Determination of capacitances in a twelve column MR-birdcage resonator using finite elements

2000 ◽  
Vol 36 (4) ◽  
pp. 1910-1914 ◽  
Author(s):  
W. Renhart ◽  
P. Wach
Keyword(s):  
Finite Elements ◽  
Birdcage Resonator

Determination of residual stresses in disk keyways by the finite-elements method

1982 ◽  
Vol 14 (7) ◽  
pp. 865-867
Author(s):  
B. A. Kravchenko ◽  
V. G. Fokin ◽  
G. N. Gutman
Keyword(s):  
Finite Elements ◽  
Residual Stresses ◽  
Finite Elements Method

Strain field determination in III–V heteroepitaxy coupling finite elements with experimental and theoretical techniques at the nanoscale

2017 ◽  
Vol 26 (1-2) ◽  
pp. 1-8
Author(s):  
Nikoletta Florini ◽  
George P. Dimitrakopulos ◽  
Joseph Kioseoglou ◽  
Nikos T. Pelekanos ◽  
Thomas Kehagias
Keyword(s):  
Finite Elements ◽  
Strain Field ◽  
Strain Distribution ◽  
Elastic Strain ◽  
Growth Direction ◽  
Current Status ◽  
Interface Plane ◽  
Fe Method ◽  
Semiconductor Nanostructure

AbstractWe are briefly reviewing the current status of elastic strain field determination in III–V heteroepitaxial nanostructures, linking finite elements (FE) calculations with quantitative nanoscale imaging and atomistic calculation techniques. III–V semiconductor nanostructure systems of various dimensions are evaluated in terms of their importance in photonic and microelectronic devices. As elastic strain distribution inside nano-heterostructures has a significant impact on the alloy composition, and thus their electronic properties, it is important to accurately map its components both at the interface plane and along the growth direction. Therefore, we focus on the determination of the stress-strain fields in III–V heteroepitaxial nanostructures by experimental and theoretical methods with emphasis on the numerical FE method by means of anisotropic continuum elasticity (CE) approximation. Subsequently, we present our contribution to the field by coupling FE simulations on InAs quantum dots (QDs) grown on (211)B GaAs substrate, either uncapped or buried, and GaAs/AlGaAs core-shell nanowires (NWs) grown on (111) Si, with quantitative high-resolution transmission electron microscopy (HRTEM) methods and atomistic molecular dynamics (MD) calculations. Full determination of the elastic strain distribution can be exploited for band gap tailoring of the heterostructures by controlling the content of the active elements, and thus influence the emitted radiation.

Consideration of the Torsional Stiffness in Hollow-Core Slabs’ Design

2019 ◽  
Vol 968 ◽  
pp. 330-341
Author(s):  
Talyat Azizov ◽  
Wit Derkowski ◽  
Nadzieja Jurkowska
Keyword(s):  
Finite Elements ◽  
Precast Concrete ◽  
Numerical Data ◽  
Torsional Stiffness ◽  
System Of Equations ◽  
Hollow Core ◽  
Floor Slabs ◽  
Formation Of Cracks ◽  
Resolving System

The paper discusses the principles of precast concrete hollow-core slabs taking into account their spatial work. It is shown that consideration of spatial work makes it possible to determine the forces in individual floor slabs significantly more precise. The fact that strain redistribution between precast floor slabs depends on slabs’ bending and torsional stiffness is shown. The research has been mostly devoted to determination of the bending stiffness with regard to formation of cracks and the change in torsional stiffness, especially considering the presence of normal cracks, which is still unstudied. This paper presents the technique for determining the torsional stiffness of hollow-core slabs with normal cracks. In order to determine the components included in the resolving system of equations, it is proposed to use an approximation method based on the processing of numerical data using spatial finite elements.

Detection of Higher Harmonics in a Slider Crank Mechanism of Variable Obliquity Ratio and its Use in the Determination of Displacement Transmissibility

2012 ◽  
Vol 40 (2) ◽  
pp. 146-159
Author(s):  
Devesh Kumar Jha ◽  
Santanu Das ◽  
A. Nandi ◽  
S. Neogy
Keyword(s):  
Finite Elements ◽  
Engineering Education ◽  
Experimental Work ◽  
Fourier Transforms ◽  
Fast Fourier Transforms ◽  
Higher Harmonics ◽  
Design And Manufacture ◽  
Theoretical Results ◽  
Crank Mechanism

The present paper deals with the design and manufacture of a slider crank mechanism with a variable obliquity ratio. It uses a double eccentric to serve this purpose. The slider crank mechanism can be operated at various speeds and different obliquity ratios. An accelerometer attached to the slider helps obtain its acceleration. The presence of higher harmonics is detected using fast Fourier transforms. The experimentally obtained values are compared with standard theoretical results. Further, a cantilever can be fixed to the slider under displacement excitation. Accelerations measured at the root and tip of the cantilever are used to calculate displacement transmissibility. The experimentally obtained values are compared with those obtained using finite elements. It is expected that such an approach will boost the interest of the students as it bridges theory with experimental work, which is so vital for engineering education.

scholarly journals GBT-Based Buckling Analysis Using the Exact Element Method

2017 ◽  
Vol 17 (10) ◽  
pp. 1750125 ◽  
Author(s):  
Rui Bebiano ◽  
Moshe Eisenberger ◽  
Dinar Camotim ◽  
Rodrigo Gonçalves
Keyword(s):  
Finite Elements ◽  
Beam Theory ◽  
Computational Effort ◽  
Power Series Method ◽  
Half Wave ◽  
Governing Differential Equation ◽  
Exact Element Method ◽  
Deformation Modes ◽  
Element Method

Generalized Beam Theory (GBT), intended to analyze the structural behavior of prismatic thin-walled members and structural systems, expresses the member deformed configuration as a combination of cross-section deformation modes multiplied by the corresponding longitudinal amplitude functions. The determination of the latter, usually the most computer-intensive step of the analysis, is almost always performed by means of GBT-based conventional 1D (beam) finite elements. This paper presents the formulation, implementation and application of the so-called “exact element method” in the framework of GBT-based linear buckling analyses. This method, originally proposed by Eisenberger (1990), uses the power series method to solve the governing differential equation and obtains the buckling eigenvalue problem from the boundary terms. A few illustrative numerical examples are presented, focusing mainly on the comparison between the combined accuracy and computational effort associated with the determination of buckling solutions with the exact and standard GBT-based (finite) elements. This comparison shows that the GBT-based exact element method may lead to significant computational savings, particularly when the buckling modes exhibit larger half-wave numbers.

Vibration of Thick Circular Plate--Determination of Elastic Properties Through the Resonant Behaviour

1983 ◽  
Vol 7 (2) ◽  
pp. 58-64
Author(s):  
P. Priolo ◽  
C. Sitzia
Keyword(s):  
Finite Elements ◽  
Elastic Properties ◽  
Thick Plate ◽  
Plate Theory ◽  
Resonant Condition ◽  
High Frequencies ◽  
Thick Circular Plate ◽  
Properties Of Materials ◽  
Points Of View

The authors examine, from two complementary points of view, the main problem deriving from the necessity of deducing elastic properties of materials by considering the resonant condition of transversely vibrating discs, that is the determination of the efficiency at high frequencies of finite elements formulated with the assumptions of the thick plate theory. The first approach consists, having standardized the basic relations for various thick annular semi-analytical finite elements, in testing convergence and correspondence to known analytical solutions. The second consists in the experimental evaluation of the influence of thickness in deducing the Young’s modulus of a series of polycarbonate resin discs at frequencies corresponding to modes with up to eight nodal circles.

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