scholarly journals Electromagnetic and Thermal Phenomena Modeling of Electrical Discharges in Liquids

2020 ◽  
Vol 10 (11) ◽  
pp. 3900
Author(s):  
Marcin Wesołowski ◽  
Sylwester Tabor ◽  
Paweł Kiełbasa ◽  
Sławomir Kurpaska
Keyword(s):  
Material Model ◽  
Engineering Problem ◽  
Field Analysis ◽  
Electrical Discharges ◽  
Cold Pasteurization ◽  
Simulation Techniques ◽  
All Solutions ◽  
Potential Applications ◽  
Thermal Phenomena ◽  
Discharge Propagation

Electrical discharges in liquids have received lots of attention with respect to their potential applications in various techniques and technical processes. Exemplary, they are useful for water treatment, chemical and thermal processes acceleration, or nanoparticles production. In this paper the special utility of discharges for cold pasteurization of fruit juices is presented. Development of devices for its implementation is a significant engineering problem and should be performed using modeling and simulation techniques to determine the real parameters of discharges. Unfortunately, there is a lack of clear and uniform description of breakdown phenomena in liquids. To overcome this limitation, new methods and algorithms for streamers propagation and breakdown phase analysis are presented in the paper. All solutions were tested in “active area” in the form of liquid material model, placed between two flat electrodes. Electromagnetic and thermal-coupled field analysis were performed to determine all the factors that affect the discharge propagation. Additionally, some circuit models were used to include the power source cooperation with discharge region. In general, presented solutions can be defined as universal and one can use them for numerical simulation of other types of discharges.

scholarly journals Tests on Pretrained Superelastic NiTi Shape Memory Alloy Rods: Towards Application in Self-Centering Link Beams

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Xian Xu ◽  
Guangming Cheng ◽  
Junhua Zheng
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Strain Amplitude ◽  
Loading Rate ◽  
Mechanical Performance ◽  
Material Model ◽  
Niti Shape Memory Alloy ◽  
Test Results ◽  
Potential Applications ◽  
Strain Model

Austenitic shape memory alloy has potential applications in self-centering seismic resistant structural systems due to its superelastic response under cyclic tension. Raw austenitic SMA needs proper pretreatments and pretraining to gain a stable superelastic property. In this paper, tests are carried out to investigate the effects of pretraining, pretreatments, loading rate, and strain amplitude on the mechanical performance on austenitic SMA rods with a given size. The tested rods are to be used in a new concept self-centering steel link beam. Customized pretraining scheme and heat treatment are determined through the tests. The effects of loading rate and strain amplitude are investigated. A simplified stress-strain model for the SMA rods oriented to numerical simulations is obtained based on the test results. An example of using the simplified material model in numerical analysis of a self-centering steel link beam is conducted to validate the applicability of the model.

scholarly journals Finite Element Analysis of Self-Pierce Riveting in Magnesium Alloys Sheets

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
J. F. C. Moraes ◽  
J. B. Jordon ◽  
D. J. Bammann
Keyword(s):  
Magnesium Alloys ◽  
Internal State ◽  
Material Model ◽  
Process Conditions ◽  
Temperature Dependent ◽  
Element Analysis ◽  
State Variable ◽  
Simulation Techniques ◽  
Lightweight Metals ◽  
Joining Process

Conventional fusion joining methods, such as resistance spot welding (RSW), have been demonstrated to be ineffective for magnesium alloys. However, self-pierce riveting (SPR) has recently been shown as an attractive joining technique for lightweight metals, including magnesium alloys. While the SPR joining process has been experimentally established on magnesium alloys through trial and error, this joining process is not fully developed. As such, in this work, we explore simulation techniques for modeling the SPR process that could be used to optimize this joining method for magnesium alloys. Due to the process conditions needed to rivet the magnesium sheets, high strain rates and adiabatic heat generation are developed that require a robust material model. Thus, we employ an internal state variable (ISV) plasticity material model that captures strain-rate and temperature dependent deformation. In addition, we explore various damage modeling techniques needed to capture the piercing process observed in the joining of magnesium alloys. The simulations were performed using a two-dimensional axisymmetric model with various element deletion criterions resulting in good agreement with experimental data. The simulations results of this study show that the ISV material model is ideally suited for capturing the complex physics of the plasticity and damage observed in the SPR of magnesium alloys.

Programmable Spiral and Helical Deformation Behaviors of Hydrogel-Based Bi-Material Beam Structures

2020 ◽  
Vol 20 (13) ◽  
pp. 2041010
Author(s):  
Rong Huang ◽  
Yiheng Xue ◽  
Zhengjie Li ◽  
Zishun Liu
Keyword(s):  
Beam Theory ◽  
Soft Materials ◽  
Material Model ◽  
Analytical Models ◽  
Shape Transformation ◽  
Beam Structures ◽  
Mismatch Strain ◽  
Potential Applications ◽  
Deformation Behaviors ◽  
Soft Actuators

Soft materials possess magnificent properties which could be harnessed for different potential applications. Compared to other soft materials, hydrogels have some unique advantages which can be used in the shape deformation or shape transformation of structures. This paper aims to investigate the deformation mechanisms of hydrogel-based bi-material beam structures and study the non-uniform geometric effects on the shape transformation including programmable scroll and helical deformations. With a sloped thickness design, the structures could be transformed from an initial quasi-2D beam configuration into some other 2D self-scroll and 3D self-helical configurations. From the hydrogel material model, a modified deformation formula for bi-material beam structures based on the framework of the classical beam theory has been developed to predict the shape morphing behaviors. The relationship between the curvature and the mismatch strain is derived in its explicit form and the theoretical results are verified through several numerical simulations. Furthermore, experiments are carried out to demonstrate the design principles for reconfigurable bi-material beam structures and the experiments show that the structures tend to deform similarly to that predicted by the analytical models. The presented work could provide guidance for future applications of responsive hydrogel-based bi-material beam structures such as in soft actuators and soft robots.

scholarly journals Microphone and Loudspeaker Array Signal Processing Steps towards a “Radiation Keyboard” for Authentic Samplers

2020 ◽  
Vol 10 (7) ◽  
pp. 2333 ◽  
Author(s):  
Tim Ziemer ◽  
Niko Plath
Keyword(s):  
Music Perception ◽  
Array Signal Processing ◽  
Music Performance ◽  
Sound Field ◽  
Field Analysis ◽  
Synthesis Methods ◽  
Time Frequency ◽  
Analysis And Synthesis ◽  
Potential Applications ◽  
Processing Steps

To date electric pianos and samplers tend to concentrate on authenticity in terms of temporal and spectral aspects of sound. However, they barely recreate the original sound radiation characteristics, which contribute to the perception of width and depth, vividness and voice separation, especially for instrumentalists, who are located near the instrument. To achieve this, a number of sound field measurement and synthesis techniques need to be applied and adequately combined. In this paper we present the theoretic foundation to combine so far isolated and fragmented sound field analysis and synthesis methods to realize a radiation keyboard, an electric harpsichord that approximates the sound of a real harpsichord precisely in time, frequency, and space domain. Potential applications for such a radiation keyboard are conservation of historic musical instruments, music performance, and psychoacoustic measurements for instrument and synthesizer building and for studies of music perception, cognition, and embodiment.

scholarly journals PET/CT Radiomics in Lung Cancer: An Overview

2020 ◽  
Vol 10 (5) ◽  
pp. 1718 ◽  
Author(s):  
Francesco Bianconi ◽  
Isabella Palumbo ◽  
Angela Spanu ◽  
Susanna Nuvoli ◽  
Mario Luca Fravolini ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Large Scale ◽  
Field Analysis ◽  
Response To Treatment ◽  
Computer Assisted ◽  
Imaging Features ◽  
Research Attention ◽  
Full Field ◽  
Pet Ct ◽  
Potential Applications

Quantitative extraction of imaging features from medical scans (‘radiomics’) has attracted a lot of research attention in the last few years. The literature has consistently emphasized the potential use of radiomics for computer-assisted diagnosis, as well as for predicting survival and response to treatment. Radiomics is appealing in that it enables full-field analysis of the lesion, provides nearly real-time results, and is non-invasive. Still, a lot of studies suffer from a series of drawbacks such as lack of standardization and repeatability. Such limitations, along with the unmet demand for large enough image datasets for training the algorithms, are major hurdles that still limit the application of radiomics on a large scale. In this paper, we review the current developments, potential applications, limitations, and perspectives of PET/CT radiomics with specific focus on the management of patients with lung cancer.

scholarly journals Scattering Optimization of Photonic Cluster: From Minimal to Maximal Reflectance

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
V. V. Prosentsov
Keyword(s):  
Perturbation Method ◽  
Theoretical Investigation ◽  
Optimization Algorithm ◽  
Engineering Problem ◽  
Local Perturbation ◽  
Small Particles ◽  
Practical Applications ◽  
Potential Applications ◽  
Multiple Interactions ◽  
Extensive List

Scattering optimization is a challenging engineering problem with an extensive list of potential applications. For some practical applications, the reflectance of the photonic cluster should be variable from minimal to maximal values. The theoretical investigation of such problem is extremely difficult due to multiple interactions between particles in the cluster. In this paper, the optimization of the light scattered by the photonic cluster made of small particles is studied with the help of the special optimization algorithm and the local perturbation method. It was shown that the photonic cluster can be transformed in such a way that its reflectance will be increased or decreased by several orders of magnitude for selected wavelength and direction.

scholarly journals Effect of linear and Mooney–Rivlin material model on carotid artery hemodynamics

2021 ◽  
Vol 43 (8) ◽  
Author(s):  
Nitesh Kumar ◽  
R. Pai ◽  
M. S. Manjunath ◽  
A. Ganesha ◽  
S. M. Abdul Khader
Keyword(s):  
Cardiovascular Diseases ◽  
Arterial Wall ◽  
Stokes Equations ◽  
Material Model ◽  
Oscillatory Behavior ◽  
Field Analysis ◽  
High Morbidity ◽  
Hemodynamic Parameters ◽  
Linear Elastic ◽  
Advantages And Disadvantages

AbstractAtherosclerosis is one of the most common cardiovascular diseases leading to high morbidity. The study of arterial dynamics using fluid–structure interaction (FSI) technique by taking into account the physiology of flow, the critical hemodynamic parameters can be determined which plays a crucial role in predictive medicine. Due to advances in the computational facilities, coupled field analysis such as FSI can facilitate understanding of the mechanics of stenosis progression and its early diagnosis. In this study a two-way FSI analysis is carried out using modified Navier–Stokes equations as the governing equations of blood flow for determining hemodynamic parameters. The arterial wall has been described at different linear elastic modulus and compared with hyperelastic Mooney–Rivlin model to evaluate the effect of different arterial stiffness on hemodynamics. The Mooney–Rivlin model predicts flow reduction with the severe backflow at arterial bifurcation resulting in decreased shear stress and oscillatory behavior. Furthermore, these findings may be used in understanding the advantages and disadvantages of using hyperelastic artery model in numerical simulations to better understand and predict the variable that causes cardiovascular diseases and as a diagnostic tool. In the present study, variation due to change in arterial wall properties such as linear elastic and Mooney Rivlin hyperelastic and its influence on hemodynamics are investigated.

Experimental and numerical investigations of springback and residual stresses in bending of a three-ply clad sheet

2021 ◽  
pp. 146442072110370
Author(s):  
Pankaj K Sharma ◽  
Vijay Gautam ◽  
Atul K Agrawal
Keyword(s):  
Tensile Properties ◽  
Yield Criterion ◽  
Rolling Direction ◽  
Material Model ◽  
Simulation Methods ◽  
Simulation Techniques ◽  
Numerical Predictions ◽  
Clad Sheet ◽  
Before And After ◽  
The Individual

In the present work, springback behaviour of a three-ply clad sheet metal, comprising of layers of SS430 and SS304 sandwiched with a layer of AA1050 is investigated in V-bending by using analytical, experimental and simulation techniques. The developed analytical model is based on theory of bending using Hill’s anisotropic yield criterion. The tensile properties of the clad sheet and individual layers oriented at three different directions w.r.t. the rolling direction are characterized. The tensile properties of the individual layers are used in the material model of analytical and numerical predictions of the springback. It is observed that the samples of the clad sheet which are transverse to the rolling direction, exhibit highest springback values due to higher tensile strength of the sheet when compared with the results acquired for other two orientations w.r.t. the rolling direction. These results are endorsed by the springback results obtained from analytical and simulation methods. The effect of sheet setting on the die during bending is also investigated using different techniques. The resulting longitudinal stresses before and after springback are analysed on inner and outer layers of the tested samples using experimental and numerical simulation procedures. In both the cases of sheet settings, the results of residual stress after springback predicted by simulations agree with the experimental results except a few cases.

scholarly journals Numerical Simulation and Experimentation of Additive Manufacturing Processes with Polyurethane Foams

2021 ◽  
pp. 48-54
Author(s):  
Elodie Paquet ◽  
Sébastien Le Loch ◽  
Benoit Furet ◽  
Alain Bernard ◽  
Sébastien Garnier
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Experimental Tests ◽  
Polyurethane Foams ◽  
Simulation Techniques ◽  
Form Deviation ◽  
Thermal Phenomena ◽  
Temperature Maps

AbstractFoam Additive Manufacturing (FAM) is the additive manufacturing process allowing parts to be obtained by depositing layers of polyurethane foam using a high-pressure machine. This inexpensive technology allows large parts to be produced in a reduced time. However, the quality of the parts produced by the FAM technique is greatly affected by the various thermal phenomena present during manufacturing and by the geometrical deviations of the layers due to the expansion of the PU foam. Numerical simulation remains an effective analytical tool for studying these phenomena. The aim of this work is to build a geometric and thermal model predictive of the FAM process by the finite element method, the final objective of which is to provide temperature maps throughout the manufacturing process and also to choose the best 3D printing strategy to have a model with constant cords and the smallest possible form deviation. The proposed model and the various simulation techniques used are detailed in this article. This model is developed under the finite element code Rem3D, and validated by experimental tests carried out on a FAM machinery or a robot, an example of which is detailed in this article.

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

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