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.

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.

Quasi-Static Characteristics Analysis for Barge Bow Structure Based on Experimental and FEA Study

2015 ◽  
Vol 723 ◽  
pp. 86-89
Author(s):  
Yi Feng Mao ◽  
Wei Qing Liu ◽  
Hai Fang
Keyword(s):  
Cross Sections ◽  
Testing Machine ◽  
Experimental Results ◽  
Collapse Mechanism ◽  
Displacement Curve ◽  
Element Analysis ◽  
Collapse Mechanisms ◽  
Crushing Force ◽  
Characteristics Analysis ◽  
Static Conditions

In this paper, an experiment in a quasi-static conditions was carried out on barge bow model with its cross sections simplified. The characteristics of the bow structure were studied experimentally and Finite Element Analysis (FEA) was conducted to compare with experimental results. The experiment was performed by a compression and shear testing machine and the model was axially collapsed by a rigid board. The collapse mechanisms, load-displacement curve and mean crushing strength were investigated. The study showed that basic collapse mechanism of barge bow was clarified in participates with inner diaphragms. Moreover, the accuracy of FEA to estimate mean crushing force were validated by comparing with experimental results.

Study on Design of Metallic Sandwish Structure and its Mechanical and Thermal Properties

2013 ◽  
Vol 461 ◽  
pp. 85-94
Author(s):  
Rui Qiao ◽  
Ce Guo ◽  
Chun Sheng Zhu ◽  
Zhen Dong Dai ◽  
Xiao Ting Jiang
Keyword(s):  
Finite Element ◽  
Compressive Force ◽  
Fem Analysis ◽  
Displacement Curve ◽  
Mechanical And Thermal Properties ◽  
Stainless Steel Sheet ◽  
Metallic Structure ◽  
Element Analysis ◽  
Static Experiment ◽  
Force Displacement

Based on the microstructure of the beetles elytras cross-section, a bio-inspired metallic structure was designed. The mechanical property and the thermal property of the structure were analyzed with finite element method, and the compressive force-displacement curve and temperature distribution the structure were obtained, respectively. At the same time, the bio-inspired metallic structure sample was made with the material of the stainless steel sheet, and the quasi-static experiment and the thermal experiment of the structure were carried out. Comparing the experimental results with the FEM analysis, the results proved both the accuracy and reliability of FEM. Key words:beetle elytra;microstructure;bio-inspired structure; finite element analysis

Evolutive and Kinematic Limit Analysis Algorithms for Large-Scale 3D Truss-Frame Structures: Comparison Application to Historic Iron Bridge Arch

2019 ◽  
Vol 17 (05) ◽  
pp. 1940020 ◽  
Author(s):  
Rosalba Ferrari ◽  
Giuseppe Cocchetti ◽  
Egidio Rizzi
Keyword(s):  
Limit Analysis ◽  
Large Scale ◽  
Computational Time ◽  
Frame Structures ◽  
Collapse Mechanism ◽  
Displacement Curve ◽  
Plastic Collapse ◽  
Collapse Load ◽  
Structural Element ◽  
Plastic Mechanism

Two new computational algorithms for the Limit Analysis (LA) of large-scale 3D truss-frame structures recently proposed by the authors are reconsidered and adapted for a comparison prediction of the elastoplastic response of a strategic beautiful historic infrastructure, namely the Paderno d’Adda bridge (or San Michele bridge), a riveted wrought iron railway viaduct that was built in northern Italy in 1889. The first LA algorithm traces a fully exact evolutive piece-wise linear elastoplastic response of the structure, up to plastic collapse, by reconstructing the true sequence of activation of made-available plastic joints (as a generalization of plastic hinges), in the true spirit of LA. The second LA algorithm develops an independent kinematic iterative approach apt to directly determine the plastic collapse state, in terms of collapse load multiplier and plastic mechanism, based on the upper-bound theorem of LA. Specifically, the marvelous doubly built-in parabolic arch of the bridge is analyzed, under a static loading configuration at try-out stage, and its elastoplastic response is investigated, in terms of evolutive load-displacement curve, collapse load multiplier and plastic collapse mechanism. The two LA algorithms are found to much effectively run and perform, despite the rather large size of the computational model, with a number of dofs in the order of four thousands, by achieving good corresponding matches in terms of the estimate of the load-bearing capacity and of the collapse characteristics of the arch substructure, showing this to constitute a well-set structural element. Moreover, the direct kinematic method displays a rather dramatic performance, in truly precipitating from above onto the collapse load multiplier and rapidly adjusting to the collapse mode, in very few iterations, by a considerable saving of computational time, with respect to the complete evolutive elastoplastic analysis. This shall open up the way for further adoption of such advanced LA tools, with LA regaining a new momentum within the modern optimization analysis of structural design and form-finding problems.

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.

scholarly journals Large-Scale Experimental and Numerical Study of Blast Acceleration Created by Close-In Buried Explosion on Underground Tunnel Lining

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Mohamad Reza Soheyli ◽  
A. H. Akhaveissy ◽  
S. M. Mirhosseini
Keyword(s):  
Field Data ◽  
Large Scale ◽  
Numerical Study ◽  
Free Field ◽  
Vertical Wall ◽  
Ground Surface ◽  
Vertical Acceleration ◽  
Element Analysis ◽  
Underground Tunnel ◽  
Water Transportation

Despite growing demands for structures in water transportation tunnels, underground installations, subsurface dams, and subterranean channels, there is limited field knowledge about the dynamic behavior of these structures in the face of near-fault earthquakes or impulse excitations. This study conducted a large-scale test on underground tunnel excited by two close-in subsurface explosions. The horizontal and vertical acceleration were recorded on the vertical wall of the tunnel and the free field data including the acceleration on the ground surface at 11-meter distance from the tunnel. The frequency domain analysis of recorded results determined the frequency 961 Hz and 968 Hz for 1.69 kg and 2.76 kg equivalent T.N.T., respectively. Then, finite element analysis results were compared with the test data. The comparisons demonstrated a good correlation and satisfied the field data. Finally, based on numerical modeling, a parametric study was applied to determine the effects of shear wave velocity distance of the crater with respect to the tunnel on impulse response of the tunnel.

Bending Capacity of Corroded Pipeline Subjected to Internal Pressure and Axial Loadings

2018 ◽  
Author(s):  
Jie Gao ◽  
Zengli Peng ◽  
Xin Li ◽  
Jing Zhou ◽  
Wenxing Zhou
Keyword(s):  
Internal Pressure ◽  
Local Buckling ◽  
Compressive Force ◽  
Bending Moment ◽  
Corrosive Media ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Offshore Pipelines ◽  
Bending Capacity ◽  
The Moment

Offshore pipelines operating in a harsh environment are usually subjected to combinations of bending moment and axial loadings in addition to internal pressure. Due to the corrosive media transported in the pipelines and corrosive substances within seawater and soil outside the pipelines, local corrosion defects will generate on the pipeline’s inner and outer walls, reducing its ultimate bearing capacity. This paper presents a series of full-scale failure tests and nonlinear finite element analysis (FEA) to study the bending capacity and failure mode of corroded pipelines with outside locally-thinned-areas (LTAs) subjected to combinations of internal pressure, axial compressive force and bending moment. The LTAs are loaded in compression to simulate corrosion. Material tests of API 5L X56 seamless pipe steel were conducted and the stress-strain relationship was obtained. FEA results of the moment versus curvature relation, bending capacity and local buckling behavior of each specimen model matched the experimental results very well, validating the accuracy of this simulation. Additional FEA is then performed to investigate the effect of corrosion geometric parameters, such as corrosion depth, corrosion width, and corrosion length, on the ultimate moment. Among them, the width is of the greatest impact, followed by is the depth, the length impact can be ignored.

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.

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