Fully coupled seakeeping, slamming, and whipping calculations

2009 ◽  
Vol 223 (3) ◽  
pp. 439-456 ◽  
Author(s):  
J T Tuitman ◽  
Š Malenica
Keyword(s):  
Linear Time ◽  
Three Dimensional ◽  
Bending Moment ◽  
Fatigue Loading ◽  
Element Model ◽  
Beam Model ◽  
Full Wave ◽  
Elastic Modes ◽  
Large Container ◽  
Fully Coupled

This paper presents a methodology to solve the seakeeping, slamming, and whipping problems coupled within a single calculation. The coupled problem is solved within a partly non-linear time domain seakeeping program. The elastic modes used in this hydroelastic problem can be calculated using a beam model or full three-dimensional (3D) finite element model of the ship structure. The slamming loading is calculated by a two-dimensional (2D) method. The main focus of this paper is the creation of an accurate and consistent coupling between the 3D seakeeping program and the 2D slamming calculation. Differences in timescale and integration methods make this coupling complex. A large container ship is used to illustrate the application of the presented methodology. The contribution of the non-linearities and the whipping response to the expected maximum bending moment and fatigue damage of this ship for a full-wave scatter diagram is calculated. The results show that the slamming-induced whipping response has a significant contribution to both the ultimate bending moment and the fatigue loading of the ship.

scholarly journals On the Nonlinear Vibrational Responses of a Large Vessel with a Broad Bow Flare under Wave Excitation: Theory and Experiment

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Haicheng Yu ◽  
Huilong Ren ◽  
Yingbo Xu ◽  
Tiange Li
Keyword(s):  
Three Dimensional ◽  
Green Water ◽  
Beam Model ◽  
Numerical Predictions ◽  
Bow Flare ◽  
Elastic Modes ◽  
Incident Waves ◽  
Euler Bernoulli Beam ◽  
Fully Coupled ◽  
Bernoulli Beam Model

A fully coupled nonlinear three-dimensional (3D) hydroelastic method is developed to investigate vibrational responses of a large ship with a pronounced bow flare subjected to high seas. This numerical model consists of a 3D boundary element method, 1D Euler-Bernoulli beam model, and a 2D generalized Wagner model. Green water loads were considered. Experimental study was carried out in a towing tank on a self-propelled segmented model with nonuniform steel backbones. The ship model was tested in regular incident waves of large amplitude. Impact pressure and nonlinear vertical bending moments were measured and compared with numerical predictions. The proposed nonlinear model produced similar results to the experimental model. Furthermore, the effects of elastic modes and nonlinearities on the numerical results were analyzed.

scholarly journals Internal Force on and Deformation of Steel Assembled Supporting Structure of Foundation Pit under Thermal Stress

2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bending Moment ◽  
High Strength ◽  
Element Model ◽  
Internal Force ◽  
Foundation Pit ◽  
Dimensional Finite Element ◽  
Influence Of Temperature On ◽  
Scale Experiment ◽  
Three Dimensional Finite Element

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.

Flexible Riser Top Connection Analysis With I-Tube Interface and Bending Hysteresis Effect

2019 ◽  
Author(s):  
Yangye He ◽  
Hailong Lu ◽  
Murilo Augusto Vaz ◽  
Marcelo Caire
Keyword(s):  
Kinematic Hardening ◽  
Bending Moment ◽  
Element Model ◽  
Beam Model ◽  
Flexible Riser ◽  
Nonlinear Bending ◽  
Cross Sectional ◽  
Irregular Wave ◽  
Global Dynamic ◽  
Curvature Distribution

Abstract The flexible riser top connection to the floating production platform is a critical region for fatigue lifetime (re)assessment. The interface with the I-tube and its curved sleeve combined with the gap between the riser and bend stiffener may lead to different curvature distribution when compared to the traditional modeling approach that considers the bend stiffener attached to the pipe. For a more accurate top connection assessment, the flexible riser bending hysteresis can also be directly incorporated in the global dynamic analysis helping to reduce curvature amplitude and lifetime prediction conservatism. This work investigates a 7” flexible riser-bend stiffener top connection with I-tube interface by performing irregular wave global dynamic analyses with the OrcaFlex package and considering a nonlinear bending moment vs curvature riser behavior obtained from a detailed cross sectional model developed in Abaqus. OrcaFlex curvature distribution results are also compared with a quasi-static finite element model that uses an elasto-plastic formulation with kinematic hardening to represent riser hysteresis through an equivalent beam model. A good curvature distribution correlation is observed for both top connection models (OrcaFlex x Abaqus) in the bend stiffener area with reduced amplitudes when riser bending hysteresis is considered.

Assessment of Corner Failure Depths in the Deep Drawing of 3D Panels Using Simplified 2D Numerical and Analytical Models

2000 ◽  
Vol 123 (2) ◽  
pp. 248-257 ◽  
Author(s):  
Hong Yao ◽  
Jian Cao
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Analytical Models ◽  
Design Stage ◽  
Beam Model ◽  
Preliminary Design ◽  
Powerful Means ◽  
Preliminary Design Stage ◽  
Blank Size

Methodologies of rapidly assessing maximum possible forming heights are needed for three-dimensional 3D sheet metal forming processes at the preliminary design stage. In our previous work, we proposed to use an axisymmetric finite element model with an enlarged tooling and blank size to calculate the corner failure height in a 3D part forming. The amount of enlargement is called center offset, which provides a powerful means using 2D models for the prediction of 3D forming behaviors. In this work, an analytical beam model to calculate the center offset is developed. Starting from the study of a square cup forming, a simple analytical model is proposed and later generalized to problems with corners of an arbitrary geometry. The 2D axisymmetric models incorporated with calculated center offsets were compared to 3D finite element simulations for various cases. Good assessments of failure height were obtained.

Three-dimensional numerical investigation of multifaced tunneling in water-bearing soft ground

2008 ◽  
Vol 45 (10) ◽  
pp. 1467-1486 ◽  
Author(s):  
Chungsik Yoo ◽  
Sun-Bin Kim
Keyword(s):  
Numerical Investigation ◽  
Three Dimensional ◽  
Element Model ◽  
Soft Ground ◽  
Single Pile ◽  
Ground Settlement ◽  
Axial Loads ◽  
Groundwater Drawdown ◽  
Fully Coupled ◽  
Ground Settlements

This paper presents the results of a numerical investigation of the performance of multifaced tunneling under a pile-supported building in water-bearing soft ground. Special attention was paid to the effect of tunneling and groundwater interaction on the tunneling performance. A fully coupled three-dimensional (3D) stress – pore pressure finite element model was adopted to realistically capture the mechanical and hydrological interaction between the tunneling and groundwater. The results indicate that the groundwater drawdown during tunneling yields a considerably larger settlement-affected zone than for cases with no groundwater drawdown, with a tendency for large portions of ground settlement and groundwater drawdown to be completed before the tunnel passes a monitoring section. Also revealed is that the presence of a building tends to reduce the ground settlements and cause subsurface settlements more or less uniformly with depth. It is shown that the lining deformation, and thus its stresses are not significantly affected by the presence of the building for the multifaced tunneling considered in this study. Axial loads in the piles supporting the building tend to either increase or decrease depending on the pile location relative to the tunnel axis. The patterns of changes in pile axial loads are different from the results of previous studies concerning a single pile.

scholarly journals Design finite element method based models of floating dry docks strength

2021 ◽  
pp. 43-52
Author(s):  
Anatoly Mironov ◽  
Dmitry Y. Titko
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Base ◽  
Beam Model ◽  
Buoyant Force ◽  
Dry Dock ◽  
Global Strength ◽  
Element Method

The features of global strength modelling of floating dry docks using finite element method are considered. Comparative analysis of two- and three-dimensional models was performed considering the interaction of the floating dry dock and the ship. To solve the problem of reducing the complexity of creating and the size of the finite element model, it is proposed to use the elements of a volumetric orthotropic body to model the main transverse beams of the pontoon. Hydrostatic elastic base of floating dry dock is represented as spring elements. The model of the dock support device includes spring and gap elements. The vessel is considered in the equivalent beam model. Results were obtained on such effects as redistribution of buoyant force due to deformation of the dock, incomplete inclusion of the towers in the general longitudinal bending of the dock, the effect of ship stiffness not only on the longitudinal, but also on the transverse bending of the dock.

scholarly journals A novel analytical curved beam model for predicting elastic properties of 3D eight-harness satin weave composites

2018 ◽  
Vol 25 (4) ◽  
pp. 689-706 ◽  
Author(s):  
Faqi Liu ◽  
Zhidong Guan ◽  
Tianya Bian ◽  
Wei Sun ◽  
Riming Tan
Keyword(s):  
Finite Element ◽  
Elastic Properties ◽  
Three Dimensional ◽  
Element Model ◽  
Close Correlation ◽  
Sensitivity Study ◽  
Curved Beam ◽  
Beam Model ◽  
Energy Principle ◽  
Representative Unit Cell

AbstractAn offset representative unit cell (ORUC) is introduced to predict elastic properties of three-dimensional (3D) eight-harness satin weave composites both analytically and numerically. A curved beam model is presented based on minimum complementary energy principle, which establishes an analytical solution for elastic modulus and Poisson’s ratio calculation. Finite element method is developed to predict engineering constants of composites. Modified periodic boundary conditions and load method for ORUC are also presented. Experiments of simulated material are performed under tensile test. Close correlation is obtained between experimental data and predictions. Sensitivity study is conducted and manifests that within a large variation of constitutive material properties, the curved beam model derives close predictions comparing to finite element model, which indicates the stability of the curved beam model. Parametric study is also conducted to discuss the effect of weave type and geometric dimensions on elastic properties. It is argued that the curved beam model could manifest fine predictions accurately and stably, and is recommended for the prediction of elastic properties of satin weave composite.

Estimates of Elastic Crack Opening Displacements of Slanted Through-Wall Cracks in Plate and Cylinder

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Nam-Su Huh ◽  
Do-Jun Shim ◽  
Yeon-Sik Yoo ◽  
Suhn Choi ◽  
Keun-Bae Park
Keyword(s):  
Finite Element ◽  
Crack Opening ◽  
Three Dimensional ◽  
Bending Moment ◽  
Element Model ◽  
Finite Element Analyses ◽  
Opening Displacement ◽  
Elastic Crack ◽  
Leak Before Break ◽  
The Finite Element Model

This paper provides tractable solutions for elastic crack opening displacement (COD) of slanted through-wall cracks in plates and cylinders. The solutions were developed via detailed three dimensional elastic finite element analyses. The COD values were calculated along the thickness at the center of the crack. As for the loading conditions, only remote tension was considered for the plates, whereas remote tension, global bending moment, and internal pressure were considered for the cylinders. The finite element model employed in the present analysis was verified by using existing solutions for a cylinder with an idealized circumferential through-wall crack. The present results can be used to evaluate leak rates of slanted through-wall cracks, which can be used as a part of a detailed leak-before-break analysis considering more realistic crack shape development.

scholarly journals Wind-induced collapse analysis of long-span transmission tower–line system considering the member buckling effect

2018 ◽  
Vol 22 (1) ◽  
pp. 30-41 ◽  
Author(s):  
Li Tian ◽  
Haiyang Pan ◽  
Canxing Qiu ◽  
Ruisheng Ma ◽  
Qiqi Yu
Keyword(s):  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Bending Moment ◽  
Element Model ◽  
Collapse Mechanism ◽  
Transmission Tower ◽  
Line System ◽  
Long Span ◽  
Collapse Analysis ◽  
Three Dimensional Finite Element

The collapse problem of transmission tower upon strong winds was well noted in past few years. This article analyses the wind-induced collapse problem of a long-span transmission tower–line system. The member buckling effect was particularly considered. In doing so, a three-dimensional finite element model of the long-span transmission tower–line system was established in ABAQUS based on a practical project. The transmission tower and line were simulated by the frame and truss elements, respectively. The nonlinear behavior of a compressive member was simulated using the Marshall model, and the nonconvergence of numerical calculation was set to be the collapse criterion. The critical wind speed, damage position, and collapse probability were obtained from a collapse analysis of the long-span transmission tower–line system under different wind attack angles. The collapse mechanism of the long-span transmission tower–line system under a wind attack angle of 45° was investigated, and an incremental dynamic analysis was performed to evaluate the collapse-resistant capacity of the transmission tower. The study reveals that the interaction between bending moment and shear deformation is critical to the collapse of transmission tower.

scholarly journals Ratcheting Simulation of a Steel Pipe with Assembly Parts under Internal Pressure and a Cyclic Bending Load

2019 ◽  
Vol 9 (23) ◽  
pp. 5025
Author(s):  
Yang ◽  
Dai ◽  
He
Keyword(s):  
Internal Pressure ◽  
Kinematic Hardening ◽  
Three Dimensional ◽  
Bending Moment ◽  
Element Model ◽  
Steel Pipe ◽  
Cyclic Bending ◽  
Ratcheting Strain ◽  
Bending Load ◽  
Transition Points

The ratcheting behavior of a steel pipe with assembly parts was examined under internal pressure and a cyclic bending load, which has not been seen in previous research. An experimentally validated and three dimensional (3D) elastic-plastic finite element model (FEM)—with a nonlinear isotropic/kinematic hardening model—was used for the pipe’s ratcheting simulation and considered the assembly contact effects outlined in this paper. A comparison of the ratcheting response of pipes with and without assembly parts showed that assembly contact between the sleeve and pipe suppressed the ratcheting response by changing its trend. In this work, the assembly contact effect on the ratcheting response of the pipe with assembly parts is discussed. Both the assembly contact and bending moment were found to control the ratcheting response, and the valley and peak values of the hoop ratcheting strain were the transition points of the two control modes. Finally, while the clearance between the sleeve and the pipe had an effect on the ratcheting response when it was not large, it had no effect when it reached a certain value.

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