Numerical Study on the Residual Ultimate Strength of Hull Girder of a Bulk Carrier After Ship-Ship Collision

2014 ◽  
Author(s):  
Yasuhira Yamada
Keyword(s):  
Large Scale ◽  
Numerical Study ◽  
Bending Moment ◽  
Second Step ◽  
Collapse Mechanism ◽  
Bulk Carrier ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Hull Girder ◽  
Ship Collision

The purpose of the present study is to investigate residual Ultimate Longitudinal Strength (ULS) of bulk carriers after ship-ship collision. A series of a large-scale explicit finite element analysis (FEA) as well as simplified analysis (SA) are carried out using a cape size bulk carrier. In order to accurately investigate collapse mechanism of “damaged ships” under vertical bending moment nonlinear FEA are carried out where two steps analysis is adopted. First step is ship-ship collision analysis; Second step is ULS analysis of the damaged ship. Ship-ship collision analysis is carried out assuming the right angle collision at the midship region of the struck ship, and damage extent of the struck ship is estimated with varying collision speed of 3kt, 6kt, 9kt and 12kt. In the second step of analysis, residual ULS analysis is carried out taking into account residual stress and deformation of the struck ship caused by ship-ship collision. Collapse mechanism of the bulk carrier in damaged condition due to sagging moment as well as combination of longitudinal and horizontal bending moment is investigated and discussed in detail. ULS of hull girder of the bulk carrier in intact condition is also estimated and compared with that in damaged condition. The effect of damaged condition on the reduction of ULS is discussed in detail. Finally some of numerical methodologies are summarized in assessing residual ULS of hull girder after collision.

Experimental and Numerical Study on the Collapse Strength of the Bulbous Bow Structure in Oblique Collision

2008 ◽  
Vol 45 (01) ◽  
pp. 42-53
Author(s):  
Yasuhira Yamada ◽  
Hisayoshi Endo
Keyword(s):  
Large Scale ◽  
Numerical Study ◽  
Compressive Force ◽  
Bending Moment ◽  
Collapse Mechanism ◽  
Displacement Curve ◽  
Element Analysis ◽  
Oblique Collision ◽  
Collapse Strength ◽  
Bulbous Bow

The purpose of this paper is to investigate the collapse strength and the mechanism of the bulbous bow structure in case of an oblique collision. In this study, quasi-static experiments were conducted using two types of large-scale bulbous bow models using the scenario that a ship collides with another ship at oblique angle. One of the models is a prototype buffer bow adopting a transverse stiffening system, and the other model is a standard bow adopting a longitudinal stiffening system. Each model was collapsed by a thrusting rigid board while being subject to the combined action of compressive force and bending moment. Collapse mechanism, load-displacement curve, and energy absorption capability of the buffer bow structure were investigated as compared with those of standard bow structure. Nonlinear finite element analysis (FEA) corresponding to the experiments was also conducted, and fairly good agreement was achieved between FEA and the experiments. It is also found from these investigations that the buffer bow structure is expected to be efficient in reducing the risk of an oil spill, especially in case of oblique collision.

Dynamic Collapse Mechanism of Global Hull Girder of Container Ships Subjected to Hogging Moment

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Yasuhira Yamada
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Ultimate Strength ◽  
Large Scale ◽  
Nonlinear Finite Element ◽  
Elastoplastic Material ◽  
Collapse Mechanism ◽  
Time Duration ◽  
Element Analysis ◽  
Hull Girder

The purpose of the present study is to investigate dynamic ultimate strength of global hull girder of container ships using large-scale nonlinear finite element analysis (FEA). A series of time domain nonlinear finite element (FE)-simulation is carried out using large-scale FE models of a 8000 twenty-foot equivalent unit (TEU) container ship where a hogging moment is applied to the midship section. Five types of finite element models (three full models, a half hold model, a one transverse model) are used. These models adopt elastoplastic material model, which includes strain rate effect. The hogging moment, which is modeled by sinusoidal impulse, is applied to these models, and collapse mechanism as well as dynamic hull girder ultimate strength is investigated by varying the load time duration. Moreover, effects of load time duration, mass inertia, strain rate, and analysis models are investigated in detail. It is found from the present study that ultimate strength as well as collapse mode is significantly dependent on load time duration of hogging moment.

A Study on the Dynamic Ultimate Strength of Global Hull Girder of Container Ships Subjected to Hogging Moment

2018 ◽  
Author(s):  
Yasuhira Yamada ◽  
Kyoko Kameya
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Ultimate Strength ◽  
Large Scale ◽  
Plastic Material ◽  
Collapse Mechanism ◽  
Time Duration ◽  
Element Analysis ◽  
Hull Girder ◽  
Non Linear

The purpose of the present study is to investigate dynamic ultimate strength of global hull girder of container ships using large scale non-linear finite element analysis. A series of time domain non-linear FE-simulation is carried out using large scale FE models of a 8000 TEU container ship where a hogging moment is applied to the midship section. 5 types of finite element models (three full models, a half hold model, a 1 transverse model) are used. These models adopt elasto-plastic material model which includes strain rate effect. The hogging moment which is modeled by sinusoidal impulse is applied to these models, and collapse mechanism as well as dynamic hull girder ultimate strength is investigated by varying the load time duration. Moreover effects of load time duration, mass inertia, strain rate and analysis models are investigated in detail. It is found from the present study that ultimate strength as well as collapse mode are significantly dependent on load time duration of hogging moment.

Structural Analysis for a Panamax Bulk Carrier

2008 ◽  
Author(s):  
Sandita Pacuraru-Popoiu ◽  
Paulina Iancu ◽  
Liviu I. Crudu
Keyword(s):  
Structural Analysis ◽  
Stress Distribution ◽  
Structural Integrity ◽  
Dynamic Pressure ◽  
Uniform Structure ◽  
Bulk Carrier ◽  
Element Analysis ◽  
Hull Girder ◽  
Fine Mesh ◽  
Hull Structure

This paper is devoted to the development of a structural analysis for a bulk carrier vessel. According to the CSR requirements for bulk carriers, an assessment of the hull structure using FEA (Finite Element Analysis) on a model extended over 3 cargo holds is presented. This method is used in order to assess the structural integrity of the cargo holds under the considered loads. The selected vessel is a PANAMAX bulk carrier with double hull and longitudinal uniform structure. There are three main priorities for the FE-analysis: one is to perform a fine mesh necessary to capture the stressed induced by the considered loads. The second priority is to apply the right boundary conditions in order to approach the hull girder bending and stress distribution on the cargo holds. The stress distribution is induced by the cargo weight, the hydrostatic pressure and the external water considered as dynamic pressure. The dynamic pressure was computed using an in-house code, neglecting the inertia forces induced by the ship motions and the horizontal accelerations. Also shear forces and bending moments were obtained for head angles of 0, 45 and 180 degrees.

Experimental Assessment of Form Based Approach for Predicting Extreme Value Distribution of Hull Girder Bending Moment in a Ship

2019 ◽  
Author(s):  
Tomoki Takami ◽  
Yusuke Komoriyama ◽  
Takahiro Ando ◽  
Kazuhiro Iijima
Keyword(s):  
Estimation Method ◽  
Bending Moment ◽  
Extreme Value Distribution ◽  
Irregular Waves ◽  
Extreme Wave ◽  
Scaled Model ◽  
Element Analysis ◽  
Hull Girder ◽  
Reliability Method ◽  
Wave Induced

Abstract This paper describes a series of towing tank tests using a scaled model of a recent container ship for validating the First Order Reliability Method (FORM) based approach to predict the maximum response. The FORM based approach is adopted in conjunction with the nonlinear strip method as an estimation method for the most probable wave episodes (MPWEs) leading to the given extreme wave-induced vertical bending moments (VBMs). Tank tests under the pre-determined MPWEs are conducted to evaluate the extreme wave-induced VBMs. Numerical simulations based on the coupled Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) are also conducted and are compared with the test results under the MPWEs. Furthermore, to estimate the extreme VBM statistics, tank tests under random irregular waves are conducted. A series of validations of the probability of exceedances (PoEs) of the VBM evaluated from the FORM based approach is carried out. The effect of hydroelastic (whipping) vibrations on the extreme VBM statistics are finally discussed.

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.

Numerical Study for the Progressive Collapse of Scale Model for ULCS Hull Girder Under Longitudinal Bending

2018 ◽  
Author(s):  
Chonglei Wang ◽  
Deyu Wang
Keyword(s):  
Numerical Study ◽  
Progressive Collapse ◽  
Similarity Criterion ◽  
Bending Moment ◽  
Scale Model ◽  
Stiffened Panels ◽  
Hull Girder ◽  
Load Carrying ◽  
Longitudinal Bending ◽  
Large Container

For evaluating reliable load carrying capacity of actual hull girder, experiments for similar scale model are necessary. The object of the present paper is to figure out a reliable FE analysis method in the similar scale model experiment regarding hull girder ultimate strength. The compared results between the true hull girder of a typical ultra large container ship (ULCS) and the scale experimental model created by the similarity criterion proposed in this paper assessed by finite element method (FEM) under longitudinal bending moment considering the effects of initial deflections are obtained guaranteeing the similarity in both elastic and inelastic range during the progressive collapse of plates, stiffened panels and hull girder. Finally, a series of elastic-plastic large deflection analyses is conducted to ensure the failure mode of hull girder is consistent with the actual ship.

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.

scholarly journals Numerical Study on Plastic Strain Distributions and Mechanical Behaviour of a Tube under Bending

Inventions ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 9
Author(s):  
Chiemela Victor Amaechi ◽  
Emmanuel Folarin Adefuye ◽  
Abiodun Kolawole Oyetunji ◽  
Idris Ahmed Ja’e ◽  
Ibitoye Adelusi ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Mechanical Behaviour ◽  
Numerical Study ◽  
Bending Moment ◽  
Thickness Effect ◽  
Element Analysis ◽  
Cross Sectional ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Pipe Bending

Tubular pipe structures have been used in various applications—domestic, aviation, marine, manufacturing and material testing. The applications of tubular pipes have been considered greatly in the installation of tubular pipes, marine risers and pipe bending. For the investigation of plastic strains and the mechanical behaviour of a tube under bending, considerations were made utilising an exponent model with assumptions on the plane strain. The bending moment, wall thickness effect, cross-sectional distribution, stresses during bending and neutral layer boundaries were all presented as necessary theoretical formulations on the physics of tubular pipe bending. This model was based on the analytical and numerical investigation. In principle, the application can be observed as the spooling of pipes, bending of pipes and reeling. Comparisons were made on two models developed on the finite element analysis in Simscale OpenFEA, namely the linear-elastic and the elasto-plastic models. This study presents visualization profiles using plastic strain to assess its effect on the tubular pipes. This can increase due to the limitation of plastic deformation on the composite materials selected.

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