scholarly journals PVDF Based Pressure Sensor for the Characterisation of the Mechanical Loading during High Explosive Hydro Forming of Metal Plates

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4429
Author(s):  
Jérémie Tartière ◽  
Michel Arrigoni ◽  
Alain Nême ◽  
Hugo Groeneveld ◽  
Sjoerd Van Der Veen
Keyword(s):  
Mechanical Loading ◽  
High Explosive ◽  
Low Cost ◽  
Mesh Size ◽  
Metal Plate ◽  
Computational Time ◽  
Metal Plates ◽  
Waves Propagation ◽  
Suitable Technique ◽  
Mechanical Impulse

High explosive hydro forming (HEHF) is a suitable technique for large metal plate forming. Manufacturing stages of such a part requires an adapted design of explosive charge configurations to define the mechanical loading exerted on the part. This mechanical loading remains challenging to be experimentally determined but necessary for predictive numerical simulation in the design of parts to form. Providing that the actual mechanical impulse would allow the neglecting of the modelling of the detonation stage, this considerably increases the computational time. The present work proposes an experimental method for obtaining the exerted mechanical loading by HEHF on the part to form. It relies on the development of low-cost sensor based on a polyvinyliden fluorid (PVDF) gauge. In addition to it, an analytical approach based on shock physics is proposed for the sensor signal interpretation. The method considers the multi-layer aspect of the sensor and its intrusiveness with respect to waves propagation. Measurements were repeated to assess their relevance and the reproducibility by using steel and aluminium anvils in HEHF. Numerical modelling in 2D plane geometry of the experiments was performed with two commercial hydrocodes. The comparison of mechanical impulses shows an agreement in terms of chronology but a noticeable difference in terms of amplitude, explained by mesh size and numerical diffusion.

FEM Simulation of Laser Forming of Metal Plates*

2000 ◽  
Vol 123 (3) ◽  
pp. 405-410 ◽  
Author(s):  
G. Yu ◽  
K. Masubuchi ◽  
T. Maekawa ◽  
N. M. Patrikalakis
Keyword(s):  
Fem Simulation ◽  
Mesh Size ◽  
Element Model ◽  
Mechanical Analysis ◽  
Metal Plate ◽  
Laser Forming ◽  
Forming Process ◽  
Metal Plates ◽  
Simulation Time ◽  
Good Agreement

A finite element model is developed for thermo-mechanical analysis of the process of metal plate forming by laser line heating. A rezoning technique is adopted to greatly reduce the simulation time. The effects of the refinement of mesh size on temperature distribution and final distortion are studied. Comparison between numerical and experimental results shows a good agreement in final distortion of the formed plate. Finally, edge effects in the laser forming process are studied.

scholarly journals Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duy Tung Phan ◽  
Chang Won Jung
Keyword(s):  
Electromagnetic Pulse ◽  
Low Cost ◽  
High Energy ◽  
Metal Plate ◽  
Optical Transparency ◽  
Shielding Effectiveness ◽  
Concrete Wall ◽  
Metal Mesh ◽  
Wide Range ◽  
Optically Transparent

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

scholarly journals Computational Complexity Reduction of Neural Networks of Brain Tumor Image Segmentation by Introducing Fermi–Dirac Correction Functions

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 223
Author(s):  
Yen-Ling Tai ◽  
Shin-Jhe Huang ◽  
Chien-Chang Chen ◽  
Henry Horng-Shing Lu
Keyword(s):  
Neural Networks ◽  
Deep Learning ◽  
Computational Complexity ◽  
High Performance ◽  
Low Cost ◽  
Structural Complexity ◽  
Correction Function ◽  
Computational Time ◽  
Learning Methods ◽  
Band Theory

Nowadays, deep learning methods with high structural complexity and flexibility inevitably lean on the computational capability of the hardware. A platform with high-performance GPUs and large amounts of memory could support neural networks having large numbers of layers and kernels. However, naively pursuing high-cost hardware would probably drag the technical development of deep learning methods. In the article, we thus establish a new preprocessing method to reduce the computational complexity of the neural networks. Inspired by the band theory of solids in physics, we map the image space into a noninteraction physical system isomorphically and then treat image voxels as particle-like clusters. Then, we reconstruct the Fermi–Dirac distribution to be a correction function for the normalization of the voxel intensity and as a filter of insignificant cluster components. The filtered clusters at the circumstance can delineate the morphological heterogeneity of the image voxels. We used the BraTS 2019 datasets and the dimensional fusion U-net for the algorithmic validation, and the proposed Fermi–Dirac correction function exhibited comparable performance to other employed preprocessing methods. By comparing to the conventional z-score normalization function and the Gamma correction function, the proposed algorithm can save at least 38% of computational time cost under a low-cost hardware architecture. Even though the correction function of global histogram equalization has the lowest computational time among the employed correction functions, the proposed Fermi–Dirac correction function exhibits better capabilities of image augmentation and segmentation.

Analysis on Metal Plate Connection Property of Larch Dimension Lumber

2012 ◽  
Vol 174-177 ◽  
pp. 2170-2175
Author(s):  
Rong Jun Zhao ◽  
Jun Zhen Zhang ◽  
Hai Bin Zhou ◽  
Ben Hua Fei
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Metal Plate ◽  
Seismic Structure ◽  
Performance Parameters ◽  
Metal Plates ◽  
Dimension Lumber ◽  
Design Value ◽  
Plate Connection ◽  
Ductility Ratio

In this study, Larix gemilinii and metal plate were selected as the main materials. According to GB5005-2003, the connection properties of tension-splice joint and larch wood were investigated. The results showed that the elastic modulus of Larix gemilinii was not affected by the performance parameters of tension-splice joint greatly and three kinds of failure modes were introduced. Besides the design value for the ultimate bearing capacity of Larix gemilinii and the design value for the ultimate tensile bearing capacity of the metal plates were determined. A conservative calculation method for ductility ratio of metal plates was proposed. The ductility ratio of the metal plate connected joint changed with the construction modes, and the ductility ratio for metal plate parallel to the grain (more than 2.4) was obviously bigger than that of perpendicular to the grain, which complies with the requirements for ductility ratio in anti-seismic structure.

scholarly journals Calculation of Wave Dispersion Curves in Multilayered Composite-Metal Plates

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ameneh Maghsoodi ◽  
Abdolreza Ohadi ◽  
Mojtaba Sadighi
Keyword(s):  
Transfer Matrix ◽  
Equations Of Motion ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Metal Plate ◽  
Material Symmetry ◽  
Major Purpose ◽  
Characteristic Equations ◽  
Multilayered Composite ◽  
Metal Plates

The major purpose of this paper is the development of wave dispersion curves calculation in multilayered composite-metal plates. At first, equations of motion and characteristic equations for the free waves on a single-layered orthotropic plate are presented. Since direction of wave propagation in composite materials is effective on equations of motion and dispersion curves, two different cases are considered: propagation of wave along an axis of material symmetry and along off-axes of material symmetry. Then, presented equations are extended for a multilayered orthotropic composite-metal plate using the transfer matrix method in which a global transfer matrix may be extracted which relates stresses and displacements on the top layer to those on the bottom one. By satisfying appropriate boundary conditions on the outer boundaries, wave characteristic equations and then dispersion curves are obtained. Moreover, presented equations may be applied to other materials such as monoclinic, transversely isotropic, cubic, and isotropic materials. To verify the solution procedure, a number of numerical illustrations for a single-layered orthotropic and double-layered orthotropic-metal are presented.

Localized Corrosion of UNS A95052 Aluminum Alloy for Application in Multi-Effect Desalinator Plants

CORROSION ◽  
10.5006/2815 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 1023-1032
Author(s):  
Dannisa R. Chalfoun ◽  
Mariano A. Kappes ◽  
Mauricio Chocrón ◽  
Raul B. Rebak
Keyword(s):  
Aluminum Alloy ◽  
Crevice Corrosion ◽  
Low Cost ◽  
Localized Corrosion ◽  
Complete Evaluation ◽  
Electrochemical Tests ◽  
Metal Plates ◽  
Different Temperatures ◽  
Partially Occluded ◽  
Desalination Plants

Aluminum alloy UNS A95052 (AA5052) is very attractive for desalination applications because of its good corrosion resistance in seawater at temperatures up to 125°C, low cost, good thermal conductivity, and non-toxicity of its corrosion products. The pitting corrosion potential, Epit, and the pit repassivation potential, Er,pit, of AA5052 were measured in deaerated 65,000 ppm sodium chloride (NaCl) solutions at 30°C, 60°C, and 85°C. Epit decreased with temperature, in accord with literature results. Er,pit was a function of anodic charge passed during pit growth stage. A complete evaluation of suitability of this alloy from a corrosion perspective requires also studies of crevice corrosion at different temperatures, considering that multi-plate designs of desalinators have metal plates in contact with rubber gaskets and seals. Cyclic potentiodynamic polarization was used to estimate crevice repassivation potentials, Er,crev, at 30°C, 60°C, and 85°C, in specimens with an attached rubber O-ring as a crevice former. This crevice former simulated the partially occluded geometry expected in desalination plants. Stable crevice corrosion potentials, Ecrev, were similar to Epit, and, when polarized to a similar anodic charge density, Er,crev were similar to Er,pit. Based on this result, from a corrosion perspective, the presence of crevices in the desalination plant is not expected to present an additional risk during operation of the plant. Electrochemical tests were also performed in saturated AlCl3 solutions to explain the results using Galvele’s localized acidification model.

Development of Parametric Simulation Models for Metal Forming Processes of Plate Structures

2018 ◽  
Author(s):  
Tom Wurzler ◽  
Thomas Lindemann ◽  
Josefine Kistner ◽  
Patrick Kaeding
Keyword(s):  
Metal Forming ◽  
Simulation Models ◽  
Metal Plate ◽  
The Finite Element Method ◽  
Forming Process ◽  
Common Procedure ◽  
Plate Structures ◽  
Metal Plates ◽  
Die Structure ◽  
Different Types

During the process of workpiece productions in metal forming industries, it is necessary to control the results of the reshaped piece to ensure its quality. A common procedure of metal plate forming processes is given by the application of an upper and lower die. Therefore, ribbed die configurations can be used. To simulate the forming process of metal workpieces, the Finite Element Method (FEM) is a feasible tool. In this paper, a parametric model of a ribbed die structure is developed with the specification that only small imperfections on the workpiece surfaces will appear after the forming process. The workpieces in this paper are plates with thickness values equal and greater than 20mm. Furthermore, the springback behaviour of the different workpieces will be in the main focus of the proposed analyses. The results of the simulations are used to developed different types of holder configurations instead of the lower die. This concept might further reduce the costs of forming processes of large metal plates.

scholarly journals Improving Accuracy of Coarse Grid Numerical Solution of Solid-Solid Reactions by Taylor Series Expansion of the Reaction Term

2009 ◽  
Vol 2009 ◽  
pp. 1-13
Author(s):  
Hassan Hassanzadeh ◽  
Mehran Pooladi-Darvish ◽  
Jalal Abedi
Keyword(s):  
Numerical Simulations ◽  
Series Expansion ◽  
Taylor Series ◽  
Large Scale ◽  
Mesh Size ◽  
Taylor Series Expansion ◽  
Computational Time ◽  
Time Saving ◽  
Reaction Term ◽  
Reaction Fronts

Exothermic solid-solid reactions lead to sharp reaction fronts that cannot be captured by coarse spatial mesh size numerical simulations that are often required for large-scale simulations. We present a coarse-scale formulation with high accuracy by using a Taylor series expansion of the reaction term. Results show that such expansion could adequately maintain the accuracy of fine-scale behavior of a constant pattern reaction front while using a smaller number of numerical grid cells. Results for a one-dimensional solid-solid reacting system reveal reasonable computational time saving. The presented formulation improves our capabilities for conducting fast and accurate numerical simulations of industrial-scale solid-solid reactions.

scholarly journals The energy loss of cosmic ray particles in metal plates

1937 ◽  
Vol 160 (901) ◽  
pp. 304-323 ◽  
Keyword(s):  
Magnetic Field ◽  
Energy Loss ◽  
Cosmic Ray ◽  
Metal Plate ◽  
Usual Method ◽  
Cloud Chamber ◽  
Zero Magnetic Field ◽  
Metal Plates ◽  
Curvature Measurements ◽  
The Difference

Measurements have been made of the energy loss of cosmic ray particles in metal plates, making use of a counter controlled cloud chamber in a magnetic field (Blackett 1936). A metal plate was placed across the centre of the chamber and the energy loss of a ray was deduced from the difference of the curvature of a track above and below the plate. Energy loss measurements by this method have been carried out by Anderson and Neddermeyer (1936) up to an energy of about 4 x 10 8 e-volts and recently by Crussard and Leprince-Ringuet (1937) up to an energy of 1·2 x 10 9 e-volts. The curvature measurements were made mainly by means of the optical null method recently described (Blackett 1937 a ) and this proved invaluable. It would have been hard to obtain so high an accuracy by the usual method of measuring coordinates. The curvature corrections to be applied to the measured curvatures were obtained by measurements on tracks in zero magnetic field (Blackett and Brode 1936). Two separate distortion curves were required, one for the top and one for the bottom of the chamber.

Trend Predictions in Effect of Spoilers for a Mini Car: A Low Cost Solution

2003 ◽  
Author(s):  
N. MathiArasu ◽  
P. S. S. Srinivasan ◽  
K. C. K. Vijayakumar
Keyword(s):  
Finite Element ◽  
Fuel Consumption ◽  
Developing Economies ◽  
Low Cost ◽  
Computation Time ◽  
Computational Time ◽  
Vehicle Stability ◽  
Cfd Analysis ◽  
Two Dimensional ◽  
The World

Most of the CFD analysis on car aerodynamics published so far is being carried out with high-end workstations and many days of computation time, which only few laboratories in the world can afford to. In developing economies like India, many car users use large number of add-on devices, which can have significant impact on the fuel consumption, which they are not aware of. The focus of the present paper is to expose such aspects using a simple personal computer with few hours of computational time, which must be economical. A most popular mini-car on Indian roads is taken for analysis. A two dimensional CFD analysis using commercial finite element based CFD software is used. The analysis has revealed that position and size of front and rear spoilers have significant impact on Lift i.e. vehicle stability and moderate impact on Drag i.e. Fuel consumption. The effect of speed on different geometries is studied and the variations are found to be linear.

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