A high accurate hamiltonian nodal position finite element method for spatial cable structures undergoing long-term large overall motion

2019 ◽  
Vol 70 ◽  
pp. 203-222 ◽  
Author(s):  
Huaiping Ding ◽  
Xiaochun Yin ◽  
Zheng H. Zhu ◽  
Lin Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cable Structures ◽  
Nodal Position ◽  
Element Method

Dynamic Modeling of Towed Cable System Using the Nodal Position Finite Element and Symplectic Integration

2015 ◽  
Author(s):  
G. Q. Li ◽  
Lian Lian ◽  
Zheng H. Zhu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Modeling ◽  
Simulation Program ◽  
Singular Problem ◽  
Beam Model ◽  
Alternative Method ◽  
Nodal Position ◽  
Element Method

The cable of towed underwater system have a character of low tension, in order to overcome this singular problem during numerical calculation, the bending stiffness is included in the bar model, or using the beam model. however, we choose an alternative method called nodal position finite element method, it is different from the traditional finite element method, this alternative method is formulated in term of element nodal position that different with the nodal displacement used in traditional finite element. The model equation is derived from the principle of virtual work, consideration of the hydrodynamic drag force, gravity force, buoyancy and internal damping model. The energy conservative time integrator is preferred for the long term simulation, so we build up a simulation program that using the nodal position finite element method and symplectic leapfrog time integrator for the dynamic analysis of the towed body system. Firstly, the robustness of the proposed time integrator is verified by the elastic spring pendulum, and compared with the traditional frequently used time integrators such as fourth-order Runge-Kutta method and Newmark method, the results show that the proposed approach is accurate and preserves the system energy over long term simulation, then the proposed time integrator is applied to the dynamic modeling of the elastic cable towed system, the well agreement with Sea trail experiment date demonstrates that the simulation program is robust and accurate.

scholarly journals Effects of Attachment of Plastic Aligner in Closing of Diastema of Maxillary Dentition by Finite Element Method

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Yukiko Yokoi ◽  
Atsushi Arai ◽  
Jun Kawamura ◽  
Tomoko Uozumi ◽  
Yohei Usui ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Periodontal Ligament ◽  
Tooth Movement ◽  
Initial Displacement ◽  
Bodily Movement ◽  
Long Time ◽  
Maxillary Dentition ◽  
Element Method

The aim of this study was to clarify the effect of attachment on tooth movement produced by a plastic aligner. Closing of a diastema, in which the maxillary right and left central incisors moved bodily, was simulated using a finite element method. Long-term orthodontic movements of the maxillary dentition were simulated by accumulating the initial displacement of teeth produced by elastic deformation of the periodontal ligament. The incisor tipped and rotated just after placement of the aligner irrespective of the attachment. After a sufficiently long time, the incisor was upright and moved bodily in the aligner with attachment, but the incisor remained tipped in the aligner without attachment. It was demonstrated that the attachment was effective for achieving bodily movement.

Accurate Viscoelastic Large Deformation Analysis Using F-Bar Aided Edge-Based Smoothed Finite Element Method for 4-Node Tetrahedral Meshes (F-BarES-FEM-T4)

2019 ◽  
Vol 17 (02) ◽  
pp. 1845003 ◽  
Author(s):  
Yuki Onishi ◽  
Ryoya Iida ◽  
Kenji Amaya
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Large Deformation ◽  
Pressure Oscillation ◽  
Deformation Analysis ◽  
Smoothed Finite Element Method ◽  
Edge Based ◽  
Smoothing Procedure ◽  
Element Method

A state-of-the-art tetrahedral smoothed finite element method, F-barES-FEM-T4, is demonstrated on viscoelastic large deformation problems. The stress relaxation of viscoelastic materials brings near incompressibility when the long-term Poisson’s ratio is close to 0.5. The conventional hybrid 4-node tetrahedral (T4) elements cannot avoid the shear locking and pressure checkerboarding issues, meanwhile F-barES-FEM-T4 can suppress these issues successfully by adopting the edge-based smoothed finite element method (ES-FEM) with the aid of the F-bar method and the cyclic smoothing procedure. A few examples of analyses verify that F-barES-FEM-T4 is locking-free and pressure oscillation-free in viscoelastic analyses as well as in nearly incompressible hyperelastic or elastoplastic analyses.

Hamiltonian Nodal Position Finite Element Method for Cable Dynamics

2017 ◽  
Vol 09 (08) ◽  
pp. 1750109 ◽  
Author(s):  
Huaiping Ding ◽  
Zheng H. Zhu ◽  
Xiaochun Yin ◽  
Lin Zhang ◽  
Gangqiang Li ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rigid Body ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Frequency Mode ◽  
Integration Scheme ◽  
Long Period ◽  
Nodal Position ◽  
Element Method

This paper developed a new Hamiltonian nodal position finite element method (FEM) to treat the nonlinear dynamics of cable system in which the large rigid-body motion is coupled with small elastic cable elongation. The FEM is derived from the Hamiltonian theory using canonical coordinates. The resulting Hamiltonian finite element model of cable contains low frequency mode of rigid-body motion and high frequency mode of axial elastic deformation, which is prone to numerical instability due to error accumulation over a very long period. A second-order explicit Symplectic integration scheme is used naturally to enforce the conservation of energy and momentum of the Hamiltonian finite element system. Numerical analyses are conducted and compared with theoretical and experimental results as well as the commercial software LS-DYNA. The comparisons demonstrate that the new Hamiltonian nodal position FEM is numerically efficient, stable and robust for simulation of long-period motion of cable systems.

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