Remote Strain Measurement by Multi-Walled Carbon Nanotube-Dispersed Resin

2009 ◽  
Author(s):  
Katsuya Osaki ◽  
Hideki Fuji ◽  
Masato Onishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Strain Measurement ◽  
Tensile Strain ◽  
Axial Strain ◽  
Compressive Strain ◽  
Electronic Conductivity ◽  
Applied Strain ◽  
Dynamic Strain ◽  
Electric Resistance ◽  
Resistance Change ◽  
Base Materials

A new remote strain measurement method has been developed by applying the highly sensitive change of electronic conductivity of CNTs. Multi-walled CNTs were dispersed in various kinds of resins to form a thin film which can be attached rounded surfaces. The length of the CNTs was about a few μm. One of the base materials of resin employed was polycarbonate and the volumetric concentration of CNT dispersed was about 11.5%. The thickness of the film was about 500 μm. An uni-axial strain was applied to the CNT-dispersed resin by applying a 4 point bending method, and the change of the electric resistance was measured. The range of the applied strain was from −0.025% to 0.025%. The electric resistance changed almost linearly with the applied strain. The ratio of the resistance change under the tensile strain was about 40%/1000-μstrain and that under the compressive strain was about 15%/1000-μstrain. The micro wave of 99.5 GHz was irradiated to the CNT-dispersed polycarbonate film through the metallic prove 1 mm in diameter. The change of the intensity of the beam reflected from the film was measured by changing the amplitude of the uni-axial in-plane strain applied to the film. The intensity of the reflected beam increased almost linearly with the increase of the applied tensile strain and the change rate of the intensity was about 0.5%/1000-μstrain. This result clearly indicated that the surface dynamic strain can be detected by micro wave nondestructively and remotely.

Two-Dimensional Strain-Distribution Sensor Using Carbon Nanotube-Dispersed Resin

2011 ◽  
Author(s):  
Yusuke Suzuki ◽  
Yusuke Ohashi ◽  
Masato Ohnishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Density Functional ◽  
Axial Strain ◽  
Electronic Conductivity ◽  
Applied Strain ◽  
Sensitive Strain ◽  
Two Dimensional ◽  
Electric Resistance ◽  
Highly Sensitive ◽  
Walled Carbon Nanotubes

A new highly sensitive strain measurement method has been developed by applying the change of the electronic conductivity of CNTs. It is reported that most multi-walled carbon nanotubes (MWCNTs) show metallic conductivity and they are rather cheap comparing with single-walled carbon nanotubes (SWCNTs). The effect of the longitudinal axial strain on the band structures of electrons in CNTs was analyzed by applying the abinitio calculation based on the density functional theory. The change of the band structure of a MWCNT under uni-axial strain was analyzed. It was found that the electric conductivity of (MWCNTs) changes drastically because of the large change of their band gap. Therefore, the authors have focused on the possibility of the application of MWCNTs to a highly sensitive strain sensor. Multi-walled CNTs were dispersed in various kinds of resins such as epoxy, polycarbonate, and polyisoprene to form a thin film which can be easily attached to rounded surfaces. The length and diameter of the CNTs were about 5 μm and 50 nm, respectively. One of the base materials of resin employed was polycarbonate and the volumetric concentration of CNT dispersed was about 11.5%. The thickness of the film was about 500 μm. Uni-axial strain was applied to the CNT-dispersed resin by applying a 4 point bending method, and the change of the electric resistance was measured. The range of the applied strain was from −0.025% to 0.025%. The electric resistance changed almost linearly with the applied strain. The ratio of the resistance change under the tensile strain was about 400%/%strain and that under the compressive strain was about 150%/%strain. The CNTs were also dispersed in polyisoprene by about 5%. Uni-axial tesile strain was also applied to the CNT-dispersed rubber. The maximum strain was 240%. It was found that the resistance of the rubber increased monotonically with the increase of the amplitude of the applied strain. The increase rate also increased with the amplitude of the applied strain, and the maximum rate reached about 25%/%strain. Two-dimensional strain fields were evaluated by using finely area-arrayed CNT-dispersed resin made by MEMS technology with spatial resolution of 50 μm.

Highly Sensitive 2D Strain Sensor Using Carbon Nanotube

2013 ◽  
Author(s):  
Hiroshi Kawakami ◽  
Masato Ohnishi ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strain ◽  
Electronic Conductivity ◽  
Strain Sensor ◽  
Applied Strain ◽  
Uniaxial Strain ◽  
Sensitive Strain ◽  
Highly Sensitive ◽  
2D Strain ◽  
Walled Carbon Nanotubes

A new highly sensitive strain measurement method has been developed by applying the strain-induced change of the electronic conductivity of CNTs. It is reported that most multi-walled carbon nanotubes (MWCNTs) show metallic conductivity and they are rather cheap comparing with single-walled carbon nanotubes (SWCNTs). However, it was found that the electric conductivity of MWCNTs changes drastically under uniaxial strain because of the drastic change of their band gap. Therefore, the authors have developed a highly sensitive strain sensor which can detect the local strain distribution by using MWCNTs. In order to design a new sensor using MWCNT, it is very important to control the shape of the MWCNTs under strain. Thus, a method for controlling the shape of the MWCNTs was developed by applying a chemical vapor deposition (CVD) technique. It was found that the shape of the grown MWCNT could be controlled by changing the average thickness of the catalyst and the deposition temperature of the MWCNT. The electrical resistance of the grown MWCNT changed almost linearly with the applied strain, and the maximum strain sensitivity obtained under the application of uniaxial strain was about 10%/1000-μstrain (gauge factor: 100). A two-dimensional strain sensor, which consists of area-arrayed fine bundles of MWCNTs, has been developed by applying MEMS technology. Under the application of compressive strain, the electric resistance was confirmed to increase almost linearly with the applied strain.

ATOMISTIC SIMULATION OF THE MECHANICAL BEHAVIOR OF Ni3Al NANOWIRES

2010 ◽  
Vol 24 (15) ◽  
pp. 1639-1645 ◽  
Author(s):  
DENGMU CHENG ◽  
SHENGJIE WANG ◽  
CHUNDONG WANG ◽  
ZHIGUO WANG
Keyword(s):  
Atomistic Simulation ◽  
Tensile Strain ◽  
Room Temperature ◽  
Elastic Limit ◽  
Uniform Elongation ◽  
Compressive Strain ◽  
Applied Strain ◽  
Simulation Results ◽  
Mechanism Of Failure ◽  
Elastic Stage

Simulations have been carried out on [001]-oriented Ni 3 Al nanowires with square cross-section with the purpose to investigate the mechanism of failure under tensile and compressive strain. Simulation results show that the elastic limit of the nanowire is up to about 15% strain with the yield stress of 5.99–6.48 GPa under tensile strain. Under the elastic stage, the deformation is carried mainly through the uniform elongation of the bonds between atoms. With more tensile strain, the slips in the {111} planes occur to accommodate the applied strain at room temperature under tensile strain. And the nanowires accommodate the compressive strain by forming the twins within the nanowires.

Wireless Strain Monitoring of CFRP Laminates Using Electric Resistance Change with Oscillating Circuit

2006 ◽  
Vol 326-328 ◽  
pp. 1415-1418 ◽  
Author(s):  
Roysuke Matsuzaki ◽  
Akira Todoroki
Keyword(s):  
Bridge Circuit ◽  
Applied Strain ◽  
Frequency Change ◽  
Voltage Controlled Oscillator ◽  
Electric Resistance ◽  
Strain Sensing ◽  
Resistance Change ◽  
Cfrp Laminates ◽  
Sensing System ◽  
Strain Monitoring

To identify a delamination crack in a CFRP laminate wirelessly, we proposed an electric resistance change method with oscillating circuit in the previous study. Although the method detects the delamination creation, it cannot monitor condition of applied strain before delamination creation because the electric resistance change due to strain changing is quite small. In the present study, a bridge circuit, two amplifiers and voltage-controlled oscillator are added to sensing circuit so that it can monitor very little change of the electric resistance change. Using proposed strain sensing system, the electric resistance change and oscillating frequency change due to strain changing are experimentally measured. As a result, the method is found to successfully monitor the applied strain.

scholarly journals Morphology and Kinetics Evolution of Nanoscale Phase in Fe–Cr Alloys under External Strain

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 294 ◽  
Author(s):  
Lihui Zhu ◽  
Yongsheng Li ◽  
Shujing Shi ◽  
Zhengwei Yan ◽  
Jing Chen ◽  
...  
Keyword(s):  
Phase Separation ◽  
Tensile Strain ◽  
Compressive Strain ◽  
Three Dimensional ◽  
Particle Number Density ◽  
Phase Region ◽  
Applied Strain ◽  
Uniaxial Tensile ◽  
Α Phase ◽  
Kinetics Of

Uniaxial strain was applied to aging Fe–Cr alloys to study the morphological orientation and kinetics of the nanoscale α′ phase by utilizing phase-field simulation. The effects of applied uniaxial compressive and tensile strain on the two and three-dimensional morphology as well as on the separation kinetics of the α′ phase are quantitatively clarified. Compared with the applied uniaxial tensile strain, the applied uniaxial compressive strain shows a greater effect on the rate of phase separation, lath shape morphology and an increased rate of growth and coarsening in the α′ phase, the boundary of the α + α′ phase region is widened influenced by the applied compressive strain, while the applied tensile strain results in an increase of particle number density and a decrease of particle radius. The peak value of particle size distribution of the α′ phase increases with aging time, while an opposite trend is shown under the applied strain, and there is an obvious deviation from the theoretical distribution of Lifshitz–Slyozov–Wagner under compressive strain. The orientation morphology and kinetic change show the substantial effects of applied strain on the phase separation and supplies the method for the morphological control of nanoscale particles.

An Interlocking Ligamentous Spinal Disk Arthroplasty with Neural Network Infrastructure

2010 ◽  
Vol 7 ◽  
pp. 55-79 ◽  
Author(s):  
Philip Boughton ◽  
James Merhebi ◽  
C. Kim ◽  
G. Roger ◽  
Ashish D. Diwan ◽  
...  
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Axial Compression ◽  
Wire Array ◽  
Axial Strain ◽  
Compressive Strain ◽  
Niti Wire ◽  
Motion Segment ◽  
Flexion Extension

An elastomeric spinal disk prosthesis design (BioFI™) with vertebral interlocking anchors has been modified using an embedded TiNi wire array. Bioinert styrenic block copolymer (Kraton®) and polycarbonate urethane (Bionate®) thermoplastic elastomer (TPE) matrices were utilized. Fatigue resistant NiTi wire was pretreated to induce superelastic martensitic microstructure. Stent-like helical structures were produced for incorporation within homogenous TPE matrix. Composite prototypes were fabricated in a vacuum hot press using transfer moulding techniques. Implant prototypes were subject to axial compression using a BOSE ® ELF3400. The NiTi reinforced implants exhibited reduction in axial strain, compliance, and creep compared to TPE controls. The axial properties of the NiTi reinforced Bionate® BioFI™ implant best approximated those of a spinal disk followed by Kraton®-NiTi, Bionate® and Kraton® prototypes. An ovine lumbar segment biomechanical model was used to characterize the disk prosthesis prototypes. Specimens were subject to 7.5Nm pure moments in axial rotation, flexion-extension and lateral bending with a custom jig mounted on an Instron® 8874. The motion preserving ligamentous nature of this arthroplasty prototype was not inhibited by NiTi reinforcement. Joint stiffness for all prototypes was significantly less than the intact and discectomy controls. This was due to lack of vertebral anchor rigidity rather than BioFI™ motion segment matrix type or reinforcement. Implant stress profiles for axial compression and axial torsion conditions were obtained using finite element methods. The biomechanical testing and finite element modelling both support existing BioFI™ design specifications for higher modulus vertebral anchors, endplates and motion segment periphery with gradation to a low modulus core within the motion segment. This closer approximation of the native spinal disk form translates to improvements in prosthesis biomechanical fidelity and longevity. Axial compressive strain induced within a TiNi reinforced Kraton® BioFI™ was found to be linearly proportional to the NiTi helical coil electrical resistance. This neural network capability delivers opportunities to monitor and telemeterize in situ multiaxis joint structural performance and in vivo spine biomechanics.

Speed Estimation of a Three Phase Induction Motor Using Stator Dynamic Strain Measurement by Fiber Bragg Grating Sensor based in SVR

2021 ◽  
Author(s):  
Rafael Mancuso Paraiso Cavalcanti ◽  
Jaqueline Bierende ◽  
Beatriz Brusamarello ◽  
Jean Carlos Cardozo Da Silva ◽  
Giovanni Alfredo Guarneri ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Induction Motor ◽  
Strain Measurement ◽  
Fiber Bragg Grating Sensor ◽  
Dynamic Strain ◽  
Bragg Grating ◽  
Speed Estimation ◽  
Three Phase ◽  
Bragg Grating Sensor

A Study on Thermal and Electrical Conductivities of Ethylene-Butene Copolymer Composites with Carbon Fibers

2021 ◽  
Vol 36 (4) ◽  
pp. 417-422
Author(s):  
Y. Hamid ◽  
P. Svoboda
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Fiber ◽  
Electric Conductivity ◽  
Carbon Fibers ◽  
Mechanical Strain ◽  
Electric Resistance ◽  
Resistance Change ◽  
Electrical Conductivities ◽  
Fiber Sample

Abstract Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.

Required Linepipe Properties for High Strain Applications and Possible Resolution by Pipe Manufacturing Technology

2008 ◽  
Author(s):  
Hitoshi Asahi ◽  
Eiji Tsuru
Keyword(s):  
Tensile Strain ◽  
Compressive Strain ◽  
Bending Moment ◽  
Uniaxial Tensile ◽  
Buckling Behavior ◽  
Strain Limit ◽  
Bent Pipe ◽  
Uniaxial Tensile Stress ◽  
The Relationship ◽  
Pipe Manufacturing

Application of strain based design to pipelines in arctic or seismic areas has recently been recognized as important. So far, there has been much study performed on tensile strain limit and compressive strain limit. However, the relationship between bending buckling (compressive strain limit) and tensile strain limit has not been discussed. A model using actual stress strain curves suggests that the tensile strain limit increases as Y/T rises under uniaxial tensile stress because a pipe manufacturer usually raises TS instead of lowering YS to achieve low Y/T. Under bending of a pipe with a high D/t, an increase in compressive strain on intrados of a bent pipe at the maximum bending moment (ε-cp*) improves the tensile strain limit because the tensile strain limit is controlled by the onset of buckling or ε-cp* which is increased by lowering Y/T. On the other hand, under bending of a pipe with a low D/t, the tensile strain limit may not be influenced by improvement of buckling behavior because tensile strain on the extrados is already larger than the tensile limit at ε-cp*. Finally, we argue that the balance of major linepipe properties is important. Efforts other than the strict demands for pipe properties are also very important and inevitable to improve the strain capacity of a pipeline.

scholarly journals Minimizing Vibratory Strain Measurement Error

1998 ◽  
Author(s):  
Mark D. Sensmeier ◽  
Kurt L. Nichol
Keyword(s):  
Measurement Error ◽  
Objective Function ◽  
Strain Gage ◽  
Strain Measurement ◽  
Measured Data ◽  
Dynamic Strain ◽  
Model Predictions ◽  
Modes Of Vibration ◽  
Instrumentation Error ◽  
Time Basis

Correlation between dynamic strain gage measurements and modal analysis results can be adversely affected by gage misplacement and gage misorientation. An optimization algorithm has been developed which allows the modeled strain gage locations and orientations to be varied within specified tolerances. An objective function is defined based on the least squares sum of the differences between experimental and model results. The Kuhn-Tucker conditions are then applied to find the gage locations and orientations which minimize this objective function. The procedure is applied on a one-time basis considering all measured modes of vibration simultaneously. This procedure minimizes instrumentation error which then allows the analyst to modify the model to more accurately represent other factors, including boundary conditions. Flat plate vibratory data was used to demonstrate a significant improvement in correlation between measured data and model predictions.

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