Experimental and numerical analysis of ultimate compressive strength of stiffened panel with openings

Abstract Ship scantlings are obtained through a linear elastic design framework. In relatively long ships, the mid-ship’s ultimate strength capacity must be checked whether it is below a certain level (given factor of safety). Smith’s method is based on an incremental-iterative approach where constitutive equations of idealized representative components are used to model the different involved buckling modes. The literature body neglects the local bending effect applied at the stiffener with the attached plating (considered here as the representative element). This work studies the eccentrically loaded representative element from its compressive resistance point of view. The eccentricity sources from the linear varying strain field produced as a result of pure bending of the ship’s mid-section and is relative to the location of the stiffened panel from the ship’s section Neutral Axis. Therefore, the representative element has been considered as a part of the ship’s structure and the inherent eccentricity is analytically calculated in terms of geometric and material properties. A computational study has been further performed in a non-linear finite element environment in order to figure out the effect of the eccentricity level to the ultimate compressive strength of the representative element. Geometric distortions have been also included in the FE models in order to allow for accurate strength calculations. Numerical results have shown that, in realistic proportions of large ships, the further the representative element is located from the mid-ship’s NA the smaller is the deviation from pure compressive load strength analysis results. However, for the element laying near the ship’s NA, idealized models overestimate the strength by 10% compared to realistic analytical / numerical results for the typical scantling case considered.

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Ultimate Compressive Strength of Stiffened Panel: An Empirical Formulation for Flat-Bar Type

Journal of Marine Science and Engineering ◽

10.3390/jmse8080605 ◽

2020 ◽

Vol 8 (8) ◽

pp. 605 ◽

Cited By ~ 1

Author(s):

Do Kyun Kim ◽

Su Young Yu ◽

Hui Ling Lim ◽

Nak-Kyun Cho

Keyword(s):

Finite Element ◽

Compressive Strength ◽

Ultimate Strength ◽

Limit State ◽

Ultimate Compressive Strength ◽

Stiffened Panel ◽

Ultimate Limit State ◽

Longitudinal Compression ◽

Strength Performance ◽

Ultimate Limit

This research aims to study the ultimate limit state (ULS) behaviour of stiffened panel under longitudinal compression by a non-linear finite element method (NLFEM). There are different types of stiffeners mainly being used in shipbuilding, i.e., T-bar, flat-bar, and angle-bar. However, this research focuses on the ultimate compressive strength behaviour of flat-bar stiffened panel. A total of 420 reliable scenarios of flat-bar stiffened panel were selected for numerical simulation by the ANSYS NLFEM. The ultimate strength behaviours obtained were used as data for the development of closed form shape empirical formulation. Recently, our group proposed an advanced empirical formulation for T-bar stiffened panel, and the applicability of the proposed formulation to flat-bar stiffened panel is confirmed by this study. The accuracy of the empirical formulation obtained for flat-bar stiffened panel was validated by finite element (FE) simulation results of statistical analysis (R2 = 0.9435). The outcome obtained will be useful for ship structural designers in predicting the ultimate strength performance of flat-bar type stiffened panel under longitudinal compression.

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Ultimate Compressive Strength of Stiffened Panel: An Empirical Formulation for Flat-bar Type

10.20944/preprints202007.0572.v1 ◽

2020 ◽

Author(s):

Do Kyun Kim ◽

Su Young Yu ◽

Hui Ling Lim ◽

Nak-Kyun Cho

Keyword(s):

Compressive Strength ◽

Ultimate Strength ◽

Limit State ◽

Ultimate Compressive Strength ◽

Stiffened Panel ◽

Ultimate Limit State ◽

Longitudinal Compression ◽

Strength Performance ◽

Different Types ◽

Ultimate Limit

This research aims to study the ultimate limit state (ULS) behaviour of stiffened panel under longitudinal compression by non-linear finite element method (NLFEM). There are different types of stiffeners being used in shipbuilding i.e. T-bar, flat-bar and angle-bar. However, this research focuses on the ultimate compressive strength behaviour of flat-bar stiffened panel. A total of 420 of reliable scenarios of flat-bar stiffened panel are selected for numerical simulation by ANSYS NLFEM. The ultimate strength behaviours obtained were used as data for the development of closed form shape empirical formulation. Recently, Kim et al. [1] proposed for advanced empirical formulation for T-bar stiffened panel and the applicability of the proposed formulation to flat-bar stiffened panel will be confirmed by this study. The accuracy of the empirical formulation obtained for flat-bar stiffened panel has been validated by FE simulation results of statistical analysis (R2 = 0.9435). The outcome obtained will be useful for ship structural designers in predicting the ultimate strength performance of flat-bar type stiffened panel under longitudinal compression.

Download Full-text