Addition of dynamic mooring line force based on lumped-mass method in SPH

Abstract This study aims to investigate the performance changes resulted from a mooring line failure of a marine fish cage exposed to irregular waves and current. A numerical model based on the lumped mass method and Morison equation was extended to simulate the mooring line failure scenario. In this study, the failed resulting changes were compared with its normal counterpart in both the time domain and the frequency domain. After one upstream anchor loss, the maximum tension on the remaining anchor has increased significantly, as well as the drift distance of the rearing part (net chamber, floating collar, and tube-sinker) of the fish cage. The resulting changes can also be seen in both the wave-frequency and the low-frequency region in the spectra, including mooring tensions and body motions.

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Research on Influence of Horizontal Offsets of Underwater Equipment Based on Pendulous Installation Method

Volume 7B: Ocean Engineering ◽

10.1115/omae2018-77734 ◽

2018 ◽

Author(s):

Jingqian Wang ◽

Liping Sun ◽

Zhongchao Deng ◽

Gang Ma ◽

Xiaomeng Zhu ◽

...

Keyword(s):

Deep Water ◽

Water Environment ◽

Three Dimensional ◽

Mooring Line ◽

Analysis Model ◽

Lumped Mass ◽

Lumped Mass Method ◽

Traction Fluid ◽

Simulation Problem ◽

Domain Coupling

Large underwater equipment used in deep-sea engineering, which needs mooring line in order to hang down while using pendulous installation method in 1500m deep-water installation. During the procession, the mooring line will suffer the vessel’s pull, large equipment’s traction, fluid force leading to elongation, bending and other deformation, so need to analyze its motion. Aiming at the numerical simulation problem of underwater equipment installed by pendulous installation method in deep-water environment, this paper combines lumped mass method, three-dimensional potential theory and Morison equation to establish the analysis model of the whole installation system. Under the different horizontal dropping offsets of the equipment, this paper computes not only tension of mooring line, but motion performance of underwater equipment and working vessel during the pendulous lowering phase. The Pendulous Installation Method (PIM) puts a working vessel, a mooring line and a underwater equipment installed in succession, and there is a coupling interaction among them, so it is essential to do time-domain coupling analysis. So the Orcaflex Software is used to simulate the entire deep-water installation system. Using different horizontal dropping position as a variable, we can get the contrast about the different movement states of the mooring line and underwater equipment, and finally we will get the conclusion.

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A novel parallel algorithm for computing the mooring line based on lumped-mass method

International Journal of Modeling Simulation and Scientific Computing ◽

10.1142/s1793962317500040 ◽

2017 ◽

Vol 08 (01) ◽

pp. 1750004 ◽

Cited By ~ 1

Author(s):

Zhong-Xian Zhu ◽

Yong Yin ◽

Muhammad Mobeen Movania

Keyword(s):

Parallel Algorithm ◽

Real Time ◽

Mooring Line ◽

Dynamics Model ◽

Graphic Processing Units ◽

Lumped Mass ◽

The Real ◽

Runge Kutta Method ◽

Lumped Mass Method ◽

Speed Up

Dynamic modeling and simulation of the mooring system are the key technologies in anchor handling simulator (AHS). Built up the mooring line’s dynamics model based on lumped-mass method (LMM), and fourth-order Runge–Kutta method was used to solve the model; because of the huge amounts of calculation in the model’s solving, the very time-consuming process brings great impact on the real-time, fidelity and immersed feeling in the anchor handling scene simulation, seriously hindered its application in AHS. A novel parallel algorithm was proposed to speed-up the model’s solving process by taking the advantages of graphic processing units (GPU’s) massive parallel computing and float point computing capability. The model’s solving process was implemented on vertex shader based on the transform feedback (TF) mechanism in modern GPU. Experimental results show that, the new algorithm reduced the calculating time largely without losing accuracy, and can finally realize the real-time solving and simulation.

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A Novel Simplified Algorithm for Calculating the Mooring Line Based on Lumped-Mass Method

Theory, Methodology, Tools and Applications for Modeling and Simulation of Complex Systems - Communications in Computer and Information Science ◽

10.1007/978-981-10-2669-0_10 ◽

2016 ◽

pp. 89-97

Author(s):

Zhong-xian Zhu ◽

Yong Yin ◽

He-long Shen

Keyword(s):

Mooring Line ◽

Lumped Mass ◽

Lumped Mass Method ◽

Simplified Algorithm

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A Simplified Model of SSI Dynamic Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.334 ◽

2012 ◽

Vol 446-449 ◽

pp. 334-339

Author(s):

Zhi Ying Zhang ◽

Ying Li ◽

Qing Sun

Keyword(s):

Dynamic Analysis ◽

Soil Structure ◽

Design Method ◽

Simplified Model ◽

Lumped Mass ◽

Foundation Soil ◽

Linear Elastic ◽

Lumped Mass Method ◽

Actual Mechanism ◽

Seismic Design Method

Aiming at the problem of dynamic analysis of SSI system, the dynamic influence of different parts of foundation soil is studied on the linear elastic assumption according to the actual mechanism of Soil-Structure Interaction (SSI); in addition, a simplified model on the condition of the lumped mass method is put forward and the corresponding motion equations of SSI system are built, which can be a reference for the structural seismic design method considering SSI effect.

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The Anchor-Last Deployment Problem for Inextensible Mooring Lines

Journal of Engineering for Industry ◽

10.1115/1.3438654 ◽

1975 ◽

Vol 97 (3) ◽

pp. 1046-1052 ◽

Cited By ~ 2

Author(s):

Robert C. Rupe ◽

Robert W. Thresher

Keyword(s):

Numerical Model ◽

Equations Of Motion ◽

Simultaneous Equations ◽

Mooring Line ◽

Integration Scheme ◽

Lumped Mass ◽

Mooring Lines ◽

Concentrated Masses ◽

Predictor Corrector ◽

Lagrange’S Method

A lumped mass numerical model was developed which predicts the dynamic response of an inextensible mooring line during anchor-last deployment. The mooring line was modeled as a series of concentrated masses connected by massless inextensible links. A set of angles was used for displacement coordinates, and Lagrange’s Method was used to derive the equations of motion. The resulting formulation exhibited inertia coupling, which, for the predictor-corrector integration scheme used, required the solution of a set of linear simultaneous equations to determine the acceleration of each lumped mass. For the selected cases studied the results show that the maximum tension in the cable during deployment will not exceed twice the weight of the cable and anchor in water.

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Modeling and Simulation of Clamp Band Dynamic Envelope in a LV/SC Separation System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.141.359 ◽

2011 ◽

Vol 141 ◽

pp. 359-363 ◽

Cited By ~ 5

Author(s):

Jun Lan Li ◽

Shao Ze Yan ◽

Xue Feng Tan

Keyword(s):

Friction Coefficient ◽

Modeling And Simulation ◽

Band System ◽

Separation Process ◽

Impact Behavior ◽

Separation System ◽

Lumped Mass ◽

Lumped Mass Method ◽

Simulation Results ◽

Contact Impact

The clamp band system is a typical locked and separated device of the launch vehicle (LV) / the spacecraft (SC), and its release-separation process is one of the important factors that affect the LV/SC separation movement. A nonlinear spring-damper model was employed to describe the contact-impact behavior between the V-segment of the clamp band and the LV/SC interface, and lumped mass method was used to depict the clamp band. By using ADAMS, a dynamic model of the clamp band system was established. The simulation results show that the impulse of the explosive bolts and the stiffness of lateral-restraining springs have significant effects on the clamp band dynamic envelope. The shock of the satellite-vehicle separation is very vulnerable to the clamp band pretension and the friction coefficient between the V-segment and the LV/SC interface.

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Validation of a lumped-mass mooring line model with DeepCwind semisubmersible model test data

Ocean Engineering ◽

10.1016/j.oceaneng.2015.05.035 ◽

2015 ◽

Vol 104 ◽

pp. 590-603 ◽

Cited By ~ 99

Author(s):

Matthew Hall ◽

Andrew Goupee

Keyword(s):

Test Data ◽

Model Test ◽

Mooring Line ◽

Lumped Mass ◽

Line Model

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Research on Dynamic Simulation of AUV Launching a Towed Navigation Buoyage

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.433-435.1170 ◽

2013 ◽

Vol 433-435 ◽

pp. 1170-1174

Author(s):

Guang Pan ◽

Zhi Dong Yang ◽

Xiao Xu Du

Keyword(s):

Angular Momentum ◽

Boundary Conditions ◽

Dynamic Simulation ◽

Numerical Scheme ◽

Mathematic Model ◽

Dynamic Equations ◽

Lumped Mass ◽

Lumped Mass Method ◽

Towed Cable ◽

Undersea Vehicle

A mathematic model was established to simulate the process of AUV (autonomous undersea vehicle) launching a towed buoyage. Based on the lumped mass method and moment theorem and angular momentum theorem, dynamic equations of the cable and the buoyage were developed, respectively. Then the boundary conditions and the numerical scheme to deal with the cable with non-fixed length were presented. Moreover, the process of AUV launching a towed cable was simulated. By using the model, the results show the trajectory of buoyage and shape of towed cable can be well predicted.

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Numerical Simulation of Subsea Cluster Manifold Installation by the Sheave Method

Volume 5: Pipelines, Risers, and Subsea Systems ◽

10.1115/omae2018-77336 ◽

2018 ◽

Author(s):

Yu Zhao ◽

Yingying Wang ◽

Liwei Li ◽

Chao Yang ◽

Yang Du ◽

...

Keyword(s):

Numerical Simulation ◽

Mathematical Model ◽

South China Sea ◽

Deep Sea ◽

High Reliability ◽

Two Dimensional ◽

Complex Environment ◽

Lumped Mass ◽

Lumped Mass Method ◽

The Mathematical Model

The sheave installation method (SIM) is an effective and non-conventional method to solve the installation of subsea equipment in deep water (>1000m), which has been developed to deploy the 175t Roncador Manifold I into 1,885 meters water depth in 2002. With the weight increment of subsea cluster manifold, how to solve its installation with the high reliability in the deep sea is still a great challenge. In this paper, the installation of the 300t subsea cluster manifold using the SIM is studied in the two-dimensional coordinate system. The mathematical model is established and the lumped mass method is used to calculate the hydrodynamic forces of the wireropes. Taking into account the complex environment loads, the numerical simulation of the lowering process is carried out by OrcaFlex. The displacement and vibration of the subsea cluster manifold in the z-axis direction and the effective tension at the top of the wireropes can be gotten, which can provide guidance for the installation of the cluster manifold in the South China Sea.

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