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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

Performance-based assessment of steel jacket platforms by wave endurance time method Jahanmard, Dastan , Mehdigholi, Tabeshpour and Seif Ships and Offshore Structures In this article, wave endurance time (WET) is addressed as an applicable method for performance-based assessment of fixed offshore structures under extreme waves. In this method, inspired by the endurance time method in the field of earthquake engineering, artificial wave records called wave functions are designed so that their excitations gradually increase with time. Therefore, the main advantage of the proposed method is that it can assess the structural performance under various wave load conditions through a single time-history analysis. Moreover, the reliability of structures can be evaluated on the basis of the time that the structural response is still acceptable. In this study, generation of these artificial records and their application to assessment finite element model of a fixed offshore structure are described based on the extreme waves of the Persian Gulf. In order to consider the accuracy of this method in estimation of the structural response, finite element method is utilised to compare the results of the WET method with the results of typical 3-hour random records. It is concluded that WET is a computationally attractive method to estimate the structural response with reasonable accuracy. منبع دانلود Tabeshpour_Performance-based.2015.pdf