scholarly journals Finite Element and Experimental Analysis of an Axisymmetric Electromechanical Converter with a Magnetostrictive Rod

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1230 ◽  
Author(s):  
Dorota Stachowiak ◽  
Andrzej Demenko
Keyword(s):  
Finite Element ◽  
Constitutive Law ◽  
Experimental Investigations ◽  
Field Equations ◽  
Displacement Fields ◽  
Applied Model ◽  
Measurement Results ◽  
Proper Definition ◽  
Definition Of ◽  
Electromechanical Converter

The paper presents the numerical and experimental investigations of the axisymmetric magnetostrictive actuator with a Terfenol-D rod. The applied model consists of equations that describe the magnetic and mechanical displacement fields. The equations of both fields are coupled through a nonlinear magneto-mechanical constitutive law. The model is considered as 2D axisymmetric. The finite element method is used to solve the field equations. Special attention is paid to the proper definition of magneto-mechanical relations. These relations are formed from measurements. A unique test stand is designed for the experimental investigation. The selected results of the simulation are compared with the measurement results. The comparison shows that the applied numerical model is sufficiently accurate.

scholarly journals Finite Element Simulations on the Tensile Resistance of Bolted End-Plate Connections with Tubular Members

2018 ◽  
Vol 12 (1) ◽  
pp. 177-186 ◽  
Author(s):  
Maël Couchaux ◽  
Mario D’Aniello ◽  
Lucia Falciano ◽  
Beatrice Faggiano ◽  
Mohammed Hjiaj ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulations ◽  
Effective Length ◽  
Finite Element Analyses ◽  
Hollow Section ◽  
End Plate ◽  
General Rules ◽  
Proper Definition ◽  
Plate Connections ◽  
Definition Of

Background: Bolted end-plate connections represent the simplest and cheapest way to connect tubular members. EN1993:1-8 provides the general rules based on component method. However, in the case of splices with tubular members the proper definition of the effective length around corner bolts is not clearly addressed. Objective: The objective of the study is to investigate the accuracy and the effectiveness of the existing analytical predictions to estimate the tensile resistance of end-plate connections with tubular members where corner bolts are adopted. Method: Parametric finite element analyses were carried out to investigate the tensile strength of connections of both square and rectangular hollow sections. Results: The tension resistance is largely influenced by the corner bolts. Indeed, the connections with corner bolts exhibit larger resistance that increases when the bolts are closer to the corner of the tubular member. However, reducing the distance between the bolt and the wall of the tubular section can affect the splice ductility. Conclusion: • The method proposed Steige and Weynand to calculate the tension resistance of connections with bolts distributed on all sides of the splice is consistent with EN 1993-1-8. • The finite element simulations showed that the corner bolts can increase the resistance of the connection. In addition, the bolt layout can be optimised by placing the bolts as close to the hollow section as possible.

scholarly journals Probabilistic Finite Element Modeling of Textile Reinforced SHCC Subjected to Uniaxial Tension

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3631
Author(s):  
Iurie Curosu ◽  
Amr Omara ◽  
Ameer Hamza Ahmed ◽  
Viktor Mechtcherine
Keyword(s):  
Finite Element ◽  
Probabilistic Approach ◽  
Constitutive Law ◽  
Fiber Reinforced Composites ◽  
Experimental Investigations ◽  
Crack Model ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Multiple Cracking

The paper presents a finite element investigation of the effect of material composition and the constituents’ interaction on the tensile behavior of strain-hardening cement-based composites (SHCC) both with and without textile reinforcement. The input material parameters for the SHCC and continuous reinforcement models, as well for their bond, were adopted from reference experimental investigations. The textile reinforcement was discretized by truss elements in the loaded direction only, with the constitutive relationships simulating a carbon and a polymer textile, respectively. For realistic simulation of macroscopic tensile response and multiple cracking patterns in hybrid fiber-reinforced composites subjected to tension, a multi-scale and probabilistic approach was adopted. SHCC was simulated using the smeared crack model, and the input constitutive law reflected the single-crack opening behavior. The probabilistic definition and spatial fluctuation of matrix strength and tensile strength of the SHCC enabled realistic multiple cracking and fracture localization within the loaded model specimens. Two-dimensional (2D) simulations enabled a detailed material assessment with reasonable computational effort and showed adequate accuracy in predicting the experimental findings in terms of macroscopic stress–strain properties, extent of multiple cracking, and average crack width. Besides material optimization, the model is suitable for assessing the strengthening performance of hybrid fiber-reinforced composites on structural elements.

Simultaneous heat and mass transfer during evaporation from a film of liquid into the turbulent gas

1982 ◽  
Vol 47 (3) ◽  
pp. 766-775 ◽  
Author(s):  
Václav Kolář ◽  
Jan Červenka
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Driving Forces ◽  
Proper Definition ◽  
Definition Of ◽  
Simultaneous Heat ◽  
Theory And Experiment

The paper presents results obtained by processing a series of published experimental data on heat and mass transfer during evaporation of pure liquids from the free board of a liquid film into the turbulent gas phone. The data has been processed on the basis of the earlier theory of mechanism of heat and mass transfer. In spite of the fact that this process exhibits a strong Stefan's flow, the results indicate that with a proper definition of the driving forces the agreement between theory and experiment is very good.

scholarly journals Shape Sensing of a Complex Aeronautical Structure with Inverse Finite Element Method

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1388
Author(s):  
Daniele Oboe ◽  
Luca Colombo ◽  
Claudio Sbarufatti ◽  
Marco Giglio
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Strain Field ◽  
Element Analysis ◽  
Inverse Finite Element Method ◽  
Shape Sensing ◽  
Definition Of ◽  
High Level ◽  
Element Method

The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.

scholarly journals A higher-order parametric nonlinear reduced-order model for imperfect structures using Neumann expansion

2021 ◽  
Author(s):  
J. Marconi ◽  
P. Tiso ◽  
D. E. Quadrelli ◽  
F. Braghin
Keyword(s):  
Reduced Order Model ◽  
Galerkin Projection ◽  
Order Model ◽  
Displacement Fields ◽  
Reduced Order ◽  
Total Displacement ◽  
Elastic Forces ◽  
Strain Formulation ◽  
The One ◽  
Definition Of

AbstractWe present an enhanced version of the parametric nonlinear reduced-order model for shape imperfections in structural dynamics we studied in a previous work. In this model, the total displacement is split between the one due to the presence of a shape defect and the one due to the motion of the structure. This allows to expand the two fields independently using different bases. The defected geometry is described by some user-defined displacement fields which can be embedded in the strain formulation. This way, a polynomial function of both the defect field and actual displacement field provides the nonlinear internal elastic forces. The latter can be thus expressed using tensors, and owning the reduction in size of the model given by a Galerkin projection, high simulation speedups can be achieved. We show that the adopted deformation framework, exploiting Neumann expansion in the definition of the strains, leads to better accuracy as compared to the previous work. Two numerical examples of a clamped beam and a MEMS gyroscope finally demonstrate the benefits of the method in terms of speed and increased accuracy.

WoCoVA consensus on the clinical use of in-line filtration during intravenous infusions: Current evidence and recommendations for future research

2021 ◽  
pp. 112972982198916
Author(s):  
Ton Van Boxtel ◽  
Mauro Pittiruti ◽  
Annemarie Arkema ◽  
Patrick Ball ◽  
Giovanni Barone ◽  
...  
Keyword(s):  
Potential Benefit ◽  
Scientific Evidence ◽  
Venous Access ◽  
Current Evidence ◽  
Future Research ◽  
Global Awareness ◽  
Current State ◽  
Intravenous Infusions ◽  
Proper Definition ◽  
Definition Of

The need for filtering intravenous infusions has long been recognized in the field of venous access, though hard scientific evidence about the actual indications for in-line filters has been scarce. In the last few years, several papers and a few clinical studies have raised again this issue, suggesting that the time has come for a proper definition of the type of filtration, of its potential benefit, and of its proper indications in clinical practice. The WoCoVA Foundation, whose goal is to increase the global awareness on the risk of intravenous access and on patients’ safety, developed the project of a consensus on intravenous filtration. A panel of experts in different aspects of intravenous infusion was chosen to express the current state of knowledge about filtration and to indicate the direction of future research in this field. The present document reports the final conclusions of the panel.

scholarly journals Killing superalgebras for lorentzian five-manifolds

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Andrew Beckett ◽  
José Figueroa-O’Farrill
Keyword(s):  
Spin Manifold ◽  
Field Equations ◽  
Spinor Bundle ◽  
Killing Spinors ◽  
Spinor Connection ◽  
Spencer Cohomology ◽  
Definition Of ◽  
Supersymmetric Theories ◽  
Filtered Deformations

Abstract We calculate the relevant Spencer cohomology of the minimal Poincaré superalgebra in 5 spacetime dimensions and use it to define Killing spinors via a connection on the spinor bundle of a 5-dimensional lorentzian spin manifold. We give a definition of bosonic backgrounds in terms of this data. By imposing constraints on the curvature of the spinor connection, we recover the field equations of minimal (ungauged) 5-dimensional supergravity, but also find a set of field equations for an $$ \mathfrak{sp} $$ sp (1)-valued one-form which we interpret as the bosonic data of a class of rigid supersymmetric theories on curved backgrounds. We define the Killing superalgebra of bosonic backgrounds and show that their existence is implied by the field equations. The maximally supersymmetric backgrounds are characterised and their Killing superalgebras are explicitly described as filtered deformations of the Poincaré superalgebra.

Numerical and Experimental Investigations of the Transient Thermal Behavior of a Steam By-Pass Valve at Steam Temperatures Beyond 700 °C

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Anis Haj Ayed ◽  
Martin Kemper ◽  
Karsten Kusterer ◽  
Hailu Tadesse ◽  
Manfred Wirsum ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Power Plants ◽  
Numerical Approach ◽  
Life Assessment ◽  
Experimental Investigations ◽  
Steam Power ◽  
Steam Power Plants ◽  
Cyclic Operation ◽  
Measurement Results ◽  
Transient Thermal

Increasing the efficiency of steam power plants is important to reduce their CO2 emissions and can be achieved by increasing steam temperatures beyond 700 °C. Within the present study, the thermal behavior of a steam by-pass valve subject to cyclic operation with 700 °C steam is investigated experimentally and numerically. An innovative numerical approach was applied to predict the valve’s thermal behavior during cyclic operation, which is essential for fatigue life assessment of such a component. Validation of the applied numerical approach has shown good agreement with measurement results, indicating the potential of its application for the valve design process.

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