Influence of Mesh Option "PATTERN" for Fluid Region Using Finite Element Method

2015 ◽  
Vol 769 ◽  
pp. 241-244
Author(s):  
Kamila Kotrasova ◽  
Eva Kormanikova

Ground-supported tanks are used to store a variety of fluids. The liquid develops a hydrodynamic effect on walls and bottom of the tank during earthquake. This paper presents influence of mesh parameter “PATTERN” for numerical model fluid region of liquid seismic response in rectangular tank – endlessly long shipping channel. Finite Element Method (FEM) was used in software Adina.

Author(s):  
Виктор Григорьевич Чеверев ◽  
Евгений Викторович Сафронов ◽  
Алексей Александрович Коротков ◽  
Александр Сергеевич Чернятин

Существуют два основных подхода решения задачи тепломассопереноса при численном моделировании промерзания грунтов: 1) решение методом конечных разностей с учетом граничных условий (границей, например, является фронт промерзания); 2) решение методом конечных элементов без учета границ модели. Оба подхода имеют существенные недостатки, что оставляет проблему решения задачи для численной модели промерзания грунтов острой и актуальной. В данной работе представлена физическая постановка промерзания, которая позволяет создать численную модель, базирующуюся на решении методом конечных элементов, но при этом отражающую ход фронта промерзания - то есть модель, в которой объединены оба подхода к решению задачи промерзания грунтов. Для подтверждения корректности модели был проделан ряд экспериментов по физическому моделированию промерзания модельного грунта и выполнен сравнительный анализ полученных экспериментальных данных и результатов расчетов на базе представленной численной модели с такими же граничными условиями, как в экспериментах. There are two basic approaches to solving the problem of heat and mass transfer in the numerical modeling of soil freezing: 1) using the finite difference method taking into account boundary conditions (the boundary, for example, is the freezing front); 2) using the finite element method without consideration of model boundaries. Both approaches have significant drawbacks, which leaves the issue of solving the problem for the numerical model of soil freezing acute and up-to-date. This article provides the physical setting of freezing that allows us to create a numerical model based on the solution by the finite element method, but at the same time reflecting the route of the freezing front, i.e. the model that combines both approaches to solving the problem of soil freezing. In order to confirm the correctness of the model, a number of experiments on physical modeling of model soil freezing have been performed, and a comparative analysis of the experimental data obtained and the calculation results based on the provided numerical model with the same boundary conditions as in the experiments was performed.


Author(s):  
Xiaofei Cheng ◽  
Yongxue Wang ◽  
Bing Ren ◽  
Guoyu Wang

In the paper, a 2D numerical model is established to simulate the hydrodynamic forces on a submarine piggyback pipeline under regular wave action. The two-dimensional Reynolds-averaged Navier-Stokes equations with a κ-ω turbulence model closure are solved by using a three-step Taylor-Galerkin finite element method (FEM). A Computational Lagrangian-Eulerian Advection Remap Volume of Fluid (CLEAR-VOF) method is employed to simulate free surface problems, which is inherently compatible with unstructured meshes and finite element method. The numerical results of in-line force and lift (transverse) force on the piggyback pipeline for e/D = G/D = 0.25 and KC = 25.1 are compared with physical model test results, which are conducted in a marine environmental flume in the State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, China. It is indicated that the numerical results coincide with the experimental results and that the numerical model can be used to predict the hydrodynamic forces on the piggyback pipeline under wave action. Based on the numerical model, the surface pressure distribution and the motion of vortices around the piggyback pipeline for e/D = G/D = 0.25, KC = 25.1 are investigated, and a characteristic vortex pattern around the piggyback pipeline denoted “anti-phase-synchronized” pattern is recognized.


2017 ◽  
Vol 16 (3) ◽  
pp. 095-102
Author(s):  
Daniel Pietras ◽  
Tomasz Sadowski

In this paper the application of the Extended Finite Element Method (XFEM) to anticipate change of the behaviour of composite with complex internal structure after use of the admixtures was presented. The response to mechanical loadings of bent beams made of hydraulically bonded mixture with rubber admixture was considered. The impact of the rubber granulate on the value of fracture energy was analysed. Moreover, the influence of an interfacial transmission zone quality on the achieved effect was assessed. Calculations were conducted by means of the muli-scale numerical model which was built in ABAQUS finite element method environment. The results derived indicate beneficial effect of rubber granulate on fracture energy of hydraulically bonded mixture.


Aviation ◽  
2010 ◽  
Vol 14 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Tadeusz Markowski ◽  
Stanislaw Noga ◽  
Stanislaw Rudy

The development of computer techniques and computational systems based on the finite element method allows one to conduct a free vibration analysis of large systems like an aviation gearbox test rig. The object of this paper is to present a free vibration analysis of a gear fatigue test rig working in a closed loop configuration. A numerical model of the test rig based on the finite element method is presented in this paper. The base model contains all the essential structures of the real system. After the numerical results of the natural frequencies of the rig were obtained, they were then verified by the experimental results on a real object. Numerical analysis was performed using the ANSYS code. Santrauka Baigtiniu elementu metodu paremtas kompiuterines technikos ir kompiuteriniu sistemu kūrimas leidžia atlikti laisvuju svyravimu analize tokios dideles sistemos, kaip aviacines pavaru dežes, testavimo irenginys. Šio darbo tikslas buvo atlikti pavaru dežes nuovargio bandymu irenginio, veikiančio uždaro kontūro konfigūracijoje, laisvuju svyravimu analize. Taip pat pateikiamas testavimo irenginio skaitinis modelis, kurio veikimas yra pagristas baigtiniu elementu metodu. Pagrindinis modelis turi visas tikrosios sistemos svarbiausias struktūras. Gavus irenginio savuju dažniu kiekybinius rezultatus, buvo patikrinti realaus objekto eksperimentiniai rezultatai. Naudojantis ANSYS sistema buvo atlikta skaitine analize.


2009 ◽  
Vol 67 ◽  
pp. 33-38 ◽  
Author(s):  
Prasenjit Khanikar ◽  
Arun Kumar ◽  
Anandh Subramaniam

A dislocation near a free surface feels a force towards the boundary, which is called the image force. In this investigation, a simple edge dislocation is simulated using Finite Element Method (FEM) by feeding-in the appropriate stress-free strain in idealized domains, corresponding to the introduction of an extra half-plane of atoms. The strains are imposed as thermal strains in the numerical model using standard commercially available software. The results of the simulation (stress fields and energy) are compared with the standard theoretical equations to validate the model. The energy of the system as a function of the position of the simulated dislocation is plotted and the gradient of the curve is calculated at various points along the curve. This slope corresponds to the image force experienced by the dislocation. The image force can be resolved into a glide component and a climb component, which are determined from the simulation by appropriately positioning the dislocation at various points in the domain. The term image force is used in literature (for the force experienced by a dislocation in the vicinity of a free-surface), because a hypothetical negative dislocation is assumed to exist on the other side of the boundary for the calculation of the force. In the current model no such assumption is required for the determination of the image force. In nanocrystals the dislocation will be proximal to more than one surface and hence the resultant image force experienced by the dislocation is superimposition of these forces. The utilization of the numerical model for the calculation of image forces in nanocrystals requires no further modifications to the simulation methodology as the image force is determined from 'first principles' as a gradient of the energy field.


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