Nondestructive and electromagnetic evaluations of stealth structures damaged by lightning strike

2019 ◽  
Vol 30 (17) ◽  
pp. 2567-2574 ◽  
Author(s):  
Jae-Kyeong Jang ◽  
Jong-Min Hyun ◽  
Dae-Sung Son ◽  
Jung-Ryul Lee
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Structural Damage ◽  
Electromagnetic Properties ◽  
Lightning Strike ◽  
Multiwalled Carbon ◽  
Full Field ◽  
Impulse Current Generator ◽  
Ultrasonic Propagation ◽  
Radar Absorbing Structure

Stealth technology is very important for the survival of military aircraft. A stealth aircraft structure has both electromagnetic and mechanical functions. Lightning can cause failure on both the points. In this study, we claim that the stealth structure should be evaluated nondestructively and electromagnetically, and we propose a method for full-field evaluations of both the functions. First, a radar absorbing structure was designed and fabricated with stealth capability in the X-band. The radar absorbing structure consisted of a carbon nanotube layer (glass/epoxy dispersed with multiwalled carbon nanotubes), a spacer layer (glass/epoxy) and a perfect electrical conductor layer. A lightning test was performed using an impulse current generator according to standard regulations. Then, nondestructive damage and electromagnetic performance evaluations were performed using a pulse-echo laser ultrasonic propagation imager and a scanning free-space measurement system, respectively. The results showed that neither structural damage nor changes in the electromagnetic properties were observed during the two evaluations. In general, the composites were severely damaged by lightning. However, it turned out that the radar absorbing structure with the carbon nanotube layer could prevent serious damage to stealth function as well as material damage owing to the high conductivity of the carbon nanotubes dispersed in its surface layer.

scholarly journals A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Waris Obitayo ◽  
Tao Liu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Strain Sensors ◽  
Voltage Response ◽  
Strain Sensing ◽  
Multiwalled Carbon ◽  
Sensing Applications ◽  
Mechanical Deformations ◽  
Electrical Resistivities

The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

Neuron-like polyelectrolyte–carbon nanotube composites for ultra-high loading of metal nanoparticles

2014 ◽  
Vol 38 (10) ◽  
pp. 4799-4806 ◽  
Author(s):  
Md. Shahinul Islam ◽  
Won San Choi ◽  
Tae Sung Bae ◽  
Young Boo Lee ◽  
Ha-Jin Lee
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Metal Nanoparticles ◽  
Multiwalled Carbon Nanotubes ◽  
High Loading ◽  
Multiwalled Carbon ◽  
Simple Protocol ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites

We report a simple protocol for the fabrication of multiwalled carbon nanotubes (MWCNTs) with a neuron-like structure for loading ultra-high densities of metal nanoparticles (NPs).

Mechanical Properties Of Polyaniline / Multi-walled Carbon Nanotube Composite Films

2003 ◽  
Vol 791 ◽  
Author(s):  
P. C. Ramamurthy ◽  
W. R. Harrell ◽  
R. V. Gregory ◽  
B. Sadanadan ◽  
A. M. Rao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Weight Percent ◽  
Organic Electronic Devices ◽  
Multiwalled Carbon ◽  
Multi Walled Carbon Nanotube ◽  
Contact Devices ◽  
Carbon Nanotube Composite

ABSTRACTHigh molecular weight polyaniline / multi-walled carbon nanotube composite films were fabricated using solution processing. Composite films with various weight percentages of multiwalled carbon nanotubes were fabricated. Physical properties of these composites were analyzed by thermogravimetric analysis, tensile testing, and scanning electron microscopy. These results indicate that the addition of multiwalled nanotubes to polyaniline significantly enhances the mechanical properties of the films. In addition, metal–semiconductor (composite) (MS) contact devices were fabricated, and it was observed that the current level in the films increased with increasing multiwalled nanotube content. Furthermore, it was observed that polyaniline containing one weight percent of carbon nanotubes appears to be the most promising composition for applications in organic electronic devices.

scholarly journals Autonomous self-healing multiwalled carbon nanotube nanocomposites with piezoresistive effect

RSC Advances ◽  
2017 ◽  
Vol 7 (33) ◽  
pp. 20422-20429 ◽  
Author(s):  
Tongfei Wu ◽  
Biqiong Chen
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon Nanotube ◽  
Self Healing ◽  
Multiwalled Carbon ◽  
Piezoresistive Effect

Viscoelastic rubber reinforced by multiwalled carbon nanotubes exhibited rapid, autonomous, mechanically and electrically self-healing properties and piezoresistive behavior.

Highly Organized Carbon Nanotube-PDMS Hybrid System for Multifunctional Flexible Devices

2007 ◽  
Author(s):  
Yung J. Jung ◽  
Laila Jaber-Ansari ◽  
Xugang Xiong ◽  
Sinan Mu¨ftu¨ ◽  
Ahmed Busnaina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electric Fields ◽  
Composite Structures ◽  
Field Enhancement ◽  
Chemical Vapor ◽  
Casting Process ◽  
Dip Coating ◽  
Network Architectures ◽  
Multiwalled Carbon

We will present a method to fabricate a new class of hybrid composite structures based on highly organized multiwalled carbon nanotube (MWNT) and singlewalled carbon nanotube (SWNT) network architectures and a polydimethylsiloxane (PDMS) matrix for the prototype high performance flexible systems which could be used for many daily-use applications. To build 1–3 dimensional highly organized network architectures with carbon nanotubes (both MWNT and SWNT) in macro/micro/nanoscale we used various nanotube assembly processes such as selective growth of carbon nanotubes using chemical vapor deposition (CVD) and self-assembly of nanotubes on the patterned trenches through solution evaporation with dip coating. Then these vertically or horizontally aligned and assembled nanotube architectures and networks are transferred in PDMS matrix using casting process thereby creating highly organized carbon nanotube based flexible composite structures. The PDMS matrix undergoes excellent conformal filling within the dense nanotube network, giving rise to extremely flexible conducting structures with unique electromechanical properties. We will demonstrate its robustness under large stress conditions, under which the composite is found to retain its conducting nature. We will also demonstrate that these structures can be directly utilized as flexible field-emission devices. Our devices show some of the best field enhancement factors and turn-on electric fields reported so far.

Monitoring of Carboxylic Carbon Nanotubes in Surface Water by Using Multiwalled Carbon Nanotube-Modified Filter As Preconcentration Unit

2008 ◽  
Vol 42 (16) ◽  
pp. 6100-6104 ◽  
Author(s):  
Beatriz Suárez ◽  
Yolanda Moliner-Martínez ◽  
Soledad Cárdenas ◽  
Bartolomé M. Simonet ◽  
Miguel Valcárcel
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Surface Water ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon

scholarly journals Fabrication of cm scale buckypapers of horizontally aligned multiwalled carbon nanotubes highly filled with Fe3C: the key roles of Cl and Ar-flow rates

2016 ◽  
Vol 52 (22) ◽  
pp. 4195-4198 ◽  
Author(s):  
Filippo S. Boi ◽  
Jian Guo ◽  
Shanling Wang ◽  
Yi He ◽  
Gang Xiang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
Flow Rates

A key challenge in the fabrication of ferromagnetically filled carbon-nanotube buckypapers in the presence of Cl-radicals is the achievement of a preferential horizontal nanotube-alignment.

Reactor Scale Model of Multiwalled Carbon Nanotube Growth in a Tube Flow Chemical Vapor Deposition Reactor

2009 ◽  
Author(s):  
Jeffrey J. Lombardo ◽  
Wilson K. S. Chiu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotubes ◽  
Computational Models ◽  
Chemical Vapor ◽  
Scale Model ◽  
Tube Flow ◽  
Multiwalled Carbon ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

Even though a large number of applications for multiwalled carbon nanotubes have been proposed, there is relatively limited knowledge about the optimal conditions in which to create multiwalled carbon nanotubes (MWNTs). Computational models have been shown to be a promising tool to determine the best carbon nanotube growth conditions. In this paper the growth of MWNTs in a tube flow CVD reactor was studied through the use of the commercial software package COMSOL, where details steps have been described to reformulate an existing single walled carbon nanotube (SWNT) growth model to accommodate MWNTs followed by validation and growth rate prediction. Higher growth rates were predicted for MWNTs than SWNTs which is a result of the increase in pathways for carbon to form carbon nanotubes based on the additional walls. Results indicate that selecting the correct number of walls can be important to the results of the model.

scholarly journals Modified Sol-Gel Synthesis of Carbon Nanotubes Supported Titania Composites with Enhanced Visible Light Induced Photocatalytic Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Quanjie Wang ◽  
Yanqing Wang ◽  
Baorong Duan ◽  
Mengmeng Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Photocatalytic Activity ◽  
Carbon Nanotube ◽  
Visible Light ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Raw Material ◽  
Tetrabutyl Titanate ◽  
Multiwalled Carbon ◽  
Photodegradation Efficiency

Multiwalled carbon nanotube (MWCNT) enhanced MWCNT/TiO2nanocomposites were synthesized by surface coating of carbon nanotube with mixed phase of anatase and rutile TiO2through a modified sol-gel approach using tetrabutyl titanate as raw material. The morphological structures and physicochemical properties of the nanocomposites were characterized by FT-IR, XRD, DTA-TG, TEM, and UV-Vis spectra. The results show that TiO2nanoparticles with size of around 15 nm are closely attached on the sidewall of MWCNT. The nanocomposites possess good absorption properties not only in the ultraviolet but also in the visible light region. Under irradiation of ultraviolet lamp, the prepared composites have the highest photodegradation efficiency of 83% within 4 hours towards the degradation of Methyl Orange (MO) aqueous solution. The results indicate that the carbon nanotubes supported TiO2nanocomposites exhibit high photocatalytic activity and stability, showing great potentials in the treatment of wastewater.

Self-aligned Split Gate Electrodes Fabricated on Suspended Carbon Nanotubes

2002 ◽  
Vol 741 ◽  
Author(s):  
S.-B. Lee ◽  
L.A.W. Robinson ◽  
K.B.K. Teo ◽  
M. Chhowalla ◽  
G.A.J. Amaratunga ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotube ◽  
Metal Electrodes ◽  
Multiwalled Carbon ◽  
Gate Electrodes ◽  
Lithography Step ◽  
Lift Off ◽  
And Control ◽  
Contact Electrodes

ABSTRACTWe describe the fabrication of self-aligned split gate electrodes on suspended multiwalled carbon nanotube structures. A suspended multiwalled carbon nanotube structure was used as an evaporation mask for the deposition of metal electrodes resulting in the formation of discontinuous wire deposition. The metal deposits on the nanotubes are removed with lift-off due to the poor adhesion of metal to the nanotube surface. Using Al sacrificial layers, it was possible to fabricate self-aligned contact electrodes and control electrodes nanometers from the suspended carbon nanotubes with a single lithography step. It was also shown that the fabrication technique may also be used to form nano-gaped contact electrodes. The technique should prove useful for the fabrication of nano-electromechanical systems.

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