Ultimate and residual strength of benchmark hull models


  1. Smith, M. J.
Corporate Authors
Defence Research and Development Canada, Atlantic Research Centre, Halifax NS (CAN)
The ultimate and residual strength in vertical bending of three benchmark hull girder models are evaluated using nonlinear Finite Element Analysis (FEA) and using Smith’s simplified method. The benchmark models are evaluated in three conditions: intact, with simulated grounding damage, and with simulated collision damage. Two different Smith’s method calculations are performed for each model, in which load shortening curves are generated either using the International Association of Classification Societies (IACS) analytical formulas, or by interpolating from the Ultimate Strength ULTMAT database of pre-calculated curves. Smith’s method predictions using the IACS formulas are found to agree well with FEA predictions for interframe collapse of longitudinal structure with high-column slenderness, whereas Smith’s method does not agree well with FEA when an overall collapse mode is predicted. For structures with low-column slenderness, Smith’s method is found to predict ultimate strengths that are higher than the FEA predictions. Gross damage to the main deck and shear strake, or to the hull bottom, is found to reduce ultimate strength by more than 50% in some cases. In percentage terms, strength reductions are up to three to four times the percentage reduction in the effective cross sectional area. Overall collapse is the preferred mode of failure with collision damage, whereas interframe collapse is preferred with grounding damage.

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Ship Structure;ultimate strength;residual strength;gross damage;Finite Element Analysis
Report Number
DRDC-RDDC-2019-R021 — Scientific Report
Date of publication
01 Mar 2019
Number of Pages
Electronic Document(PDF)

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