scholarly journals VD-PQ; A Velocity-Dependent Viscous Damping Model for Wave-Structure Interaction Analysis

2021 ◽  
Vol 9 (2) ◽  
pp. 175
Author(s):  
Constantine Michailides
Keyword(s):  
Numerical Analysis ◽  
Wave Structure ◽  
Viscous Damping ◽  
Analysis Method ◽  
Dynamics Model ◽  
Computational Fluid Dynamics Model ◽  
Structure Interaction ◽  
Numerical Analysis Method ◽  
Damping Model ◽  
Wave Structure Interaction

For the analysis and design of coastal and offshore structures, viscous loads represent one of the most influential parameters that dominate their response. Very commonly, the potential flow theory is used for identifying the excitation wave loads, while the viscous damping loads are taken into consideration as distributed drag type loads and/or as linear and quadratic damping loads approximated with the use of motion decay curves of the structure in specific degrees of freedom. In the present paper, is developed and proposed a numerical analysis method for addressing wave-structure interaction effects through a velocity-dependent viscous damping model. Results derived by a computational fluid dynamics model are coupled with a model that uses the boundary element method for the estimation of the viscous damping loads iteratively in every time-step of the analysis. The computational fluid dynamics model solves the Navier–Stokes equations considering incompressible flow, while the second model solves the modified Cummins Equation of motion of the structure in the time domain. Details about the development of the coupling method and the velocity-dependent viscous damping (VD-PQ) are presented. The coupling between the different models is realized through a dynamic-link library. The proposed coupling method is applied for the case of a wave energy converter. Results derived with the use of the developed numerical analysis method are compared against experimental data and relevant numerical analysis predictions. The importance of considering the instantaneous velocity of the structure in estimating the viscous damping loads is demonstrated. The proposed numerical analysis method for estimating the viscous damping loads provides good accuracy compared to experimental data and, at the same time, low computational cost.

scholarly journals Research on Numerical Method for Fluid-Structure Interaction in Engine Blades

2011 ◽  
Vol 2-3 ◽  
pp. 906-911
Author(s):  
Zhen Tan ◽  
Peng Zhang ◽  
Guang Yu Du ◽  
Bang Chun Wen
Keyword(s):  
Numerical Analysis ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Research Field ◽  
Analysis Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Numerical Analysis Method ◽  
Advantages And Disadvantages ◽  
Fluid Solid Interaction

A numerical analysis method for fluid-structure interaction (FSI) to analyze engine blades dynamic response was presented. Fluid-structure interaction is an important research field. It is mostly studies the interaction between the influence upon the fluid by the deformation of the solids, the important characteristic of fluid-solid interaction mechanics is the fluid-solid interaction between the both phase mediums. The solutions of strongly coupling and weakly coupling were discussed firstly in this paper. We compared the advantages and disadvantages of the strongly coupling and weakly coupling. And using numerical analysis method based on weakly coupling, we established a fluid-solid interaction control equation taking solid and fluid as a unified mathematical model. And we study about blades deformation and displacement under the action of air loading in engine. Using computational structural dynamics (CSD) calculate the displacements of blades, and using computational fluidic dynamics (CFD) calculate the pressures of blades, completing the fluid-structure interaction analysis in engine blades by iterating this two values(the displacements and the pressures) until the computational convergence solution is obtained. At the end of this paper, the model of fluid-structure interaction and the simulate procession of the numerical analysis method were presented. Based on the analysis, the simulation result is qualitatively discussed referring to the factual conditions of the engine for validating the feasibility of analysis method.

scholarly journals Investigation of a Stochastic Inverse Method to Estimate an External Force: Applications to a Wave-Structure Interaction

2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
S. L. Han ◽  
Takeshi Kinoshita
Keyword(s):  
External Force ◽  
Inverse Method ◽  
Inverse Function ◽  
Wave Structure ◽  
Dynamic Responses ◽  
Structure Interaction ◽  
External Forces ◽  
Interaction Problem ◽  
Wave Structure Interaction

The determination of an external force is a very important task for the purpose of control, monitoring, and analysis of damages on structural system. This paper studies a stochastic inverse method that can be used for determining external forces acting on a nonlinear vibrating system. For the purpose of estimation, a stochastic inverse function is formulated to link an unknown external force to an observable quantity. The external force is then estimated from measurements of dynamic responses through the formulated stochastic inverse model. The applicability of the proposed method was verified with numerical examples and laboratory tests concerning the wave-structure interaction problem. The results showed that the proposed method is reliable to estimate the external force acting on a nonlinear system.

Dynamic Analysis of the Pipe Lifting Mechanism on the Deepwater Pipelaying Vessel

2011 ◽  
Vol 199-200 ◽  
pp. 251-256
Author(s):  
Kai An Yu ◽  
Ke Yu Chen
Keyword(s):  
Numerical Analysis ◽  
Dynamic Analysis ◽  
High Efficiency ◽  
Transport Systems ◽  
Kinematic Pair ◽  
Analysis Method ◽  
Numerical Analysis Method ◽  
Upper Limit ◽  
Lifting Capacity ◽  
Limit Position

Based on requirements of pipe transport systems on deepwater pipelaying vessel, a new pipe lifting mechanism was designed. It was composed of crank-rocker and rocker-slider mechanism with good lifting capacity and high efficiency. When the slider went to the upper limit position, the mechanism could approximatively dwell, meeting the requirement for transverse conveyor operation. According to the theory of dynamics, numerical analysis method was used to the dynamic analysis of the mechanism. The results showed the maximum counterforce was at the joint between the rocker and ground, and this calculation could be a guideline for the kinematic pair structure designing.

scholarly journals Numerical analysis of stability of an axially-compressed i-beam rod subjected to constrained torsion

2020 ◽  
pp. 11-27
Author(s):  
Amirshokh Kh. Abdurakhmonov
Keyword(s):  
Numerical Analysis ◽  
Axial Force ◽  
Analytical Data ◽  
Practical Interest ◽  
Numerical Calculations ◽  
Analysis Method ◽  
Numerical Analysis Method ◽  
Open Section ◽  
Thin Walled ◽  
Analysis Of Stability

Introduction. Today thin-walled structures are widely used in the construction industry. The analysis of their rigidity, strength and stability is a relevant task which is of particular practical interest. The article addresses a method for the numerical analysis of stability of an axially-compressed i-beam rod subjected to the axial force and the bimoment. An axially compressed i-beam rod is the subject of the study. Materials and methods. Femap with NX Nastran were chosen as the analysis toolkit. Axially compressed cantilever steel rods having i-beam profiles and different flexibility values were analyzed under the action of the bimoment. The steel class is C245. Analytical data were applied within the framework of the Euler method and the standard method of analysis pursuant to Construction Regulations 16.13330 to determine the numerical analysis method. Results. The results of numerical calculations are presented in geometrically and physically nonlinear settings. The results of numerical calculations of thin-walled open-section rods, exposed to the axial force and the bimoment, are compared with the results of analytical calculations. Conclusions. Given the results of numerical calculations, obtained in geometrically and physically nonlinear settings, recommendations for the choice of a variable density FEM model are provided. The convergence of results is estimated for different diagrams describing the steel behavior. The bearing capacity of compressed cantilever rods, exposed to the bimoment, is estimated for the studied flexibility values beyond the elastic limit. A simplified diagram, describing the steel behaviour pursuant to Construction regulations 16.13330, governing the design of steel structures, is recommended to ensure the due regard for the elastoplastic behaviour of steel. The numerical analysis method, developed for axially-compressed rods, is to be applied to axially-compressed thin-walled open-section rods. National Research Moscow State University is planning to conduct a series of experiments to test the behaviour of axially-compressed i-beams exposed to the bimoment and the axial force. Cantilever i-beams 10B1 will be used in experimental testing.

scholarly journals Efficient Solution of the 3D Laplace Problem for Nonlinear Wave-Structure Interaction

2008 ◽  
Author(s):  
Harry B. Bingham ◽  
Allan P. Engsig-Karup
Keyword(s):  
Nonlinear Wave ◽  
Efficient Solution ◽  
Wave Structure ◽  
Finite Difference Schemes ◽  
Surface Boundary ◽  
Computational Domain ◽  
Problem Size ◽  
Structure Interaction ◽  
Nonlinear Wave Structure ◽  
Wave Structure Interaction

This contribution presents our recent progress on developing an efficient solution for fully nonlinear wave-structure interaction. The approach is to solve directly the three-dimensional (3D) potential flow problem. The time evolution of the wave field is captured by integrating the free-surface boundary conditions using a fourth-order Runge-Kutta scheme. A coordinate-transformation is employed to obtain a time-constant spatial computational domain which is discretized using arbitrary-order finite difference schemes on a grid with one stretching in each coordinate direction. The resultant linear system of equations is solved by the GMRES iterative method, preconditioned using a multigrid solution to the linearized, lowest-order version of the matrix. The computational effort and required memory use are shown to scale linearly with increasing problem size (total number of grid points). Preliminary examples of nonlinear wave interaction with variable bottom bathymetry and simple bottom mounted structures are given.

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