scholarly journals Detection of Single Steel Strand Distribution in Grouting Duct Based on Capacitive Sensing Technique

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2564 ◽  
Author(s):  
Nan Li ◽  
Mingchen Cao ◽  
Hangben Du ◽  
Cunfu He ◽  
Bin Wu
Keyword(s):  
Capacitive Sensor ◽  
Experimental Results ◽  
Capacitive Sensing ◽  
Capacitance Measurements ◽  
Position Detection ◽  
Steel Bar ◽  
Sensor Structure ◽  
Steel Strand ◽  
Center Distance ◽  
Post Tensioned

Grouting ducts (containing steel strands) are widely used to increase the structural strengths of infrastructures. The determination of the steel strand’s integrity inside of ducts and the grouting quality are important for a strength evaluation of the structure. In this study, a capacitive sensing technique was applied to identify the cross-sectional distribution of the steel strands. The distribution was expressed in polar coordinates in an external post-tensioned pre-stressed duct model. An improved capacitive sensor structure was designed, which consisted of four electrodes, and different electrode-pairs were used to determine various locations’ information of the steel strands. Two rounds of measurements were conducted using the designed sensor to detect the angle (θ) and center distance (r) of the steel strand in the duct. The simulated and experimental results are presented and analyzed. In general, it is difficult to locate the angle of a steel strand directly from first-round capacitance measurements by analyzing the experimental results. Our method based on Q-factor analysis was presented for the position detection of a steel bar in an external post-tensioned pre-stressed duct. The center distance of the steel bar could be identified by second-round capacitance measurements. The processed results verified the effectiveness of the proposed capacitive sensor structure. Thus, the capacitive sensing technique exhibited potential for steel strand cross-section distribution detection in external post-tensioned pre-stressed ducts.

A Planar Capacitive Sensor Parameter Design for Security Detection

2015 ◽  
Vol 713-715 ◽  
pp. 642-646
Author(s):  
Xiang Dong Yang ◽  
Yu Gong ◽  
Nan Li ◽  
Pai Wang
Keyword(s):  
Potential Distribution ◽  
Signal Strength ◽  
Capacitive Sensor ◽  
Measurement Range ◽  
Experimental Results ◽  
Parameter Design ◽  
Structure Parameters ◽  
Sensor Parameter ◽  
Sensor Structure

A planar capacitive sensor is designed for security detection. The different length of the sensor electrodes are design and the experiments are presented. For the relations between sensor structure parameters and the sensor potential distribution, detailed analyses are presented and the qualitative conclusions are discussed. The signal strength and measurement range of the sensor can be improved by enlarge the length of the sensor electrodes. The experimental results indicate that the sensor is more portable, easy to minimize, and applicable to the detection of a variety of sizes of containers. It is feasible to be applied to security detection.

Study on a Novel MEMS High G Acceleration Sensor

2012 ◽  
Vol 490-495 ◽  
pp. 499-503
Author(s):  
Ping Li ◽  
Yun Bo Shi ◽  
Jun Liu ◽  
Shi Qiao Gao
Keyword(s):  
Resonant Frequency ◽  
Natural Frequency ◽  
Impact Load ◽  
Hopkinson Bar ◽  
Experimental Results ◽  
Structure Parameters ◽  
Acceleration Sensor ◽  
Piezoresistive Effect ◽  
Sensor Structure ◽  
The Impact

This paper presents a novel MEMS high g acceleration sensor based on piezoresistive effect. For the designed sensor structure, the formula of stress, natural frequency and damping was derived in theory, and the resonant frequency can up to 500kHz. After the structure parameters were designed, the sensor was fabricated by the standard processing technology, and the sensitivity was tested by Hopkinson bar. According to the experimental results, the sensitivity of the high g acceleration sensor is 0.125μV/g at the impact load of 164,002g.

scholarly journals A Simple Method for the Detection of Biofilms Using a Heatable Capacitive Sensor Structure (CSS): Description, Proof of Concept, and Some Technical Improvements

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 445
Author(s):  
Kai-Uwe Zirk ◽  
Manuel Olze ◽  
Harald Pötzschke
Keyword(s):  
Printed Circuit Boards ◽  
Free Water ◽  
Spray Coating ◽  
Internal Surface ◽  
Capacitive Sensor ◽  
Simple Method ◽  
Realistic Condition ◽  
Main Challenge ◽  
Sensor Structure ◽  
The Difference

This article presents a novel method for the detection of biofilms based on a heatable, capacitive sensor structure (CSS). Biofilms are capable of strongly binding large amounts of water to their extracellular biopolymer matrix, which is detectable via its dielectric properties. A main challenge is to determine the difference between the inherent occurring presence of moisture in the ecosystem, which is necessary to form a biofilm and an actual formed biofilm. Therefore, the CSS is carefully heated to evaporate unbound surface moisture and determine whether there is a remaining residual alternation of the capacitance in comparison to the dry state. As a reproduceable substitute for complex, real biofilms, a hygroscopic, medical hydrogel-based on polysaccharides was used and applied by spray coating. Printed circuit boards (PCB) in different geometries and materials were used as CSS and compared in terms of their performance. A layer-thickness of 20 µm for the hydrogel coating to be sufficiently detected was defined as a realistic condition based on known values for real biofilms cited in literature. For this thickness a double-meander structure proves to be preferable over interdigitating and spiral geometries. It does offer a 30% lower, yet sufficient sensitivity, but shows advantages in manufacturing (one layer instead of two) and conductive heating capability. In the experiments, free water showed virtually no residual change, while the hydrogel-coated CSS still shows an approx. 300% higher value compared to a dry capacity. Yet, the overall small capacities of about 6–30 pF in dry state are difficult to measure and therefore sensitive to interferences and noise, which results in a high deviation. The principle of measurement can be evaluated as proofed by the carried out experiments, though offering room for improvement in the design of the study. The new method might be especially useful for pipes (e.g., hydrodynamically ineffective sensors installed in a pipe wall) if they at least are not permanently flooded with an aqueous medium, but can occasionally dry. If the internal surface is still only moist, it can be dried by initial heating.

scholarly journals Torsional Strengthening of Low-Strength RC Beams with Post-Tensioned Metal Straps: An Experimental Investigation

2020 ◽  
Vol 17 (12) ◽  
pp. 1399-1411
Author(s):  
Monthian SETKIT ◽  
Thanongsak IMJAI ◽  
Udomvit CHAISAKULKIET ◽  
Reyes GARCIA ◽  
Komsan DANGYEM ◽  
...  
Keyword(s):  
Failure Modes ◽  
Beam Current ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Control Beam ◽  
Torque Capacity ◽  
Low Strength ◽  
Conservative Values ◽  
Post Tensioned

This article investigates the behaviour of low-strength reinforced concrete beams under pure torsion with and without strengthening. Four beams were cast and tested in torsion: i) a control beam without vertical reinforcement, ii) two beams with internal stirrups designed for shear and torsion demands using different stirrup spacing (50 and 100 mm), and iii) a beam having steel stirrups with a spacing of 100 mm strengthened using high ductile post-tensioned metal straps (PTMS). The main objective of the PTMS strengthening solution was to investigate the enhancement of torsional strength confined along the beam. The failure modes, torsional capacities, rotation, and strengthening performance in torsion are discussed in in this study. The experimental results indicate that the PTMS improved the cracking torque capacity by up to 15 % compared to the control beam. Moreover, the PTMS also increased the ultimate torque by up to 19 % compared to the unstrengthened beam. Current code equations to predict the torsional capacity of RC beams are also compared with the experimental results. It is found that the predictions obtained by current ACI equation gives a good agreement and yield in general conservative values compared to the experimental ones.

Real-Time System for Liquid Level Measurement

2013 ◽  
Vol 441 ◽  
pp. 356-359
Author(s):  
Wei Wei ◽  
Hai Ying Jiang ◽  
Qin Jian Sun ◽  
Qiang Huang ◽  
Zhi Wei Wang
Keyword(s):  
Harmonic Oscillation ◽  
High Sensitivity ◽  
Capacitive Sensor ◽  
Liquid Level ◽  
Capacitance Measurement ◽  
Measurement Circuit ◽  
Real Time System ◽  
Level Measurement ◽  
Sensor Structure ◽  
Level Height

A small level measurement system is designed by installing a compact capacitive level sensor in the small container. By analyzing the capacitive sensor structure, a sensor measurement circuit is designed with high sensitivity, measuring stability and good repeatability. Capacitance measurement circuit makes use of multiple harmonic oscillation principle. The microcomputer measures the oscillation frequency of the multivibrator, and calculates the liquid level height based on the monotonic function about the liquid level height and frequency.

Development and application of a novel low-cost capacitive sensor for accurate rebar position detection

2020 ◽  
Vol 257 ◽  
pp. 119506
Author(s):  
Yu Cheng ◽  
Su Diao ◽  
Asad Hanif ◽  
Pavithra Parthasarathy ◽  
Zongjin Li
Keyword(s):  
Low Cost ◽  
Capacitive Sensor ◽  
Position Detection

Study on the transfer and anchorage length of steel strand in ultra high performance concrete material

2020 ◽  
Vol 10 (2) ◽  
pp. 153-164
Author(s):  
Hui Zheng ◽  
Dongdong Zhou ◽  
Xinfeng Yin ◽  
Lei Wang
Keyword(s):  
Bond Strength ◽  
High Performance ◽  
Failure Modes ◽  
High Performance Concrete ◽  
Protective Layer ◽  
Experimental Results ◽  
Ultra High Performance Concrete ◽  
Anchorage Length ◽  
Pull Out ◽  
Steel Strand

Ultra-high-performance concrete (UHPC) material, a new type of cement-based composite material, is usually employed in the bridge engineering. The transfer and anchorage length of steel strand in UHPC material is different from that in ordinary concrete; nevertheless, few design standards are found that how to anchor the transfer and anchoring length of steel strand in UHPC material under normal curing. Through central pull-out test under the different conditions of protective layer thickness and embedded length, the load-slip curves, failure modes, and bond strength of 36 UHPC material specimens under normal curing were studied. The experimental results showed that the ultimate bond stress between UHPC material and steel strand under natural curing conditions is 7.01∼11.68 MPa. When the compressive strength of cube was 157 MPa; the bond strength under natural curing was smaller than that under thermal curing; when the thickness of the protective layer of steel strand with a diameter of 15.2 mm is greater than 30 mm, it had a little influence on bond strength. The regression analysis of the test results based on the experimental results proves that the recommended formulas for the design of transfer length and anchorage length of steel strand in UHPC material were in great agreement with the results of published studies.

Approach and Effect Analysis of Amplitude Frequency Performance Improvement in Metal Bar Cropping with Variable Frequency Vibration

2012 ◽  
Vol 152-154 ◽  
pp. 770-774
Author(s):  
Li Jun Zhang ◽  
Jie Qiong Xue ◽  
Sheng Dun Zhao ◽  
Yong Rui Zhao
Keyword(s):  
Performance Improvement ◽  
Cross Section ◽  
Narrow Range ◽  
Experimental Results ◽  
Variable Frequency ◽  
Structure Model ◽  
Effect Analysis ◽  
Steel Bar ◽  
Different Types ◽  
And Control

In order to solve the narrow range and control difficulties of the excited frequency in metal bar cropping with variable frequency vibration, the structure of the eccentric block in cropping machine was improved on in the paper and a new structure model of changing the integral eccentric block into one of main eccentric block and some small adjustable eccentric blocks, was also proposed. The key parameters of the cropping machine in the action of two different types of eccentric blocks were analyzed theoretically in detail. At the same time, the corresponding amplitude frequency characteristics of the cropping machine were also obtained. The cropping experimental results of 45 steel bar show that the cross-section quality and the cropping time are improved remarkably in the action of one main eccentric block and four adjustable eccentric blocks, comparing with the cropping results in the action of the whole eccentric block.

A capacitive angular sensor with flexible digitated electrodes

Sensor Review ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 382-388 ◽  
Author(s):  
Damir Krklješ ◽  
Dragana Vasiljević ◽  
Goran Stojanović
Keyword(s):  
Printed Electronics ◽  
Angular Displacement ◽  
Angular Position ◽  
Capacitive Sensor ◽  
Measurement Range ◽  
Content Type ◽  
Full Turn ◽  
Sensor Structure ◽  
Capacitor Structure ◽  
Incremental Encoder

Purpose – This paper aims to present a prototype of a capacitive angular-position sensor which exploits advantages of flexible/printed electronics. The novelty of the sensor is that the capacitor structure is placed at the circumference of the rotor and stator, that it posses two channels (capacitor structures) electrically shifted for p/4 and that the rotor is common for both channels. The electrodes of the sensing capacitor are digitated, providing a triangular transfer function. Design/methodology/approach – This sensor prototype consists of two flexible inkjet-printed silver electrodes forming a cylindrical capacitor structure. One of them is wrapped around the stator and another is wrapped around the rotor part of a simple mechanical platform used to precisely adjust the angular displacement. Findings – The capacitance as a function of angular position was measured using an inductance capacitance impedance (LCZ) Meter, and results are presented for a full-turn measurement range. The experimental results are compared with analytical ones and very good agreement has been achieved. Originality/value – The proposed capacitive sensor structure can be used as an absolute or an incremental encoder with different resolutions, and it can be applied in automotive industry or robotics.

Research for Raising Data Stability of the Digital Leather Thickness Gauge with Capacitive Sensor

2011 ◽  
Vol 65 ◽  
pp. 372-375
Author(s):  
Duo Ning ◽  
Pan Pan Wang ◽  
Jian Bing Huang
Keyword(s):  
Experimental Data ◽  
Capacitive Sensor ◽  
Comprehensive Analysis ◽  
Experimental Results ◽  
Good Stability ◽  
Thickness Gauge ◽  
Structural Factors ◽  
Effective Contact ◽  
Main Factors

Low data stability exists in the measurement of the developed leather thickness gauge (MH-YD1). After studying the whole working principles and a comprehensive analysis of experimental results, we find the main factors. Which are the structural factors and the working principles of the capacitive sensor collected the displacement. Then, we put forward improvements. In hardware, we solve the effective contact between the static and dynamic film and the pivoting of the guide bar. Also including the instability of data displayed in software. Then the experimental data measured by using the improved gauge proved to have good stability.

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