Modeling of Underwater Flexible Structures and Its Application to the Fishing Gear System Simulation

2004 ◽  
Author(s):  
Chun-Woo Lee ◽  
Ju-Hee Lee ◽  
Bong-Jin Cha ◽  
Hyun-Young Kim ◽  
Ji-Hoon Lee
Keyword(s):  
Flexible Structures ◽  
Three Dimensional ◽  
Stable Solution ◽  
Commercial Fishing ◽  
Flexible Systems ◽  
Physically Based Model ◽  
Mass Spring Model ◽  
Physically Based ◽  
External Forces ◽  
Mass Spring

This paper describes a physically based model for underwater flexible systems and presents its simulation results. In this study, a flexible structure is divided into a finite number of elements and those elements are connected with flexible lines. The elements of a structure can be modeled using the mass-spring model. The model is described as a nonlinear and stiff equation by considering the elasticity of the lines and external forces. The Newmark β method is used for the numerical integration of the system. It is found that this method offers low computational times and a stable solution. Also introduced is an algorithm to design various flexible systems using computer graphics, an automatic model creating system from the designed plan and a three-dimensional graphics tool that can show the calculated results. Application examples in design and simulation for the commercial fishing gears are presented.

scholarly journals Definition of Mass Spring Parameters for Knitted Fabric Simulation Using the Imperialist Competitive Algorithm

2017 ◽  
Vol 25 (0) ◽  
pp. 65-74 ◽  
Author(s):  
Vajiha Mozafary ◽  
Pedram Payvandy
Keyword(s):  
Imperialist Competitive Algorithm ◽  
Model Parameters ◽  
Knitted Fabric ◽  
Spring Model ◽  
Computer Engineering ◽  
Competitive Algorithm ◽  
Mass Spring Model ◽  
Physically Based ◽  
Definition Of ◽  
Mass Spring

The 3D simulation of fabrics is an interesting issue in many fields, such as computer engineering, textile engineering, cloth design and so on. Several methods have been presented for fabric simulation. The mass spring model, a typical physically-based method, is one of the methods for fabric simulation which is widely considered by researchers due to rapid simulation and being more consistent with reality. The aim of this paper is the optimization of mass spring parameters in the simulation of the drape behaviour of knitted fabric using the Imperialist Competitive Algorithm. First a mass spring model is proposed to simulate the drape behavior of knitted fabric. Then in order to reduce the error value between the simulated and actual result (reducing the simulation error value), parameters of the mass spring model such as the stiffness coefficient, damping coefficient, elongation rate, topology and natural length of the spring are optimized using the Imperialist Competitive Algorithm (ICA). The ICA parameters are specified using the Taguchi Design of Experiment. Finally fabrics drape shapes are simulated in other situations and compared with their actual results to validate the model parameters. Results show that the optimized model is able to predict the drape behavior of knitted fabric with an error value of 2.4 percent.

Study and comparison techniques in fabric simulation using mass spring model

2016 ◽  
Vol 28 (5) ◽  
pp. 634-689 ◽  
Author(s):  
Vajiha Mozafary ◽  
Pedram Payvandy
Keyword(s):  
Spring Model ◽  
Computer Engineering ◽  
Content Type ◽  
Mass Spring Model ◽  
Physically Based ◽  
Solving Equations ◽  
Numerical Integration Methods ◽  
Spring Method ◽  
The Common ◽  
Mass Spring

Purpose The purpose of this paper is to conduct a survey on research in fabric and cloth simulation using mass spring model. Also in this paper some of the common methods in process of fabric simulation in mass spring model are discussed and compared. Design/methodology/approach This paper reviews and compares presented mesh types in mass spring model, forces applied on model, super elastic effect and ways to settle the super elasticity problem, numerical integration methods for solving equations, collision detection and its response. Some of common methods in fabric simulation are compared to each other. And by using examples of fabric simulation, advantages and limitations of each technique are mentioned. Findings Mass spring method is a fast and flexible technique with high ability to simulate fabric behavior in real time with different environmental conditions. Mass spring model has more accuracy than geometrical models and also it is faster than other physical modeling. Originality/value In the edge of digital, fabric simulation technology has been considered into many fields. 3D fabric simulation is complex and its implementation requires knowledge in different fields such as textile engineering, computer engineering and mechanical engineering. Several methods have been presented for fabric simulation such as physical and geometrical models. Mass spring model, the typical physically based method, is one of the methods for fabric simulation which widely considered by researchers.

A Topology Optimization Problem in Control of Structures Using Modal Disparity

2005 ◽  
Vol 128 (3) ◽  
pp. 536-541 ◽  
Author(s):  
A. R. Diaz ◽  
R. Mukherjee
Keyword(s):  
Topology Optimization ◽  
Optimization Problem ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Vibration Energy ◽  
Frame Structures ◽  
Topology Optimization Problem ◽  
Small Set ◽  
Simulation Results ◽  
External Forces

Modal disparity and a topology optimization problem seeking to maximize this disparity are introduced, with the goal of developing a new methodology for control of vibration in flexible structures. Modal disparity is generated in a structure by the application of external forces that vary the stiffness of the structure. When the forces are switched on and off and, as a result, the structure is switched between two stiffness states, modal disparity results in vibration energy being transferred from a set of not-controlled modes to a set of controlled modes. This allows the vibration of the structure to be completely attenuated by removing energy only from a small set of controlled modes. A topology optimization problem determines the best locations for application of the external forces. Simulation results are presented to demonstrate control of vibration exploiting modal disparity in two three-dimensional (3D) frame structures.

scholarly journals Snow avalanche friction relation based on extended kinetic theory

2016 ◽  
Author(s):  
Matthias Rauter ◽  
Jan-Thomas Fischer ◽  
Wolfgang Fellin ◽  
Andreas Kofler
Keyword(s):  
Kinetic Theory ◽  
Three Dimensional ◽  
Field Tests ◽  
Friction Model ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Rheological Models ◽  
Physically Based Model ◽  
Physically Based

Abstract. Rheological models for granular materials play an important role in the numerical simulation of dry dense snow avalanches. This article describes the application of a physically based model from the field of kinetic theory to snow avalanche simulations. Those are usually based on depth-averaged two-dimensional models. Therefore a method to adapt the three-dimensional rheological model is presented. In a further step simulation results are compared to velocity and runout observations of avalanches, recorded from different field tests. As reference we utilize a classic phenomenological friction model, which is commonly applied for hazard estimation. The quantitative comparison is based on the combination of normalized residuals of different observation variables in order to take into account the quality of the simulations in various regards. It is demonstrated that the kinetic theory provides a physically based explanation for the structure of phenomenological friction relations and contributes improvements, in particular when different events and various observation variables are investigated.

Dynamic Behavior of a Submersible Fish Cage

2009 ◽  
Author(s):  
Chun Woo Lee ◽  
Gun Ho Lee ◽  
Moo Youl Choe ◽  
Dae Ho Song ◽  
Seyed Abbas Hosseini
Keyword(s):  
Current Velocity ◽  
Tensile Load ◽  
Mooring Line ◽  
Optimized Design ◽  
Cage System ◽  
Mass Spring Model ◽  
Average Tension ◽  
External Forces ◽  
Mass Spring ◽  
The Waves

Fish cage system is influenced by various external forces from the ocean environments, and the movements and the deformation of the cage by these external forces affect the safety of the cage itself, as well as that of the cultured organisms. In this research, submersible fish cage was designed to endure less physical stress by harsh sea conditions, and to keep the organisms in safer life by reducing the stress through exposure and movement. The submersible cage system consists of netting, mooring ropes, floating collar, floats, sinkers and anchors. Mass-spring model was used to predict the dynamic response of the cage subjected to tidal currents and waves. Computer simulation was performed for fish cage at the surface and submerged positions to investigate the dynamics of the motion and to calculate mooring line tensions. As expected, the average tension value of the mooring line for the submerged cage were less, being 64% of what we got in the case of surface position under the current velocity of 0.5 m/s combined with the waves. As the waves was used in combination with the current velocity of 1.0 m/s, the average tensile load for the submerged cage showed 85% of the value for the floating cage. The simulation results provide an improved understanding of the dynamic behaviors of the structure and their capability to withstand in subject to sever environmental loadings, and also valuable information on the optimized design of the cage system exposed to the open ocean environmental factors.

Design Patterns of Soft Products Using Surface Flattening

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Dongliang Zhang ◽  
Jituo Li ◽  
Jin Wang
Keyword(s):  
Design Patterns ◽  
Three Dimensional ◽  
Optimization Method ◽  
Surface Flattening ◽  
Manufactured Products ◽  
Mass Spring Model ◽  
Boundary Optimization ◽  
Pattern Development ◽  
Mass Spring ◽  
Flattening Process

In this paper, we present a pattern development method for soft product design. We utilize a surface fattening method based on a mass-spring model to create 2D patterns unfolding from a three-dimensional (3D) model. Multilevel meshes are proposed to expedite the flattening process, and a boundary optimization method is employed to guarantee 2D patterns can be sewn well. We apply the proposed method to the design of real soft products. Experimental results show that it can deal with complex surfaces efficiently and robustly, and manufactured products are satisfactory.

A Three-Dimensional Lumped Parameter Model of Nanoscale Phononic Crystals

2009 ◽  
Author(s):  
Bruce L. Davis ◽  
Mahmoud I. Hussein
Keyword(s):  
Equations Of Motion ◽  
Three Dimensional ◽  
Phononic Crystals ◽  
Lumped Parameter Model ◽  
Lagrangian Equations ◽  
Area Of Interest ◽  
Simple Cubic ◽  
Lumped Parameter ◽  
Mass Spring Model ◽  
Mass Spring

This work focuses on modeling nanoscale phononic crystals by setting up the appropriate Lagrangian equations of motion. The atomic structure and force constants are accounted for by means of a lumped parameter mass-spring model. In particular we focus on a simple cubic lattice with one mass per primitive unit cell. We use the model to predict the wave propagation frequency spectrum. We then use the model to conduct a series of studies on the influence of defects intentionally introduced to the lattice at a supercell level. One area of interest is the effect of such alterations on the size and location of band gaps.

3D Garment Real-Time Simulation in Character Animation

2010 ◽  
Vol 108-111 ◽  
pp. 753-758 ◽  
Author(s):  
Yang Liu
Keyword(s):  
Real Time ◽  
Character Animation ◽  
Virtual Character ◽  
Real Time Simulation ◽  
Time Simulation ◽  
Mass Spring Model ◽  
Collision Handling ◽  
Physically Based ◽  
Deformable Bodies ◽  
Mass Spring

In this paper, a framework of 3D Real-time Garment Simulation System for character animation is presented .For the problem of computational efficiency and stability for cloth physical modeling, we proposed a cloth mass-spring model based on constraint. Take geometry sphere and cylinder as example to explaining the whole strategy which used to dealing with cloth deformable bodies colliding with environment object. We described the procedure of physically based simulation, and illustrated the result and analysis of the experiment. By using the technique of parameterized human body modelling, virtual try-on was realized with the different shape of virtual character. Finally, integrating the techniques of character animation, physically based cloth simulation and non-precise deformable object collision handling, we create the real-time simulation animation of virtual character.

Tuning of Bandgap Structures in Three-Dimensional Kagome-Sphere Lattice

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Ying Liu ◽  
Xiu-zhan Sun ◽  
Wen-zheng Jiang ◽  
Yu Gu
Keyword(s):  
Phononic Crystal ◽  
Three Dimensional ◽  
Structure Design ◽  
Geometrical Parameters ◽  
Geometrical Condition ◽  
Mass Spring Model ◽  
Sphere Radius ◽  
Equivalent Mass ◽  
Kagome Truss ◽  
Mass Spring

In this manuscript, acoustic wave propagation in a novel three-dimensional porous phononic crystal-Kagome lattice, is studied by using finite element method. Firstly, a Kagome-sphere structure is established based on Kagome truss. For lattice with fixed rods (sphere radius varied) or fixed spheres (rod radius varied), the band structures are calculated in order to clarify the influence of geometrical parameters (sphere and rod sizes) on the bandgap characteristics in Kagome-sphere lattice. The vibration modes at the band edges of the lowest bandgaps are investigated with the aim to understand the mechanism of the bandgap generation. It is found that the emergence of the bandgap is due to the local resonant vibration of the unit cell at the adjacent bands. The width and position of this bandgap can be tuned by adjusting the geometrical parameters. An equivalent mass-spring model is proposed and the equivalent system resonance frequency can be evaluated which predicts well the upper and lower edges of the complete bandgaps. Moreover, the critical geometrical parameter is formulated which gives the critical geometrical condition for the opening of the complete bandgaps. The results in this paper are relevant to the bandgap structure design of three-dimensional porous phononic crystals (PPCs).

scholarly journals ANÁLISE COMPARATIVA DOS MODOS E FREQUENCIAS NATURAIS DE VIBRAÇÃO DE VIGAS ENGASTADA LIVRE E BI-ENGASTADA SUJEITAS À OSCILAÇÕES LIVRES

2018 ◽  
Vol 10 (4) ◽  
pp. 18-27
Author(s):  
Cássio Fabian Sarquis de Campos ◽  
Daniele Araújo Altran ◽  
Gustavo Figueiredo Formagio
Keyword(s):  
Natural Vibration ◽  
Natural Frequencies ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Free Form ◽  
Vibration Modes ◽  
Structural Problems ◽  
External Forces ◽  
Computational Resources ◽  
Free Sets

The objective of this work was the theoretical and computational modeling of free-form and bi-set beams, objectively showing their ways of vibrations and their natural frequencies. The study of the dynamics of rigid or flexible structures, under the action of external forces, such as regular marine waves, winds, external mechanical vibrations of any order, is of extreme importance for the prevention of possible structural problems, for example, displacements, partial or total ruptures of these structures. All the study was carried out Recebido em: 10/08/2018Revisado em: 28/08/2018Aprovado em: 20/09/2018 19Colloquium Exactarum, v. 10, n.4,Out-Dez. 2018, p.18–27. DOI: 10.5747/ce.2018.v10.n4.e252using the methods of Computational Analysis of the Natural Vibration Modes and Frequencies of a Free Beam of Forms for Free Frequencies and Computational Calculation of Lies and Natural Vibration Frequencies of a Beam Without Free Sets of Free Oscillations and the Computational Computation of Lies and Natural Frequencies of Vibration of a Bi Beam established by the Method ofAssumed Modalities. The computational resources used to do the theoretical remodeling of the beams and their functions were Matlab®and Maple®. Employees to implement three-dimensional vibration modes and development of new studies with different bundles and physical properties. This comparative work of the beams provided the mathematical and dynamic knowledge of modeling of the structures, being they, modeling skills through programming.

Sign in / Sign up

Export Citation Format

Share Document