Inverse-Motion-Based Modeling for Electromechanics With Application to Electrostrictive Polyurethane

Author(s):  
Anna Ask ◽  
Ralf Denzer ◽  
Andreas Menzel ◽  
Matti Ristinmaa

In this work the inverse motion problem for electroelasticity is considered. For given loads and boundary conditions, and a given deformed shape of the electro elastic body, the initially unknown undeformed configuration is sought. The boundary-value problem for the inverse motion is obtained by reparameterization of the forward motion equations in terms of the inverse deformation map. In order to account for incompressibility, a mixed formulation is adopted. The finite element method is used to calculate the undeformed configuration for an electro-active gripper application.

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.


1999 ◽  
Vol 21 (2) ◽  
pp. 116-128
Author(s):  
Pham Thi Toan

In the present paper, the goffered multilayered composite cylindrical shells is directly calculated by finite element method. Numerical results on displacements, internal forces and moments are obtained for various kinds of external loads and different boundary conditions.


2021 ◽  
Author(s):  
Marek Macák ◽  
Zuzana Minarechová ◽  
Róbert Čunderlík ◽  
Karol Mikula

<p><span>We presents local gravity field modelling in a spatial domain using the finite element method (FEM). FEM as a numerical method is applied for solving the geodetic boundary value problem with oblique derivative boundary conditions (BC). We derive a novel FEM numerical scheme which is the second order accurate and more stable than the previous one published in [1]. A main difference is in applying the oblique derivative BC. While in the previous FEM approach it is considered as an average value on the bottom side of finite elements, the novel FEM approach is based on the oblique derivative BC considered in relevant computational nodes. Such an approach should reduce a loss of accuracy due to averaging. Numerical experiments present </span><span>(i) </span><span>a reconstruction of EGM2008 as a harmonic function over the extremely complicated Earth’s topography in the Himalayas and Tibetan Plateau, and (ii) local gravity field modelling in Slovakia with the high-resolution 100 x 100 m while using terrestrial gravimetric data.</span></p><p><span>[1] </span>Macák, Z. Minarechová, R. Čunderlík, K. Mikula, The finite element method as a tool to solve the oblique derivative boundary value problem in geodesy. Tatra Mountains Mathematical Publications. Vol. 75, no. 1, 63-80, (2020)</p>


2011 ◽  
Vol 243-249 ◽  
pp. 5994-5998
Author(s):  
Lang Cao ◽  
Xing Jie Xing ◽  
Feng Guang Ge

According to the bending equation and boundary conditions of skew plate in the oblique coordinates system parallel to the edge of the plate, expanding deflection and load into form of Fourier series, the paper derives and obtains unified solution of bending problem for the four-edge-supported skew plate under arbitrary load. Programmed and calculated by mathematica language, the paper also comes with deflections and moments under the condition of any oblique angles, ratios of side length and Poisson ratios. The results of the paper is compared with those by the finite element method in the example, and they’re in good agreement with each other. The paper extends the bending theory of rectangular plate to the skew plate of any angle. The theory being reliable and the result being accurate, the research of the paper can provide reference for engineering design.


1968 ◽  
Vol 35 (2) ◽  
pp. 274-278 ◽  
Author(s):  
M. W. Johnson ◽  
R. W. McLay

The foundations of the theory of the finite element method as it applies to linear elasticity are investigated. A particular boundary-value problem in plane stress is considered and the variational principle for the finite element method is shown to be equivalent to it. Mean and uniform convergence of the finite element solution to that of the boundary-value problem is demonstrated with careful consideration given to the stress singularities. A counterexample is presented in which a set of functions, admissible to the variational principle, is shown not to converge.


2013 ◽  
Vol 26 ◽  
pp. 143-151 ◽  
Author(s):  
Sadegh Imani Yengejeh ◽  
Mojtaba Akbarzade ◽  
Andreas Öchsner

In this study, numerous types of straight hetero-junction carbon nanotubes (CNTs) and their fundamental CNTs were investigated by the finite element method (FEM). By applying the FEM, the shear behavior of these hetero-junctions was obtained thorough numerical simulation. The behavior of hetero-junctions and their constituent CNTs were investigated. The investigations revealed that the twisting angle of straight hetero-junction CNTs lies within the range of twisting angle of their fundamental CNTs. In addition, change of boundary conditions did not significantly change the value of obtained twisting angle of hetero-junctions. It was also concluded that the shear behavior of straight hetero-junctions and their constituent CNTs increases by increasing the chiral number of both armchair and zigzag CNTs. The current study provides a better insight towards the prediction of straight hetero-junction CNTs behavior.


2018 ◽  
Vol 9 (1) ◽  
pp. 171-174
Author(s):  
Richárd Molnár ◽  
Gergely Dezső

Abstract Nowadays more and more ultralight aircraft are being built because the building process itself and the acquisition of the necessary documentation is relatively easy. Furthermore, these planes are easier to fly than larger types of aircraft. This article presents the engineering work and documentation that is necessary for the building process. The calculations can be done traditionally on paper which is an extremely complex task. With the innovations and developments in the technical field though, it is possible now to simplify these calculations, the basis of which is the finite element method and aerodynamics simulations. If the finite element method is adequate, the boundary conditions are ideal and input-output settings for the simulations are correct, it is possible to compare the traditional calculations to the modern simulated engineering work, thus the time necessary for achieving precise results becomes significantly shorter.


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