Session: 01-04-02 Design & Analysis-II

Paper Number: 127920

127920 - An Equivalent Wind State Method for Efficient Fatigue Assessments 

The current paper proposes a method that can condense wind scatter diagrams to a much fewer number of wind states/blocks to represent the fatigue damage, which can dramatically reduce the fatigue calculation efforts. In the proposed method, both the probability distribution of occurrence and the wind turbulence variation associated with different mean wind speeds are explicitly accounted for. Furthermore, the nonlinearities in wind loads and variation in wind profile and turbulence over height are considered.  By adopting nonlinear time domain dynamic analyses and applying the proposed method into the fatigue damage calculation of two types of structures (with different characteristics in dynamics, dimensions, and relative height from ground/sea surface), the obtained fatigue damage using the proposed method is compared with that using full wind scatter diagram. The comparisons show a satisfied engineering accuracy of the proposed simplified method, which justify its engineering applications. To further reduce the engineering efforts, based on the determined equivalent wind state(s), a fatigue damage assessment method by using static analysis results is proposed. The method is especially suitable for engineering applications requiring a large amount of assessment efforts for wind induced fatigue. It can be applied for assessing the fatigue damages for a wide range of offshore structures with different characteristics.

Presenting Author: Junbo Jia Odfjell Technology

Presenting Author Biography: Dr. Junbo Jia is currently a senior principal engineer at Odfjell Technology, Norway.He has been extensively involved in engineering projects for offshore and energy industries, associated with different types of offshore and onshore infrastructures.

Dr. Jia is the sole author of three comprehensive scientific monographs by Springer: Essentials of Applied Dynamic Analysis (2013), Modern Earthquake Engineering (2017) and Soil Dynamics and Foundation Modeling (2018). All the three books receive an extensive amount of downloads based on Springer official data. He is also the editor of a book volume by CRC press: Engineering Dynamics and Vibrations - Recent Developments (2019).

Dr. Jia is an elected member of Norwegian Academy of Technological Sciences (2019). He is listed in several global versions of the Who's Who publications. He has received several international and national awards such as the Vice Admiral E.L. Cochrane award by SNAME and the Best Paper Award by Journal of Ships and Offshore Structures (Taylor & Francis).

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