scholarly journals A High-Strength Strain Sensor Based on a Reshaped Micro-Air-Cavity

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4530
Author(s):  
Yanping Chen ◽  
Junxian Luo ◽  
Shen Liu ◽  
Mengqiang Zou ◽  
Shengzhen Lu ◽  
...  
Keyword(s):  
Tensile Strain ◽  
Arc Discharge ◽  
Thermal Sensitivity ◽  
Strain Sensor ◽  
High Strength ◽  
Single Mode ◽  
Measurement Range ◽  
Fringe Contrast ◽  
Air Cavity ◽  
Free Spectrum

We demonstrate a high-strength strain sensor based on a micro-air-cavity reshaped through repeating arc discharge. The strain sensor has a micro-scale cavity, approximate plane reflection, and large wall thickness, contributing to a broad free spectrum range ~36 nm at 1555 nm, high fringe contrast ~38 dB, and super-high mechanical robustness, respectively. A sensitivity of ~2.39 pm/με and a large measurement range of 0 to 9800 με are achieved for this strain sensor. The strain sensor has a high strength, e.g., the tensile strain applied the sensor is up to 10,000 με until the tested the single-mode fiber is broken into two sections. In addition, it exhibited low thermal sensitivity of less than 1.0 pm/°C reducing the cross-sensitivity between tensile strain and temperature.

Multiwall carbon nanotubes: A review on synthesis and applications

2021 ◽  
Vol 11 ◽  
Author(s):  
Manisha Vijay Makwana ◽  
Ajay M Patel
Keyword(s):  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Arc Discharge ◽  
Multiwall Carbon Nanotubes ◽  
High Strength ◽  
Energy Storage And Conversion ◽  
Synthesis Methods ◽  
Mechanical And Thermal Properties ◽  
Nano Materials ◽  
Flexible Sensors

: MWCNTs are elongated cylindrical nanoobjects made of sp2 carbon. They have a diameter of 3–30 nm and can grow to be several centimetres long. Therefore, their aspect ratio can range between 10 to 10 million. Carbon nanotubes are the foundation of nanotechnology. It is an exceptionally fascinating material. CNTs possess excellent properties such as mechanical, electrical, thermal, high adsorption, outstanding stiffness, high strength and low density with a high aspect ratio. These properties can be useful in the fabrication of revolutionary smart nano materials. Demand for lighter and more robust nano materials in different applications of nanotechnology is increasing every day. Various synthesis techniques for the fabrication of MWCNTs, such as CVD, Arc discharge, flame synthesis, laser ablation, and spray pyrolysis, are discussed in this review article, as are their recent applications in a variety of significant fields. The first section presents a brief introduction of CNTs, then the descriptions of synthesis methods and various applications of MWCNTs in the field of energy storage and conversion, biomedical, water treatment, drug delivery, biosensors, bucky papers and resonance-based biosensors are introduced in the second section. Due to their improved electrical, mechanical, and thermal properties, MWCNTs have been extensively used in the manufacturing and deployment of flexible sensors.

scholarly journals Corrugated Photoactive Thin Films for Flexible Strain Sensor

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1970 ◽  
Author(s):  
Donghyeon Ryu ◽  
Alfred Mongare
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Tensile Strain ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Optical And Electrical Properties ◽  
Strain Sensing ◽  
Dc Voltage ◽  
Flexible Strain Sensor

In this study, a flexible strain sensor is devised using corrugated bilayer thin films consisting of poly(3-hexylthiophene) (P3HT) and poly(3,4-ethylenedioxythiophene)-polystyrene(sulfonate) (PEDOT:PSS). In previous studies, the P3HT-based photoactive non-corrugated thin film was shown to generate direct current (DC) under broadband light, and the generated DC voltage varied with applied tensile strain. Yet, the mechanical resiliency and strain sensing range of the P3HT-based thin film strain sensor were limited due to brittle non-corrugated thin film constituents. To address this issue, it is aimed to design a mechanically resilient strain sensor using corrugated thin film constituents. Buckling is induced to form corrugation in the thin films by applying pre-strain to the substrate, where the thin films are deposited, and releasing the pre-strain afterwards. It is known that corrugated thin film constituents exhibit different optical and electronic properties from non-corrugated ones. Therefore, to design the flexible strain sensor, it was studied to understand how the applied pre-strain and thickness of the PEDOT:PSS conductive thin film affects the optical and electrical properties. In addition, strain effect was investigated on the optical and electrical properties of the corrugated thin film constituents. Finally, flexible strain sensors are fabricated by following the design guideline, which is suggested from the studies on the corrugated thin film constituents, and the DC voltage strain sensing capability of the flexible strain sensors was validated. As a result, the flexible strain sensor exhibited a tensile strain sensing range up to 5% at a frequency up to 15 Hz with a maximum gauge factor ~7.

scholarly journals Opto-Microfluidic Fabry-Perot Sensor with Extended Air Cavity and Enhanced Pressure Sensitivity

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 19
Author(s):  
Pengfei Zhang ◽  
Chao Wang ◽  
Liuwei Wan ◽  
Qianqian Zhang ◽  
Zidan Gong ◽  
...  
Keyword(s):  
Static Pressure ◽  
Liquid Surface ◽  
Microfluidic Channel ◽  
Single Mode ◽  
Pressure Sensitivity ◽  
Air Cavity ◽  
Surface Reflection ◽  
Sensor Structure ◽  
Fabry Perot ◽  
Silica Capillary

An opto-microfluidic static pressure sensor based on a fiber Fabry-Perot Interferometer (FPI) with extended air cavity for enhancing the measuring sensitivity is proposed. The FPI is constructed in a microfluidic channel by the combination of the fixed fiber-end reflection and floating liquid surface reflection faces. A change of the aquatic pressure will cause a drift of the liquid surface and the pressure can be measured by detecting the shift of the FPI spectrum. Sensitivity of the sensor structure can be enhanced significantly by extending the air region of the FPI. The structure is manufactured by using a common single-mode optical fiber, and a silica capillary with the inner wall coated with a hydrophobic film. A sample with 3500 μm air cavity length has demonstrated the pressure sensitivity of about 32.4 μm/kPa, and the temperature cross-sensitivity of about 0.33 kPa/K.

scholarly journals Nonlinear Hydraulic Pressure Response of an Improved Fiber Tip Interferometric High-Pressure Sensor

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2548
Author(s):  
Wei Huang ◽  
Zhe Zhang ◽  
Jun He ◽  
Bin Du ◽  
Changrui Liao ◽  
...  
Keyword(s):  
High Pressure ◽  
Nonlinear Response ◽  
Arc Discharge ◽  
High Sensitivity ◽  
Measurement Range ◽  
Hydraulic Pressure ◽  
Discharge Process ◽  
Pressure Sensitivity ◽  
Diaphragm Thickness ◽  
Order Of Magnitude

We demonstrate a silica diaphragm-based fiber tip Fabry–Perot interferometer (FPI) for high-pressure (40 MPa) sensing. By using a fiber tip polishing technique, the thickness of the silica diaphragm could be precisely controlled and the pressure sensitivity of the fabricated FPI sensor was enhanced significantly by reducing the diaphragm thickness; however, the relationship between the pressure sensitivity and diaphragm thickness is not linear. A high sensitivity of −1.436 nm/MPa and a linearity of 0.99124 in hydraulic pressure range of 0 to 40 MPa were demonstrated for a sensor with a diaphragm thickness of 4.63 μm. The achieved sensitivity was about one order of magnitude higher than the previous results reported on similar fiber tip FPI sensors in the same pressure measurement range. Sensors with a thinner silica diaphragm (i.e., 4.01 and 2.09 μm) rendered further increased hydraulic pressure sensitivity, but yield a significant nonlinear response. Two geometric models and a finite element method (FEM) were carried out to explain the nonlinear response. The simulation results indicated the formation of cambered internal silica surface during the arc discharge process in the fiber tip FPI sensor fabrication.

scholarly journals The Relationship between Tensile Strain and Residual Stress of High Strength Dual Phase Steel Sheet

2018 ◽  
Vol 175 ◽  
pp. 01033
Author(s):  
Maoyu Zhao a ◽  
Zhengzheng Meng ◽  
Chunyan Tian ◽  
Ping Li
Keyword(s):  
Residual Stress ◽  
Tensile Strain ◽  
Steel Sheet ◽  
Least Squares Method ◽  
Elastic Recovery ◽  
High Strength ◽  
Surface Residual Stress ◽  
Average Residual ◽  
Forming Condition ◽  
The Relationship

The relation between residual stress and tensile strain is an important factor for evaluating plastic formation grade of steel sheet. The degree of plastic deformation (Δl) and elastic recovery (δ) were obtained by measuring the length of DP600 steel sheet sample under different tensile test conditions, i.e. five tensile strains (ε). Furthermore, the average residual stress value in the surface middle (the diameter of 10 mm) region of above tensile samples was analyzed by x-ray diffraction (XRD) in the crystal plane of (211). By processing the diffraction peak angle (2θ) with half width high method (FWHM), the relationship between sin2(ψ) and diffraction angle is attained by least squares method. On this basis, a mathematical model was established to correlate the tensile strain with the residual stress in the present study. The results show that the residual stress decreases and the elastic recovery increases with the increase of tensile strain (ε≤0.205). The relation between residual stress and tensile strain can be described with an exponential function . Finally, a function of tensile strain, elastic recovery and surface residual stress is established, by which a reasonable forming condition, viz. ε=0.205, δ=2.65 mm is determined for achieving the smallest σψ.

Application of Fiber Point Diffraction in Measurement of Optical Surface

2011 ◽  
Vol 55-57 ◽  
pp. 1200-1205
Author(s):  
Liang Nie ◽  
Jun Han ◽  
Xu Jiang
Keyword(s):  
High Performance ◽  
Spherical Surface ◽  
Spherical Wave ◽  
Numerical Aperture ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Optical Surface ◽  
Fiber System ◽  
Core Diameter ◽  
Fringe Contrast

The fiber point diffraction technology is applied in interferometer to measure optical surface with high precision. The wavefront diffracted from the single mode fiber with microns core diameter can be considered as ideal spherical wave and used as the referenced wave in interferometry. To estimate the quality of diffracted wavefront, the theoretical model of optical point diffraction is introduced at first. Based on the model, the influence of fiber core diameter, deformation and end-face shape on wavefront error is studied with numerical analysis. The analysis result shows that the single mode fiber used in experiment is available for instrument design and its influence over systematic error should be negligible within certain numerical aperture. Then a point diffraction interferometer with a single fiber is designed. Compared with the double fiber system, it has merit of noise immunity, high fringe contrast and high performance. Finally, the fiber point diffraction interferometer system is put up to measure spherical surface in experiment. The interference fringes are collected and analyzed with five-step shifting, least squares unwrapping and Zernike fitting method. The results show that the interferometer with optical fiber has achieved a worthy measurement precision and has great development potential.

Application of Tensile Strain Models to Multiple Grades of Pipelines

2014 ◽  
Author(s):  
Wenwei Zhang ◽  
Zhenyong Zhang ◽  
Jinyuan Zhang ◽  
Peng Yang
Keyword(s):  
Tensile Strain ◽  
Large Diameter ◽  
High Strength ◽  
Slope Movement ◽  
Experimental Database ◽  
Mine Subsidence ◽  
The Past ◽  
Discontinuous Permafrost ◽  
China National Petroleum Corporation ◽  
Tensile Strain Capacity

China National Petroleum Corporation (CNPC) has constructed large-diameter high-strength pipelines (X70 and X80) in the past decades in areas of seismic activities, mine subsidence, and slope movement using strain-based design (SBD) technology. More pipelines being constructed now traverse regions of active seismic activities, mine subsidence, slope movement, and discontinuous permafrost. CNPC is also interested in moving to linepipe grades higher than X80. In view of the recent development of various tensile strain models, work was undertaken to evaluate those models and determine the most appropriate models for current and future applications. In this paper, selected tensile strain models are reviewed and evaluated against an experimental database. The database of 80 tests from public-domain publications contains both full-scale pipe tests and curved wide plate tests with 46 tests from high strength pipes (X80 and above). The calculated tensile strain capacity from the selected models was compared with the test data. The models were evaluated and the applicability of the models to the linepipes of different strength levels was discussed.

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