Post Necking Behaviour and Hardening Characterization of Mild Steel

2021 ◽  
Vol 319 ◽  
pp. 7-12
Author(s):  
Manish Kumar Gupta ◽  
Nilamber Kumar Singh
Keyword(s):  
Mild Steel ◽  
Tensile Deformation ◽  
Steel Specimen ◽  
Static Condition ◽  
Element Simulation ◽  
Reference Flow ◽  
Fitting Method ◽  
Before And After ◽  
Curve Fitting Method

This paper investigates the post necking phenomenon in mild steel using six different hardening laws (Hollomon, Swift, Ludwik, Ghosh, Voce and Hockett-Sherby) by extrapolation method. This is carried out through the finite element simulation on tensile deformation of a mild steel specimen under quasi-static condition. Reference flow curves are obtained analytically and found helpful for the numerical simulation. The material parameters of the above hardening laws are evaluated by curve fitting method based on the pre necking experimental data and their suitability is examined before and after necking.

Characterization and Formulation of Microstrip-Slot Impedance with Different Thickness and Relative Permittivity

2015 ◽  
Vol 781 ◽  
pp. 53-56
Author(s):  
Khairul Huda Yusof ◽  
Norhudah Seman ◽  
Mohd Haizal Jamaluddin ◽  
D.N.A. Zaidel
Keyword(s):  
Curve Fitting ◽  
Relative Permittivity ◽  
Slot Line ◽  
Fitting Method ◽  
Curve Fitting Method ◽  
Different Thickness ◽  
Cst Microwave Studio

This paper presents the characterization of a microstrip-slot line in terms of its impedance and dimension. The characterization is made by referring to the analysis of different relative permittivity and thicknesses of substrates, which conducted by using CST Microwave Studio. Based on the characterization with the use of completing square curve fitting method, new formulated equations are proposed for microstrip-slot line. These formulated equations are suitable for thin substrate with low relative permittivity. The characterization is made based on the substrates with the selected thickness of 0.508 mm, 0.762 mm and 1.542 mm, for relative permittivity of 4.5 (TMM4), 3.38 (RO 4003C) and 2.94 (RT 6002).

scholarly journals A Prony-based curve-fitting method for characterization of RF pulses from optoelectronic devices

2021 ◽  
pp. 1-1
Author(s):  
Saptarshi Mukherjee ◽  
Karen M Dowling ◽  
Yicong Dong ◽  
Kexin Li ◽  
Adam Conway ◽  
...  
Keyword(s):  
Curve Fitting ◽  
Optoelectronic Devices ◽  
Rf Pulses ◽  
Fitting Method ◽  
Curve Fitting Method

scholarly journals A Pixelated Microwave Near-Field Sensor for Precise Characterization of Dielectric Materials

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maryam Saadat-Safa ◽  
Vahid Nayyeri ◽  
Ali Ghadimi ◽  
Mohammad Soleimani ◽  
Omar M. Ramahi
Keyword(s):  
Near Field ◽  
Optimization Procedure ◽  
Dielectric Materials ◽  
Dielectric Constants ◽  
Closed Form Expression ◽  
Binary Particle Swarm Optimization ◽  
Fitting Method ◽  
Field Sensor ◽  
Curve Fitting Method

Abstract A highly sensitive microwave near-field sensor based on electrically-small planar resonators is proposed for highly accurate characterization of dielectric materials. The proposed sensor was developed in a robust complete-cycle topology optimization procedure wherein first the sensing area was pixelated. By maximizing the sensitivity as our goal, a binary particle swarm optimization algorithm was applied to determine whether each pixel is metalized or not. The outcome of the optimization is a pixelated pattern of the resonator yielding the maximum possible sensitivity. A curve fitting method was applied to the full-wave simulation results to derive a closed form expression for extracting the dielectric constant of a chemical material from the shift in the resonance frequency of the sensor. As a proof of concept, the sensor was fabricated and used to measure the permittivity of two known liquids (cyclohexane and chloroform) and their mixtures with different volume ratios. The experimentally extracted dielectric constants were in an excellent agreement with the reference data (for pure cyclohexane and chloroform) or those obtained by mixture formulas.

An Electron Microscope Study of Interdiffusion and Compound Formation in Ta-Au Thin Films

1973 ◽  
Vol 31 ◽  
pp. 32-33 ◽  
Author(s):  
T. C. Tisone ◽  
S. Lau
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Thermally Grown Oxide ◽  
Ion Milling ◽  
Compound Formation ◽  
Technology Application ◽  
Transmission Electron ◽  
Before And After ◽  
Au Thin Films

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.

Using A Segmented Voltage Sweep Mode and A Gaussian Curve Fitting Method to Improve Heavy Metal Measurement System Performance

2012 ◽  
Vol 19 (2) ◽  
pp. 381-394
Author(s):  
José Pereira ◽  
Octavian Postolache ◽  
Pedro Girão
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Measurement System ◽  
Curve Fitting ◽  
System Performance ◽  
Redox Potentials ◽  
Voltage Sweep ◽  
Gaussian Curve ◽  
Fitting Method ◽  
Curve Fitting Method

Using A Segmented Voltage Sweep Mode and A Gaussian Curve Fitting Method to Improve Heavy Metal Measurement System PerformanceThis paper presents a voltammetric segmented voltage sweep mode that can be used to identify and measure heavy metals' concentrations. The proposed sweep mode covers a set of voltage ranges that are centered around the redox potentials of the metals that are under analysis. The heavy metal measurement system can take advantage of the historical database of measurements to identify the metals with higher concentrations in a given geographical area, and perform a segmented sweep around predefined voltage ranges or, alternatively, the system can perform a fast linear voltage sweep to identify the voltammetric current peaks and then perform a segmented voltage sweep around the set of voltages that are associated with the voltammetric current peaks. The paper also includes the presentation of two auto-calibration modes that can be used to improve system's reliability and proposes the usage of a Gaussian curve fitting of voltammetric data to identify heavy metals and to evaluate their concentrations. Several simulation and experimental results, that validate the theoretical expectations, are also presented in the paper.

A Useful Curve Fitting Method for Concrete Uniaxial Compressive Experiment Data

2011 ◽  
Vol 291-294 ◽  
pp. 1015-1020 ◽  
Author(s):  
Chong Jin ◽  
Hong Wang ◽  
Xiao Zhou Xia
Keyword(s):  
Experimental Data ◽  
Orthogonal Polynomial ◽  
Least Square ◽  
Base Function ◽  
Concrete Material ◽  
Fitting Method ◽  
Orthogonal Base ◽  
The Matrix ◽  
Uniform Function ◽  
Curve Fitting Method

Based on the superiority avoiding the matrix equation to be morbid for those fitting functions constructed by orthogonal base, the Legendre orthogonal polynomial is adopted to fit the experimental data of concrete uniaxial compression stress-strain curves under the frame of least-square. With the help of FORTRAN programming, 3 series of experimental data is fitted. And the fitting effect is very satisfactory when the item number of orthogonal base is not less than 5. What’s more, compared with those piecewise fitting functions, the Legendre orthogonal polynomial fitting function obtained can be introduced into the nonlinear harden-soften character of concrete constitute law more convenient because of its uniform function form and continuous derived feature. And the fitting idea by orthogonal base function will provide a widely road for studying the constitute law of concrete material.

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