-endurance-wave.pdf