A CALIBRATION METHOD OF MECHANICAL STRAINS FROM A TEMPERATURE-COMPENSATING FBG SENSOR

2008 ◽  
Vol 22 (11) ◽  
pp. 1111-1115 ◽  
Author(s):  
NAK-SAM CHOI ◽  
DAL-WOO JUNG
Keyword(s):  
Calibration Method ◽  
Retardation Factor ◽  
Heating Process ◽  
Normal Strain ◽  
Heating Rates ◽  
Resistance Strain Gage ◽  
Fbg Sensor ◽  
Real Time Measurement ◽  
Beam Surface ◽  
Aluminum Beam

The sensitivity of a temperature-compensating fiber Bragg grating (FBG) sensor which has different FBGs in one fiber line was analyzed for the real time measurement of mechanical normal strain in structures. Measurement of mechanical strains of the aluminum beam surface by the double FBG sensor was performed under various heating rates and temperature range. The results were compared with those of an electrical resistance strain gage. A considerable delay in the strain measurement by the double FBG sensor during the heating process was shown, which could be quantified for the strain compensation by the introduction of a strain retardation factor to the FBG sensor.

Application of a Temperature-Compensating FBG Sensor to Strain Measurement

2007 ◽  
Vol 26-28 ◽  
pp. 1089-1092 ◽  
Author(s):  
Dal Woo Jung ◽  
Il Bum Kwon ◽  
Nak Sam Choi
Keyword(s):  
Thermal Strain ◽  
Thermal Conditions ◽  
Time Measurement ◽  
Strain Component ◽  
Normal Strain ◽  
Resistance Strain Gage ◽  
Fbg Sensor ◽  
Real Time Measurement ◽  
Beam Surface ◽  
Aluminum Beam

A temperature-compensating fiber Bragg grating(FBG) sensor having two different FBGs in one fiber line was applied to the real time measurement of mechanical normal strain in structures. Measurement of mechanical strains of the aluminum beam surface by the double FBG sensor was performed under various thermal conditions, which was compared with results of electrical resistance strain gage. The FBG sensor fabricated in this study could detect accurately values of mechanical strains without containing any thermal strain component.

Refinement of Cementite in High Strength Steel Plates by Rapid Heating and Tempering

2007 ◽  
Vol 539-543 ◽  
pp. 4720-4725 ◽  
Author(s):  
A. Nagao ◽  
K. Hayashi ◽  
K. Oi ◽  
S. Mitao ◽  
N. Shikanai
Keyword(s):  
Rapid Heating ◽  
High Strength ◽  
Average Diameter ◽  
Carbon Steels ◽  
Steel Plates ◽  
Heating Process ◽  
Low Carbon ◽  
Precipitation Behavior ◽  
Heating Rates ◽  
Extraction Replica

The precipitation behavior of cementite in low carbon steels at various heating rates from 0.3 to 100 K/s has been studied using a high-frequency induction heating apparatus. The materials used in this study were steel platesfor welded structures: 610 and 780 MPa class steel plates with a mixed microstructure of bainite and martensite.Cementite was observed using a carbon extraction replica method and the hardness and toughness were also examined. When heated at the conventional slow rate of 0.3 K/s, relatively large cementite particles with an average diameter of 72 nm precipitated at the lath boundaries, whereas when heated at a rapid rate over 3.0 K/s, cementite precipitated both within the laths and at the lath boundaries, and the cementite was refined down to an average diameter of 54 nm. With such refinement of the cementite, the toughness was improved. On the other hand, the hardness was irrespective of the heating rate and was dependent on the tempering parameter. TEM observations of the cementite precipitation behavior during the rapid heating process revealed that cementite begins to precipitate at the lath boundaries at about 773 K and within the laths at about 873 K. It is concluded that rapid heating especially from 773 to 873 K contributes to the cementite refinement and consequently the improvement in toughness. The effect of alloying elements such as chromium, molybdenum or silicon on the cementite growth during the rapid heating and tempering treatment is also discussed.

Influence of Hydrocolloid Concentration, Salinity and Citric Acid Addition on Heat Transfer in the Ohmic Heating Process

2011 ◽  
Vol 7 (5) ◽  
Author(s):  
Mostafa Keshavarz Moraveji ◽  
Emad Ghaderi ◽  
Reza Davarnejad
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Citric Acid ◽  
Ohmic Heating ◽  
Solid Particles ◽  
Heating Process ◽  
Process Conditions ◽  
Heating Rates ◽  
Acid Addition ◽  
Ph Level

In this article, the effects of Ohmic heating process conditions on electrical conductivity and heat transfer were investigated. In order to study the Ohmic heating process, various hydrocolloid solutions containing starch in water with concentrations of 4–8% in the static cells were used. Temperature increments increased electrical conductivity of the solution, linearly. The concentration of dispersed solid particles in the solution caused a progressive trend in time-temperature curve for hydrocolloid solutions (with concentrations of 4, 5.5 and 8%) without electrolytes. The electrical conductivity was raised by increasing temperatures. In order to consider the salinity impact on electrical conductivity and the heating rate, sodium chloride (with concentrations of 1–0.25%) was added to the solution. It was observed that the salt addition to the system had a major effect on electrical conductivity and time-temperature curves. The pH level was modified with Citric acid addition, and the influence of pH level on the time-temperature curves and heating rates were investigated. The Citric acid addition had no on significant effect on the time-temperature curves.

Microstructural Evolution of a Commercial 0.04%C Steel During Batch Annealing

2006 ◽  
Vol 509 ◽  
pp. 17-24
Author(s):  
J.C. Millán ◽  
A.L. Rivas ◽  
Jose María Cabrera ◽  
Sonia Camero ◽  
Leo Kestens
Keyword(s):  
Grain Growth ◽  
Microstructural Evolution ◽  
Plastic Anisotropy ◽  
Tensile Tests ◽  
Grain Structure ◽  
Heating Process ◽  
Heating Rates ◽  
Hold Period ◽  
Transmission Electron ◽  
Batch Annealing

The effect of heating rate and annealing time on the microstructure and texture of a commercial 0.04 %C steel, cold rolled up to 80 %, is studied. Samples have been isothermally annealed at various heating rates (12 °C/h, 20 °C/h, 40 °C/h and 650 °C/min) and then soaked at 700 °C for 15 hours. The microstructural evolution of the samples during the heating process and hold period has been followed by optical microscopy, scanning and transmission electron microscopy. The electron back-scattered diffraction technique is used to reveal the texture of the samples. Tensile tests and hardness measurements are correlated with the microstructural features. Results show that (a) recrystallization occurs between 600 and 650 °C; (b) a “pancake” structure develops during recrystallization at low heating rates without appreciable grain growth; (c) samples heated at 650 °C/min exhibit an equiaxed grain structure and significant grain growth; (d) only at low heating rates the material develops a strong {111}<uvw> recrystallization texture, in ccordance with the high plastic anisotropy found by mechanical testing.

Evaluation of grain-average stress tensor in a tensile-deformed Al–Mn polycrystal by high-energy X-ray diffraction

2017 ◽  
Vol 50 (4) ◽  
pp. 1144-1157 ◽  
Author(s):  
Loïc Renversade ◽  
András Borbély
Keyword(s):  
Rotation Axis ◽  
Three Dimensional ◽  
Calibration Method ◽  
High Energy ◽  
Normal Strain ◽  
X Ray Diffraction ◽  
Synchrotron Source ◽  
X Ray ◽  
Strain Stress ◽  
Individual Grains

Three-dimensional X-ray diffraction was applied to characterize the strain/stress evolution in individual grains of an Al–0.3 wt% Mn polycrystal deformedin situat a synchrotron source. Methodological aspects concerning the calibration of the geometrical setup and the evaluation of the strain/stress tensors are discussed. A two-step calibration method separately treating the detector and the rotation axis allows one to determine the centre-of-mass position and crystallographic orientation of grains with standard errors of about 1.5 µm and 0.02°, respectively. Numerical simulations indicate that the error of normal strain components (about 1 × 10−4) is mainly caused by calibration errors, while the error of shear components (about 0.5 × 10−4) is largely influenced by counting statistics and random spot-centre errors due to detector distortion. The importance of monitoring the beam energy is emphasized.

Properties of Municipal Solid Waste Incineration (MSWI) Fly Ash during Heating Process

2012 ◽  
Vol 217-219 ◽  
pp. 869-878
Author(s):  
Xiao Bo Wang ◽  
Zeng Li Zhao ◽  
Chang Feng Yan ◽  
Hai Bin Li ◽  
Yong Chen
Keyword(s):  
Weight Loss ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Waste Incineration ◽  
Heating Process ◽  
Municipal Solid Waste Incineration ◽  
Heating Rates ◽  
Mswi Fly Ash ◽  
Kinetics Parameters

Weight loss and heat flow during heating process of municipal solid waste incineration (MSWI) fly ash were investigated through the DSC-DTG experiment carried out from 40°C°C to 1400°C°C, with different heating rates (5°C/min, 10°C°C/min, 20°C°C/min) and different atmosphere (N2, Air). Two main weight loss peaks were found at 800°C°C-1000°C°C and 1000°C°C-1200°C0°C for three different samples. Weight loss ingredients were analyzed by comparing the difference of components between fly ash and slag. Then Kinetics parameters of fly ash melting were acquired by Numerical Solution using a C++ program.Introduction

Identifying Magnitudes and Locations of Loads on Slender Beams With Welded and Bolted Joints Using a Strain Gage Based Force Transducer With Application to a Portable Army Bridge

2013 ◽  
Author(s):  
E. T. Bednarz ◽  
W. D. Zhu
Keyword(s):  
Strain Gage ◽  
Calibration Method ◽  
Force Transducer ◽  
Bolted Joints ◽  
Bottom Surface ◽  
Strain Gages ◽  
Bolted Joint ◽  
Stress Concentrations ◽  
Slender Beams ◽  
Aluminum Beam

A strain gage based force transducer has been developed to identify magnitudes and locations of loads on non-continuous slender beams with welded and bolted joints. The slopes of the bending moment curves on the two sides of a load are calculated from measured strains on a beam. Four uniaxial strain gages are mounted to the bottom surface of the beam, with two strain gages on each side of the load. A calibration method developed earlier can be used to account for the discrepancies between the theoretical and actual scaling factors arising from stress concentrations and unpredictable stress patterns in the beams due to the presence of the joints. The force transducer methodology is experimentally validated on a continuously tapered aluminum beam with a series of welded joints, an aluminum beam with a constant cross section and a bolted joint, a half aluminum and half steel beam with two different cross sections and a bolted joint, and a full scale portable army bridge at the US Army Aberdeen Test Center.

Surface Treatment of Quartz Fiber in SiO2/SiO2f with Composite Properties of Materials

2012 ◽  
Vol 600 ◽  
pp. 218-221 ◽  
Author(s):  
Juan Wang ◽  
Si Yu Lai ◽  
Da Li
Keyword(s):  
Heat Treatment ◽  
Organic Solvent ◽  
Surface Treatment ◽  
Loss Rate ◽  
Heating Process ◽  
Quartz Fiber ◽  
Heating Rates ◽  
Before And After ◽  
Properties Of Materials ◽  
Composite Properties

Two methods are adopted to remove wetting agents on surface of the quartz fiber, one is heat treatment, and the other is the combination of organic solvent and heat treatment. By comparing the changes of weight loss rate of quartz fiber before and after surface treatment, analyzing variation of morphology and composition of surface in SEM and XPS approaches, we conclude that the combination of organic solvent and heat treatment is superior to the pure thermal treatment in dealing with surface of quartz fiber. In heating process, different heating rates are used, the results show that: the lower the heating rate is, the greater the mechanical strength of the quartz fiber losses.

scholarly journals The phase transitions in selective laser-melted 18-NI (300-grade) maraging steel

2020 ◽  
Vol 142 (2) ◽  
pp. 1011-1018 ◽  
Author(s):  
Mariusz Król ◽  
Przemysław Snopiński ◽  
Adam Czech
Keyword(s):  
Activation Energy ◽  
Intermetallic Phases ◽  
Solid State Reactions ◽  
Heating Process ◽  
Heating Rates ◽  
Laser Melting ◽  
Heating And Cooling ◽  
Melting Technique ◽  
Dilatometric Studies ◽  
Simplified Procedure

Abstract Dilatometric studies in 18-Ni steel components fabricated by selective laser melting technique were carried out to determine the influence of heating rate on transitions occurring during the heating cycle. SLM components have been examined in controlled heating and cooling cycles. For analysis, heating of the analysed materials was carried out at heating rates of 10, 15, 20, 30 and 60 °C min−1. During the heating process, two solid-state reactions were identified—i.e. precipitation of intermetallic phases and the reversion of martensite to austenite. A simplified procedure based on the Kissinger equation was used to determine the activation energy of individual reactions. For precipitation of intermetallic phases, the activation energy was estimated 301 kJ mol−1, while the martensite to austenite reversion was determined at the activation energy 478 kJ mol−1.

scholarly journals Microstructural Evolution of Cold-Rolled AA7075 Sheet during Solution Treatment

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2734 ◽  
Author(s):  
Lu Wang ◽  
Xiaofang Yang ◽  
Joseph D. Robson ◽  
Robert E. Sanders ◽  
Qing Liu
Keyword(s):  
Electron Microscopy ◽  
Microstructural Evolution ◽  
Boundary Migration ◽  
Solution Treatment ◽  
Alloy Sheet ◽  
Slow Heating ◽  
Heating Process ◽  
Heating Rates ◽  
Heated Sample ◽  
Cold Rolled

The influence of heating rate on the microstructural evolution of a cold-rolled AA7075 alloy sheet during solution heat treatment was examined using electrical conductivity, scanning electron microscopy, X-ray diffraction, transmission electron microscopy and electron backscatter diffraction. The results indicate that the dissolution of soluble phases takes place during the heating process. The heating rates affect the dissolution process of soluble phases, and these phases completely dissolve into matrix after solution treatment. Recrystallized and elongated grains are produced after solution treatment by both fast and slow heating rates, while the grains of the rapidly heated sample are much finer. The elongated grains are attributed to the difference in the pinning pressure of boundary migration between the rolling and normal directions. The {111}<110> texture, as well as typical recrystallization textures, were found in both fast and slowly heated samples after solution treatment, but the textures, especially the {111}<110> component in the slow-heated sample, are much stronger, leading to an anisotropy in the tensile properties after artificial aging.

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