scholarly journals Overview of the Constitutive Model and Numerical Calibration by FEM to Compute Bearing Capacity and Embankment-Core Deformability

2021 ◽  
Vol 42 (1) ◽  
pp. e93712
Author(s):  
Milena Mesa Lavista ◽  
Francisco Lamas-Fernández ◽  
Eduardo Tejeda-Piusseaut ◽  
Rafael Bravo-Pareja ◽  
Carolina Cabrera-González ◽  
...  

Numerical modeling is a powerful tool to determine the stress-strain relationships of structures. However, for a reliable application, physical and mathematical models must be calibrated and validated. This paper presents an overview of numerical calibration through the finite element method and plate-load tests in an embankment. Additionally, an analysis of the constitutive models used in soils is performed, and the elastic-plastic constitutive model of Mohr-Coulomb was selected since it is the best suited for this study. The results from three test areas within a refinery project that the Cuban government undertook in the province of Cienfuegos are used. The numerical model used in this study was calibrated by means of the error theory and the non-parametric hypothesis tests from Mann-Whitney U. From the practical point of view, this study gives two procedures to calibrate the numerical model with experimental results.

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.


1975 ◽  
Vol 10 (3) ◽  
pp. 167-171 ◽  
Author(s):  
F Ginesu ◽  
B Picasso ◽  
P Priolo

Results on the plastic collapse behaviour of an axisymmetric rotating shell, obtained by Limit Analysis and the Finite Element Method, are in good agreement with experimental data. The Finite Element Method, though computationally rather costly, permits, however, a more complete analysis of elasto-plastic behaviour. For the present case, the Limit Analysis has the advantage of greater computational simplicity and leads to a quite satisfactory forecast of collapse speed from the engineering point of view.


1990 ◽  
Vol 112 (2) ◽  
pp. 202-209 ◽  
Author(s):  
T. Adachi ◽  
F. Oka ◽  
M. Mimura

The mathematical structure of Adachi and Oka’s model, a typical overstress type elasto-viscoplastic constitutive model, for normally consolidated clays is discussed. Since it has been recognized that the overstress type models cannot describe the acceleration creep and creep rupture, the Adachi and Oka’s model was modified so that it can explain the creep rupture including acceleration creep of normally consolidated clays. In addition, based on the Adachi and Oka’s constitutive model and Biot’s consolidation theory, one-dimensional consolidation problems were analyzed numerically by the finite element method. Results show that the proposed method can describe the effect of sample thickness and aging on consolidation phenomena.


2021 ◽  
Vol 11 (22) ◽  
pp. 10998
Author(s):  
Bartosz Chmielewski ◽  
Iván Herrero-Durá ◽  
Paweł Nieradka

Dissipative splitter silencers are widely used in industry for the reduction of propagated sound waves in ducts. Even though these systems are effective from the acoustics point of view when they are properly designed, they also introduce a pressure loss in the system, due to the modification of the properties of the flow circulating inside the duct. This effect is not desired in some industrial applications, so it is necessary to be able to predict the pressure loss as precisely as possible to design silencers according to the needs. Nevertheless, the prediction made by standards are usually limited to given geometries or flow speed. In this work, we present a comparative study on the results obtained for the pressure loss by means of the standards ISO 14163 and VDI 1801-1, numerical simulations with the finite element method, and experimental measurements. Additionally, two different profile shapes and four input face velocities are tested in order to know the influence of these parameters in the variations of the flow and the accuracy of the prediction of the different methods.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Krzysztof Kosiuczenko ◽  
◽  
Robert Sosnowicz ◽  

The paper presents the results of simulation tests of the entry of a floating transporter to a water obstacle. The simulation tests were performed with the use of LS Dyna program, based on the finite element method (FEM). The computational model was developed and used in the simulation of the manoeuvre of entering the water obstacle for the extreme conditions, which are described by NATO standards. For a model, as an example vehicle, the floating transporter PTS-M was used. The results of the application of the elaborated model confirmed the possibility to utilise the method to verify the behaviour of a vehicle in a very important and difficult problem from the point of view of vehicle safety conditions.


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.


Author(s):  
Ste´phane E´tienne ◽  
Dominique Pelletier

Vortex and wake induced vibrations (VIV/WIV) of a circular cylinder at low values of the Reynolds number (Re) are simulated by means of a fully coupled fluid-structure interaction numerical model based on the finite element method. It is shown that VIV/WIV could occur far below the first Hopf bifurcation (Re <47). The main objective of this study is to determine the limiting Reynolds-Reduced velocity (Ur) curve that separates the non-vibrational area from the possible vibrations occurrence area. We assume that by taking a zero mass cylinder and zero structural damping we will obtain the low limit of vibrations in terms of Re and Ur. It is shown in particular that transverse vibrations could occur for reduced velocities larger than 40 and not below 3.5.


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