<p style="text-align: justify">&nbsp; &nbsp; The present paper continues the recent works reported by Liu and Guedes Soares (2020) where finite element simulations were reported to investigate the ultimate strength of a container ship hull girder under cyclic bending moments. Here a membrane LNG carrier is investigated to evaluate the “cyclic ultimate strength” of specialized ship hull structures including double bottoms, sides and decks. In navigating in waves a ship is subjected to alternate bending moments in hogging and sagging conditions. The specialized ship hull structures may collapse due to the alternating structural plasticity in extreme sea conditions when the cyclic external load is greater than the elastic limit but lower than the monotonic ultimate limit. The ship hull girder can experience a weaker ultimate strength under cyclic loading than under monotonically increasing bending moment as assumed in the conventional analysis. The main work of this paper aims to analyse the ultimate strength and to compare the collapse modes of a LNG carrier hull girder under monotonic and dynamic cyclic bending moments, revealing the difference in their failure principles. The nonlinear finite element numerical analyses under cyclic loading consider the ratcheting effect and the Bauschinger effect in steel. In the view of ship structural analysis, future developments of the limit state analysis should pay attention to the concept of “cyclic ultimate strength”.</p>

Evaluation of Cumulative Collapse of a Lng Carrier Hull Girder Under Dynamic Cyclic Bending Moments

Paper Proceedings: https://asmedigitalcollection.asme.org/OMAE/OMAE2021/volume/85116

OMAE 2021

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