scholarly journals Piezoresistive Characteristics of Nanocarbon Composite Strain Sensor by Its Longitudinal Pattern Design

2021 ◽  
Vol 11 (13) ◽  
pp. 5760
Author(s):  
Sung-Yong Kim ◽  
Baek-Gyu Choi ◽  
Gwang-Won Oh ◽  
Chan-Jung Kim ◽  
Young-Seok Jung ◽  
...  
Keyword(s):  
Axial Load ◽  
Filler Content ◽  
Factor Model ◽  
Strain Sensor ◽  
Gauge Factor ◽  
Geometric Pattern ◽  
Pattern Design ◽  
Macro Scale ◽  
Composite Strain ◽  
Longitudinal Pattern

For an engineering feasibility study, we studied a simple design to improve NCSS (nanocarbon composite strain sensor) sensitivity by using its geometric pattern at a macro scale. We fabricated bulk- and grid-type sensors with different filler content weights (wt.%) and different sensor lengths and investigated their sensitivity characteristics. We also proposed a unit gauge factor model of NCSS to find a correlation between sensor length and its sensitivity. NCSS sensitivity was improved proportional to its length incremental ratio and we were able to achieve better linear and consistent data from the grid type than the bulk type one. We conclude that the longer sensor length results in a larger change of resistance due to its piezoresistive unit summation and that sensor geometric pattern design is one of the important issues for axial load and deformation measurement.

scholarly journals Research the Composite Strain Sensors for CNT/Polymer

2019 ◽  
Vol 8 (12S) ◽  
pp. 196-199
Keyword(s):  
Polymer Composite ◽  
Dynamic Range ◽  
Mass Density ◽  
Strain Sensor ◽  
Young Modulus ◽  
High Dynamic Range ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Composite Strain ◽  
Property Changes

CNT means carbon nanotube possess piezoelectric due to that behavior its electrical property changes even with the strain applied on the CNT is at the nanoscale. Due to the advantages of composite strain sensor like their multidirectional sensing capability, high strain sensitivity, high dynamic range, flexibility, and low mass density they are turning out to be an ultimate replacement to conventional strain sensors in various applications. CNT film can also be incorporated into the polymer to form a CNT/polymer composite strain sensor. Some of the most famous polymers employed to fabricate CNT/polymer composite strain sensors are thermoplastic polymers polymethyl methacrylate, polystyrene, etc., thermosetting polymers like epoxy resins, polyurethanes, etc., and polydimethylsiloxane (PDMS). The small addition of CNTs to polymer significantly increases their electromechanical properties by enhancing its tensile strength & young modulus, which in turn improves their sensing performance. CNT/polymer composite strain sensor exhibits better strain transfer, gauge factor, linearity, repeatability, and cost than that of pure CNT strain sensor. There are different factors which are affecting the performance of CNT/polymer composite strain sensor including quality and quantity of CNT filler particles in composite, type of fabrication technique adopted to form a composite, alignment and agglomerates of CNT in composite, cracks or defect in composite and environmental conditions. This paper reviews the performance of various different types of CNT/polymer composite strain sensors.

scholarly journals Significant strain-rate dependence of sensing behavior in TiO2@carbon fibre/PDMS composites for flexible strain sensors

2021 ◽  
Author(s):  
Fan Zhang ◽  
Hailong Hu ◽  
Simin Hu ◽  
Jianling Yue
Keyword(s):  
Carbon Fibre ◽  
Strain Rate ◽  
Flexible Electronics ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Small Strain ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Hydrothermal Route ◽  
Composite Strain

AbstractCarbon fibre (CF) embedded into elastomeric media has been attracting incredible interest as flexible strain sensors in the application of skin electronics owing to their high sensitivity in a very small strain gauge. To further improve the sensitivity of CF/PDMS composite strain sensor, the relatively low temperature prepared TiO2 nanowire via hydrothermal route was employed herein to functionalize CF. The results showed a significant increase in the sensitivity of the TiO2@CF/PDMS composite strain sensors which was reflected by the calculated gauge factor. As the prepared TiO2 nanowire vertically embraced the surroundings of the CF, the introduced TiO2 nanowire contributed to a highly porous structure which played a predominant role in improving the sensitivity of strain sensors. Moreover, the significant strain rate dependent behavior of TiO2@CF/PDMS strain sensor was revealed when performing monotonic tests at varied strain rate. Therefore, introducing TiO2 nanowire on CF offers a new technique for fabricating flexible strain sensors with improved sensitivity for the application of flexible electronics.

scholarly journals Development of Highly Sensitive Strain Sensor Using Area-Arrayed Graphene Nanoribbons

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1701
Author(s):  
Ken Suzuki ◽  
Ryohei Nakagawa ◽  
Qinqiang Zhang ◽  
Hideo Miura
Keyword(s):  
Graphene Nanoribbons ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Bending Test ◽  
Gauge Factor ◽  
Four Point Bending ◽  
Current Voltage ◽  
Highly Sensitive ◽  
Current Voltage Relationship

In this study, a basic design of area-arrayed graphene nanoribbon (GNR) strain sensors was proposed to realize the next generation of strain sensors. To fabricate the area-arrayed GNRs, a top-down approach was employed, in which GNRs were cut out from a large graphene sheet using an electron beam lithography technique. GNRs with widths of 400 nm, 300 nm, 200 nm, and 50 nm were fabricated, and their current-voltage characteristics were evaluated. The current values of GNRs with widths of 200 nm and above increased linearly with increasing applied voltage, indicating that these GNRs were metallic conductors and a good ohmic junction was formed between graphene and the electrode. There were two types of GNRs with a width of 50 nm, one with a linear current–voltage relationship and the other with a nonlinear one. We evaluated the strain sensitivity of the 50 nm GNR exhibiting metallic conduction by applying a four-point bending test, and found that the gauge factor of this GNR was about 50. Thus, GNRs with a width of about 50 nm can be used to realize a highly sensitive strain sensor.

Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud Haghighi ◽  
Hossein Golestanian ◽  
Farshid Aghadavoudi
Keyword(s):  
Mechanical Properties ◽  
Ultimate Strength ◽  
Multiscale Modeling ◽  
Filler Content ◽  
Hybrid Nanocomposites ◽  
Dynamics Simulation ◽  
Strength Increase ◽  
Two Phase ◽  
Macro Scale ◽  
Elongation To Failure

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

scholarly journals A Novel Textile Stitch-Based Strain Sensor for Wearable End Users

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1469 ◽  
Author(s):  
Orathai Tangsirinaruenart ◽  
George Stylios
Keyword(s):  
Mechanical Properties ◽  
Electrical Resistance ◽  
Body Movement ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Heart Monitoring ◽  
Textile Sensors ◽  
Good Repeatability ◽  
The Ideal

This research presents an investigation of novel textile-based strain sensors and evaluates their performance. The electrical resistance and mechanical properties of seven different textile sensors were measured. The sensors are made up of a conductive thread, composed of silver plated nylon 117/17 2-ply, 33 tex and 234/34 4-ply, 92 tex and formed in different stitch structures (304, 406, 506, 605), and sewn directly onto a knit fabric substrate (4.44 tex/2 ply, with 2.22, 4.44 and 7.78 tex spandex and 7.78 tex/2 ply, with 2.22 and 4.44 tex spandex). Analysis of the effects of elongation with respect to resistance indicated the ideal configuration for electrical properties, especially electrical sensitivity and repeatability. The optimum linear working range of the sensor with minimal hysteresis was found, and the sensor’s gauge factor indicated that the sensitivity of the sensor varied significantly with repeating cycles. The electrical resistance of the various stitch structures changed significantly, while the amount of drift remained negligible. Stitch 304 2-ply was found to be the most suitable for strain movement. This sensor has a wide working range, well past 50%, and linearity (R2 is 0.984), low hysteresis (6.25% ΔR), good gauge factor (1.61), and baseline resistance (125 Ω), as well as good repeatability (drift in R2 is −0.0073). The stitch-based sensor developed in this research is expected to find applications in garments as wearables for physiological wellbeing monitoring such as body movement, heart monitoring, and limb articulation measurement.

scholarly journals Flexible and wearable strain sensor based on electrospun carbon sponge/polydimethylsiloxane composite for human motion detection

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4186-4193
Author(s):  
He Gong ◽  
Chuan Cai ◽  
Hongjun Gu ◽  
Qiushi Jiang ◽  
Daming Zhang ◽  
...  
Keyword(s):  
Motion Detection ◽  
Strain Sensor ◽  
Human Motion ◽  
Gauge Factor ◽  
Human Motion Detection ◽  
Tensile Strains

Electrospun carbon sponge was used to measure tensile strains with a high gauge factor.

scholarly journals A novel strain sensor using a microchannel embedded in PDMS

2018 ◽  
Vol 4 (2) ◽  
pp. 1 ◽  
Author(s):  
Angelica Campigotto ◽  
Stephane Leahy ◽  
Ayan Choudhury ◽  
Guowei Zhao ◽  
Yongjun Lai
Keyword(s):  
Finite Element ◽  
Rotation Angle ◽  
Strain Sensor ◽  
Element Model ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Sectional Area ◽  
Cross Sectional ◽  
Higher Sensitivity

A novel, inexpensive, and easy-to-use strain sensor using polydimethylsiloxane (PDMS)  was developed. The sensor consists of a microchannel that is partially filled with a coloured liquid and embedded in a piece of PDMS. A finite element model was developed to optimize the geometry of the microchannel to achieve higher sensitivity. The highest gauge factor that was measured experimentally was 41. The gauge factor was affected by the microchannel’s square cross-sectional area, the number of basic units in the microchannel, and the inlet and outlet configuration. As a case study, the developed strain sensors were used to measure the rotation angle of the wrist and finger joints.

scholarly journals Understanding the Impact of Machine Learning Models on the Performance of Different Flexible Strain Sensor Modalities

2021 ◽  
Vol 8 ◽  
Author(s):  
Brett C. Hannigan ◽  
Tyler J. Cuthbert ◽  
Wanhaoyi Geng ◽  
Mohammad Tavassolian ◽  
Carlo Menon
Keyword(s):  
Machine Learning ◽  
Mean Squared Error ◽  
Strain Sensor ◽  
High Sensitivity ◽  
Signal Amplitude ◽  
Electrical Signal ◽  
Gauge Factor ◽  
Piezoresistive Sensor ◽  
Fibre Strain ◽  
The Impact

Fibre strain sensors commonly use three major modalities to transduce strain—piezoresistance, capacitance, and inductance. The electrical signal in response to strain differs between these sensing technologies, having varying sensitivity, maximum measurable loading rate, and susceptibility to deleterious effects like hysteresis and drift. The wide variety of sensor materials and strain tracking applications makes it difficult to choose the best sensor modality for a wearable device when considering signal quality, cost, and difficulty of manufacture. Fibre strain sensor samples employing the three sensing mechanisms are fabricated and subjected to strain using a tensile tester. Their mechanical and electrical properties are measured in response to strain profiles designed to exhibit particular shortcomings of sensor behaviour. Using these data, the sensors are compared to identify materials and sensing technologies well suited for different textile motion tracking applications. Several regression models are trained and validated on random strain pattern data, providing guidance for pairing each sensor with a model architecture that compensates for non-ideal effects. A thermoplastic elastomer-core piezoresistive sensor had the highest sensitivity (average gauge factor: 12.6) and a piezoresistive sensor of similar construction with a polyether urethane-urea core had the largest bandwidth, capable of resolving strain rates above 300% s−1 with 36% signal amplitude attenuation. However, both piezoresistve sensors suffered from larger hysteresis and drift than a coaxial polymer sensor using the capacitive strain sensing mechanism. Machine learning improved the piezoresistive sensors’ root-mean-squared error when tracking a random strain signal by up to 58% while maintaining their high sensitivity, bandwidth, and ease of interfacing electronically.

Fabrication of Multilayered Polymer Composite Fibers for Enhanced Functionalities

2021 ◽  
Author(s):  
Weiheng Xu ◽  
Dharneedar Ravichandran ◽  
Sayli Jambhulkar ◽  
Yuxiang Zhu ◽  
Kenan Song
Keyword(s):  
Mechanical Stability ◽  
Thermoplastic Polyurethane ◽  
Hot Isostatic Pressing ◽  
Air Pressure ◽  
Gauge Factor ◽  
Piezoresistive Sensor ◽  
Macro Scale ◽  
Facile Fabrication ◽  
Surface Morphologies ◽  
Hierarchal Structure

Abstract Carbon nanoparticles-based polymer composites have wide applications across different fields for their unique functional properties, durability, and chemical stability. When combining nanoparticle morphologies with micro- or macro-scale morphologies, the hierarchal structure often would greatly enhance the composites’ functionalities. Here in this work, a thermoplastic polyurethane (TPU) and graphene nanoplatelets (GnPs) based multilayered fiber is fabricated through the combination of dry-jet-wet spinning, based on an in-house designed spinneret which accommodates three layers spinning solution, and hot isostatic pressing (HIP), at 220 °C. The multilayered spinneret enables the spinnability of a high GnPs loaded spinning dope, highly elastic, with great mechanical strength, elongation, and flexibility. The HIP process resulted in superior electrical properties as well as a newly emerged fourth hollow layer. Together, such a scalable fabrication method promotes a piezoresistive sensor that is sensitive to uniaxial strain and radial air pressure. The hollow fiber is characterized based on surface morphologies, layer formation, percolation threshold, piezoresistive gauge factor, mechanical stability and reversibility, and air-pressure sensitivity and reversibility. Such facile fabrication methods and unique structures have combined the mechanically robust outer shell with a highly conductive middle sensing layer for a new sensor with great potentials in wearable, robotics, biomedical, and other areas.

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