64028 Computational Time Reduction for Neurosurgical Training System Based on Finite Element Method(Biomechanics)

2010 ◽  
Vol 2010.5 (0) ◽  
pp. _64028-1_-_64028-7_
Author(s):  
Osuke Kobayashi ◽  
Kazuhiko Adachi ◽  
Yohei Azuma ◽  
Atsushi Fujita ◽  
Eiji Kohmura
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Training System ◽  
Computational Time ◽  
Neurosurgical Training ◽  
Time Reduction ◽  
Element Method

An efficient iterative algorithm for the natural convection equations based on finite element method

2018 ◽  
Vol 28 (3) ◽  
pp. 584-605 ◽  
Author(s):  
Lei Wang ◽  
Jian Li ◽  
Pengzhan Huang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Convection ◽  
Iterative Method ◽  
Error Correction ◽  
Computational Time ◽  
Content Type ◽  
Natural Convection Problem ◽  
New Iterative Method ◽  
Element Method

Purpose This paper aims to propose a new highly efficient iterative method based on classical Oseen iteration for the natural convection equations. Design/methodology/approach First, the authors solve the problem by the Oseen iterative scheme based on finite element method, then use the error correction strategy to control the error arising. Findings The new iterative method not only retains the advantage of the Oseen scheme but also saves computational time and iterative step for solving the considered problem. Originality/value In this work, the authors introduce a new iterative method to solve the natural convection equations. The new algorithm consists of the Oseen scheme and the error correction which can control the errors from the iterative step arising for solving the nonlinear problem. Comparing with the classical iterative method, the new scheme requires less iterations and is also capable of solving the natural convection problem at higher Rayleigh number.

Evaluation of Relative Permeability Models in CO2/Brine System Using Mixed and Hybrid Finite Element Method

2016 ◽  
Vol 819 ◽  
pp. 401-405
Author(s):  
J.S. Pau ◽  
William K.S. Pao ◽  
Suet Peng Yong ◽  
Paras Qadir Memon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Relative Permeability ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Computational Time ◽  
Permeability Model ◽  
Hybrid Finite Element Method ◽  
Hybrid Finite Element ◽  
Element Method

The requirement to reduce 40% carbon emission in 2020 has lead Malaysia to adopt the carbon capture and storage (CCS) technology in 2009. In this research, the pressure and transport differential equation for CO2 – brine phases flow is discretized using mixed and hybrid finite element method (MHFEM) which ensures the local continuity of the finite elements. Result shows that CO2 flow radially outward from the injection well. Three relative permeability models are investigated and it was find out that the simplified relative permeability model (SRM) has reduced the computational time by 8.3 times (when compare to Brooks and Corey model) but it is accurate for 1 year preliminary prediction. For longer period of prediction, classical Brooks and Corey and van Genuchten models shall be used.

Finite element method based sliding wear prediction of steel-on-steel contacts using extrapolation techniques

2019 ◽  
Vol 233 (10) ◽  
pp. 1446-1463
Author(s):  
Kunal K Bose ◽  
P Ramkumar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sliding Wear ◽  
Constant Pressure ◽  
Contact Geometry ◽  
Computational Time ◽  
Linear Extrapolation ◽  
Wear Simulation ◽  
Extrapolation Technique ◽  
Element Method

Wear is a complex phenomenon, which depends on various parameters such as load, velocity, material properties, surface, environmental conditions, etc. Hence, wear prediction is a challenging part of engineering. This paper focuses on numerically predicting the wear of 304 stainless steel pin sliding against AISI 52100 bearing steel disc, using pin-on-disc tribometer setup. The experiments are performed for loads of 10 N, 30 N, and 50 N and a sliding speed of 0.4 m/s. The wear coefficient and coefficient of friction obtained from the experiments are given as input to a 2D elastic finite element method model using a commercially available finite element method-based software ABAQUS. The differential form of the Archard’s wear law is used to obtain the wear depth at the contact nodes. The UMESHMOTION+ Arbitrary Lagrangian–Eulerian technique is used to update the contact geometry after each wear increment. The major drawback of wear simulation is the large computational time requirement. To address this, three extrapolation techniques are used namely, the constant extrapolation, the linear extrapolation, and the constant pressure extrapolation technique. A new criterion for using extrapolation during sliding wear simulation was proposed. The extrapolation techniques take into consideration the evolution of the contact pressure and contact geometry during sliding wear. The effectiveness of these techniques based on the computational time and accuracy are analysed. Based on the accuracy, the linear extrapolation technique was found to be most effective, while the constant pressure extrapolation technique was most useful in reducing the computational time. The numerical results obtained are validated with the experimental results.

3D MT Anisotropic Inversion Based on Unstructured Finite-element Method

2021 ◽  
Vol 26 (1) ◽  
pp. 49-60
Author(s):  
Xiaoyue Cao ◽  
Xin Huang ◽  
Changchun Yin ◽  
Liangjun Yan ◽  
Bo Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Hessian Matrix ◽  
Synthetic Data ◽  
Forward Modeling ◽  
Explicit Calculation ◽  
Computational Time ◽  
Earth Model ◽  
Earth Structures ◽  
Element Method

The conventional 3D magnetotelluric (MT) forward modeling and inversions generally assume an isotropic earth model. However, wrong results can be obtained when using an isotropic model to interpret the data influenced by the anisotropy. To effectively model and recover the earth structures including anisotropy, we develop a 3D MT inversion framework for a triaxial anisotropic model. We use the unstructured finite-element method for our forward modeling. This offers more possibility to simulate more complex underground geology and topography. To solve the inverse modeling problem, we use a limited-memory quasi-Newton algorithm (L-BFGS) with a parallel direct solver for optimization that avoids the explicit calculation of the Hessian matrix and saves the memory and computational time. We validate our algorithm via numerical experiments on both synthetic data and MT survey data from the US Array project.

Analysis of Octagonal Pile Supporting Offshore Wind Turbines Under Wave Loads

2014 ◽  
Author(s):  
Serena Lim ◽  
Longbin Tao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Computational Cost ◽  
Offshore Wind ◽  
Computational Time ◽  
Offshore Wind Turbine ◽  
Wave Loads ◽  
Element Method

Offshore wind energy development has gained considerable momentum around the world as wind is stronger and steadier offshore compared to land. This has led to a significant increase in production in recent years, especially offshore wind turbine embedded in shallow waters, such as the recent large scale offshore wind farms in the Northern Europe region. Being at the offshore waters, the wind turbines are subjected to harsh environment. The pile supporting the wind turbine must be reliable and able to withstand such sea condition. It is an important part of the design to study the structural behaviour of the piles under the wave loads. Due to the significant capital cost associated with the fabrication of the large circular cylinders, a new recommended innovative design to overcome such problem is to substitute the circular cylinder with a vertical monopile of octagonal cross-sectional shape. This paper describes the development of an efficient numerical model for structural analysis of wave interaction with octagonal pile using a modified semi analytical Scaled Boundary Finite Element Method (SBFEM). In contrast to the existing solutions obtained using the traditional methods such as the Finite Element Method (FEM) which typically suffer from high computational cost and the Boundary Element Method (BEM) which faces limitation from fundamental equations and problems with singularities. The most prominent advantage that SBFEM has over the FEM is in terms of the number of elements used for calculation and hence a reduction in computational time. When compared with BEM, the SBFEM does not suffer from computational stability problems.

Wave Diffraction Forces on Offshore Wind Turbine Piles With an Octagonal Cross Section

2013 ◽  
Author(s):  
Serena Lim ◽  
Longbin Tao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wave Diffraction ◽  
Offshore Wind ◽  
Circular Cylinders ◽  
Computational Time ◽  
Offshore Wind Turbine ◽  
Computational Stability ◽  
Irregular Frequency ◽  
Element Method

Traditional offshore wind turbines are normally supported by circular monopiles which are fabricated by rolling thick plates and welding them longitudinally. Due to the significant capital cost associated with the fabrication of such large circular cylinders, a new recommended innovative design to overcome such problem is introduced by replacing the circular cylinder with a vertical pile of octagonal cross-sectional shape. An efficient and very accurate semi-analytical/numerical solution based on the Scaled Boundary Finite Element Method (SBFEM) is developed to calculate the wave diffraction forces acting on the octagonal cylinders where no fundamental solutions known exist. Compared to the traditional Boundary Element Method (BEM), the SBFEM is free from the irregular frequency difficulty which means that it does not suffer from computational stability problems at sharp corners. The SBFEM solution also exhibits an enormous reduction of elements used to calculate the wave diffraction compared to the Finite Element Method (FEM), hence, a significant reduction in computational time. The SBFEM computation of the diffraction force demonstrates highly accurate results with a small number of surface elements. The presented method shows significant advantages, and is suitable for engineering applications especially the wave-structure interaction in the practical design.

Optimization Algorithm of Crack Initial Angle Using the Extended Finite Element Method

2013 ◽  
Vol 444-445 ◽  
pp. 77-84 ◽  
Author(s):  
Yi Su ◽  
Sheng Nan Wang ◽  
Yong En Du
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Growth ◽  
Optimization Algorithm ◽  
Extended Finite Element Method ◽  
Crack Problem ◽  
Cholesky Factorization ◽  
Computational Time ◽  
Extended Finite Element ◽  
Element Method

The extended finite element method (XFEM) allows the entire crack to be represented independently from the mesh, which means re-mesh is unnecessary in model crack growth, reduces the computational time drastically. However, fatigue crack growth simulation has been computationally challenged by lots of analog computations in crack growth. Therefore, a new reanalysis algorithm based on incremental Cholesky factorization is derived. In this paper, we consider a variant of XFEM in which an exponent discontinuous function is used to simulate the crack through unit. Then the corresponding formula of XFEM with inclusion and crack problem with a new reanalysis algorithm is derived. In the end, we use the new reanalysis algorithm and an optimization algorithm to predict the angle of crack initiation from a hole in a plate with inclusion. It shows that the algorithm is effective.

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