Ultimate Strength Analysis of Ship Hull Girder Under Random Material and Geometric Properties

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Suhas Vhanmane ◽  
Baidurya Bhattacharya
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Initial Imperfection ◽  
Statistical Dependence ◽  
Strength Analysis ◽  
Bulk Carrier ◽  
Geometric Properties ◽  
Hull Girder ◽  
Initial Imperfections ◽  
Different Levels

The ultimate strength of a ship’s hull depends on its material and geometric properties, some or all of which may be random in nature. In addition, initial imperfections in the form of initial deflection and residual welding stresses in plating between stiffeners can significantly affect the hull ultimate strength. In this paper, the effect of randomness in yield strength and in the initial imperfections on ultimate hull girder strength is determined. Different levels of statistical dependence between yield strength and initial imperfection of stiffeners and plating between stiffeners have been considered. The methodology is applied on a bulk carrier and a VLCC tanker.

Ultimate Strength Analysis of Ship Hull Girder Under Random Material and Geometric Properties

2009 ◽  
Author(s):  
Suhas Vhanmane ◽  
Baidurya Bhattacharya
Keyword(s):  
Yield Strength ◽  
Ultimate Strength ◽  
Initial Imperfection ◽  
Statistical Dependence ◽  
Strength Analysis ◽  
Bulk Carrier ◽  
Geometric Properties ◽  
Hull Girder ◽  
Initial Imperfections ◽  
Different Levels

The ultimate strength of a ship’s hull depends on its material and geometric properties, some or all of which may be random in nature. In addition, initial imperfections in the form of the initial deflection and residual welding stresses in the plating between stiffeners, can significantly affect the hull ultimate strength. In this paper, the effect of randomness in yield strength, member thickness and in the initial imperfections on ultimate hull girder strength is determined. Different levels of statistical dependence between the yield strength and initial imperfection of all stiffeners and plating between stiffeners have been considered. The methodology is applied on a bulk carrier and a VLCC tanker.

Automated Assessment of Ultimate Hull Girder Strength

2003 ◽  
Vol 125 (3) ◽  
pp. 211-218 ◽  
Author(s):  
M. J. Smith ◽  
N. G. Pegg
Keyword(s):  
Ultimate Strength ◽  
Progressive Collapse ◽  
Three Dimensional ◽  
Strength Analysis ◽  
Cross Sectional ◽  
Strength Assessment ◽  
Hull Girder ◽  
Single User Interface ◽  
Interaction Curves ◽  
The Uk

An automated approach to ultimate hull girder strength assessment using DRDC’s ultimate strength analysis suite (ULTSAS) is described. The analysis suite improves the ability to perform rapid ultimate strength assessments by providing access to UK and Canadian analysis codes and databases under a single user interface. The interface also allows for automatic cross-sectional model generation from three-dimensional ship finite element models with the MGDSA program. The main features of the ULTSAS system are described, including cross-sectional modelling, and the use of load-shortening curve databases. The paper also provides a review of the progressive collapse method for determining ultimate strength, which is now used in both the UK and Canadian analysis codes. Two numerical approaches are described, one based on curvature incrementing and the other on moment incrementing. It is shown that the moment incrementing procedure produces more accurate bi-axial interaction curves in some instances. Results are obtained for two damage configurations of the HALIFAX class frigate.

Finite Element Analysis on the Hull Girder Ultimate Strength of Asymmetrically Damaged Ships

2016 ◽  
Author(s):  
Muhammad Zubair Muis Alie ◽  
Ganding Sitepu ◽  
Juswan Sade ◽  
Wahyuddin Mustafa ◽  
Andi Mursid Nugraha ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ultimate Strength ◽  
Cross Sections ◽  
Progressive Collapse ◽  
Ship Hull ◽  
Strength Analysis ◽  
Functional Requirements ◽  
Element Analysis ◽  
Hull Girder

This paper discusses the influence of asymmetrically damaged ships on the ultimate hull girder strength. When such damages take place at the asymmetric location of cross sections, not only translation but also inclination of instantaneous neutral axis takes place during the process of the progressive collapse. To investigate this effect, the Finite Element Analysis (FEA) is employed and the damage is assumed in the middle hold. The collision damage is modeled by removing the plate and stiffener elements at the damage region assuming the complete loss of the capacity at the damage part. For the validation results obtained by Finite Element Analysis of the asymmetrically damaged ship hull girder, the simplified method is adopted. The Finite Element method of ultimate strength analysis of a damaged hull girder can be a practical tool for the ship hull girder after damages, which has become one of the functional requirements in IMO Goal Based Ship Construction Standard.

Ultimate Strength of a Capesize Bulk Carrier in Hogging and Alternate Hold Loading Condition

2010 ◽  
Author(s):  
Zhi Shu ◽  
Torgeir Moan
Keyword(s):  
Ultimate Strength ◽  
Loading Condition ◽  
Fe Analysis ◽  
Fe Model ◽  
Bulk Carrier ◽  
Local Pressure ◽  
Local Loads ◽  
Hull Girder ◽  
Bulk Carriers ◽  
Global And Local

The ultimate hull girder strength of a Capesize bulk carrier under combined global and local loads in hogging and alternate loading condition (AHL) is evaluated using nonlinear finite element (FE) analysis with ABAQUS software. A three-cargo-hold FE model with fine mesh in the middle cargo hold is developed for the nonlinear FE analysis. The initial geometrical imperfections are introduced in the double bottom of the middle cargo hold. Both material and geometrical nonlinearities are taken into account in the FE model. The most critical situation for the longitudinal strength assessment of bulk carriers in hogging is the AHL condition with middle cargo hold empty under combined global and local loads. The local loads, i.e. the external sea pressure and internal cargo pressure are adopted according to Common Structural Rules for bulk carriers (CSR-BC). The ultimate hull girder strength with various local pressure load levels is investigated for the heavy cargo AHL in hogging condition. It is found that the ultimate strength of the hull girder can be significantly reduced due to the action of the local pressure loads compared with that obtained under pure hogging bending.

scholarly journals Analysis on the Hull Girder Ultimate Strength of a Bulk Carrier Using Simplified Method Based on an Incremental–Iterative Approach

2006 ◽  
Author(s):  
O. Ozguc ◽  
P. K. Das ◽  
N. D. P. Barltrop
Keyword(s):  
Ultimate Strength ◽  
Interaction Design ◽  
Curvature Vector ◽  
Structural Response ◽  
Bending Moment ◽  
Iterative Approach ◽  
Bulk Carrier ◽  
Hull Girder ◽  
Simplified Method ◽  
The Moment

The hull girder ultimate strength of a typical bulk carrier is analyzed using simplified method based on an incremental–iterative approach. First, vertical bending moment is examined by seven different methods. The moment versus curvature curves and the values of the ultimate longitudinal moments at collapse states are determined for both hogging and sagging cases. Secondly, the ultimate strength under coupled vertical and horizontal bending moment is accounted. An interaction curve is obtained corresponding to the results of series of calculation for the ship hull subject to bending conditions with different angles of curvature. It is found that the interaction curve is asymmetrical because the hull cross-section is not symmetrical with respect to horizontal axis and the structural response of the elements under compression is different from that under tension due to nonlinearity caused by buckling. The angles of the resultant bending moment vector and that of the curvature vector are different in investigated cases. The interaction design equations proposed by other researches are also addressed to discuss the results presented by this study.

scholarly journals Analysis on the Hull Girder Ultimate Strength of a Bulk Carrier Using Simplified Method Based on an Incremental-Iterative Approach

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Özgür Özgüç ◽  
N. D. P. Barltrop
Keyword(s):  
Ultimate Strength ◽  
Interaction Design ◽  
Curvature Vector ◽  
Structural Response ◽  
Bending Moment ◽  
Iterative Approach ◽  
Bulk Carrier ◽  
Hull Girder ◽  
Simplified Method ◽  
The Moment

The hull girder ultimate strength of a typical bulk carrier is analyzed using a simplified method based on an incremental—iterative approach. First, vertical bending moment is examined by seven different methods. The moment versus curvature curves and the values of the ultimate longitudinal moments at collapse states are determined for both hogging and sagging cases. Second, the ultimate strength under coupled vertical and horizontal bending moment is accounted. An interaction curve is obtained, which corresponds to the results of series of calculation for the ship hull subject to bending conditions with different angles of curvature. It is found that the interaction curve is asymmetrical because the hull cross section is not symmetrical with respect to the horizontal axis and the structural response of the elements under compression is different from that under tension due to nonlinearity caused by buckling. The angles of the resultant bending moment vector and that of the curvature vector are different in investigated cases. The interaction design equations proposed by other researches are also addressed to discuss the results presented by this study.

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