A Novel Hybrid Heating Method for Mechanical Testing of Miniature Specimens at Elevated Temperature

2017 ◽  
Vol 5 (2) ◽  
Author(s):  
Lin Li ◽  
Gracious Ngaile ◽  
Tasnim Hassan
Keyword(s):  
Temperature Distribution ◽  
Heat Loss ◽  
Gauge Length ◽  
Electric Resistance ◽  
Uniform Heating ◽  
Thermo Electric ◽  
Heating Method ◽  
Hybrid Heating ◽  
Miniature Specimen ◽  
Miniature Specimens

A novel hybrid heating method which combines the conventional electric-resistance specimen heating with microcoil heating of specimen ends to achieve uniform heating over the gauge length is presented. Resistive heating of a miniature specimen develops a parabolic temperature profile with lowest temperature at the grip ends because of the heat loss to the gripper. Coil heating at the specimen ends compensates for this heat loss resulting in uniform temperature distribution over the central segment of the specimen. Thermo-electric finite element simulations were carried out to analyze the transient and steady temperature distribution in miniature specimens followed by experimental validation.

A Novel Hybrid Heating Method for Elevated Temperature Mechanical Testing of Miniature Specimens

2016 ◽  
Author(s):  
Lin Li ◽  
Gracious Ngaile ◽  
Tasnim Hassan
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Heating Process ◽  
Electric Resistance ◽  
Heating Method ◽  
Hybrid Heating ◽  
Testing Technology ◽  
Heating Coils ◽  
Highly Uniform ◽  
Material Tests

The lack of robust testing systems to generate uniform elevated temperatures on specimens in material tests is hindering the advancement of small specimen testing technology (SSTT). The purpose of this study is to develop a novel hybrid heating method combining coil heating and electric-resistance specimen heating to uniformly heat micro specimens in material tests. In a hybrid heating process, two heating coils are used to heat the local temperatures on the specimen ends, and electric current is conducted through the specimen to generate Joule heat and compensate the heat transfer effects of natural convection and radiation around the specimen center area. In this way, a highly uniform temperature distribution can be generated on the specimen between the heating coils. In this study, Thermal-Electrical and Transient Thermal FEA simulations are applied to analyze the temperature distributions and preheating times on the micro specimens under coil heating, electric-resistance specimen heating, and hybrid heating respectively. According to the simulation results, it can be concluded that hybrid heating method can provide the ability to generate highly uniform elevated temperature conditions on different micro tubular specimens with short preheating times.

Estimation of Fracture Toughness JIC by Miniature Specimen Hydraulic Bulge Test

2017 ◽  
Vol 898 ◽  
pp. 753-757
Author(s):  
Le Le Gui ◽  
Tong Xu ◽  
Bin An Shou ◽  
Han Kui Wang ◽  
Jing Xiang
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Fracture Strain ◽  
Bulge Test ◽  
Miniature Specimen ◽  
Hydraulic Bulge Test ◽  
Hydraulic Bulge ◽  
Resistance Curves ◽  
Miniature Specimens ◽  
Load Deflection Curve

The fracture toughness tests and a new miniature specimen technology named hydraulic bulge test (HBT) of 3Cr1Mo1/4V at four service time were carried out. Four J-R resistance curves by single-specimen method with one inch CT specimens were obtained to compute the JIC. Different definitions of equivalent fracture strain according to the section morphologies of HBT testing specimens were compared, and fracture energy of miniature specimens with three different thicknesses (0.4mm, 0.5mm and 0.6mm) were also calculated. Results showed that the typical HBT load-deflection curve can be divided into four sections like SPT curve. Equivalent fracture strain and fracture energy EHB can be chosen as two fracture parameters for the HBT specimen. Ductile fracture toughness JIC can be related approximately linearly to both the equivalent fracture strain and fracture energy EHB.

scholarly journals The Effects on Thermal Efficiency of Yttria-Stabilized Zirconia and Lanthanum Zirconate-based Thermal Barrier Coatings on Aluminum Heating Block for 3d Printer

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 792
Author(s):  
Hasan Demir
Keyword(s):  
Temperature Distribution ◽  
Heat Loss ◽  
Yttria Stabilized Zirconia ◽  
Thermal Barrier ◽  
Print Quality ◽  
Stabilized Zirconia ◽  
Coating Materials ◽  
Lanthanum Zirconate ◽  
Barrier Coating ◽  
Coating Method

Fused filament fabrication is an important additive manufacturing method, for which 3D printers are the most commonly used printing tools. In this method, there are many factors that affect the printing quality, chief among which is temperature. The fusion temperature of the material is created by an aluminum heating block in the extruder. Stability and a constant temperature for the aluminum heating block are inevitable requirements for print quality. This study aims to use the thermal barrier coating method to increase the thermal efficiency and stability of the aluminum heating block by reducing heat loss. Furthermore, it aims to perform steady-state thermal analysis using finite element analysis software. The analyses are carried out in stagnant air environment and at the printing temperature of acrylonitrile butadiene styrene material. In order to examine the effects of different coating materials, blocks coated with two different coating materials, as well as uncoated blocks, were used in the analyses. The coating made with yttria-stabilized zirconia and pyrochlore-type lanthanum zirconate materials, together with the NiCRAl bond layer, prevent temperature fluctuation by preventing heat loss. The effects of the coating method on average heat flux density, temperature distribution of blocks, and temperature distribution of the filament tube hole were investigated. Additionally, changes in flow velocity were determined by examining the effects of the thermal barrier coating method on temperature distribution. The average heat flux density in the coated blocks decreased by 10.258%. Throughout the investigation, the temperature distributions in the coated blocks became homogeneous. It was also observed that both coating materials produce the same effect. This article performs a steady-state thermal analysis of a conventional model and thermal-barrier-coated models to increase print quality by reducing heat loss from the aluminum heating block.

Investigations on Physical and Mechanical Characterization of the Joints Fabricated through Microwave Hybrid Heating Method

2021 ◽  
Vol 105 ◽  
pp. 25-41
Author(s):  
Parminder Singh ◽  
D.R. Prajapati ◽  
Shankar Sehgal
Keyword(s):  
Power Level ◽  
Dissimilar Materials ◽  
Hardness Test ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Heating Method ◽  
Hybrid Heating ◽  
Microwave Hybrid Heating ◽  
Point Bend

This paper presents the current major research developments and growths in the area of microwave hybrid heating-based joining of similar and dissimilar materials. The study discusses on the different types of specimen materials, susceptor materials, fillers and microwave power level used by researchers for joining process. Comparative studies of joints using different parametric conditions are also mentioned. Physical characterization of joint has been investigated with optical microscope, scanning electron microscope, energy dispersive spectroscopy, electron probe micro analysis, X-ray diffraction and mechanically with hardness test, tensile test, 3-point bend test, impact test. Various methods for design of experiment and optimization are also used to obtain better results. Current study will facilitate the proper choice of input parameters for easy and good joints formation through the microwave hybrid heating method.

Application of Electric Resistance Heating Method on Titanium Hot Forming at Industrial Scale

2016 ◽  
Vol 41 (11) ◽  
pp. 4441-4448 ◽  
Author(s):  
Fahrettin Ozturk ◽  
Remzi Ecmel Ece ◽  
Naki Polat ◽  
Arif Koksal ◽  
Zafer Evis ◽  
...  
Keyword(s):  
Hot Forming ◽  
Industrial Scale ◽  
Resistance Heating ◽  
Electric Resistance ◽  
Heating Method ◽  
Electric Resistance Heating

Thermal Field Analysis of Matrix Heating System on Thermoforming Machine

2013 ◽  
Vol 664 ◽  
pp. 853-858
Author(s):  
Chun Hui Situ ◽  
Qing Qing Luo ◽  
Tao Mei ◽  
Jiang Zhuang
Keyword(s):  
Temperature Distribution ◽  
Food Packaging ◽  
Thermal Field ◽  
Heating System ◽  
Field Analysis ◽  
Heating Zone ◽  
The Finite Element Method ◽  
Uniform Heating ◽  
Linear Distribution ◽  
Uneven Heating

Thermoforming machine plays a very important role in industrial production, food packaging and other industries. In traditional thermoforming machine, highest temperature often appears in the center of the heating zone, and gradually reduces from the middle to both sides. It results in uneven heating, reducing the rate of finished products and a waste of resources. According to the finite element method, this article established the thermal field model of matrix heating system in thermoforming machine and simulated the temperature distribution of plastic in heating system under the conditions of “uniform heating” and “non-uniform heating” separately. It found that under the condition of “non-uniform heating”, the temperature distribution appeared uniform. The temperature of main region to be heated appeared approximately linear distribution, with the variation range of less than 5 °C, resulted in better effect than that under the condition of “uniform heating”

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