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Sample records for ceramic strain sensor

  1. Thin Film Ceramic Strain Sensor Development for High Temperature Environments

    Science.gov (United States)

    Wrbanek, John D.; Fralick, Gustave C.; Gonzalez, Jose M.; Laster, Kimala L.

    2008-01-01

    The need for sensors to operate in harsh environments is illustrated by the need for measurements in the turbine engine hot section. The degradation and damage that develops over time in hot section components can lead to catastrophic failure. At present, the degradation processes that occur in the harsh hot section environment are poorly characterized, which hinders development of more durable components, and since it is so difficult to model turbine blade temperatures, strains, etc, actual measurements are needed. The need to consider ceramic sensing elements is brought about by the temperature limits of metal thin film sensors in harsh environments. The effort at the NASA Glenn Research Center (GRC) to develop high temperature thin film ceramic static strain gauges for application in turbine engines is described, first in the fan and compressor modules, and then in the hot section. The near-term goal of this research effort was to identify candidate thin film ceramic sensor materials and provide a list of possible thin film ceramic sensor materials and corresponding properties to test for viability. A thorough literature search was conducted for ceramics that have the potential for application as high temperature thin film strain gauges chemically and physically compatible with the NASA GRCs microfabrication procedures and substrate materials. Test results are given for tantalum, titanium and zirconium-based nitride and oxynitride ceramic films.

  2. High Strain Rate Compression Testing of Ceramics and Ceramic Composites.

    Energy Technology Data Exchange (ETDEWEB)

    Blumenthal, W. R. (William R.)

    2005-01-01

    The compressive deformation and failure behavior of ceramics and ceramic-metal composites for armor applications has been studied as a function of strain rate at Los Alamos National Laboratory since the late 1980s. High strain rate ({approx}10{sup 3} s{sup -1}) uniaxial compression loading can be achieved using the Kolsky-split-Hopkinson pressure bar (SHPB) technique, but special methods must be used to obtain valid strength results. This paper reviews these methods and the limitations of the Kolsky-SHPB technique for this class of materials. The Kolsky-split-Hopkinson pressure bar (Kolsky-SHPB) technique was originally developed to characterize the mechanical behavior of ductile materials such as metals and polymers where the results can be used to develop strain-rate and temperature-dependent constitutive behavior models that empirically describe macroscopic plastic flow. The flow behavior of metals and polymers is generally controlled by thermally-activated and rate-dependent dislocation motion or polymer chain motion in response to shear stresses. Conversely, the macroscopic mechanical behavior of dense, brittle, ceramic-based materials is dominated by elastic deformation terminated by rapid failure associated with the propagation of defects in the material in response to resolved tensile stresses. This behavior is usually characterized by a distribution of macroscopically measured failure strengths and strains. The basis for any strain-rate dependence observed in the failure strength must originate from rate-dependence in the damage and fracture process, since uniform, uniaxial elastic behavior is rate-independent (e.g. inertial effects on crack growth). The study of microscopic damage and fracture processes and their rate-dependence under dynamic loading conditions is a difficult experimental challenge that is not addressed in this paper. The purpose of this paper is to review the methods that have been developed at the Los Alamos National Laboratory to

  3. A high-strain-rate superplastic ceramic.

    Science.gov (United States)

    Kim, B N; Hiraga, K; Morita, K; Sakka, Y

    2001-09-20

    High-strain-rate superplasticity describes the ability of a material to sustain large plastic deformation in tension at high strain rates of the order of 10-2 to 10-1 s-1 and is of great technological interest for the shape-forming of engineering materials. High-strain-rate superplasticity has been observed in aluminium-based and magnesium-based alloys. But for ceramic materials, superplastic deformation has been restricted to low strain rates of the order of 10-5 to 10-4 s-1 for most oxides and nitrides with the presence of intergranular cavities leading to premature failure. Here we show that a composite ceramic material consisting of tetragonal zirconium oxide, magnesium aluminate spinel and alpha-alumina phases exhibits superplasticity at strain rates up to 1 s-1. The composite also exhibits a large tensile elongation, exceeding 1,050 per cent for a strain rate of 0.4 s-1. The tensile flow behaviour and deformed microstructure of the material indicate that superplasticity is due to a combination of limited grain growth in the constitutive phases and the intervention of dislocation-induced plasticity in the zirconium oxide phase. We suggest that the present results hold promise for the application of shape-forming technologies to ceramic materials.

  4. Development of Sensors for Ceramic Components in Advanced Propulsion Systems. Phase 2; Temperature Sensor Systems Evaluation

    Science.gov (United States)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1994-01-01

    The 'development of sensors for ceramic components in advanced propulsion systems' program is divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objective of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. Six materials, mutually agreed upon by NASA and Pratt & Whitney, were investigated under this program. This report summarizes the Phase 2 effort and provides conclusions and recommendations for each of the categories evaluated.

  5. Sensor for Measuring Strain in Textile

    Directory of Open Access Journals (Sweden)

    Gerhard Tröster

    2008-06-01

    Full Text Available In this paper a stain sensor to measure large strain (80% in textiles is presented. It consists of a mixture of 50wt-% thermoplastic elastomer (TPE and 50wt-% carbon black particles and is fiber-shaped with a diameter of 0.315mm. The attachment of the sensor to the textile is realized using a silicone film. This sensor configuration was characterized using a strain tester and measuring the resistance (extension-retraction cycles: It showed a linear resistance response to strain, a small hysteresis, no ageing effects and a small dependance on the strain velocity. The total mean error caused by all these effects was +/-5.5% in strain. Washing several times in a conventional washing machine did not influence the sensor properties. The paper finishes by showing an example application where 21 strain sensors were integrated into a catsuit. With this garment, 27 upper body postures could be recognized with an accuracy of 97%.

  6. Thin film ceramic thermocouples

    Science.gov (United States)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  7. Aerosol printed carbon nanotube strain sensor

    Science.gov (United States)

    Thompson, Bradley; Yoon, Hwan-Sik

    2012-04-01

    In recent years, printed electronics have received attention as a method to produce low-cost macro electronics on flexible substrates. In this regard, inkjet and aerosol printing have been the primary printing methods for producing passive electrical components, transistors, and a number of sensors. In this research, a custom aerosol printer was utilized to create a strain sensor capable of measuring static and dynamic strain. The proposed sensor was created by aerosol printing a multiwall carbon nanotube solution onto an aluminum beam covered with an insulating layer. After printing the carbon nanotube-based sensor, the sensor was tested under quasi-static and vibration strain conditions, and the results are presented. The results show that the printed sensor could potentially serve as an effective method for measuring dynamic strain of structural components.

  8. Review of graphene-based strain sensors

    Institute of Scientific and Technical Information of China (English)

    Zhao Jing; Zhang Guang-Yu; Shi Dong-Xia

    2013-01-01

    In this paper,we review various types of graphene-based strain sensors.Graphene is a monolayer of carbon atoms,which exhibits prominent electrical and mechanical properties and can be a good candidate in compact strain sensor applications.However,a perfect graphene is robust and has a low piezoresistive sensitivity.So scientists have been driven to increase the sensitivity using different kinds of methods since the first graphene-based strain sensor was reported.We give a comprehensive review of graphene-based strain sensors with different structures and mechanisms.It is obvious that graphene offers some advantages and has potential for the strain sensor application in the near future.

  9. Improved Internal Reference Oxygen Sensors with Composite Ceramic Electrodes

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2012-01-01

    Potentiometric oxygen sensors with an internal reference electrode, which uses the equilibrium pO2 of the binary mixture of Ni/NiO as the reference, are demonstrated. The cells employ Pt or composite ceramics as the sensing electrode. The cells are fabricated by a flexible and potentially low cost...... and performance are highly reproducible. The composite ceramics, based on strontium doped manganite and yttria doped zirconia, are proven superior over Pt to serve as the electrode material....

  10. High sensitivity knitted fabric strain sensors

    Science.gov (United States)

    Xie, Juan; Long, Hairu; Miao, Menghe

    2016-10-01

    Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

  11. Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach

    Energy Technology Data Exchange (ETDEWEB)

    Khansur, Neamul H.; Daniels, John E. [School of Materials Science and Engineering, University of New South Wales, NSW 2052 (Australia); Groh, Claudia; Jo, Wook; Webber, Kyle G. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Reinhard, Christina [Diamond Light Source, Beamline I12 JEEP, Didcot, Oxfordshire OX11 0DE (United Kingdom); Kimpton, Justin A. [The Australian Synchrotron, Clayton, Victoria 3168 (Australia)

    2014-03-28

    The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions.

  12. Atmospheric corrosion sensor based on strain measurement

    Science.gov (United States)

    Kasai, Naoya; Hiroki, Masatoshi; Yamada, Toshirou; Kihira, Hiroshi; Matsuoka, Kazumi; Kuriyama, Yukihisa; Okazaki, Shinji

    2017-01-01

    In this paper, an in situ atmospheric corrosion sensor based on strain measurement is discussed. The theoretical background for measuring the reduction in thickness of low carbon steel is also presented. Based on the theoretical considerations, a test piece and apparatus for an atmospheric corrosion sensor were designed. Furthermore, in a dry–wet cyclic accelerated exposure experiment, the measured strain indicated thinning of the test piece, although the corrosion product generated on the surface of the test piece affected the results. The atmospheric corrosion sensor would be effective for evaluating atmospheric corrosion of many types of infrastructure.

  13. Boron Rich Solids Sensors, Ultra High Temperature Ceramics, Thermoelectrics, Armor

    CERN Document Server

    Orlovskaya, Nina

    2011-01-01

    The objective of this book is to discuss the current status of research and development of boron-rich solids as sensors, ultra-high temperature ceramics, thermoelectrics, and armor. Novel biological and chemical sensors made of stiff and light-weight boron-rich solids are very exciting and efficient for applications in medical diagnoses, environmental surveillance and the detection of pathogen and biological/chemical terrorism agents. Ultra-high temperature ceramic composites exhibit excellent oxidation and corrosion resistance for hypersonic vehicle applications. Boron-rich solids are also promising candidates for high-temperature thermoelectric conversion. Armor is another very important application of boron-rich solids, since most of them exhibit very high hardness, which makes them perfect candidates with high resistance to ballistic impact. The following topical areas are presented: •boron-rich solids: science and technology; •synthesis and sintering strategies of boron rich solids; •microcantileve...

  14. Construction Of A Piezoelectric-Based Resonance Ceramic Pressure Sensor Designed For High-Temperature Applications

    OpenAIRE

    Belavič Darko; Bradeško Andraž; Zarnik Marina Santo; Rojac Tadej

    2015-01-01

    In this work the design aspects of a piezoelectric-based resonance ceramic pressure sensor made using low-temperature co-fired ceramic (LTCC) technology and designed for high-temperature applications is presented. The basic pressure-sensor structure consists of a circular, edge-clamped, deformable diaphragm that is bonded to a ring, which is part of the rigid ceramic structure. The resonance pressure sensor has an additional element – a piezoelectric actuator – for stimulating oscillation of ...

  15. Proton conducting ceramics for potentiometric hydrogen sensors for molten metals

    Energy Technology Data Exchange (ETDEWEB)

    Borland, H.; Llivina, L.; Colominas, S.; Abellà, J., E-mail: jordi.abella@iqs.edu

    2013-10-15

    Highlights: • Synthesis and chemical characterization of proton conductor ceramics. • Qualification of ceramics for hydrogen sensors in molten lithium–lead. • Ceramics have well-defined grains with a wide distribution of sizes. • Good agreement with predictions obtained with BaZrY, BaCeZrY and SrFeCo ceramics. -- Abstract: Tritium monitoring in lithium–lead eutectic (Pb–15.7Li) is of great importance for the performance of liquid blankets in fusion reactors. Also, tritium measurements will be required in order to proof tritium self-sufficiency in liquid metal breeding systems. On-line hydrogen (isotopes) sensors must be design and tested in order to accomplish these goals. Potentiometric hydrogen sensors for molten lithium–lead eutectic have been designed at the Electrochemical Methods Lab at Institut Quimic de Sarria (IQS) at Barcelona and are under development and qualification. The probes are based on the use of solid state electrolytes and works as proton exchange membranes (PEM). In this work the following compounds: BaZr{sub 0.9}Y{sub 0.1}O{sub 3}, BaCe{sub 0.6}Zr{sub 0.3}Y{sub 0.1}O{sub 3−α}, Sr(Ce{sub 0.6}-Zr{sub 0.4}){sub 0.9}Y{sub 0.1}O{sub 3−α} and Sr{sub 3}Fe{sub 1.8}Co{sub 2}O{sub 7} have been synthesized in order to be tested as PEM H-probes. Potentiometric measurements of the synthesized ceramic elements at 500 °C have been performed at a fixed hydrogen concentration. The sensors constructed using the proton conductor elements BaZr{sub 0.9}Y{sub 0.1}O{sub 3}, BaCe{sub 0.6}Zr{sub 0.3}Y{sub 0.1}O{sub 3−δ} and Sr{sub 3}Fe{sub 1.8}Co{sub 0.2}O{sub 7−δ} exhibited stable output potential and its value was close to the theoretical value calculated with the Nernst equation (deviation around 60 mV). In contrast, the sensor constructed using the proton conductor element Sr(Ce{sub 0.6}–Zr{sub 0.4}){sub 0.9}Y{sub 0.1}O{sub 3−δ} showed a deviation higher than 100 mV between experimental an theoretical data.

  16. A tunable strain sensor using nanogranular metals.

    Science.gov (United States)

    Schwalb, Christian H; Grimm, Christina; Baranowski, Markus; Sachser, Roland; Porrati, Fabrizio; Reith, Heiko; Das, Pintu; Müller, Jens; Völklein, Friedemann; Kaya, Alexander; Huth, Michael

    2010-01-01

    This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)(3)]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.

  17. A Tunable Strain Sensor Using Nanogranular Metals

    Directory of Open Access Journals (Sweden)

    Friedemann Völklein

    2010-11-01

    Full Text Available This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.

  18. A Tunable Strain Sensor Using Nanogranular Metals

    Science.gov (United States)

    Schwalb, Christian H.; Grimm, Christina; Baranowski, Markus; Sachser, Roland; Porrati, Fabrizio; Reith, Heiko; Das, Pintu; Müller, Jens; Völklein, Friedemann; Kaya, Alexander; Huth, Michael

    2010-01-01

    This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals. PMID:22163443

  19. Internal strain analysis of ceramics using scanning laser acoustic microscopy

    Science.gov (United States)

    Kent, Renee M.

    1993-01-01

    Quantitative studies of material behavior characteristics are essential for predicting the functionality of a material under its operating conditions. A nonintrusive methodology for measuring the in situ strain of small dimeter (to 11 microns) ceramic fibers under uniaxial tensile loading and the local internal strains of ceramics and ceramic composites under flexural loading is introduced. The strain measurements and experimentally observed mechanical behavior are analyzed in terms of the microstructural development and fracture behavior of each test specimen evaluated. Measurement and analysis of Nicalon silicon carbide (SiC) fiber (15 microns diameter) indicate that the mean elastic modulus of the individual fiber is 185.3 GPa. Deviations observed in the experimentally determined elastic modulus values between specimens were attributed to microstructural variations which occur during processing. Corresponding variations in the fracture surface morphology were also observed. The observed local mechanical behavior of a lithium alumino-silicate (LAS) glass ceramic, a LAS/SiC monofilament composite, and a calcium alumino-silicate (CAS)/SiC fully reinforced composite exhibits nonlinearities and apparent hysteresis due to the subcritical mechanical loading. Local hysteresis in the LAS matrices coincided with the occurrence of multiple fracture initiation sites, localized microcracking, and secondary cracking. The observed microcracking phenomenon was attributed to stress relaxation of residual stresses developed during processing, and local interaction of the crack front with the microstructure. The relaxation strain and stress predicted on apparent mechanical hysteresis effects were defined and correlated with the magnitude of the measured fracture stress for each specimen studied. This quantitative correlation indicated a repeatable measure of the stress at which matrix microcracking occurred for stress relief of each material system. Stress relaxation occurred

  20. Modeling the Stress Strain Behavior of Woven Ceramic Matrix Composites

    Science.gov (United States)

    Morscher, Gregory N.

    2006-01-01

    Woven SiC fiber reinforced SiC matrix composites represent one of the most mature composite systems to date. Future components fabricated out of these woven ceramic matrix composites are expected to vary in shape, curvature, architecture, and thickness. The design of future components using woven ceramic matrix composites necessitates a modeling approach that can account for these variations which are physically controlled by local constituent contents and architecture. Research over the years supported primarily by NASA Glenn Research Center has led to the development of simple mechanistic-based models that can describe the entire stress-strain curve for composite systems fabricated with chemical vapor infiltrated matrices and melt-infiltrated matrices for a wide range of constituent content and architecture. Several examples will be presented that demonstrate the approach to modeling which incorporates a thorough understanding of the stress-dependent matrix cracking properties of the composite system.

  1. Spatial Compressive Sensing for Strain Data Reconstruction from Sparse Sensors

    Science.gov (United States)

    2014-10-01

    Spatial Compressive Sensing for Strain Data Reconstruction from Sparse Sensors by Mulugeta A Haile ARL-TR-7126 October 2014...Spatial Compressive Sensing for Strain Data Reconstruction from Sparse Sensors Mulugeta A Haile Vehicle Technology Directorate, ARL...

  2. Thermal strain analysis of optic fiber sensors.

    Science.gov (United States)

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2013-01-31

    An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating.

  3. Thermal effects on a passive wireless antenna sensor for strain and crack sensing

    Science.gov (United States)

    Yi, Xiaohua; Vyas, Rushi; Cho, Chunhee; Fang, Chia-Hung; Cooper, James; Wang, Yang; Leon, Roberto T.; Tentzeris, Manos M.

    2012-04-01

    For application in structural health monitoring, a folded patch antenna has been previously designed as a wireless sensor that monitors strain and crack in metallic structures. Resonance frequency of the RFID patch antenna is closely related with its dimension. To measure stress concentration in a base structure, the sensor is bonded to the structure like a traditional strain gage. When the antenna sensor is under strain/deformation together with the base structure, the antenna resonance frequency varies accordingly. The strain-related resonance frequency variation is wirelessly interrogated and recorded by a reader, and can be used to derive strain/deformation. Material properties of the antenna components can have significant effects on sensor performance. This paper investigates thermal effects through both numerical simulation and temperature chamber testing. When temperature fluctuates, previous sensor design (with a glass microfiber-reinforced PTFE substrate) shows relatively large variation in resonance frequency. To improve sensor performance, a new ceramic-filled PTFE substrate material is chosen for re-designing the antenna sensor. Temperature chamber experiments are also conducted to the sensor with new substrate material, and compared with previous design.

  4. Gas Sensors Based on Ceramic p-n Heterocontacts

    Energy Technology Data Exchange (ETDEWEB)

    Seymen Murat Aygun

    2004-12-19

    Ceramic p-n heterocontacts based on CuO/ZnO were successfully synthesized and a systematic study of their hydrogen sensitivity was conducted. The sensitivity and response rates of CuO/ZnO sensors were studied utilizing current-voltage, current-time, and impedance spectroscopy measurements. The heterocontacts showed well-defined rectifying characteristics and were observed to detect hydrogen via both dc and ac measurements. Surface coverage data were derived from current-time measurements which were then fit to a two-site Langmuir adsorption model quite satisfactorily. The fit suggested that there should be two energetically different adsorption sites in the system. The heterocontacts were doped in an attempt to increase the sensitivity and the response rate of the sensor. First, the effects of doping the p-type (CuO) on the sensor characteristics were investigated. Doping the p-type CuO with both acceptor and isovalent dopants greatly improved the hydrogen sensitivity. The sensitivity of pure heterocontact observed via I-V measurements was increased from {approx}2.3 to {approx}9.4 with Ni doping. Dopants also enhanced the rectifying characteristics of the heterocontacts. Small amounts of Li addition were shown to decrease the reverse bias (saturation) current to 0.2 mA at a bias level of -5V. No unambiguous trends were observed between the sensitivity, the conductivity, and the density of the samples. Comparing the two phase microstructure to the single phase microstructure there was no dramatic increase in the sensitivity. Kinetic studies also confirmed the improved sensor characteristics with doping. The dopants decreased the response time of the sensor by decreasing the response time of one of the adsorption sites. The n-type ZnO was doped with both acceptor and donor dopants. Li doping resulted in the degradation of the p-n junction and the response time of the sensor. However, the current-voltage behavior of Ga-doped heterocontacts showed the best rectifying

  5. Gas Sensors Based on Ceramic p-n Heterocontacts

    Energy Technology Data Exchange (ETDEWEB)

    Aygun, Seymen Murat [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Ceramic p-n heterocontacts based on CuO/ZnO were successfully synthesized and a systematic study of their hydrogen sensitivity was conducted. The sensitivity and response rates of CuO/ZnO sensors were studied utilizing current-voltage, current-time, and impedance spectroscopy measurements. The heterocontacts showed well-defined rectifying characteristics and were observed to detect hydrogen via both dc and ac measurements. Surface coverage data were derived from current-time measurements which were then fit to a two-site Langmuir adsorption model quite satisfactorily. The fit suggested that there should be two energetically different adsorption sites in the system. The heterocontacts were doped in an attempt to increase the sensitivity and the response rate of the sensor. First, the effects of doping the p-type (CuO) on the sensor characteristics were investigated. Doping the p-type CuO with both acceptor and isovalent dopants greatly improved the hydrogen sensitivity. The sensitivity of pure heterocontact observed via I-V measurements was increased from ~2.3 to ~9.4 with Ni doping. Dopants also enhanced the rectifying characteristics of the heterocontacts. Small amounts of Li addition were shown to decrease the reverse bias (saturation) current to 0.2 mA at a bias level of -5V. No unambiguous trends were observed between the sensitivity, the conductivity, and the density of the samples. Comparing the two phase microstructure to the single phase microstructure there was no dramatic increase in the sensitivity. Kinetic studies also confirmed the improved sensor characteristics with doping. The dopants decreased the response time of the sensor by decreasing the response time of one of the adsorption sites. The n-type ZnO was doped with both acceptor and donor dopants. Li doping resulted in the degradation of the p-n junction and the response time of the sensor. However, the current-voltage behavior of Ga-doped heterocontacts showed the best rectifying characteristics

  6. Corrosion induced strain monitoring through fibre optic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Grattan, S K T [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Belfast, BT9 5AG (United Kingdom); Basheer, P A M [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Belfast, BT9 5AG (United Kingdom); Taylor, S E [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Belfast, BT9 5AG (United Kingdom); Zhao, W [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom); Sun, T [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom); Grattan, K T V [School of Engineering and Mathematical Sciences, City University, Northampton Square, London, EC1V 0HB (United Kingdom)

    2007-10-15

    The use of strain sensors is commonplace within civil engineering. Fibre optic strain sensors offer a number of advantages over the current electrical resistance type gauges. In this paper the use of fibre optic strain sensors and electrical resistance gauges to monitor the production of corrosion by-products has been investigated and reported.

  7. Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

    Directory of Open Access Journals (Sweden)

    Ali Tavassolizadeh

    2016-11-01

    Full Text Available Magnetostrictive tunnel magnetoresistance (TMR sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJs with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of −3.2 kA/m under a 0.2 × 10 - 3 strain, gauge factors of 2294 and −311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μ m using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150 ± 30 and −260 for tensile and compressive stresses, respectively, under a −3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

  8. Modeling of a Surface Acoustic Wave Strain Sensor

    Science.gov (United States)

    Wilson, W. C.; Atkinson, Gary M.

    2010-01-01

    NASA Langley Research Center is investigating Surface Acoustic Wave (SAW) sensor technology for harsh environments aimed at aerospace applications. To aid in development of sensors a model of a SAW strain sensor has been developed. The new model extends the modified matrix method to include the response of Orthogonal Frequency Coded (OFC) reflectors and the response of SAW devices to strain. These results show that the model accurately captures the strain response of a SAW sensor on a Langasite substrate. The results of the model of a SAW Strain Sensor on Langasite are presented

  9. Strain monitoring of bismaleimide composites using embedded microcavity sensor

    Science.gov (United States)

    Kaur, Amardeep; Anandan, Sudharshan; Yuan, Lei; Watkins, Steve E.; Chandrashekhara, K.; Xiao, Hai; Phan, Nam

    2016-03-01

    A type of extrinsic Fabry-Perot interferometer (EFPI) fiber optic sensor, i.e., the microcavity strain sensor, is demonstrated for embedded, high-temperature applications. The sensor is fabricated using a femtosecond (fs) laser. The fs-laser-based fabrication makes the sensor thermally stable to sustain operating temperatures as high as 800°C. The sensor has low sensitivity toward the temperature as compared to its response toward the applied strain. The performance of the EFPI sensor is tested in an embedded application. The host material is carbon fiber/bismaleimide (BMI) composite laminate that offer thermally stable characteristics at high ambient temperatures. The sensor exhibits highly linear response toward the temperature and strain. Analytical work done with embedded optical-fiber sensors using the out-of-autoclave BMI laminate was limited until now. The work presented in this paper offers an insight into the strain and temperature interactions of the embedded sensors with the BMI composites.

  10. Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.

    Science.gov (United States)

    Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin

    2016-03-01

    There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.

  11. Characterization of Integrated Optical Strain Sensors Based on Silicon Waveguides

    NARCIS (Netherlands)

    Westerveld, W.J.; Leinders, S.M.; Muilwijk, P.M.; Pozo, J.

    2013-01-01

    Microscale strain gauges are widely used in micro electro-mechanical systems (MEMS) to measure strains such as those induced by force, acceleration, pressure or sound. We propose all-optical strain sensors based on micro-ring resonators to be integrated with MEMS. We characterized the strain-induced

  12. Ceramic-polymer capacitive sensors for tactile/force awareness in harsh environment robotic applications

    Science.gov (United States)

    Weadon, Timothy L.; Evans, Thomas H.; Sabolsky, Edward M.

    2013-12-01

    The need for force feedback and spatial awareness of contact in harsh environment applications, such as space servicing, has been unsatisfied due to the inability of current sensor technology to resist environmental effects. In this work, capacitive sensors based on a thick film 0:3 connectivity ceramic:polymer composite structure were evaluated for potential use in future operations within robotic end effectors, withstanding temperatures ranging from -80 ° C to 120 ° C and forces up to 350 kPa. A thick film design is utilized to allow for ease of embedding, allowing sensors to be implemented into exciting robotic hardware with minimal intrusion, and protecting sensors from electron bombardment, radiation, and point concentrations from metal-on-metal contact. Taguchi design of experiments allows composition variables including sensor thickness, ceramic composition, ceramic particle size, ceramic volume loading, polymer character, modifier character, and the polymer:modifier ratio to be evaluated simultaneously. Dynamic thermal and mechanical loading techniques were implemented to characterize the composite sensors with in situ electrical acquisition. Individual composition variables were linked to the sensor magnitude, sensitivity, drift, and hysteresis, showing that the sensor response is optimized with a thickness of single microns, 10 vol% loading of nano-particle ceramics, and high molecular weight polymers with a low content of simple architecture modifiers lacking glass or melting temperatures in the working range.

  13. A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

    Directory of Open Access Journals (Sweden)

    Waris Obitayo

    2012-01-01

    Full Text Available 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.

  14. Thin Film Heat Flux Sensor Development for Ceramic Matrix Composite (CMC) Systems

    Science.gov (United States)

    Wrbanek, John D.; Fralick, Gustave C.; Hunter, Gary W.; Zhu, Dongming; Laster, Kimala L.; Gonzalez, Jose M.; Gregory, Otto J.

    2010-01-01

    The NASA Glenn Research Center (GRC) has an on-going effort for developing high temperature thin film sensors for advanced turbine engine components. Stable, high temperature thin film ceramic thermocouples have been demonstrated in the lab, and novel methods of fabricating sensors have been developed. To fabricate thin film heat flux sensors for Ceramic Matrix Composite (CMC) systems, the rough and porous nature of the CMC system posed a significant challenge for patterning the fine features required. The status of the effort to develop thin film heat flux sensors specifically for use on silicon carbide (SiC) CMC systems with these new technologies is described.

  15. Strain localization in compressed ZrO2(Y2O3) ceramics

    Science.gov (United States)

    Barannikova, S. A.; Buyakova, S. P.; Zuev, L. B.; Kul'Kov, S. N.

    2007-06-01

    Spatiotemporal distributions of local components of the distortion tensor of a nonplastic material—yttria partially stabilized tetragonal zirconia (YTZ) ceramics—have been studied under active compressive straining conditions using double-exposure speckle photography techniques. The strain localization patterns are presented and the features of macroscopic strain inhomogeneity in the elastic state of YTZ ceramics are considered.

  16. Development of a Wireless Temperature Sensor Using Polymer-Derived Ceramics

    Directory of Open Access Journals (Sweden)

    Ran Zhao

    2016-01-01

    Full Text Available A temperature sensor has been developed using an embedded system and a sensor head made of polymer-derived SiAlCN ceramics (PDCs. PDC is a promising material for measuring high temperature and the embedded system features low-power consumption, compact size, and wireless transmission. The developed temperature sensor has been experimentally tested to demonstrate the possibility of using such sensors for real world applications.

  17. High-Temperature SAW Wireless Strain Sensor with Langasite.

    Science.gov (United States)

    Shu, Lin; Peng, Bin; Yang, Zhengbing; Wang, Rui; Deng, Senyang; Liu, Xingzhao

    2015-11-11

    Two Surface acoustic wave (SAW) resonators were fabricated on langasite substrates with Euler angle of (0°, 138.5°, 117°) and (0°, 138.5°, 27°). A dipole antenna was bonded to the prepared SAW resonator to form a wireless sensor. The characteristics of the SAW sensors were measured by wireless frequency domain interrogation methods from 20 °C to 600 °C. Different temperature behaviors of the sensors were observed. Strain sensing was achieved using a cantilever configuration. The sensors were measured under applied strain from 20 °C to 500 °C. The shift of the resonance frequency contributed merely by strain is extracted from the combined effects of temperature and strain. Both the strain factors of the two SAW sensors increase with rising ambient temperature, and the SAW sensor deposited on (0°, 138.5°, 117°) cut is more sensitive to applied strain. The measurement errors of the two sensors are also discussed. The relative errors of the two sensors are between 0.63% and 2.09%. Even at 500 °C, the hysteresis errors of the two sensors are less than 5%.

  18. High-Temperature SAW Wireless Strain Sensor with Langasite

    Directory of Open Access Journals (Sweden)

    Lin Shu

    2015-11-01

    Full Text Available Two Surface acoustic wave (SAW resonators were fabricated on langasite substrates with Euler angle of (0°, 138.5°, 117° and (0°, 138.5°, 27°. A dipole antenna was bonded to the prepared SAW resonator to form a wireless sensor. The characteristics of the SAW sensors were measured by wireless frequency domain interrogation methods from 20 °C to 600 °C. Different temperature behaviors of the sensors were observed. Strain sensing was achieved using a cantilever configuration. The sensors were measured under applied strain from 20 °C to 500 °C. The shift of the resonance frequency contributed merely by strain is extracted from the combined effects of temperature and strain. Both the strain factors of the two SAW sensors increase with rising ambient temperature, and the SAW sensor deposited on (0°, 138.5°, 117° cut is more sensitive to applied strain. The measurement errors of the two sensors are also discussed. The relative errors of the two sensors are between 0.63% and 2.09%. Even at 500 °C, the hysteresis errors of the two sensors are less than 5%.

  19. Characterization of ceramic materials for electrochemical hydrogen sensors

    Energy Technology Data Exchange (ETDEWEB)

    Serret, P.; Colominas, S. [Electrochemical Methods Laboratory - Analytical Chemistry Department ETS Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta, 390, 08017 Barcelona (Spain); Reyes, G. [Industrial Engineering Department ETS Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta, 390, 08017 Barcelona (Spain); Abella, J., E-mail: jordi.abella@iqs.es [Electrochemical Methods Laboratory - Analytical Chemistry Department ETS Institut Quimic de Sarria, Universitat Ramon Llull, Via Augusta, 390, 08017 Barcelona (Spain)

    2011-10-15

    Accurate and reliable tritium management is of basic importance for the correct operation conditions of the blanket tritium cycle. The Electrochemical Methods Lab at Institut Quimic de Sarria (IQS) is working in the design and development of tritium sensors, based on proton solid state electrolytes to be used in molten lithium-lead eutectic. Different solid electrolyte proton conductors have been synthesized (Sr{sub 3}CaZr{sub 0.9}Ta{sub 1.1}O{sub 8.55}, SrCe{sub 0.95}Yb{sub 0.05}O{sub 3-{alpha}}, CaZr{sub 0.9}In{sub 0.1}O{sub 3-{alpha}}, Ba{sub 3}(Ca{sub 1.18}Nb{sub 1.82})O{sub 9-{alpha}}) in order to be evaluated in a testing apparatus for hydrogen gas. Potentiometric measurements of the synthesized ceramic elements have been performed. In all experiments the working temperature was 500 {sup o}C. The sensors constructed using the proton conductor element Sr{sub 3}CaZr{sub 0.9}Ta{sub 1.1}O{sub 8.55} exhibited stable output potential and its value was close to the theoretical value calculated with the Nernst equation. When the proton conductor elements SrCe{sub 0.95}Yb{sub 0.05}O{sub 3-{alpha}} and CaZr{sub 0.9}In{sub 0.1}O{sub 3-{alpha}} and Ba{sub 3}(Ca{sub 1.18}Nb{sub 1.82})O{sub 9-{alpha}} were used a deviation higher than 100 mV between theoretical and experimental data was obtained.

  20. Flexible Bond Wire Capacitive Strain Sensor for Vehicle Tyres

    Directory of Open Access Journals (Sweden)

    Siyang Cao

    2016-06-01

    Full Text Available The safety of the driving experience and manoeuvrability of a vehicle can be improved by detecting the strain in tyres. To measure strain accurately in rubber, the strain sensor needs to be flexible so that it does not deform the medium that it is measuring. In this work, a novel flexible bond wire capacitive strain sensor for measuring the strain in tyres is developed, fabricated and calibrated. An array of 25 micron diameter wire bonds in an approximately 8 mm × 8 mm area is built to create an interdigitated structure, which consists of 50 wire loops resulting in 49 capacitor pairs in parallel. Laser machining was used to pattern copper on a flexible printed circuit board PCB to make the bond pads for the wire attachment. The wire array was finally packaged and embedded in polydimethylsiloxane (PDMS, which acts as the structural material that is strained. The capacitance of the device is in a linear like relationship with respect to the strain, which can measure the strain up to at least ±60,000 micro-strain (±6% with a resolution of ~132 micro-strain (0.013%. In-tyre testing under static loading has shown the ability of the sensor to measure large tyre strains. The technology used for sensor fabrication lends itself to mass production and so the design is considered to be consistent with low cost commercialisable strain sensing technology.

  1. On the use of strain sensor technologies for strain modal analysis: Case studies in aeronautical applications

    Science.gov (United States)

    Marques dos Santos, Fábio Luis; Peeters, Bart

    2016-10-01

    This paper discusses the use of optical fiber Bragg grating (FBG) and piezo strain sensors for structural dynamic measurements. For certain industrial applications, there is an interest to use strain sensors rather than in combination with accelerometers for experimental modal analysis. Classical electrical strain gauges can be used hereto, but other types of strain sensors are an interesting alternative with some very specific advantages. This work gives an overview of two types of dynamic strain sensors, applied to two industrial applications (a helicopter main rotor blade and an F-16 aircraft), FBG sensors and dynamic piezo strain sensors, discussing their use and benefits. Moreover, the concept of strain modal analysis is introduced and it is shown how it can be beneficial to apply strain measurements to experimental modal analysis. Finally, experimental results for the two applications are shown, with an experimental modal analysis carried out on the helicopter main rotor blade using FBG sensors and a similar experiment is done with the aircraft but using piezo strain sensors instead.

  2. Flexible Carbon Nanotube Films for High Performance Strain Sensors

    Directory of Open Access Journals (Sweden)

    Olfa Kanoun

    2014-06-01

    Full Text Available Compared with traditional conductive fillers, carbon nanotubes (CNTs have unique advantages, i.e., excellent mechanical properties, high electrical conductivity and thermal stability. Nanocomposites as piezoresistive films provide an interesting approach for the realization of large area strain sensors with high sensitivity and low manufacturing costs. A polymer-based nanocomposite with carbon nanomaterials as conductive filler can be deposited on a flexible substrate of choice and this leads to mechanically flexible layers. Such sensors allow the strain measurement for both integral measurement on a certain surface and local measurement at a certain position depending on the sensor geometry. Strain sensors based on carbon nanostructures can overcome several limitations of conventional strain sensors, e.g., sensitivity, adjustable measurement range and integral measurement on big surfaces. The novel technology allows realizing strain sensors which can be easily integrated even as buried layers in material systems. In this review paper, we discuss the dependence of strain sensitivity on different experimental parameters such as composition of the carbon nanomaterial/polymer layer, type of polymer, fabrication process and processing parameters. The insights about the relationship between film parameters and electromechanical properties can be used to improve the design and fabrication of CNT strain sensors.

  3. Ultrasensitive, Stretchable Strain Sensors Based on Fragmented Carbon Nanotube Papers

    KAUST Repository

    Zhou, Jian

    2017-01-17

    The development of strain sensors featuring both ultra high sensitivity and high stretchability is still a challenge. We demonstrate that strain sensors based on fragmented single-walled carbon nanotube (SWCNT) paper embedded in poly(dimethylsiloxane) (PDMS) can sustain their sensitivity even at very high strain levels (with a gauge factor of over 10(7) at 50% strain). This record sensitivity is ascribed to the low initial electrical resistance (5-28 Omega) of the SWCNT paper and the wide change in resistance (up to 10(6) Omega) governed by the percolated network of SWCNT in the cracked region. The sensor response remains nearly unchanged after 10 000 strain cycles at 20% proving the robustness of this technology. This fragmentation based sensing system brings opportunities to engineer highly sensitive stretchable sensors.

  4. Fiber Optic Strain Sensor for Planetary Gear Diagnostics

    Science.gov (United States)

    Kiddy, Jason S.; Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    This paper presents a new sensing approach for helicopter damage detection in the planetary stage of a helicopter transmission based on a fiber optic strain sensor array. Complete helicopter transmission damage detection has proven itself a difficult task due to the complex geometry of the planetary reduction stage. The crowded and complex nature of the gearbox interior does not allow for attachment of sensors within the rotating frame. Hence, traditional vibration-based diagnostics are instead based on measurements from externally mounted sensors, typically accelerometers, fixed to the gearbox exterior. However, this type of sensor is susceptible to a number of external disturbances that can corrupt the data, leading to false positives or missed detection of potentially catastrophic faults. Fiber optic strain sensors represent an appealing alternative to the accelerometer. Their small size and multiplexibility allows for potentially greater sensing resolution and accuracy, as well as redundancy, when employed as an array of sensors. The work presented in this paper is focused on the detection of gear damage in the planetary stage of a helicopter transmission using a fiber optic strain sensor band. The sensor band includes an array of 13 strain sensors, and is mounted on the ring gear of a Bell Helicopter OH-58C transmission. Data collected from the sensor array is compared to accelerometer data, and the damage detection results are presented

  5. Ceramic thermal wind sensor based on advanced direct chip attaching package

    Science.gov (United States)

    Lin, Zhou; Ming, Qin; Shengqi, Chen; Bei, Chen

    2014-07-01

    An advanced direct chip attaching packaged two-dimensional ceramic thermal wind sensor is studied. The thermal wind sensor chip is fabricated by metal lift-off processes on the ceramic substrate. An advanced direct chip attaching (DCA) packaging is adopted and this new packaged method simplifies the processes of packaging further. Simulations of the advanced DCA packaged sensor based on computational fluid dynamics (CFD) model show the sensor can detect wind speed and direction effectively. The wind tunnel testing results show the advanced DCA packaged sensor can detect the wind direction from 0° to 360° and wind speed from 0 to 20 m/s with the error less than 0.5 m/s. The nonlinear fitting based least square method in Matlab is used to analyze the performance of the sensor.

  6. Construction Of A Piezoelectric-Based Resonance Ceramic Pressure Sensor Designed For High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Belavič Darko

    2015-09-01

    Full Text Available In this work the design aspects of a piezoelectric-based resonance ceramic pressure sensor made using low-temperature co-fired ceramic (LTCC technology and designed for high-temperature applications is presented. The basic pressure-sensor structure consists of a circular, edge-clamped, deformable diaphragm that is bonded to a ring, which is part of the rigid ceramic structure. The resonance pressure sensor has an additional element – a piezoelectric actuator – for stimulating oscillation of the diaphragm in the resonance-frequency mode. The natural resonance frequency is dependent on the diaphragm construction (i.e., its materials and geometry and on the actuator. This resonance frequency then changes due to the static deflection of the diaphragm caused by the applied pressure. The frequency shift is used as the output signal of the piezoelectric resonance pressure sensor and makes it possible to measure the static pressure. The characteristics of the pressure sensor also depend on the temperature, i.e., the temperature affects both the ceramic structure (its material and geometry and the properties of the actuator. This work is focused on the ceramic structure, while the actuator will be investigated later.

  7. A New Theoretical Model of a Carbon Nanotube Strain Sensor

    Institute of Scientific and Technical Information of China (English)

    QIU Wei; KANG Yi-Lan; LEI Zhen-Kun; QIN Qing-Hua; LI Qiu

    2009-01-01

    Carbon nanotubes (CNTs) are potential strain sensors due to their excellent mechanical and spectral properties.A new theoretical model of a CNT strain sensor is obtained by applying the polarized Raman properties of CNTs,which calculates the synthetic contributions of Raman spectra from the CNTs in random directions.By using this theoretical model,the analytic relationship between planar strain components and the Raman shift increment of uniformly dispersed CNTs is obtained,which is applicable for accurately characterizing the strain in random directions on the surface of a measured microsystem.

  8. Carbon nanotube strain sensors for wearable patient monitoring applications

    Science.gov (United States)

    Abraham, Jose K.; Aryasomayajula, Lavanya; Whitchurch, Ashwin; Varadan, Vijay K.

    2008-03-01

    Wearable health monitoring systems have recently attracted widespread interest for their application in long term patient monitoring. Wireless wearable technology enables continuous observation of patients while they perform their normal everyday activities. This involves the development of flexible and conformable sensors that could be easily integrated to the smart fabrics. Carbon nanotubes are found to be one of the ideal candidate materials for the design of multifunctional e-textiles because of their capability to change conductance based on any mechanical deformation as well as surface functionalization. This paper presents the development and characterization of a carbon nanotube (CNT)-polymer nanocomposite flexible strain sensor for wearable health monitoring applications. These strain sensors can be used to measure the respiration rhythm which is a vital signal required in health monitoring. A number of strain sensor prototypes with different CNT compositions have been fabricated and their characteristics for both static as well as dynamic strain have been measured.

  9. Characterization of optical strain sensors based on silicon waveguides

    NARCIS (Netherlands)

    Westerveld, W.J.; Pozo Torres, J.M.; Muilwijk, P.M.; Leinders, S.M.; Harmsma, P.J.; Tabak, E.; Dool, T.C. van den; Dongen, K.W.A. van; Yousefi, M.; Urbach, H.P.

    2013-01-01

    Strain gauges are widely employed in microelectromechanical systems (MEMS) for sensing of, for example, deformation, acceleration, pressure, or sound [1]. Such gauges are typically based on electronic piezoresistivity. We propose integrated optical sensors which have particular benefits: insensitivi

  10. Wireless Zigbee strain gage sensor system for structural health monitoring

    Science.gov (United States)

    Ide, Hiroshi; Abdi, Frank; Miraj, Rashid; Dang, Chau; Takahashi, Tatsuya; Sauer, Bruce

    2009-05-01

    A compact cell phone size radio frequency (ZigBee) wireless strain measurement sensor system to measure the structural strain deformation was developed. The developed system provides an accurate strain measurement data stream to the Internet for further Diagnostic and Prognostic (DPS) correlation. Existing methods of structural measurement by strain sensors (gauges) do not completely satisfy problems posed by continuous structural health monitoring. The need for efficient health monitoring methods with real-time requirements to bidirectional data flow from sensors and to a commanding device is becoming critical for keeping our daily life safety. The use of full-field strain measurement techniques could reduce costly experimental programs through better understanding of material behavior. Wireless sensor-network technology is a monitoring method that is estimated to grow rapidly providing potential for cost savings over traditional wired sensors. The many of currently available wireless monitoring methods have: the proactive and constant data rate character of the data streams rather than traditional reactive, event-driven data delivery; mostly static node placement on structures with limited number of nodes. Alpha STAR Electronics' wireless sensor network system, ASWN, addresses some of these deficiencies, making the system easier to operate. The ASWN strain measurement system utilizes off-the-shelf sensors, namely strain gauges, with an analog-to-digital converter/amplifier and ZigBee radio chips to keep cost lower. Strain data is captured by the sensor, converted to digital form and delivered to the ZigBee radio chip, which in turn broadcasts the information using wireless protocols to a Personal Data Assistant (PDA) or Laptop/Desktop computers. From here, data is forwarded to remote computers for higher-level analysis and feedback using traditional cellular and satellite communication or the Ethernet infrastructure. This system offers a compact size, lower cost

  11. Alumina ceramic based high-temperature performance of wireless passive pressure sensor

    Science.gov (United States)

    Wang, Bo; Wu, Guozhu; Guo, Tao; Tan, Qiulin

    2016-12-01

    A wireless passive pressure sensor equivalent to inductive-capacitive (LC) resonance circuit and based on alumina ceramic is fabricated by using high temperature sintering ceramic and post-fire metallization processes. Cylindrical copper spiral reader antenna and insulation layer are designed to realize the wireless measurement for the sensor in high temperature environment. The high temperature performance of the sensor is analyzed and discussed by studying the phase-frequency and amplitude-frequency characteristics of reader antenna. The average frequency change of sensor is 0.68 kHz/°C when the temperature changes from 27°C to 700°C and the relative change of twice measurements is 2.12%, with high characteristic of repeatability. The study of temperature-drift characteristic of pressure sensor in high temperature environment lays a good basis for the temperature compensation methods and insures the pressure signal readout accurately.

  12. Alumina ceramic based high-temperature performance of wireless passive pressure sensor

    Science.gov (United States)

    Wang, Bo; Wu, Guozhu; Guo, Tao; Tan, Qiulin

    2016-07-01

    A wireless passive pressure sensor equivalent to inductive-capacitive (LC) resonance circuit and based on alumina ceramic is fabricated by using high temperature sintering ceramic and post-fire metallization processes. Cylindrical copper spiral reader antenna and insulation layer are designed to realize the wireless measurement for the sensor in high temperature environment. The high temperature performance of the sensor is analyzed and discussed by studying the phase-frequency and amplitude-frequency characteristics of reader antenna. The average frequency change of sensor is 0.68 kHz/°C when the temperature changes from 27°C to 700°C and the relative change of twice measurements is 2.12%, with high characteristic of repeatability. The study of temperature-drift characteristic of pressure sensor in high temperature environment lays a good basis for the temperature compensation methods and insures the pressure signal readout accurately.

  13. Piezoelectric ceramic-polymer composites for weigh-in-motion sensors

    Science.gov (United States)

    Panda, Rajesh K.; Szary, Patrick J.; Maher, Ali; Safari, Ahmad

    1998-07-01

    Piezoelectric materials produce a voltage proportional to an applied pressure. Using this phenomenon, piezoelectric polymer sensors are already being used for collecting traffic data including weight-in-motion, measuring speeds and counting axles. The polymer sensors are usually in the form of a long tape or cable embedded within long blocks of elastomeric material. These sensor assemblies are then installed into grooves, which are cut into roads perpendicular to the traffic flow. The biggest disadvantage of these sensors is that the piezoelectric output is not uniform with temperature, thus leading to large uncertainty in the data collected. Piezoelectric ceramics have a much more stable response over a large temperature range. However, until now they have not been used for traffic data sensors because of their inherent brittleness. In this research project flexible ceramic/polymer composite strips have been fabricated for use as piezoelectric sensors for measuring large vehicle loads. Here, the ceramic is the active piezoelectric material that is embedded in a flexible non-piezoelectric polymer. After encapsulating these sensors in elastomeric blocks in aluminum channels, the voltage output of the composite for different loads have been determined. Also, these composite sensor assemblies are being installed on a test road in order to perform actual measurements.

  14. SVAS3: Strain Vector Aided Sensorization of Soft Structures

    Directory of Open Access Journals (Sweden)

    Utku Culha

    2014-07-01

    Full Text Available Soft material structures exhibit high deformability and conformability which can be useful for many engineering applications such as robots adapting to unstructured and dynamic environments. However, the fact that they have almost infinite degrees of freedom challenges conventional sensory systems and sensorization approaches due to the difficulties in adapting to soft structure deformations. In this paper, we address this challenge by proposing a novel method which designs flexible sensor morphologies to sense soft material deformations by using a functional material called conductive thermoplastic elastomer (CTPE. This model-based design method, called Strain Vector Aided Sensorization of Soft Structures (SVAS3, provides a simulation platform which analyzes soft body deformations and automatically finds suitable locations for CTPE-based strain gauge sensors to gather strain information which best characterizes the deformation. Our chosen sensor material CTPE exhibits a set of unique behaviors in terms of strain length electrical conductivity, elasticity, and shape adaptability, allowing us to flexibly design sensor morphology that can best capture strain distributions in a given soft structure. We evaluate the performance of our approach by both simulated and real-world experiments and discuss the potential and limitations.

  15. An ionic liquid based strain sensor for large displacement measurement.

    Science.gov (United States)

    Keulemans, Grim; Ceyssens, Frederik; Puers, Robert

    2017-03-01

    A robust and low cost ionic liquid based strain sensor is fabricated for high strain measurements in biomedical applications (up to 40 % and higher). A tubular 5 mm long silicone microchannel with an inner diameter of 310 µm and an outer diameter of 650 µm is filled with an ionic liquid. Three ionic liquids have been investigated: 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, ethylammonium nitrate and cholinium ethanoate. When the channel is axially stretched, geometrical deformations change the electrical impedance of the liquid channel. The sensors display a linear response and low hysteresis with an average gauge factors of 1.99 for strains up to 40 %. Additionally, to fix the sensor by surgical stitching to soft biological tissue, a sensor with tube clamps consisting of photopatternable SU-8 epoxy-based resin is proposed.

  16. Dynamic Strain and Crack Monitoring Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of condition-based monitoring sensor network systems has the potential to provide an enhanced aircraft safety by real time assessment of the...

  17. Dynamic Strain and Crack Monitoring Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a new automated vehicle health monitoring sensor system capable of measuring loads and detecting crack, corrosion, and...

  18. Soft metal constructs for large strain sensor membrane

    Science.gov (United States)

    Michaud, Hadrien O.; Teixidor, Joan; Lacour, Stéphanie P.

    2015-03-01

    Thin gold films on silicone display large reversible change in electrical resistance upon stretching. Eutectic liquid metal conductors maintain bulk metal conductivity, even upon extensive elongation. When integrated together, the soft metals enable multidirectional, large strain sensor skin. Their fabrication process combines thermal evaporation of thin gold film patterns through stencil mask with microplotting of eutectic gallium indium microwires, and packaging in silicone rubber. Using three-element rectangular rosettes, we demonstrate a sensor skin that can reliably and locally quantify the plane strain vector in surfaces subject to stretch (up to 50% strain) and indentation. This hybrid technology will find applications in soft robotics, prosthetics and wearable health monitoring systems.

  19. Optical fiber strain sensor with improved linearity range

    Science.gov (United States)

    Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)

    1995-01-01

    A strain sensor is constructed from a two mode optical fiber. When the optical fiber is surface mounted in a straight line and the object to which the optical fiber is mounted is subjected to strain within a predetermined range, the light intensity of any point at the output of the optical fiber will have a linear relationship to strain, provided the intermodal phase difference is less than 0.17 radians.

  20. High-Temperature SAW Wireless Strain Sensor with Langasite

    OpenAIRE

    Lin Shu; Bin Peng; Zhengbing Yang; Rui Wang; Senyang Deng; Xingzhao Liu

    2015-01-01

    Two Surface acoustic wave (SAW) resonators were fabricated on langasite substrates with Euler angle of (0°, 138.5°, 117°) and (0°, 138.5°, 27°). A dipole antenna was bonded to the prepared SAW resonator to form a wireless sensor. The characteristics of the SAW sensors were measured by wireless frequency domain interrogation methods from 20 °C to 600 °C. Different temperature behaviors of the sensors were observed. Strain sensing was achieved using a cantilever configuration. The sensors were ...

  1. Modeling of stress/strain behavior of fiber-reinforced ceramic matrix composites including stress redistribution

    Science.gov (United States)

    Mital, Subodh K.; Murthy, Pappu L. N.; Chamis, Christos C.

    1994-01-01

    A computational simulation procedure is presented for nonlinear analyses which incorporates microstress redistribution due to progressive fracture in ceramic matrix composites. This procedure facilitates an accurate simulation of the stress-strain behavior of ceramic matrix composites up to failure. The nonlinearity in the material behavior is accounted for at the constituent (fiber/matrix/interphase) level. This computational procedure is a part of recent upgrades to CEMCAN (Ceramic Matrix Composite Analyzer) computer code. The fiber substructuring technique in CEMCAN is used to monitor the damage initiation and progression as the load increases. The room-temperature tensile stress-strain curves for SiC fiber reinforced reaction-bonded silicon nitride (RBSN) matrix unidirectional and angle-ply laminates are simulated and compared with experimentally observed stress-strain behavior. Comparison between the predicted stress/strain behavior and experimental stress/strain curves is good. Collectively the results demonstrate that CEMCAN computer code provides the user with an effective computational tool to simulate the behavior of ceramic matrix composites.

  2. Online, In-Situ Monitoring Combustion Turbines Using Wireless Passive Ceramic Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xun; An, Linan; Xu, Chengying

    2013-06-30

    The overall objective of this project is to develop high-temperature wireless passive ceramic sensors for online, real-time monitoring combustion turbines. During this project period, we have successfully demonstrated temperature sensors up to 1300{degrees}C and pressure sensors up to 800oC. The temperature sensor is based on a high-Q-factor dielectric resonator and the pressure sensor utilizes the evanescent-mode cavity to realize a pressure-sensitive high-Q-factor resonator. Both sensors are efficiently integrated with a compact antenna. These sensors are wirelessly interrogated. The resonant frequency change corresponding to either temperature or pressure can be identified using a time-domain gating technique. The sensors realized in this project can survive harsh environments characterized by high temperatures (>1000{degrees}C) and corrosive gases, owing to the excellent material properties of polymer-derived ceramics (PDCs) developed at University of Central Florida. It is anticipated that this work will significantly advance the capability of high-temperature sensor technologies and be of a great benefit to turbine industry and their customers.

  3. Flexible strain sensor based on carbon nanotube rubber composites

    Science.gov (United States)

    Kim, Jin-Ho; Kim, Young-Ju; Baek, Woon Kyung; Lim, Kwon Taek; Kang, Inpil

    2010-04-01

    Electrically conducting rubber composites (CRC) with carbon nanotubes (CNTs) filler have received much attention as potential materials for sensors. In this work, Ethylene propylene diene M-class rubber (EPDM)/CNT composites as a novel nano sensory material were prepared to develop flexible strain sensors that can measure large deformation of flexible structures. The EPDM/CNT composites were prepared by using a Brabender mixer with multi-walled CNTs and organo-clay. A strain sensor made of EPDM/CNT composite was attached to the surface of a flexible beam and change of resistance of the strain sensor was measured with respect to the beam deflection. Resistance of the sensor was change quite linearly under the bending and compressive large beam deflection. Upon external forces, CRC deformation takes place with the micro scale change of inter-electrical condition in rubber matrix due to the change of contact resistance, and CRC reveals macro scale piezoresistivity. It is anticipated that the CNT/EPDM fibrous strain sensor can be eligible to develop a biomimetic artificial neuron that can continuously sense deformation, pressure and shear force.

  4. POF strain sensor using phase measurement techniques

    Science.gov (United States)

    Poisel, H.

    2008-03-01

    Polymer optical fiber (POF) elongation sensors have been proposed e.g. by Doering as a low-cost alternative to FBG (single mode Fiber Bragg Gratings) sensors targeting the lower sensitivity range. A recently recovered detection system known from laser distance meters turned out to be very sensitive while staying simple and thus offering low cost potential. The approach is based on measuring the phase shift of a (e.g. sinusoidally) modulated light signal guided in a POF under different tensions resulting in different transit times and thus different phase shifts.

  5. High Sensitivity MEMS Strain Sensor: Design and Simulation

    Directory of Open Access Journals (Sweden)

    Edmond Lou

    2008-04-01

    Full Text Available In this article, we report on the new design of a miniaturized strain microsensor. The proposed sensor utilizes the piezoresistive properties of doped single crystal silicon. Employing the Micro Electro Mechanical Systems (MEMS technology, high sensor sensitivities and resolutions have been achieved. The current sensor design employs different levels of signal amplifications. These amplifications include geometric, material and electronic levels. The sensor and the electronic circuits can be integrated on a single chip, and packaged as a small functional unit. The sensor converts input strain to resistance change, which can be transformed to bridge imbalance voltage. An analog output that demonstrates high sensitivity (0.03mV/me, high absolute resolution (1μe and low power consumption (100μA with a maximum range of ±4000μe has been reported. These performance characteristics have been achieved with high signal stability over a wide temperature range (±50oC, which introduces the proposed MEMS strain sensor as a strong candidate for wireless strain sensing applications under harsh environmental conditions. Moreover, this sensor has been designed, verified and can be easily modified to measure other values such as force, torque…etc. In this work, the sensor design is achieved using Finite Element Method (FEM with the application of the piezoresistivity theory. This design process and the microfabrication process flow to prototype the design have been presented.

  6. Fibre optic Bragg grating sensors: an alternative method to strain gauges for measuring deformation in bone.

    Science.gov (United States)

    Fresvig, T; Ludvigsen, P; Steen, H; Reikerås, O

    2008-01-01

    Strain gauges are currently the default method for measuring deformation in bone. Strain gauges are not well suited for in vivo measurements because of their size and because they are difficult to use in bone. They are also unsuitable for repeated measurements over time since they cannot be left in the patient. The optical Bragg grating fibres behave like selective filters of light. As a result the structure will transmit most wavelengths of light, but will reflect certain specific wavelengths. If the Bragg grating is strained along the fibre axis, the wavelength will shift, and this change represents a measure of strain. The optical fibres are very thin, no thicker than a standard surgical suture and are easy to adhere to bone by use of the FDA approved polymethyl-methacrylate (PMMA) as bonding adhesive. Since they are made of biocompatible silica porous bioglass ceramics, it should also be possible to leave the fibres in the patient between and after measurements. We have shown that fibre optic Bragg grating sensors can be used as a measurement tool for bone strain by performing measurements both on an acryl tube and on an extracted sample of human femur diaphysis. On either of them we used four fibre optic sensors and four strain gauges, interspersed at every 45 degrees around the circumference. The standard deviation of the measurements on the acrylic tube for each of the sensors, both optical fibres and strain gauges, varied from 1.0 to 5.2%. Every sensor, both optical fibre and strain gauge, correlated significantly with all of the rest at the 0.01 level with a Pearson correlation coefficient r ranging from 0.986 to 1.0. The linearity for all of the sensors versus load was excellent, the lowest linearity of the eight sensors was 0.996 as expressed by r(2) (coefficient of determination), with no significant difference in linearity between optical fibres and strain gauges. Bone is not an ideal isotropic material, and we found that the strain readings of the

  7. Towards Scalable Strain Gauge-Based Joint Torque Sensors

    Science.gov (United States)

    D’Imperio, Mariapaola; Cannella, Ferdinando; Caldwell, Darwin G.; Cuschieri, Alfred

    2017-01-01

    During recent decades, strain gauge-based joint torque sensors have been commonly used to provide high-fidelity torque measurements in robotics. Although measurement of joint torque/force is often required in engineering research and development, the gluing and wiring of strain gauges used as torque sensors pose difficulties during integration within the restricted space available in small joints. The problem is compounded by the need for a scalable geometric design to measure joint torque. In this communication, we describe a novel design of a strain gauge-based mono-axial torque sensor referred to as square-cut torque sensor (SCTS), the significant features of which are high degree of linearity, symmetry, and high scalability in terms of both size and measuring range. Most importantly, SCTS provides easy access for gluing and wiring of the strain gauges on sensor surface despite the limited available space. We demonstrated that the SCTS was better in terms of symmetry (clockwise and counterclockwise rotation) and more linear. These capabilities have been shown through finite element modeling (ANSYS) confirmed by observed data obtained by load testing experiments. The high performance of SCTS was confirmed by studies involving changes in size, material and/or wings width and thickness. Finally, we demonstrated that the SCTS can be successfully implementation inside the hip joints of miniaturized hydraulically actuated quadruped robot-MiniHyQ. This communication is based on work presented at the 18th International Conference on Climbing and Walking Robots (CLAWAR). PMID:28820446

  8. Ground strain measuring system using optical fiber sensors

    Science.gov (United States)

    Sato, Tadanobu; Honda, Riki; Shibata, Shunjiro; Takegawa, Naoki

    2001-08-01

    This paper presents a device to measure the dynamic horizontal shear strain of the ground during earthquake. The proposed device consists of a bronze plate with fiber Bragg grating sensors attached on it. The device is vertically installed in the ground, and horizontal shear strain of the ground is measured as deflection angle of the plate. Employment of optical fiber sensors makes the proposed device simple in mechanism and highly durable, which makes it easy to install our device in the ground. We conducted shaking table tests using ground model to verify applicability of the proposed device.

  9. Flexible strain sensor for air muscles using polypyrrole coated rubber

    Science.gov (United States)

    Tjahyono, Arief P.; Aw, Kean C.; Travas-Sejdic, Jadranka; Li, K. C.

    2010-04-01

    A novel flexible large strain sensor was developed to be use with an air muscle. A piece of butyl rubber was coated with the conducting polymer, polypyrrole through bulk solution and chemical vapour deposition method. The strain sensor was able to response to sudden movements represented by the multiple step functions of the applied strain. Consistency of the sensor's output was studied and the average error in the change of resistance was calculated to be 0.32% and 0.72% for elongation and contraction respectively for the sample made using chemical vapour deposition. However, a hysteresis was observed for this sample for a single cycle of elongation and contraction with the highest error calculated to be 3.2% at a 0% applied strain. SEM images showed the propagation of surface micro-cracks as the cause of the variation in surface resistance with applied strain. In addition, slower relaxation rate of the rubber prevented the surface micro-cracks to open and close at the same rate. The idea of utilizing conducting polymer coating can be applied to the inner rubber tube of the air muscle. As such, a complete integration between actuator and sensor can be realized.

  10. Development and sintering of alumina based mixed oxide ceramic products for sensor applications in petroleum industries

    Energy Technology Data Exchange (ETDEWEB)

    Yadava, Y.P.; Muniz, L.B.; Aguiar, L.A.R.; Sanguinetti Ferreira, R.A. [Departamento de Engenharia Mecanica, Universidade Federal de Pernambuco, CEP 50741-530, Recife-PE (Brazil); Albino Aguiar, J. [Departamento de Fisica, Universidade Federal de Pernambuco, CEP 50670-901 Recife-PE (Brazil)

    2005-07-01

    In petroleum production, different types of sensors are required to monitor temperature, pressure, leakage of inflammable gases, etc. These sensors work in very hostile environmental conditions and frequently suffer from abrasion and corrosion problems. Presently perovskite oxide based ceramic materials are increasingly being used for such purposes, due to their highly inert behavior in hostile environment. In the present work, we have developed and characterized alumina based complex perovskite oxide ceramics, Ba{sub 2}AlSnO{sub 5.5}. These ceramics were prepared by solid state reaction process and produced in the form of circular discs by uniaxial pressure compaction technique. Green ceramic bodies were sintered at different sintering temperatures (1200 to 1500 deg. C) in air atmosphere. Structural and microstructural characteristics of sintered Ba{sub 2}AlMO{sub 5.5} were studied by XRD and SEM techniques. Mechanical properties were tested by Vickers microhardness tests. Ceramics sintered in the temperature range 1300 deg. C 1400 deg. C presented best results in terms of microstructural characteristics and mechanical performance. (authors)

  11. Scaffold metamaterial and its application as strain sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wei; Ren, Mengxin, E-mail: ren-mengxin@nankai.edu.cn; Pi, Biao; Cai, Wei, E-mail: weicai@nankai.edu.cn; Xu, Jingjun, E-mail: jjxu@nankai.edu.cn [The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics Institute, Nankai University, Tianjin 300071 (China); Wu, Yang [Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084 (China)

    2015-08-31

    In this paper, strain sensors based on planar scaffold metamaterial design are demonstrated. The optical properties of such metamaterials are studied, which are proved to be highly dependent on the deformation of the structure. Fabricating such metamaterial on compliant polymeric substrate, the geometric parameters could be tuned with external strain and hence are found to control the reflection resonance condition of the metamaterial. Such mechanical tunability provides the opportunity to realize efficient strain sensors and about 27 nm resonance wavelength shift is observed by applying as much as 37% tensile strain. Furthermore, distinct from most of the previous works, our structures are based on “intaglio” design, which could be manufactured directly by one step fabrication using focused ion beam cutting, hence makes the fabrication process much simpler.

  12. Understanding the deformation of ceramic materials at high strain rates.

    OpenAIRE

    Hallam, David A.

    2015-01-01

    Ceramic hardness and plasticity have been highlighted as important characteristics in ballistic performance; both of which can be measured and semi-quantified from indentation experiments, respectively. However, relatively little work has investigated the accompanying type, on-set and evolution of indentation-induced damage that may also be contributing an influential role. Pressureless sintered SiC and spark plasma sintered B4C, SiC-AlN-C and range of SiC-B4C composite samples were invest...

  13. Knitted Strain Sensors: Impact of Design Parameters on Sensing Properties

    Directory of Open Access Journals (Sweden)

    Ozgur Atalay

    2014-03-01

    Full Text Available This paper presents a study of the sensing properties exhibited by textile-based knitted strain sensors. Knitted sensors were manufactured using flat-bed knitting technology, and electro-mechanical tests were subsequently performed on the specimens using a tensile testing machine to apply strain whilst the sensor was incorporated into a Wheatstone bridge arrangement to allow electrical monitoring. The sensing fabrics were manufactured from silver-plated nylon and elastomeric yarns. The component yarns offered similar diameters, bending characteristics and surface friction, but their production parameters differed in respect of the required yarn input tension, the number of conductive courses in the sensing structure and the elastomeric yarn extension characteristics. Experimental results showed that these manufacturing controls significantly affected the sensing properties of the knitted structures such that the gauge factor values, the working range and the linearity of the sensors varied according to the knitted structure. These results confirm that production parameters play a fundamental role in determining the physical behavior and the sensing properties of knitted sensors. It is thus possible to manipulate the sensing properties of knitted sensors and the sensor response may be engineered by varying the production parameters applied to specific designs.

  14. Ultrasonic sensor based defect detection and characterisation of ceramics.

    Science.gov (United States)

    Kesharaju, Manasa; Nagarajah, Romesh; Zhang, Tonzhua; Crouch, Ian

    2014-01-01

    Ceramic tiles, used in body armour systems, are currently inspected visually offline using an X-ray technique that is both time consuming and very expensive. The aim of this research is to develop a methodology to detect, locate and classify various manufacturing defects in Reaction Sintered Silicon Carbide (RSSC) ceramic tiles, using an ultrasonic sensing technique. Defects such as free silicon, un-sintered silicon carbide material and conventional porosity are often difficult to detect using conventional X-radiography. An alternative inspection system was developed to detect defects in ceramic components using an Artificial Neural Network (ANN) based signal processing technique. The inspection methodology proposed focuses on pre-processing of signals, de-noising, wavelet decomposition, feature extraction and post-processing of the signals for classification purposes. This research contributes to developing an on-line inspection system that would be far more cost effective than present methods and, moreover, assist manufacturers in checking the location of high density areas, defects and enable real time quality control, including the implementation of accept/reject criteria. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. A Novel Vehicle Classification Using Embedded Strain Gauge Sensors

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2008-11-01

    Full Text Available Abstract: This paper presents a new vehicle classification and develops a traffic monitoring detector to provide reliable vehicle classification to aid traffic management systems. The basic principle of this approach is based on measuring the dynamic strain caused by vehicles across pavement to obtain the corresponding vehicle parameters – wheelbase and number of axles – to then accurately classify the vehicle. A system prototype with five embedded strain sensors was developed to validate the accuracy and effectiveness of the classification method. According to the special arrangement of the sensors and the different time a vehicle arrived at the sensors one can estimate the vehicle’s speed accurately, corresponding to the estimated vehicle wheelbase and number of axles. Because of measurement errors and vehicle characteristics, there is a lot of overlap between vehicle wheelbase patterns. Therefore, directly setting up a fixed threshold for vehicle classification often leads to low-accuracy results. Using the machine learning pattern recognition method to deal with this problem is believed as one of the most effective tools. In this study, support vector machines (SVMs were used to integrate the classification features extracted from the strain sensors to automatically classify vehicles into five types, ranging from small vehicles to combination trucks, along the lines of the Federal Highway Administration vehicle classification guide. Test bench and field experiments will be introduced in this paper. Two support vector machines classification algorithms (one-against-all, one-against-one are used to classify single sensor data and multiple sensor combination data. Comparison of the two classification method results shows that the classification accuracy is very close using single data or multiple data. Our results indicate that using multiclass SVM-based fusion multiple sensor data significantly improves

  16. Rockslide deformation monitoring with fiber optic strain sensors

    Directory of Open Access Journals (Sweden)

    J. R. Moore

    2010-02-01

    Full Text Available With micro-strain resolution and the capability to sample at rates of 100 Hz and higher, fiber optic (FO strain sensors offer exciting new possibilities for in-situ landslide monitoring. Here we describe a new FO monitoring system based on long-gauge fiber Bragg grating sensors installed at the Randa Rockslide Laboratory in southern Switzerland. The new FO monitoring system can detect sub-micrometer scale deformations in both triggered-dynamic and continuous measurements. Two types of sensors have been installed: (1 fully embedded borehole sensors and (2 surface extensometers. Dynamic measurements are triggered by sensor deformation and recorded at 100 Hz, while continuous data are logged every 5 min. Deformation time series for all sensors show displacements consistent with previous monitoring. Accelerated shortening following installation of the borehole sensors is likely related to long-term shrinkage of the grout. A number of transient signals have been observed, which in some cases were large enough to trigger rapid sampling. The combination of short- and long-term observation offers new insight into the deformation process. Accelerated surface crack opening in spring is shown to have a diurnal trend, which we attribute to the effect of snowmelt seeping into the crack void space and freezing at night to generate pressure on the crack walls. Controlled-source tests investigated the sensor response to dynamic inputs, which compared an independent measure of ground motion against the strain measured across a surface crack. Low frequency signals were comparable but the FO record suffered from aliasing, where undersampling of higher frequency signals generated spectral peaks not related to ground motion.

  17. Robust polarization and strain behavior of Sm-modified BiFeO3 piezoelectric ceramics.

    Science.gov (United States)

    Walker, Julian; Budic, Bojan; Bryant, Peter; Kurusingal, Valsala; Sorrell, Charles C; Bencan, Andreja; Rojac, Tadej; Valanoor, Nagarajan

    2015-01-01

    The route to phase-pure BiFeO3 (BFO) ceramics with excellent ferroelectric and electromechanical properties is severely impeded by difficulties associated with the perovskite phase stability during synthesis. This has meant that dopants and solid solutions with BFO have been investigated as a means of not only improving the functional properties, but also of improving the perovskite phase formation of BFO-based ceramics. The present work focuses on Sm-modified BFO ceramics of composition Bi0.88Sm0.12FeO3. The polarization and strain behaviors were investigated as a function of the phase composition, microstructure, and chemical composition. Addition of Sm reduces the susceptibility of the BFO perovskite to phase degradation by Si impurities. Si was observed to react into Sm-rich grains dispersed within the microstructure, with no large increases in the amount of bismuth-parasitic phases, namely Bi25FeO39 and Bi2Fe4O9. These as-prepared ceramics exhibited robust polarization behavior showing maximum remnant polarizations of ~40 to 50 μC/cm(2). The electric-fieldinduced strain showed an appreciable stability in terms of the driving field frequency with maximum peak-to-peak strains of ~0.3% and a coercive field of ~130 kV/cm.

  18. Electric field induced strain, switching and energy storage behaviour of lead free Barium Zirconium Titanate ceramic

    Science.gov (United States)

    Badapanda, T.; Chaterjee, S.; Mishra, Anupam; Ranjan, Rajeev; Anwar, S.

    2017-09-01

    There is a huge demand of lead-free high performance ceramics with large strain, low hysteresis loss and high-energy storage ability at room temperature. In this context, we investigated the large electric field induced strain, switching behaviour and energy storage properties of BaZr0.05Ti0.95O3 ceramic (BZT) prepared by high energy ball milling technique, reportedly exhibiting a triple point transition near the room temperature. The X-ray diffraction of the BZT ceramic confirms orthorhombic symmetry with space group Amm2 at room temperature. The room temperature dielectric study reveals that there is a negligible variation of dielectric constant and dielectric loss with frequency. The polarization behaviour at various applied electric fields was studied and the energy storage densities were obtained from the integral area of P-E loops. Electric field induced strain behaviour has been studied with due emphasis on the electrostrictive response at room temperature. The ferroelectric and electromechanical properties derived from the P-E and S-E loops suggest that the present ceramic encompass the properties of actuation and energy storage simultaneously.

  19. Damage Detection and Localization from Dense Network of Strain Sensors

    Directory of Open Access Journals (Sweden)

    Simon Laflamme

    2016-01-01

    Full Text Available Structural health monitoring of large systems is a complex engineering task due to important practical issues. When dealing with large structures, damage diagnosis, localization, and prognosis necessitate a large number of sensors, which is a nontrivial task due to the lack of scalability of traditional sensing technologies. In order to address this challenge, the authors have recently proposed a novel sensing solution consisting of a low-cost soft elastomeric capacitor that transduces surface strains into measurable changes in capacitance. This paper demonstrates the potential of this technology for damage detection, localization, and prognosis when utilized in dense network configurations over large surfaces. A wind turbine blade is adopted as a case study, and numerical simulations demonstrate the effectiveness of a data-driven algorithm relying on distributed strain data in evidencing the presence and location of damage, and sequentially ranking its severity. Numerical results further show that the soft elastomeric capacitor may outperform traditional strain sensors in damage identification as it provides additive strain measurements without any preferential direction. Finally, simulation with reconstruction of measurements from missing or malfunctioning sensors using the concepts of virtual sensors and Kriging demonstrates the robustness of the proposed condition assessment methodology for sparser or malfunctioning grids.

  20. Microfabrication of a Novel Ceramic Pressure Sensor with High Sensitivity Based on Low-Temperature Co-Fired Ceramic (LTCC) Technology

    OpenAIRE

    Chen Li; Qiulin Tan; Wendong Zhang; Chenyang Xue; Yunzhi Li; Jijun Xiong

    2014-01-01

    In this paper, a novel capacitance pressure sensor based on Low-Temperature Co-Fired Ceramic (LTCC) technology is proposed for pressure measurement. This approach differs from the traditional fabrication process for a LTCC pressure sensor because a 4J33 iron-nickel-cobalt alloy is applied to avoid the collapse of the cavity and to improve the performance of the sensor. Unlike the traditional LTCC sensor, the sensitive membrane of the proposed sensor is very flat, and the deformation of the se...

  1. Textile-based weft knitted strain sensors: effect of fabric parameters on sensor properties.

    Science.gov (United States)

    Atalay, Ozgur; Kennon, William Richard; Husain, Muhammad Dawood

    2013-08-21

    The design and development of textile-based strain sensors has been a focus of research and many investigators have studied this subject. This paper presents a new textile-based strain sensor design and shows the effect of base fabric parameters on its sensing properties. Sensing fabric could be used to measure articulations of the human body in the real environment. The strain sensing fabric was produced by using electronic flat-bed knitting technology; the base fabric was produced with elastomeric yarns in an interlock arrangement and a conductive yarn was embedded in this substrate to create a series of single loop structures. Experimental results show that there is a strong relationship between base fabric parameters and sensor properties.

  2. Textile-Based Weft Knitted Strain Sensors: Effect of Fabric Parameters on Sensor Properties

    Directory of Open Access Journals (Sweden)

    William Richard Kennon

    2013-08-01

    Full Text Available The design and development of textile-based strain sensors has been a focus of research and many investigators have studied this subject. This paper presents a new textile-based strain sensor design and shows the effect of base fabric parameters on its sensing properties. Sensing fabric could be used to measure articulations of the human body in the real environment. The strain sensing fabric was produced by using electronic flat-bed knitting technology; the base fabric was produced with elastomeric yarns in an interlock arrangement and a conductive yarn was embedded in this substrate to create a series of single loop structures. Experimental results show that there is a strong relationship between base fabric parameters and sensor properties.

  3. Microfabrication of a Novel Ceramic Pressure Sensor with High Sensitivity Based on Low-Temperature Co-Fired Ceramic (LTCC Technology

    Directory of Open Access Journals (Sweden)

    Chen Li

    2014-06-01

    Full Text Available In this paper, a novel capacitance pressure sensor based on Low-Temperature Co-Fired Ceramic (LTCC technology is proposed for pressure measurement. This approach differs from the traditional fabrication process for a LTCC pressure sensor because a 4J33 iron-nickel-cobalt alloy is applied to avoid the collapse of the cavity and to improve the performance of the sensor. Unlike the traditional LTCC sensor, the sensitive membrane of the proposed sensor is very flat, and the deformation of the sensitivity membrane is smaller. The proposed sensor also demonstrates a greater responsivity, which reaches as high as 13 kHz/kPa in range of 0–100 kPa. During experiments, the newly fabricated sensor, which is only about 6.5 cm2, demonstrated very good performance: the repeatability error, hysteresis error, and nonlinearity of the sensor are about 4.25%, 2.13%, and 1.77%, respectively.

  4. Printed strain sensor array for application to structural health monitoring

    Science.gov (United States)

    Zymelka, Daniel; Togashi, Kazuyoshi; Ohigashi, Ryoichi; Yamashita, Takahiro; Takamatsu, Seiichi; Itoh, Toshihiro; Kobayashi, Takeshi

    2017-10-01

    We demonstrate the development and practical use of low-cost printed strain sensor arrays built for applications in structural health monitoring. Sensors embedded in the array were designed to provide compensation for temperature variations and to enable their use in different seasons. The evaluation was carried out in laboratory tests and with practical application on a highway bridge. Measurements on the bridge were performed 7 months and 1 year after their installation. The developed devices were fully operational and could detect and localize cracks accurately in the monitored bridge structure.

  5. A Piezoelectric Plethysmograph Sensor Based on a Pt Wire Implanted Lead Lanthanum Zirconate Titanate Bulk Ceramic

    Directory of Open Access Journals (Sweden)

    Ernesto Suaste-Gómez

    2010-07-01

    Full Text Available This work reports on the development of a Lead Lanthanum Zirconate Titanate (PLZT bulk ferroelectric poled ceramic structure as a Piezoelectric Plethysmograph (PZPG sensor. The ceramic was implanted during its fabrication with a platinum (Pt wire which works as an internal electrode. The ceramic was then submitted to an experimental setup in order to validate and determine the Pt-wire mechanical effects. This PZPG sensor was also mounted on a finger splint in order to measure the blood flow that results from the pulsations of blood occurring with each heartbeat. Fingertip pulses were recorded jointly with an ECG signal from a 25 year old male to compare the time shift; the PZPG sensor guarantees the electrical isolation of the patient. The proposed PZPG has several advantages: it can be adjusted for fingertip measurements, but it can easily be extended by means of spare bands, therefore making possible PZPG measurements from different body locations, e.g., forehead, forearm, knee, neck, etc.

  6. Residual strain scanning of alumina-based ceramic composites by neutron diffraction

    Science.gov (United States)

    Ruiz-Hervias, J.; Bruno, G.; Bueno, S.; Gurauskis, J.; Baudín, C.; Fan, K. Y.

    2014-11-01

    Residual strain profiles were measured by neutron diffraction in alumina-aluminum titanate ceramic composites sintered at two different temperatures, namely 1450 and 1550°C. The results show that irrespective of the direction and the sintering temperature, the obtained profiles are almost flat, with very similar results for both temperatures. In addition, the results demonstrate that the alumina is in compression whereas the aluminium titanate is subjected to tensile residual stresses.

  7. Polymer-Based Self-Standing Flexible Strain Sensor

    Directory of Open Access Journals (Sweden)

    Fernando Martinez

    2010-01-01

    Full Text Available The design and characterization of polymer-based self-standing flexible strain sensors are presented in this work. Properties as lightness and flexibility make them suitable for the measurement of strain in applications related with wearable electronics such as robotics or rehabilitation devices. Several sensors have been fabricated to analyze the influence of size and electrical conductivity on their behavior. Elongation and applied charge were precisely controlled in order to measure different parameters as electrical resistance, gauge factor (GF, hysteresis, and repeatability. The results clearly show the influence of size and electrical conductivity on the gauge factor, but it is also important to point out the necessity of controlling the hysteresis and repeatability of the response for precision-demanding applications.

  8. Planetary Gearbox Fault Diagnosis Using a Single Piezoelectric Strain Sensor

    Science.gov (United States)

    2014-12-23

    to process signals acquired from a si ngle piezoelectric strain sensor mounted on the housing of a planetary gearbox a nd extracting condition... Melbourne , Australia, pp. 171 - 178. Jiang, X., Kim, K., Zha ng, S., Johnson, J., & Salazar, G. (2014). High-temperature piezoelectic sensing...epicyclic gearbox by signal averaging of th e vibration, Aeronautical Research Laboratory, Melbourne , Victoria, Australia. McFadden, P. D . (1991). A

  9. Printing of microstructure strain sensor for structural health monitoring

    Science.gov (United States)

    Le, Minh Quyen; Ganet, Florent; Audigier, David; Capsal, Jean-Fabien; Cottinet, Pierre-Jean

    2017-05-01

    Recent advances in microelectronics and materials should allow the development of integrated sensors with transduction properties compatible with being printed directly onto a 3D substrate, especially metallic and polymer substrates. Inorganic and organic electronic materials in microstructured and nanostructured forms, intimately integrated in ink, offer particularly attractive characteristics, with realistic pathways to sophisticated embodiments. Here, we report on these strategies and demonstrate the potential of 3D-printed microelectronics based on a structural health monitoring (SHM) application for the precision weapon systems. We show that our printed sensors can be employed in non-invasive, high-fidelity and continuous strain monitoring of handguns, making it possible to implement printed sensors on a 3D substrate in either SHM or remote diagnostics. We propose routes to commercialization and novel device opportunities and highlight the remaining challenges for research.

  10. Silicon strain gages bonded on stainless steel using glass frit for strain sensor applications

    Science.gov (United States)

    Zhang, Zongyang; Cheng, Xingguo; Leng, Yi; Cao, Gang; Liu, Sheng

    2014-05-01

    In this paper, a steel pressure sensor using strain gages bonded on a 17-4 PH stainless steel (SS) diaphragm based on glass frit technology is proposed. The strain gages with uniform resistance are obtained by growing an epi-silicon layer on a single crystal silicon wafer using epitaxial deposition technique. The inorganic glass frits are used as the bonding material between the strain gages and the 17-4 PH SS diaphragm. Our results show that the output performances of sensors at a high temperature of 125 °C are almost equal those at room temperature, which indicates that the glass frit bonding is a good method and may lead to a significant advance in the high temperature applicability of silicon strain gage sensors. Finally, the microstructure of the cured organic adhesive and the fired glass frit are compared. It may be concluded that the defects of the cured organic adhesive deteriorate the hysteresis and repeatability errors of the sensors.

  11. Sensor evaluation for wearable strain gauges in neurological rehabilitation.

    Science.gov (United States)

    Giorgino, Toni; Tormene, Paolo; Lorussi, Federico; De Rossi, Danilo; Quaglini, Silvana

    2009-08-01

    Conductive elastomers are a novel strain sensing technology which can be unobtrusively embedded into a garment's fabric, allowing a new type of sensorized cloths for motion analysis. A possible application for this technology is remote monitoring and control of motor rehabilitation exercises. The present work describes a sensorized shirt for upper limb posture recognition. Supervised learning techniques have been employed to compare classification models for the analysis of strains, simultaneously measured at multiple points of the shirt. The instantaneous position of the limb was classified into a finite set of predefined postures, and the movement was decomposed in an ordered sequence of discrete states. The amount of information given by the observation of each sensor during the execution of a specific exercise was quantitatively estimated by computing the information gain for each sensor, which in turn allows the data-driven optimization of the garment. Real-time feedback on exercise progress can also be provided by reconstructing the sequence of consecutive positions assumed by the limb.

  12. Ultra high strain properties of lanthanum substituted PZT electro-ceramics prepared via mechanical activation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ajeet, E-mail: jkajeet@yahoo.co.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India); Bhanu Prasad, V.V., E-mail: bhanu@dmrl.drdo.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); James Raju, K.C., E-mail: kcjrsp@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); James, A.R., E-mail: james@dmrl.drdo.in [Ceramics and Composites Group, Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

    2014-06-25

    Highlights: • PLZT comparable with PMN–PT and their hot-pressed counterparts synthesized. • HEM applied for ceramic preparation at reduced sintering temperature. • Strain value (0.27%) comparable to previous reported values for PLZT 8/60/40. • The electric field induced (strain) hysteresis loss was also found to be very less. - Abstract: Substitution of lanthanum at the A sites of perovskite lead zirconate titanate ceramics shows an improvement in the structural and electrical properties. (Pb{sub 0.92}La{sub 0.08})(Zr{sub 0.60}Ti{sub 0.40})O{sub 3} (PLZT 8/60/40) was prepared using high energy mechano-chemical milling. The effect of milling on the microstructure and electrical properties of PLZT 8/60/40 has been studied. X-ray diffraction shows the phase formation after milling itself. TEM was used to measure the particle size. The SEM image of the sintered pellet shows a dense microstructure and the average grain size was found to be <1.5 μm. Electrical properties of the ceramics were characterized. Piezoelectric charge coefficient (d{sub 33}) was found to be 561 pC/N. Resonance studies were performed on poled ceramics and the electromechanical coupling factor was calculated by the resonance method. The PLZT 8/60/40 composition showed a well saturated and uniform P–E hysteresis loop with remanent polarization (P{sub r}) of 33.29 μC/cm{sup 2} and a coercive field (E{sub c}) of 10.57 kV/cm. Electric field induced strain (S–E loop) shows a value of ∼0.27% with minimum loss.

  13. Strain mediated self-assembly of ceramic nano islands

    Science.gov (United States)

    Rauscher, Michael

    This dissertation presents the first observations of self-assembled arrays of epitaxial nano islands in ceramic systems, based on RF sputtering and thermal processing of Gadolinia-doped ceria (GDC) thin films on an yttria-stabilized zirconia (YSZ) single crystal substrate. In contrast to the conventional semiconductor nano island self-assembly systems, the island arrays in the GDC-YSZ system provide materials with categorically different physical properties and functionalities, and they exhibit a stronger ordering at a larger characteristic length scale. The initial focus of this study was on the processing and characterization of thin GDC layers on YSZ, which are used in SOFCs as barriers to prevent the reaction of some cathode materials with the YSZ electrolyte. Chapter 3 of this document describes studies on relatively thin (300 nm) were found to fail by spalling from the YSZ substrate, leaving behind patches of unspalled film and exposing a sputter-mixed GDC-YSZ surface. Upon annealing, the modified surface spontaneously broke up into two-dimensional arrays of epitaxial islands with sub-micron dimensions, exhibiting order in spacing and alignment. In addition to the classical local effects that drive dewetting processes, the self-assembly of the epitaxial GDC-bearing islands is driven by elastic interactions between them, and these interactions are mediated by the elastically anisotropic underlying YSZ substrate. The stresses in the initial mixed surface layers are modified by two factors: The thermal-expansion mismatch leads to stresses, depending on temperature and heating rates. The lattice-parameter mismatch leads to coherency stresses, depending on chemical composition variations and interdiffusion rates. When the initial surface layers cannot relieve their stress by other mechanisms, they break up by surface diffusion to introduce stress-free surfaces and relax the stresses in their vicinity, at the expense of increasing surface area and energy. The

  14. Fiber Bragg gratings strain measuring system and a sensor calibration setup based on mechanical nanomotion transducer

    Science.gov (United States)

    Lazarev, Vladimir A.; Leonov, Stanislav O.; Tarabrin, Mikhail K.; Karasik, Valerii E.

    2017-06-01

    Fiber Bragg grating (FBG) strain sensors are powerful tools for structural health monitoring applications. However, FBG sensor fabrication and packaging processes can lead to a non-linear behavior, that affects the accuracy of the strain measurements. Here we present a novel nondestructive calibration technique for FBG strain sensors that use a mechanical nanomotion transducer. A customized calibration setup was designed based on dovetail-type slideways that were mechanized using a stepping motor. The performance of the FBG strain sensor was investigated through analysis of experimental data, and the calibration curves for the FBG strain sensor are presented.

  15. High frequency strain measurements with fiber Bragg grating sensors

    Science.gov (United States)

    Koch, J.; Angelmahr, M.; Schade, W.

    2015-05-01

    In recent years fiber Bragg grating sensors gained interest in structural health monitoring and concepts for smart structures. They are small, lightweight, and immune to electromagnetic interference. Using multiplexing techniques, several sensors can be addressed by a single fiber. Therefore, well-established structures and materials in industrial applications can be easily equipped with fiber optical sensors with marginal influence on their mechanical properties. In return, critical components can be monitored in real-time, leading to reduced maintenance intervals and a great reduction of costs. Beside of generally condition monitoring, the localization of failures in a structure is a desired feature of the condition monitoring system. Detecting the acoustic emission of a sudden event, its place of origin can be determined by analyzing the delay time of distributed sensor signals. To achieve high localization accuracies for the detection of cracks, breaks, and impacts high sampling rates combined with the simultaneous interrogation of several fiber Bragg grating sensors are required. In this article a fiber Bragg grating interrogator for high frequency measurements up to the megahertz range is presented. The interrogator is based on a passive wavelength to intensity conversion applying arrayed waveguide gratings. Light power fluctuations are suppressed by a differential data evaluation, leading to a reduced signal-to-noise ratio and a low strain detection limit. The measurement system is used to detect, inter alia, wire breaks in steel wire ropes for dockside cranes.

  16. Distributed perfluorinated POF strain sensor using OTDR and OFDR techniques

    Science.gov (United States)

    Liehr, Sascha; Wendt, Mario; Krebber, Katerina

    2009-10-01

    This paper presents the latest advances in distributed strain sensing using perfluorinated (PF) polymer optical fibers (POF). Compared to previously introduced PMMA POF strain sensors, PF POF have the advantage of lower loss and therefore extended measurement length of more than 500 m at increased spatial resolution of 10 cm. It is shown that PF POF can measure strain distributed up to 100 %. The characteristic backscatter signature of this fiber type provides additional evaluation possibilities. We show that, by applying a cross-correlation algorithm to the backscatter signal, the distributed length change can be measured along the fiber. We also present, to our knowledge for the first time, incoherent Optical Frequency Domain Reflectometry (OFDR) in POF to measure distributed reflections and loss along the fiber. The OFDR technique proves superior to existing OTDR techniques in measurement speed, resolution and potential instrument costs.

  17. Downsized Sheath-Core Conducting Fibers for Weavable Superelastic Wires, Biosensors, Supercapacitors, and Strain Sensors.

    Science.gov (United States)

    Wang, Hongyan; Liu, Zunfeng; Ding, Jianning; Lepró, Xavier; Fang, Shaoli; Jiang, Nan; Yuan, Ninyi; Wang, Run; Yin, Qu; Lv, Wei; Liu, Zhongsheng; Zhang, Mei; Ovalle-Robles, Raquel; Inoue, Kanzan; Yin, Shougen; Baughman, Ray H

    2016-07-01

    Hair-like-diameter superelastic conducting fibers, comprising a buckled carbon nanotube sheath on a rubber core, are fabricated, characterized, and deployed as weavable wires, biosensors, supercapacitors, and strain sensors. These downsized sheath-core fibers provide the demonstrated basis for glucose sensors, supercapacitors, and electrical interconnects whose performance is undegraded by giant strain, as well as ultrafast strain sensors that exploit strain-dependent capacitance changes.

  18. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  19. Ultrasensitive Cracking-Assisted Strain Sensors Based on Silver Nanowires/Graphene Hybrid Particles.

    Science.gov (United States)

    Chen, Song; Wei, Yong; Wei, Siman; Lin, Yong; Liu, Lan

    2016-09-28

    Strain sensors with ultrahigh sensitivity under microstrain have numerous potential applications in heartbeat monitoring, pulsebeat detection, sound signal acquisition, and recognition. In this work, a two-part strain sensor (i.e., polyurethane part and brittle conductive hybrid particles layer on top) based on silver nanowires/graphene hybrid particles is developed via a simple coprecipitation, reduction, vacuum filtration, and casting process. Because of the nonuniform interface, weak interfacial bonding, and the hybrid particles' point-to-point conductive networks, the crack and overlap morphologies are successfully formed on the strain sensor after a prestretching; the crack-based stain sensor exhibits gauge factors as high as 20 (Δε sensor. Combined with its good response to bending, high strain resolution, and high working stability, the developed strain sensor is promising in the applications of electronic skins, motion sensors, and health monitoring sensors.

  20. Optical sensor for measuring humidity, strain and temperature

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to an optical sensor (100) adapted to measure at least three physical parameters, said optical sensor comprising a polymer-based optical waveguide structure comprising a first Bragg grating structure (101) being adapted to provide information about a first, a second...... and a third physical parameter, a second Bragg grating structure (102) being adapted to provide information about the second and the third physical parameter only, and a third Bragg grating structure (103) being adapted to provide information about the third physical parameter only. The invention further...... relates to a method for measuring the first, the second and the third physical parameter. Preferably, the first, the second and the third physical parameter, are humidity, strain and temperature, respectively....

  1. Maximising electro-mechanical response by minimising grain-scale strain heterogeneity in phase-change actuator ceramics

    DEFF Research Database (Denmark)

    Oddershede, Jette; Hossain, Mohammad Jahangir; Daniels, John E.

    2016-01-01

    Phase-change actuator ceramics directly couple electrical and mechanical energies through an electric-field-induced phase transformation. These materials are promising for the replacement of the most common electro-mechanical ceramic, lead zirconate titanate, which has environmental concerns. Here......, we show that by compositional modification, we reduce the grain-scale heterogeneity of the electro-mechanical response by 40%. In the materials investigated, this leads to an increase in the achievable electric-field-induced strain of the bulk ceramic of 45%. Compositions of (100-x)Bi0.5Na0.5TiO3-(x...... heterogeneity can be achieved by precise control of the lattice distortions and orientation distributions of the induced phases. The current results can be used to guide the design of next generation high-strain electro-mechanical ceramic actuator materials....

  2. Investigation of low-temperature cofired ceramics packages for high-temperature SAW sensors

    OpenAIRE

    Bardong, Jochen; Binder, Alfred; Toskov, Sasa; Miskovic, Goran; Radosavljevic, Goran

    2016-01-01

    Surface acoustic wave (SAW) temperature sensor devices have been developed for operating temperatures up to and above 1000 °C. A challenging task to make these devices available on the market is to develop an appropriate housing concept. A concept based on low-temperature cofired ceramics (LTCC) has been investigated and tested under elevated temperatures up to 600 °C. The devices showed promising results up to 450 °C. Thorough analysis of the possible failure mechanisms was do...

  3. Highly Stretchable Strain Sensors Using an Electrospun Polyurethane Nanofiber/Graphene Composite.

    Science.gov (United States)

    Hu, Daqing; Wang, Qinghe; Yu, Jixian; Hao, Wentao; Lu, Hongbo; Zhang, Guobing; Wang, Xianghua; Qiu, Longzhen

    2016-06-01

    A highly flexible and stretchable strain sensor has been prepared by coating chemical reduction of graphene oxide on electrospun polyurethane nanofiber mats. The sensor exhibits an ohmic behavior regardless of applied strains and the current monotonically increases with the increase of the tensile strain. The morphology and stability of electrospun polyurethane nanocomposite mats were also studied. The flexible and stretchable strain sensor has great potential for practical application such as efficient human-motion detection. This cheap and simple process of graphene layer provides an effective fabrication for graphene stretchable electronic devices and strain sensors due to excellent stability and electrical proper.

  4. Demonstration of a passive sub-picostrain fiber strain sensor

    CERN Document Server

    Chow, J H; McClelland, D E; Gray, M B; Chow, Jong H.; Littler, Ian C. M.; Clelland, David E. Mc; Gray, Malcolm B.

    2005-01-01

    We demonstrate a fiber Fabry-Perot (FFP) sensor capable of detecting sub-picostrain signals, from 100 Hz and extending beyond 100 kHz, using the Pound-Drever-Hall frequency locking technique. A low power diode laser at 1550 nm is locked to a free-space reference cavity to suppress its free-running frequency noise, thereby stabilizing the laser. The stabilized laser is then used to interrogate a FFP where the PDH error signal yields the instantaneous fiber strain.

  5. Research of three-dimensional force sensor based on multiplexed fiber Bragg grating strain sensors

    Science.gov (United States)

    Xu, Hui-Chao; Wang, Su; Miao, Xin-Gang

    2017-04-01

    Most safety problems of architectural structures are caused by structural deformation, and the structures usually deform in more than one direction. So it is important and necessary to collect the safety monitoring data from all directions. Conventional fiber Bragg grating (FBG) sensors cannot fully meet the requirements of a modern safety monitoring system in practical application. Therefore, the research of a three-dimensional (3-D) force sensor that can expand the application range of fiber optic sensing technology is necessary and significant. A 3-D force sensor based on multiplexed FBG strain sensors is proposed, which can be used to measure 3-D force on a structure under test, force distribution, and the trend of relative microdeformation. The sensor that has an integral structure with a design has been described in detail, and its sensing principle has been investigated. The results of calibration experiments show that it can accurately and effectively realize the 3-D force measurement with good linearity, repeatability, and consistency. Experimental and analytical results both demonstrate its feasibility. It can work in harsh environments due to its good stability and anti-interference ability. The sensor proposed in this paper has great engineering application value and application prospects in the field of structure health monitoring.

  6. Equivalent thermal history reconstruction from a partially crystallized glass-ceramic sensor array

    Science.gov (United States)

    Heeg, Bauke

    2015-11-01

    The basic concept of a thermal history sensor is that it records the accumulated exposure to some unknown, typically varying temperature profile for a certain amount of time. Such a sensor is considered to be capable of measuring the duration of several (N) temperature intervals. For this purpose, the sensor deploys multiple (M) sensing elements, each with different temperature sensitivity. At the end of some thermal exposure for a known period of time, the sensor array is read-out and an estimate is made of the set of N durations of the different temperature ranges. A potential implementation of such a sensor was pioneered by Fair et al. [Sens. Actuators, A 141, 245 (2008)], based on glass-ceramic materials with different temperature-dependent crystallization dynamics. In their work, it was demonstrated that an array of sensor elements can be made sensitive to slight differences in temperature history. Further, a forward crystallization model was used to simulate the variations in sensor array response to differences in the temperature history. The current paper focusses on the inverse aspect of temperature history reconstruction from a hypothetical sensor array output. The goal of such a reconstruction is to find an equivalent thermal history that is the closest representation of the true thermal history, i.e., the durations of a set of temperature intervals that result in a set of fractional crystallization values which is closest to the one resulting from the true thermal history. One particular useful simplification in both the sensor model as well as in its practical implementation is the omission of nucleation effects. In that case, least squares models can be used to approximate the sensor response and make reconstruction estimates. Even with this simplification, sensor noise can have a destabilizing effect on possible reconstruction solutions, which is evaluated using simulations. Both regularization and non-negativity constrained least squares

  7. A High-Performance LC Wireless Passive Pressure Sensor Fabricated Using Low-Temperature Co-Fired Ceramic (LTCC Technology

    Directory of Open Access Journals (Sweden)

    Chen Li

    2014-12-01

    Full Text Available An LC resonant pressure sensor with improved performance is presented in this paper. The sensor is designed with a buried structure, which protects the electrical components from contact with harsh environments and reduces the resonant-frequency drift of the sensor in high-temperature environments. The pressure-sensitive membrane of the sensor is optimized according to small-deflection-plate theory, which allows the sensor to operate in high-pressure environments. The sensor is fabricated using low-temperature co-fired ceramic (LTCC technology, and a fugitive film is used to create a completed sealed embedded cavity without an evacuation channel. The experimental results show that the frequency drift of the sensor versus the temperature is approximately 0.75 kHz/°C, and the responsivity of the sensor can be up to 31 kHz/bar within the pressure range from atmospheric pressure to 60 bar.

  8. A high-performance LC wireless passive pressure sensor fabricated using low-temperature co-fired ceramic (LTCC) technology.

    Science.gov (United States)

    Li, Chen; Tan, Qiulin; Xue, Chenyang; Zhang, Wendong; Li, Yunzhi; Xiong, Jijun

    2014-12-05

    An LC resonant pressure sensor with improved performance is presented in this paper. The sensor is designed with a buried structure, which protects the electrical components from contact with harsh environments and reduces the resonant-frequency drift of the sensor in high-temperature environments. The pressure-sensitive membrane of the sensor is optimized according to small-deflection-plate theory, which allows the sensor to operate in high-pressure environments. The sensor is fabricated using low-temperature co-fired ceramic (LTCC) technology, and a fugitive film is used to create a completed sealed embedded cavity without an evacuation channel. The experimental results show that the frequency drift of the sensor versus the temperature is approximately 0.75 kHz/°C, and the responsivity of the sensor can be up to 31 kHz/bar within the pressure range from atmospheric pressure to 60 bar.

  9. A Ceramic Thick Film Humidity Sensor Based on MnZn Ferrite

    Directory of Open Access Journals (Sweden)

    D. Egan

    2002-02-01

    Full Text Available A ceramic thick film humidity sensor, produced from MnZn ferrite, is presented. The proposed sensing mechanism is a combination of proton hopping, hydronium diffusion, and vacancy donor traps releasing electrons into the conduction band. The sensor structure comprises a two-layer device; the first layer is an interdigitated conductor and the second layer is a 30μm thick sensing layer. The effects of sintering the sensing pastes in air and vacuum have been reported. The air-fired sample exhibits the highest humidity sensitivity (1.54%/RH% and the lowest temperature sensitivity (0.37%/oC. The vacuum-fired sample has the lowest humidity sensitivity (0.043%/RH and the highest temperature sensitivity (0.77%/oC. The sensitivity results indicate that the air-fired sample has the best potential for use in humidity sensing applications.

  10. Carbon Nanotube/Polymer Nanocomposites Flexible Stress and Strain Sensors

    Science.gov (United States)

    Kang, Jin Ho; Sauti, Godfrey; Park, Cheol; Scholl, Jonathan A.; Lowther, Sharon E.; Harrison, Joycelyn S.

    2008-01-01

    Conformable stress and strain sensors are required for monitoring the integrity of airframe structures as well as for sensing the mechanical stimuli in prosthetic arms. For this purpose, we have developed a series of piezoresistive single-wall carbon nanotube (SWCNT)/polymer nanocomposites. The electromechanical coupling of pressure with resistance changes in these nanocomposites is exceptionally greater than that of metallic piezoresistive materials. In fact, the piezoresistive stress coefficient (pi) of a SWCNT/polymer nanocomposite is approximately two orders of magnitude higher than that of a typical metallic piezoresistive. The piezoresistive stress coefficient is a function of the nanotube concentration wherein the maximum value occurs at a concentration just above the percolation threshold concentration (phi approx. 0.05 %). This response appears to originate from a change in intrinsic resistivity under compression/tension. A systematic study of the effect of the modulus of the polymer matrix on piezoresistivity allowed us to make flexible and conformable sensors for biomedical applications. The prototype haptic sensors using these nanocomposites are demonstrated. The piezocapacitive properties of SWCNT/polymer are also characterized by monitoring the capacitance change under pressure.

  11. Prediction of stress-strain behavior of ceramic matrix composites using unit cell model

    Directory of Open Access Journals (Sweden)

    Suzuki Takuya

    2015-01-01

    Full Text Available In this study, the elastic modulus and the stress-strain curve of ceramic matrix composites (CMCs were predicted by using the unit cell model that consists of fiber bundles and matrix. The unit cell model was developed based on the observation of cross sections of CMCs. The elastic modulus of CMCs was calculated from the results of finite element analysis using the developed model. The non-linear behavior of stress-strain curve of CMCs was also predicted by taking the degradation of the elastic modulus into consideration, where the degradation was related to the experimentally measured crack density in CMCs. The approach using the unit cell model was applied to two kinds of CMCs, and good agreement was obtained between the experimental and the calculated results.

  12. Ultrasonic sensitivity of strain-insensitive fiber Bragg grating sensors and evaluation of ultrasound-induced strain.

    Science.gov (United States)

    Tsuda, Hiroshi; Kumakura, Kenji; Ogihara, Shinji

    2010-01-01

    In conventional ultrasound detection in structures, a fiber Bragg grating (FBG) is glued on or embedded in the structure. However, application of strain to the structure can influence the sensitivity of the FBG toward ultrasound and can prevent its effective detection. An FBG can work as a strain-insensitive ultrasound sensor when it is not directly glued to the monitored structure, but is instead applied to a small thin plate to form a mobile sensor. Another possible configuration is to affix an FBG-inscribed optical fiber without the grating section attached to the monitored structure. In the present study, sensitivity to ultrasound propagated through an aluminum plate was compared for a strain-insensitive FBG sensor and an FBG sensor installed in a conventional manner. Strains induced by ultrasound from a piezoelectric transducer and by quasi-acoustic emission of a pencil lead break were also quantitatively evaluated from the response amplitude of the FBG sensor. Experimental results showed that the reduction in the signal-to-noise ratio for ultrasound detection with strain-insensitive FBG sensors, relative to traditionally-installed FBG sensors, was only 6 dB, and the ultrasound-induced strain varied within a range of sub-micron strains.

  13. Stretchable and Flexible High-Strain Sensors Made Using Carbon Nanotubes and Graphite Films on Natural Rubber

    Directory of Open Access Journals (Sweden)

    Sreenivasulu Tadakaluru

    2014-01-01

    Full Text Available Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ~5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain. As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor and 620% (carbon nanotube sensor were measured; these values are respectively ~50 and ~120 times greater than those of conventional metallic strain sensors.

  14. Stretchable and flexible high-strain sensors made using carbon nanotubes and graphite films on natural rubber.

    Science.gov (United States)

    Tadakaluru, Sreenivasulu; Thongsuwan, Wiradej; Singjai, Pisith

    2014-01-06

    Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ~5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain). As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor) and 620% (carbon nanotube sensor) were measured; these values are respectively ~50 and ~120 times greater than those of conventional metallic strain sensors.

  15. Application of High-Temperature Extrinsic Fabry-Perot Interferometer Strain Sensor

    Science.gov (United States)

    Piazza, Anthony

    2008-01-01

    In this presentation to the NASA Aeronautics Sensor Working Group the application of a strain sensor is outlined. The high-temperature extrinsic Fabry-Perot interferometer (EFPI) strain sensor was developed due to a need for robust strain sensors that operate accurately and reliably beyond 1800 F. Specifically, the new strain sensor would provide data for validating finite element models and thermal-structural analyses. Sensor attachment techniques were also developed to improve methods of handling and protecting the fragile sensors during the harsh installation process. It was determined that thermal sprayed attachments are preferable even though cements are simpler to apply as cements are more prone to bond failure and are often corrosive. Previous thermal/mechanical cantilever beam testing of EFPI yielded very little change to 1200 F, with excellent correlation with SG to 550 F. Current combined thermal/mechanical loading for sensitivity testing is accomplished by a furnace/cantilever beam loading system. Dilatometer testing has can also be used in sensor characterization to evaluate bond integrity, evaluate sensitivity and accuracy and to evaluate sensor-to-sensor scatter, repeatability, hysteresis and drift. Future fiber optic testing will examine single-mode silica EFPIs in a combined thermal/mechanical load fixture on C-C and C-SiC substrates, develop a multi-mode Sapphire strain-sensor, test and evaluate high-temperature fiber Bragg Gratings for use as strain and temperature sensors and attach and evaluate a high-temperature heat flux gauge.

  16. Method for independent strain and temperature measurement in polymeric tensile test specimen using embedded FBG sensors

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; McGugan, Malcolm; Mikkelsen, Lars Pilgaard

    2016-01-01

    A novel method to obtain independent strain and temperature measurements using embedded Fibre Bragg Grating (FBG) in polymeric tensile test specimens is presented in this paper. The FBG strain and temperature cross-sensitivity was decoupled using two single mode FBG sensors, which were embedded...... in the specimen material with a certain angle between them. It is demonstrated that, during temperature variation, both FBG sensors show the same signal response. However, for any applied load the signal response is different, which is caused by the different levels of strain acting in each sensor. Equations...... calibration procedure (temperature and strain) was performed to this material-sensor pair, where a calibration error

  17. Ceramic thick film humidity sensor based on MgTiO{sub 3} + LiF

    Energy Technology Data Exchange (ETDEWEB)

    Kassas, Ahmad, E-mail: a.kassas.mcema@ul.edu.lb [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Bernard, Jérôme; Lelièvre, Céline; Besq, Anthony; Guhel, Yannick; Houivet, David; Boudart, Bertrand [Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Lakiss, Hassan [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Faculty of Engineering, Section III, Hariri Campus, Hadath, Beirut (Lebanon); Hamieh, Tayssir [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon)

    2013-10-15

    Graphical abstract: - Highlights: • The fabricated sensor based on MgTiO{sub 3} + LiF materials used the spin coating technology. • The response time is 70 s to detect variation between 5 and 95% relative humidity. • The addition of Scleroglucan controls the viscosity and decreases the roughness of thick film surface. • This humidity sensor is a promising, low-cost, high-quality, reliable ceramic films, that is highly sensitive to humidity. - Abstract: The feasibility of humidity sensor, consisting of a thick layer of MgTiO{sub 3}/LiF materials on alumina substrate, was studied. The thermal analysis TGA-DTGA and dilatometric analysis worked out to confirm the sintering temperature. An experimental plan was applied to describe the effects of different parameters in the development of the thick film sensor. Structural and microstructural characterizations of the developed thick film were made. Rheological study with different amounts of a thickener (scleroglucan “sclg”), showing the behavior variation, as a function of sclg weight % was illustrated and rapprochement with the results of thickness variation as a function of angular velocity applied in the spin coater. The electrical and dielectric measurements confirmed the sensitivity of the elaborated thick film against moisture, along with low response time.

  18. DETERMINATION OF INTERNAL STRAIN IN 3-D BRAIDED COMPOSITES USING OPTIC FIBER STRAIN SENSORS

    Institute of Scientific and Technical Information of China (English)

    YuanShenfang; HuangRui; LiXianghua; LiuXiaohui

    2004-01-01

    A reliable understanding of the properties of 3-D braided composites is of primary importance for proper utilization of these materials. A new method is introduced to study the mechanical performance of braided composite materials using embedded optic fiber sensors. Experimental research is performed to devise a method of incorporating optic fibers into a 3-D braided composite structure. The efficacy of this new testing method is evaluated on two counts. First,the optical performance of optic fibers is studied before and after incorporated into 3-D braided composites, as well as after completion of the manufacturing process for 3-D braided composites,to validate the ability of the optic fiber to survive the manufacturing process. On the other hand,the influence of incorporated optic fiber on the original braided composite is also researched by tension and compression experiments. Second, two kinds of optic fiber sensors are co-embedded into 3-D braided composites to evaluate their respective ability to measure the internal strain.Experimental results show that multiple optic fiber sensors can be co-braided into 3-D braided composites to determine their internal strain which is difficult to be fulfilled by other current existing methods.

  19. Effect of Prior Exposure at Elevated Temperatures on Tensile Properties and Stress-Strain Behavior of Four Non-Oxide Ceramic Matrix Composites

    Science.gov (United States)

    2015-06-18

    OF FOUR NON-OXIDE CERAMIC MATRIX COMPOSITES THESIS JUNE 2015 Sarah M. Wallentine, Captain, USAF AFIT-ENY-MS-15-J-048 DEPARTMENT OF THE...TEMPERATURES ON TENSILE PROPERTIES AND STRESS-STRAIN BEHAVIOR OF FOUR NON-OXIDE CERAMIC MATRIX COMPOSITES THESIS Presented to the Faculty...PRIOR EXPOSURE AT ELEVATED TEMPERATURES ON TENSILE PROPERTIES AND STRESS-STRAIN BEHAVIOR OF FOUR NON-OXIDE CERAMIC MATRIX COMPOSITES Sarah M

  20. Maximising electro-mechanical response by minimising grain-scale strain heterogeneity in phase-change actuator ceramics

    Science.gov (United States)

    Oddershede, Jette; Hossain, Mohammad Jahangir; Daniels, John E.

    2016-08-01

    Phase-change actuator ceramics directly couple electrical and mechanical energies through an electric-field-induced phase transformation. These materials are promising for the replacement of the most common electro-mechanical ceramic, lead zirconate titanate, which has environmental concerns. Here, we show that by compositional modification, we reduce the grain-scale heterogeneity of the electro-mechanical response by 40%. In the materials investigated, this leads to an increase in the achievable electric-field-induced strain of the bulk ceramic of 45%. Compositions of (100-x)Bi0.5Na0.5TiO3-(x)BaTiO3, which initially possess a pseudo-cubic symmetry, can be tuned to undergo phase transformations to combined lower symmetry phases, thus decreasing the anisotropy of the transformation strain. Further, modelling of transformation strains of individual grains shows that minimum grain-scale strain heterogeneity can be achieved by precise control of the lattice distortions and orientation distributions of the induced phases. The current results can be used to guide the design of next generation high-strain electro-mechanical ceramic actuator materials.

  1. Strain Sensor Using Optical Fiber Unsymmetrical F-P Cavity and the Characteristic Analysis

    Institute of Scientific and Technical Information of China (English)

    BI Weihong

    2000-01-01

    An intrinsic Fabry-Perot cavity consisted of different reflective mirrors is used in fiber-optical sensors for measuring the strain. The character of the unsymmetrical fiber-optical Fabry-Perot cavity and fiber-optic longitudinal stress-strain effect is analysed. The general theory and measurement method of strain are presented. A low fineness Fabry-Perot cavity is used to improve the linearity of optical fiber strain sensors. The result of experiment agrees well with the theory.

  2. Application of Tube-Packaged FBG Strain Sensor in Vibration Experiment of Submarine Pipeline Model

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Optical fiber sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability to stand explosion, immunity to electromagnetic interference and high accuracy, especially fit for measurement applications in harsh environment. In this study, a novel FBG (fiber Bragg grating) strain sensor, which is packaged in a 1.2 mm stainless steel tube with epoxy resin, is developed. Experiments are conducted on the universal material testing machine to calibrate its strain transferring characteristics. The sensor has the advantages of small size, high precision and flexible use, and exhibits promising potentials. Five tube-packaged strain FBG sensors have been applied to the vibration experiment of a submarine pipeline model. The strain measured with the FBG sensor agrees well with that measured with the electric resistance strain sensor.

  3. A fibre optic sensor for ambiguity measurement of apparent strain produced by electrical strain gauge-transient-heating-effect

    Energy Technology Data Exchange (ETDEWEB)

    El-Wakad, Mohamed-Tarek; Elsarnagawy, Tarek [King Saud Univ., Riyadh (Saudi Arabia)

    2010-07-01

    Strain gauges are useful sensors in many engineering and medical applications. When using one gauge for the measurement in quarter-bridge configurations, the electrical current flowing delivers power to the electrical strain gauge which causes a temperature rise (transient heat effect or THE), with a strain signal appearing as drift of the zero baseline. Fibre optic sensors on the other side are used to measure temperature as well as strain or force. The aim of this study is to evaluate the rise in temperature produced by the electrical strain gauge and to determine the equivalent apparent strain accordingly as a step towards using the reading to correct for the error due to the THE. The results of this study show that the optical fibre sensor is more sensitive compared to the semiconductor sensor used as a reference temperature sensor. The results also show the feasibility of determining the equivalent apparent strain values through reverse calculation of number of fringes resulting from the fibre optic sensor due to the temperature change. This was as an initial step to implement those values in the measuring electronic circuitry in order to eliminate the drift in the zero baselines. (orig.)

  4. Strain profiles in ion implanted ceramic polycrystals: An approach based on reciprocal-space crystal selection

    Energy Technology Data Exchange (ETDEWEB)

    Palancher, H., E-mail: herve.palancher@cea.fr; Martin, G.; Fouet, J. [CEA, DEN, DEC, F-13108 Saint Paul lez Durance (France); Goudeau, P. [Institut Pprime, CNRS-Université de Poitiers–ENSMA, SP2MI, F-86360 Chasseneuil (France); Boulle, A. [Science des Procédés Céramiques et Traitements de Surface (SPCTS), CNRS UMR 7315, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges (France); Rieutord, F. [CEA, DSM, INAC, F-38054 Grenoble Cedex 9 (France); Favre-Nicolin, V. [Université Grenoble-Alpes, F-38041 Grenoble, France, Institut Universitaire de France, F-75005 Paris (France); Blanc, N. [Institut NEEL, CNRS-Univ Grenoble Alpes, F-38042 Grenoble (France); Onofri, C. [CEA, DEN, DEC, F-13108 Saint Paul lez Durance (France); CEMES, CNRS UPR 8011, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4 (France)

    2016-01-18

    The determination of the state of strain in implanted materials is a key issue in the study of their mechanical stability. Whereas this question is nowadays relatively easily solved in the case of single crystals, it remains a challenging task in the case of polycrystalline materials. In this paper, we take benefit of the intense and parallel beams provided by third generation synchrotron sources combined with a two-dimensional detection system to analyze individual grains in polycrystals, hence obtaining “single crystal-like” data. The feasibility of the approach is demonstrated with implanted UO{sub 2} polycrystals where the in-depth strain profile is extracted for individual grains using numerical simulations of the diffracted signal. The influence of the implantation dose is precisely analyzed for several diffracting planes and grains. This work suggests that, at low fluences, the development of strain is mainly due to ballistic effects with little effect from He ions, independently from the crystallographic orientation. At higher fluences, the evolution of the strain profiles suggests a partial and anisotropic plastic relaxation. With the present approach, robust and reliable structural information can be obtained, even from complex polycrystalline ceramic materials.

  5. Highly Stretchable and Transparent Microfluidic Strain Sensors for Monitoring Human Body Motions.

    Science.gov (United States)

    Yoon, Sun Geun; Koo, Hyung-Jun; Chang, Suk Tai

    2015-12-16

    We report a new class of simple microfluidic strain sensors with high stretchability, transparency, sensitivity, and long-term stability with no considerable hysteresis and a fast response to various deformations by combining the merits of microfluidic techniques and ionic liquids. The high optical transparency of the strain sensors was achieved by introducing refractive-index matched ionic liquids into microfluidic networks or channels embedded in an elastomeric matrix. The microfluidic strain sensors offer the outstanding sensor performance under a variety of deformations induced by stretching, bending, pressing, and twisting of the microfluidic strain sensors. The principle of our microfluidic strain sensor is explained by a theoretical model based on the elastic channel deformation. In order to demonstrate its capability of practical usage, the simple-structured microfluidic strain sensors were performed onto a finger, wrist, and arm. The highly stretchable and transparent microfluidic strain sensors were successfully applied as potential platforms for distinctively monitoring a wide range of human body motions in real time. Our novel microfluidic strain sensors show great promise for making future stretchable electronic devices.

  6. Strain Sensors, Methods of Making Same, and Applications of Same

    Science.gov (United States)

    Biris, Alexandru S. (Inventor); Trigwell, Steven (Inventor); Hatfield, Walter (Inventor)

    2015-01-01

    In one aspect, the present invention relates to a layered structure usable in a strain sensor. In one embodiment, the layered structure has a substrate with a first surface and an opposite, second surface defining a body portion therebetween; and a film of carbon nanotubes deposited on the first surface of the substrate, wherein the film of carbon nanotubes is conductive and characterized with an electrical resistance. In one embodiment, the carbon nanotubes are aligned in a preferential direction. In one embodiment, the carbon nanotubes are formed in a yarn such that any mechanical stress increases their electrical response. In one embodiment, the carbon nanotubes are incorporated into a polymeric scaffold that is attached to the surface of the substrate. In one embodiment, the surfaces of the carbon nanotubes are functionalized such that its electrical conductivity is increased.

  7. Stretchable and Flexible High-Strain Sensors Made Using Carbon Nanotubes and Graphite Films on Natural Rubber

    OpenAIRE

    Sreenivasulu Tadakaluru; Wiradej Thongsuwan; Pisith Singjai

    2014-01-01

    Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ∼5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. U...

  8. Low temperature co-fired ceramic packaging of CMOS capacitive sensor chip towards cell viability monitoring

    Directory of Open Access Journals (Sweden)

    Niina Halonen

    2016-11-01

    Full Text Available Cell viability monitoring is an important part of biosafety evaluation for the detection of toxic effects on cells caused by nanomaterials, preferably by label-free, noninvasive, fast, and cost effective methods. These requirements can be met by monitoring cell viability with a capacitance-sensing integrated circuit (IC microchip. The capacitance provides a measurement of the surface attachment of adherent cells as an indication of their health status. However, the moist, warm, and corrosive biological environment requires reliable packaging of the sensor chip. In this work, a second generation of low temperature co-fired ceramic (LTCC technology was combined with flip-chip bonding to provide a durable package compatible with cell culture. The LTCC-packaged sensor chip was integrated with a printed circuit board, data acquisition device, and measurement-controlling software. The packaged sensor chip functioned well in the presence of cell medium and cells, with output voltages depending on the medium above the capacitors. Moreover, the manufacturing of microfluidic channels in the LTCC package was demonstrated.

  9. Twin-core fiber-based sensor for measuring the strain and bending simultaneously

    Science.gov (United States)

    Yang, Yuanyuan; Zhang, Yaxun; Liu, Zhihai; Yang, Jun; Yuan, Libo

    2013-08-01

    A novel composite interferometer sensor is presented and its sensing characteristics are investigated. Based on the infiber integrated Michelson interferometer, a quartz tube is used to encapsulate the ends of the twin-core fiber and single mode fiber to form the dual extrinsic FP cavities. Thereby, the Michelson and FP configurations are integrated into a single fiber, which we call it Michelson-FP composite interferometer sensor. The novel sensor can respond to the axial strain and radial bending simultaneously. We have derived and analyzed the interferometer principle of the new structure. The analysis results show that the interferometer sensor could be considered as the superposition of Michelson interferometer and FP interferometer. Moreover, we establish a testing system and conduct a series of experiments to investigate the strain and bending characteristics. We measure the reflection spectra with the spectrum analyzer. The spectral response of the composite interferometer sensor presents two pattern fringes with different frequencies due to the respective optical path interferometers. The experimental results indicate that the composite interferometer sensor is very sensitive to the strain and bending characteristics, and the presented sensor has different strain and bending sensitivity coefficients. Due to these characteristics, the presented sensor might be able to measure the strain and bending characteristics simultaneously. In conclusion, the presented novel interferometer sensor is of compact structure, high integration and good strain and bending sensing characteristics. Thus, many types of fiber-optic sensors may be built based on it.

  10. Nonlinear fiber-optic strain sensor based on four-wave mixing in microstructured optical fiber

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu; Frosz, Michael H.

    2012-01-01

    We demonstrate a nonlinear fiber-optic strain sensor, which uses the shifts of four-wave mixing Stokes and anti-Stokes peaks caused by the strain-induced changes in the structure and refractive index of a microstructured optical fiber. The sensor thus uses the inherent nonlinearity of the fiber...

  11. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.;

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress and ...

  12. Giant actuation strain nearly 0.6% in a periodically orthogonal poled lead titanate zirconate ceramic via reversible domain switching

    Science.gov (United States)

    Li, Faxin; Wang, Qiangzhong; Miao, Hongchen

    2017-08-01

    The widely used ferroelectric ceramics based actuators always suffer from small output strains (typically ˜0.1%-0.15%). Non-180° domain switching can generate a large strain in ferroelectrics but it is usually irreversible. In this work, we tailored the domain structures in a soft lead titanate zirconate (PZT) ceramic by periodical orthogonal poling. The non-180° switching in this domain-engineered PZT ceramics turns to be reversible, resulting in a local giant actuation strain of nearly 0.6% under a field of 2 kV/mm at 0.1 Hz. The large interfacial stresses between regions with different poling directions during electric loading/unloading were thought to be responsible for the reversible non-180° domain switching. The switching strain drops quickly with the increasing frequency, and stabilized at about 0.2% at or above 1.0 Hz. The large actuation strain remains quite stable after 104 cycles of loading, which is very promising for low-frequency, large-strain actuators.

  13. The Impact of Housing on the Characteristics of Ceramic Pressure Sensors--An Issue of Design for Manufacturability.

    Science.gov (United States)

    Santo Zarnik, Marina; Belavic, Darko; Novak, Franc

    2015-12-14

    An exploratory study of the impact of housing on the characteristics of a low-temperature co-fired ceramic (LTCC) pressure sensor is presented. The ceramic sensor structure is sealed in a plastic housing. This may have non-negligible effect on the final characteristics and should be considered in the early design phase. The manufacturability issue mainly concerning the selection of available housing and the most appropriate materials was considered with respect to different requirements for low and high pressure ranges of operation. Numerical predictions showed the trends and helped reveal the critical design parameters. Proper selection of the adhesive material remains an essential issue. Curing of the epoxy adhesive may introduce non-negligible residual stresses, which considerably influence the sensor's characteristics.

  14. Design considerations for micromechanical sensors using encapsulated built-in resonant strain gauges

    NARCIS (Netherlands)

    Tilmans, Harrie A.C.; Bouwstra, Siebe; Fluitman, Jan H.J; Spence, Scott L.

    1990-01-01

    This paper describes the various design aspects for micromechanical sensors consisting of a structure with encapsulated built-in resonant strain gauges. Analytical models are used to investigate the effect of device parameters on the behaviour of a pressure sensor and a force sensor. The analyses in

  15. Highly stretchable and wearable graphene strain sensors with controllable sensitivity for human motion monitoring.

    Science.gov (United States)

    Park, Jung Jin; Hyun, Woo Jin; Mun, Sung Cik; Park, Yong Tae; Park, O Ok

    2015-03-25

    Because of their outstanding electrical and mechanical properties, graphene strain sensors have attracted extensive attention for electronic applications in virtual reality, robotics, medical diagnostics, and healthcare. Although several strain sensors based on graphene have been reported, the stretchability and sensitivity of these sensors remain limited, and also there is a pressing need to develop a practical fabrication process. This paper reports the fabrication and characterization of new types of graphene strain sensors based on stretchable yarns. Highly stretchable, sensitive, and wearable sensors are realized by a layer-by-layer assembly method that is simple, low-cost, scalable, and solution-processable. Because of the yarn structures, these sensors exhibit high stretchability (up to 150%) and versatility, and can detect both large- and small-scale human motions. For this study, wearable electronics are fabricated with implanted sensors that can monitor diverse human motions, including joint movement, phonation, swallowing, and breathing.

  16. Strain measurement in concrete using embedded carbon roving-based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Quadflieg, Till; Gries, Thomas [RWTH Aachen Univ. (Germany). Inst. fuer Textiltechnik (ITA); Stolyarov, Oleg [St. Petersburg Polytechnic Univ. (Russian Federation)

    2016-11-01

    This paper presents the results of the application of carbon rovings as strain sensors for measuring the strain in concrete. In this work, three types of electrically conductive carbon roving with different characteristics were used. The possibility of using carbon rovings as a strain sensor is demonstrated via measurements in tensile and four point bending tests. The experimental setups and methods for measuring the electrical resistance of carbon roving in the roving and concrete are described. The results of the characterization of the electrical behavior as a function of strain of carbon rovings and concrete are presented and discussed. The obtained results indicate that the strain range of carbon rovings optimally corresponds to the strain range of concrete. This characteristic behavior makes the carbon rovings well suited for the use as strain sensors. A good correlation has been found between the electrical resistance-strain curve of the carbon roving and the measurements in the concrete.

  17. Review of the Strain Modulation Methods Used in Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Kuo Li

    2016-01-01

    Full Text Available Fiber Bragg grating (FBG is inherently sensitive to temperature and strain. By modulating FBG’s strain, various FBG sensors have been developed, such as sensors with enhanced or reduced temperature sensitivity, strain/displacement sensors, inclinometers, accelerometers, pressure meters, and magnetic field meters. This paper reviews the strain modulation methods used in these FBG sensors and categorizes them according to whether the strain of an FBG is changed evenly. Then, those even-strain-change methods are subcategorized into (1 attaching/embedding an FBG throughout to a base and (2 fixing the two ends of an FBG and (2.1 changing the distance between the two ends or (2.2 bending the FBG by applying a transverse force at the middle of the FBG. This review shows that the methods of “fixing the two ends” are prominent because of the advantages of large tunability and frequency modulation.

  18. Composite Shell Strain Detection for SRM Based on Optical Fiber Sensors

    Science.gov (United States)

    Zhang, Lei; Chang, Xin-Long; Zhang, You-hong; Chen, Xiang-dong

    2017-06-01

    As a new passive sensor, fiber Bragg grating (FBG) sensors have provided a new idea for the SRM shell damage detection, which is to integrate the FBG sensor network in the material interior or to the surface to monitor the shell structure. However, it is difficult to embed the FBG sensor in filament wound composite material structure for the reason of large tension and high temperature in process of manufacture. Therefore we propose a new method that embed FBG sensor network between the composite shell surface and the thermal protective coating. The calibration of sensor is presented by tensile test and the strain transfer coefficient is gotten. It is certified by the hydrostatic test that the FBG sensors could precisely describe the strain variation and distribution of the composite shell and effectively improve the survival rate by embedding the FBG sensors between the composite shell surface and the thermal protective coating.

  19. Effect of coating on the strain transfer of optical fiber sensors.

    Science.gov (United States)

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2011-01-01

    Optical fiber strain sensors with light weight, small dimensions and immunity to electromagnetic interference are widely used in structural health monitoring devices. As a sensor, it is expected that the strains between the optical fiber and host structure are the same. However, due to the shear deformation of the protective coating, the optical fiber strain is different from that of host structure. To improve the measurement accuracy, the strain measured by the optical fiber needs to be modified to reflect the influence of the coating. In this investigation, a theoretical model of the strain transferred from the host material to the optical fiber is developed to evaluate the interaction between the host material and coating. The theoretical predictions are validated with a numerical analysis using the finite element method. Experimental tests are performed to reveal the differential strains between the optical fiber strain sensor and test specimen. The Mach-Zehnder interferometric type fiber-optic sensor is adopted to measure the strain. Experimental results show that the strain measured at the optical fiber is lower than the true strain in the test specimen. The percentage of strain in the test specimen actually transferred to the optical fiber is dependent on the bonded length of the optical fiber and the protective coating. The general trend of the strain transformation obtained from both experimental tests and theoretical predictions shows that the longer the bonded length and the stiffer the coating the more strain is transferred to the optical fiber.

  20. Distributed fiber optic strain sensor based on the Sagnac and Michelson interferometers

    Science.gov (United States)

    Udd, Eric

    1996-04-01

    By placing fiber optic gratings in a Sagnac loop a distributed strain sensor may be formed by using the light reflected from the fiber gratings as sources for balanced Michelson and Mach- Zehnder interferometers. In this manner the resulting fiber optic sensor is capable of measuring integrated strain over lengths determined by the fiber grating position, point strain and temperature at the fiber grating locations and localizing and measuring the position of a time varying signal such as an acoustic wave.

  1. Modified Michelson fiber-optic interferometer: A remote low-coherence distributed strain sensor array

    Science.gov (United States)

    Yuan, Libo

    2003-01-01

    A simple modified Michelson fiber-optic low-coherence interferometric quasi-distributed sensing system permitting absolute length measurement in remote reflective sensor array is proposed. The sensor reflective signals characteristics have been analyzed and the relationship between light signal intensities and sensors number was given for multiplexing potential evaluation. The proposed sensing scheme will be useful for the remote measurement of strain. An important application could be deformation sensing in smart structures. Experimentally, a three sensors array has been demonstrated.

  2. Ceramic hot film sensor for exhaust gas mass flow measurements in automotive applications; Keramischer Heissfilmsensor zur Abgasmassenstrommessung in automotiven Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Dismon, Heinrich; Grimm, Karsten; Toennesmann, Andres; Nigrin, Sven [Pierburg GmbH, Neuss (Germany); Wienand, Karlheinz; Muziol, Matthias [Heraeus Sensor Technology GmbH, Kleinostheim (Germany)

    2008-07-01

    Due to increasingly stringent emission standards, a number of internal measures as well as exhaust gas aftertreatment systems have become state-of-the-art technology for passenger car and heavy duty engines. However, the full potential of these measures, for example the cooled external exhaust gas recirculation, can only be utilized if the engine control is adapted adequately well in all engine states. Thus, the requirements for future engine controls become more demanding and consequently the standards for sensors used in the control loop will increase. In this context this article introduces a new exhaust gas mass flow sensor based or the principle of hot film anemometry. The sensor comprising a ceramic sensor element is developed especially for the use in engine exhaust gases providing the exhaust gas mass flow as a direct measurement and control variable. Next to the sensor technology first results of engine tests are presented in this paper. (orig.)

  3. Analysis of strain and stress in ceramic, polymer and metal matrix composites by Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Colomban, P. [LADIR, Nanophases and Heterogeneous Solids Group, UMR 7075 CNRS and Universite Pierre et Marie Curie, 2 rue Henry-Dunant, 94320 Thiais (France)

    2002-08-01

    Raman scattering is a unique tool providing information on the structure and short-range order of matter. Stress-induced Raman shifts can be used to determine the stress/strain in films, fibres, particulate composites and, more generally, in any phase a few microns or more in scale. Quantitative results follow from a wavenumber calibration as a function of tensile strains or pressures applied to reference fibres or crystals. Furthermore, if the material is coloured, (near) resonant Raman scattering occurs, which enhances the scattered light intensity and simplifies the spectra - especially for harmonics - but drastically reduces the analysed volume (in-depth penetration {proportional_to}10-100 nm). This paper discusses the effective and potential advantages/drawbacks of Raman micro-spectrometry technique. The procedures to improve the sensitivity, the legibility and the reliability will be addressed. Examples will be chosen among (aramid, C, SiC) fibre- reinforced ceramic (CMCs), polymer (PMCs) or metal matrix (MMCs) composites. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  4. Preparation and Property Research of Strain Sensor Based on PDMS and Silver Nanomaterials

    Directory of Open Access Journals (Sweden)

    Lihua Liu

    2017-01-01

    Full Text Available Based on the advantages and broad applications of stretchable strain sensors, this study reports a simple method to fabricate a highly sensitive strain sensor with Ag nanomaterials-polydimethylsiloxane (AgNMs-PDMS to create a synergic conductive network and a sandwich-structure. Three Ag nanomaterial samples were synthesized by controlling the concentrations of the FeCl3 solution and reaction time via the heat polyols thermal method. The AgNMs network’s elastomer nanocomposite-based strain sensors show strong piezoresistivity with a high gauge factor of 547.8 and stretchability from 0.81% to 7.26%. The application of our high-performance strain sensors was demonstrated by the inducting finger of the motion detection. These highly sensitive sensors conform to the current trends of flexible electronics and have prospects for broad application.

  5. Strain Sensor of Carbon Nanotubes in Microscale: From Model to Metrology

    Directory of Open Access Journals (Sweden)

    Wei Qiu

    2014-01-01

    Full Text Available A strain sensor composed of carbon nanotubes with Raman spectroscopy can achieve measurement of the three in-plane strain components in microscale. Based on previous work on the mathematic model of carbon nanotube strain sensors, this paper presents a detailed study on the optimization, diversification, and standardization of a CNT strain sensor from the viewpoint of metrology. A new miniaccessory for polarization control is designed, and two different preparing methods for CNT films as sensing media are introduced to provide diversified choices for applications. Then, the standard procedure of creating CNT strain sensors is proposed. Application experiments confirmed the effectiveness of the above improvement, which is helpful in developing this method for convenient metrology.

  6. Strain sensor of carbon nanotubes in microscale: from model to metrology.

    Science.gov (United States)

    Qiu, Wei; Li, Shi-Lei; Deng, Wei-Lin; Gao, Di; Kang, Yi-Lan

    2014-01-01

    A strain sensor composed of carbon nanotubes with Raman spectroscopy can achieve measurement of the three in-plane strain components in microscale. Based on previous work on the mathematic model of carbon nanotube strain sensors, this paper presents a detailed study on the optimization, diversification, and standardization of a CNT strain sensor from the viewpoint of metrology. A new miniaccessory for polarization control is designed, and two different preparing methods for CNT films as sensing media are introduced to provide diversified choices for applications. Then, the standard procedure of creating CNT strain sensors is proposed. Application experiments confirmed the effectiveness of the above improvement, which is helpful in developing this method for convenient metrology.

  7. Seven-year-long crack detection monitoring by Brillouin-based fiber optic strain sensor

    Science.gov (United States)

    Imai, Michio

    2015-03-01

    As an optical fiber is able to act as a sensing medium, a Brillouin-based sensor provides continuous strain information along an optical fiber. The sensor has been used in a wide range of civil engineering applications because no other tool can satisfactorily detect discontinuity such as a crack. Cracking generates a local strain change on the embedded optical fiber, thus Brillouin optical correlation domain analysis (BOCDA), which offers a high spatial resolution by stimulated Brillouin scattering, is expected to detect a fine crack on concrete structures. The author installed the surface-mounted optical fiber on a concrete deck and periodically monitored strain distribution for seven years. This paper demonstrates how a BOCDA-based strain sensor can be employed to monitor cracks in a concrete surface. Additionally, focusing on another advantage of the sensor, the natural frequency of the deck is successfully measured by dynamic strain history.

  8. Wireless SAW Sensor Strain Gauge & Integrated Interrogator Design Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Wireless, passive, SAW sensor system operates in a multi-sensor environment with a range in excess of 45 feet. This proposed system offers unique...

  9. Wireless SAW Sensor Strain Gauge & Integrated Interrogator Design Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Wireless, passive, Surface Acoustic Wave (SAW) temperature sensors, which can operate in a multi-sensor environment, have recently been successfully demonstrated. A...

  10. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... and force sensitivity measurements are taken before and after annealing. Parameters such as annealing time and annealing temperature are investigated. The change of the fibre diameter due to water absorption and the annealing process is also considered. The results show that annealing the polymer optical...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  11. Simultaneous Static Strain, Temperature and Vibration Measurement Using an Integrated FBG/EFPI Sensor

    Institute of Scientific and Technical Information of China (English)

    曾祥楷; 饶云江

    2001-01-01

    A novel technique for simultaneous measurement of static strain, temperature and vibration in health monitoring of structures is demonstrated using an integrated in-fibre Bragg grating (FBG)/extrinsic Fabry-Pérot interferometer (EFPI) sensor. The EFPI sensor provides static strain and vibration information simultaneously by using the channel-spectrum method and the low-coherence interferometric technique, respectively. The FBG sensor is used for temperature measurement. The experimental results show that a static-strain accuracy of l20με, a temperature accuracy of +l℃ and a vibration resolution of 1 nm have been achieved with a good repeatability.

  12. Thermoresistive strain sensor and positioning method for roll-to-roll processes.

    Science.gov (United States)

    Liao, Kuan-Hsun; Lo, Cheng-Yao

    2014-05-05

    This study uses the Joule heating effect-generated temperature difference to monitor in real-time and localize both compressive and tensile strains for the polymer substrates used in the roll-to-roll process. A serpentine gold (Au) line was patterned on a polyethylenenaphthalate (PEN) substrate to form the strain sensor based on thermoresistive behavior. This strain sensor was then subjected to either current or voltage to induce the Joule heating effect on the Au resistor. An infrared (IR) detector was used to monitor the strain-induced temperature difference on the Au and PEN surfaces and the minimal detectable bending radius was 0.9 mm with a gauge factor (GF) of 1.46. The proposed design eliminates the judgment ambiguity from conventional resistive strain sensors where resistance is the only physical quantity monitored. This study precisely and successfully indicated the local strain quantitatively and qualitatively with complete simulations and measurements.

  13. Thermoresistive Strain Sensor and Positioning Method for Roll-to-Roll Processes

    Directory of Open Access Journals (Sweden)

    Kuan-Hsun Liao

    2014-05-01

    Full Text Available This study uses the Joule heating effect-generated temperature difference to monitor in real-time and localize both compressive and tensile strains for the polymer substrates used in the roll-to-roll process. A serpentine gold (Au line was patterned on a polyethylenenaphthalate (PEN substrate to form the strain sensor based on thermoresistive behavior. This strain sensor was then subjected to either current or voltage to induce the Joule heating effect on the Au resistor. An infrared (IR detector was used to monitor the strain-induced temperature difference on the Au and PEN surfaces and the minimal detectable bending radius was 0.9 mm with a gauge factor (GF of 1.46. The proposed design eliminates the judgment ambiguity from conventional resistive strain sensors where resistance is the only physical quantity monitored. This study precisely and successfully indicated the local strain quantitatively and qualitatively with complete simulations and measurements.

  14. Strain Sensors with Adjustable Sensitivity by Tailoring the Microstructure of Graphene Aerogel/PDMS Nanocomposites.

    Science.gov (United States)

    Wu, Shuying; Ladani, Raj B; Zhang, Jin; Ghorbani, Kamran; Zhang, Xuehua; Mouritz, Adrian P; Kinloch, Anthony J; Wang, Chun H

    2016-09-21

    Strain sensors with high elastic limit and high sensitivity are required to meet the rising demand for wearable electronics. Here, we present the fabrication of highly sensitive strain sensors based on nanocomposites consisting of graphene aerogel (GA) and polydimethylsiloxane (PDMS), with the primary focus being to tune the sensitivity of the sensors by tailoring the cellular microstructure through controlling the manufacturing processes. The resultant nanocomposite sensors exhibit a high sensitivity with a gauge factor of up to approximately 61.3. Of significant importance is that the sensitivity of the strain sensors can be readily altered by changing the concentration of the precursor (i.e., an aqueous dispersion of graphene oxide) and the freezing temperature used to process the GA. The results reveal that these two parameters control the cell size and cell-wall thickness of the resultant GA, which may be correlated to the observed variations in the sensitivities of the strain sensors. The higher is the concentration of graphene oxide, then the lower is the sensitivity of the resultant nanocomposite strain sensor. Upon increasing the freezing temperature from -196 to -20 °C, the sensitivity increases and reaches a maximum value of 61.3 at -50 °C and then decreases with a further increase in freezing temperature to -20 °C. Furthermore, the strain sensors offer excellent durability and stability, with their piezoresistivities remaining virtually unchanged even after 10 000 cycles of high-strain loading-unloading. These novel findings pave the way to custom design strain sensors with a desirable piezoresistive behavior.

  15. Dynamic strain measurement of hydraulic system pipeline using fibre Bragg grating sensors

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    2016-04-01

    Full Text Available Fatigue failure is a serious problem in hydraulic piping systems installed in the machinery and equipment working in harsh operational conditions. To alleviate this problem, health monitoring of pipes can be conducted by measuring and analysing vibration-induced strain. Fibre Bragg grating is considered as a promising sensing approach for dynamic load monitoring. In this article, dynamic strain measurements based on fibre Bragg grating sensors for small-bore metal pipes have been investigated. The quasi-distributed strain sensing of fibre Bragg grating sensors is introduced. Two comparison experiments were carried out under vibration and impact loads among the methods of electrical strain gauge, piezoelectric accelerometer and fibre Bragg grating sensor. Experimental results indicate that fibre Bragg grating sensor possesses an outstanding ability to resist electromagnetic interference compared with strain gauge. The natural frequency measurement results, captured by fibre Bragg grating sensor, agree well with the modal analysis results obtained from finite element analysis. In addition, the attached fibre Bragg grating sensor brings a smaller impact on the dynamic characteristics of the measured pipe than the accelerometer due to its small size and lightweight. Fibre Bragg grating sensors have great potential for the quasi-distributed measurement of dynamic strain for the dynamic characteristic research and health monitoring of hydraulic system pipeline.

  16. A Passive Pressure Sensor Fabricated by Post-Fire Metallization on Zirconia Ceramic for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Tao Luo

    2014-09-01

    Full Text Available A high-temperature pressure sensor realized by the post-fire metallization on zirconia ceramic is presented. The pressure signal can be read out wirelessly through the magnetic coupling between the reader antenna and the sensor due to that the sensor is equivalent to an inductive-capacitive (LC resonance circuit which has a pressure-sensitive resonance frequency. Considering the excellent mechanical properties in high-temperature environment, multilayered zirconia ceramic tapes were used to fabricate the pressure-sensitive structure. Owing to its low resistivity, sliver paste was chosen to form the electrical circuit via post-fire metallization, thereby enhancing the quality factor compared to sensors fabricated by cofiring with a high-melting-point metal such as platinum, tungsten or manganese. The design, fabrication, and experiments are demonstrated and discussed in detail. Experimental results showed that the sensor can operate at 600 °C with quite good coupling. Furthermore, the average sensitivity is as high as 790 kHz/bar within the measurement range between 0 and 1 Bar.

  17. High-strain-rate superplasticity in oxide ceramics: a trial of microstructural design based on creep-cavitation mechanisms

    Institute of Scientific and Technical Information of China (English)

    Keijiro HIRAGA; Byung-Nam KIM; Koji MORITA; Hidehiro YOSHIDA; Yoshio SAKKA; Masaaki TABUCHI

    2011-01-01

    From existing knowledge about high-temperature cavitation mechanisms, necessary conditions were discussed for the suppression of cavitation failure during superplastic deformation in ceramic materials. The discussion, where special attention was placed on the relaxation of stress concentrations during grain-boundary sliding and cavity nucleation and growth, leaded to a conclusion that cavitation failure could be retarded by the simultaneous controlling of the initial grain size, the number of residual defects,diffusivity, dynamic grain growth and the homogeneity of microstructure. On the basis of this conclusion, high-strain-rate superplasticity (defined as superplasticity at a strain rate higher than 0.01 s-1) could be intentionally attained in some oxide ceramic materials. This was shown in tetragonal zirconia and composites consisting of zirconia, α-alumina and a spinel phase.

  18. Strain Modal Analysis of Small and Light Pipes Using Distributed Fibre Bragg Grating Sensors.

    Science.gov (United States)

    Huang, Jun; Zhou, Zude; Zhang, Lin; Chen, Juntao; Ji, Chunqian; Pham, Duc Truong

    2016-09-25

    Vibration fatigue failure is a critical problem of hydraulic pipes under severe working conditions. Strain modal testing of small and light pipes is a good option for dynamic characteristic evaluation, structural health monitoring and damage identification. Unique features such as small size, light weight, and high multiplexing capability enable Fibre Bragg Grating (FBG) sensors to measure structural dynamic responses where sensor size and placement are critical. In this paper, experimental strain modal analysis of pipes using distributed FBG sensors ispresented. Strain modal analysis and parameter identification methods are introduced. Experimental strain modal testing and finite element analysis for a cantilever pipe have been carried out. The analysis results indicate that the natural frequencies and strain mode shapes of the tested pipe acquired by FBG sensors are in good agreement with the results obtained by a reference accelerometer and simulation outputs. The strain modal parameters of a hydraulic pipe were obtained by the proposed strain modal testing method. FBG sensors have been shown to be useful in the experimental strain modal analysis of small and light pipes in mechanical, aeronautic and aerospace applications.

  19. Bolt Shear Force Sensor

    Science.gov (United States)

    2015-03-12

    to connect to a signal conditioner 200 (See FIG. 6). The deformable ring 102 may be constructed from conventional materials (metal, composite...plastic etc.) or with piezoelectric ceramics. If the ring 102 is constructed with piezoelectric ceramics, the ring itself is the sensor; therefore...elements used (i.e., resistance strain gages, fiber optic Bragg grating or piezoelectric material ), an output is generated (i.e., resistance

  20. Fiber Bragg grating dynamic strain sensor using an adaptive reflective semiconductor optical amplifier source.

    Science.gov (United States)

    Wei, Heming; Tao, Chuanyi; Zhu, Yinian; Krishnaswamy, Sridhar

    2016-04-01

    In this paper, a reflective semiconductor optical amplifier (RSOA) is configured to demodulate dynamic spectral shifts of a fiber Bragg grating (FBG) dynamic strain sensor. The FBG sensor and the RSOA source form an adaptive fiber cavity laser. As the reflective spectrum of the FBG sensor changes due to dynamic strains, the wavelength of the laser output shifts accordingly, which is subsequently converted into a corresponding phase shift and demodulated by an unbalanced Michelson interferometer. Due to the short transition time of the RSOA, the RSOA-FBG cavity can respond to dynamic strains at high frequencies extending to megahertz. A demodulator using a PID controller is used to compensate for low-frequency drifts induced by temperature and large quasi-static strains. As the sensitivity of the demodulator is a function of the optical path difference and the FBG spectral width, optimal parameters to obtain high sensitivity are presented. Multiplexing to demodulate multiple FBG sensors is also discussed.

  1. Flat-Cladding Fiber Bragg Grating Sensors for Large Strain Amplitude Fatigue Tests

    Directory of Open Access Journals (Sweden)

    Xijia Gu

    2010-08-01

    Full Text Available We have successfully developed a flat-cladding fiber Bragg grating sensor for large cyclic strain amplitude tests of up to ±8,000 με. The increased contact area between the flat-cladding fiber and substrate, together with the application of a new bonding process, has significantly increased the bonding strength. In the push-pull fatigue tests of an aluminum alloy, the plastic strain amplitudes measured by three optical fiber sensors differ only by 0.43% at a cyclic strain amplitude of ±7,000 με and 1.9% at a cyclic strain amplitude of ±8,000 με. We also applied the sensor on an extruded magnesium alloy for evaluating the peculiar asymmetric hysteresis loops. The results obtained were in good agreement with those measured from the extensometer, a further validation of the sensor.

  2. Ultrathin epidermal strain sensor based on an elastomer nanosheet with an inkjet-printed conductive polymer

    Science.gov (United States)

    Tetsu, Yuma; Yamagishi, Kento; Kato, Akira; Matsumoto, Yuya; Tsukune, Mariko; Kobayashi, Yo; Fujie, Masakatsu G.; Takeoka, Shinji; Fujie, Toshinori

    2017-08-01

    To minimize the interference that skin-contact strain sensors cause natural skin deformation, physical conformability to the epidermal structure is critical. Here, we developed an ultrathin strain sensor made from poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) inkjet-printed on a polystyrene-polybutadiene-polystyrene (SBS) nanosheet. The sensor, whose total thickness and gauge factor were ˜1 µm and 0.73 ± 0.10, respectively, deeply conformed to the epidermal structure and successfully detected the small skin strain (˜2%) while interfering minimally with the natural deformation of the skin. Such an epidermal strain sensor will open a new avenue for precisely detecting the motion of human skin and artificial soft-robotic skin.

  3. Effect of thermally induced strain on optical fiber sensors embedded in cement-based composites

    Science.gov (United States)

    Yuan, Li-bo; Zhou, Li-min; Jin, Wei; Lau, K. T.; Poon, Chi-kin

    2003-04-01

    A critical issue in developing a fiber-optic strain gauge is its codependency on temperature and strain. Any changes in the output of the optical fiber sensor due to its own thermal sensitivity and the thermal expansion of the most material will be misinterpreted as a change in shape-induced strain in the structure. This codependence is often referred to as thermally induced apparent strain or simply apparent strain. In this paper, an analytical model was developed to evaluate the thermally induced strain in fiber optic sensors embedded in cement-based composites. The effects of thermal induced strain on embedded optical fiber were measured with a white-light fiber-optic Michelson sensing interferometer for a number of cement-based host materials.

  4. A Novel Fiber Bragg Grating with Triangular Spectrum and Its Application in Strain Sensor

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel fiber Bragg grating with triangular spectrum is presented. A strain sensor based on this fiber grating is proposed. Experiments showed that the sensor has advantages of high sensitivity, wider measuring range and immunity to fluctuation of the light source power.

  5. Development of a mechanical strain amplifying transducer with Bragg grating sensor for low-amplitude strain sensing

    Science.gov (United States)

    Nawrot, Urszula; Geernaert, Thomas; De Pauw, Ben; Anastasopoulos, Dimitrios; Reynders, Edwin; De Roeck, Guido; Berghmans, Francis

    2017-07-01

    Vibration-based damage identification is a well-known method to support health monitoring of civil engineering structures. Damage in such structures can be identified by measuring changes of the natural frequencies, damping factors or modal displacements of the structure. However, this approach suffers from the low sensitivity of these natural frequencies and modal displacements to certain types of damage. Modal strains and curvatures can be more sensitive to local damage, but direct monitoring of these quantities with sufficient spatial resolution is not possible with current measurement techniques due to the very small strain levels (sub-microstrain) caused by ambient or operational excitation. To deal with this issue, we propose a novel mechanical transducer equipped with an optical fiber Bragg grating (FBG) sensor that enhances the sensitivity to strain with a factor larger than 30. The principle of operation of the transducer exploits a symmetric cantilever structure that enlarges the strain experienced by the FBG sensor compared to the strain applied to the transducer itself. We carried out dynamic and static tests to verify the ability of the strain-amplifying transducers to measure small-amplitude strain levels and to evidence the potential for carrying out FBG based modal strain measurements on concrete civil engineering structures.

  6. Development of a low-cost and miniaturized fiber Bragg grating strain sensor system

    Science.gov (United States)

    Yuan, Lili; Zhao, Yao; Sato, Shinya

    2017-05-01

    A fiber Bragg grating (FBG) strain sensor system that measures strains from reflected power changes of FBGs is presented. A laser diode used as a light source and a power meter are used in the system, which makes the FBG sensor system inexpensive and miniaturized. The reflected power of an FBG is expressed by the product of the reflectivity of the FBG and the optical power of the laser diode. Comparison of the strain applied in the experiment with that calculated from the reflected power shows that relative errors are within 5.1%, which verifies the feasibility of the strain sensor system proposed in this work. In addition, on the basis of this method, we fabricate a cantilever load cell using an FBG as the strain gauge instead of an electrical resistance, and also quantify the load range that can be measured by this load cell.

  7. Design Considerations for Aural Vital Signs Using PZT Piezoelectric Ceramics Sensor Based on the Computerization Method

    Directory of Open Access Journals (Sweden)

    Jerapong Tantrakoon

    2007-11-01

    Full Text Available The purpose was to illustrate how system developed for measurement of the aural vital signs such as patient’s heart and lung sounds in the hospital. For heart sounds measurement must operate the frequency response between 20 – 800 Hz, and lung sounds measurement must operate the frequency response between 160 – 4,000 Hz. The method was designed PZT piezoelectric ceramics for both frequency response in the same PZT sensor. It converts a signal from aural vital sign form to voltage signal. The signal is suitably amplified and re-filtered in band pass frequency band. It is converted to digital signal by an analog to digital conversion circuitry developed for the purpose. The results were that all signals can fed to personal computer through the sound card port. With the supporting software for drawing of graphic on the screen, the signal for a specific duration is accessed and stored in the computer’s memory in term of each patient’s data. In conclusion, the data of each patient call dot pcg (.pcg for drawing graph and dot wave (.wave for sound listening or automatic sending via electronic mail to the physician for later analysis of interpreting the sounds on the basis of their time domain and frequency domain representation to diagnose heart disorders.

  8. Reconstruction of in-plane strain maps using hybrid dense sensor network composed of sensing skin

    Science.gov (United States)

    Downey, Austin; Laflamme, Simon; Ubertini, Filippo

    2016-12-01

    The authors have recently developed a soft-elastomeric capacitive (SEC)-based thin film sensor for monitoring strain on mesosurfaces. Arranged in a network configuration, the sensing system is analogous to a biological skin, where local strain can be monitored over a global area. Under plane stress conditions, the sensor output contains the additive measurement of the two principal strain components over the monitored surface. In applications where the evaluation of strain maps is useful, in structural health monitoring for instance, such signal must be decomposed into linear strain components along orthogonal directions. Previous work has led to an algorithm that enabled such decomposition by leveraging a dense sensor network configuration with the addition of assumed boundary conditions. Here, we significantly improve the algorithm’s accuracy by leveraging mature off-the-shelf solutions to create a hybrid dense sensor network (HDSN) to improve on the boundary condition assumptions. The system’s boundary conditions are enforced using unidirectional RSGs and assumed virtual sensors. Results from an extensive experimental investigation demonstrate the good performance of the proposed algorithm and its robustness with respect to sensors’ layout. Overall, the proposed algorithm is seen to effectively leverage the advantages of a hybrid dense network for application of the thin film sensor to reconstruct surface strain fields over large surfaces.

  9. High strain FBG sensors for structural fatigue testing of military aircraft

    Science.gov (United States)

    Tejedor, S.; Kopczyk, J.; Nuyens, T.; Davis, C.

    2012-02-01

    This paper reports on a series of tests investigating the performance of Draw Tower Gratings (DTGs) combined with custom-designed broad area packaging and bonding techniques for high-strain sensing applications on Defence platforms. The sensors and packaging were subjected to a series of high-strain static and cyclic loading tests and a summary of these results is presented.

  10. Metal-packaged fibre Bragg grating strain sensors for surface-mounting onto spalled concrete wind turbine foundations

    Science.gov (United States)

    Perry, M.; Fusiek, G.; McKeeman, I.; Niewczas, P.; Saafi, M.

    2015-09-01

    In this work, we demonstrate preliminary results for a hermetically sealed, metal-packaged fibre Bragg grating strain sensor for monitoring existing concrete wind turbine foundations. As the sensor is bolted to the sub-surface of the concrete, it is suitable for mounting onto uneven, wet and degraded surfaces, which may be found in buried foundations. The sensor was able to provide reliable measurements of concrete beam strain during cyclic three- and four- point bend tests. The strain sensitivity of the prototype sensor is currently 10 % of that of commercial, epoxied fibre strain sensors.

  11. Processing and Characterization of a Novel Distributed Strain Sensor Using Carbon Nanotube-Based Nonwoven Composites

    Directory of Open Access Journals (Sweden)

    Hongbo Dai

    2015-07-01

    Full Text Available This paper describes the development of an innovative carbon nanotube-based non-woven composite sensor that can be tailored for strain sensing properties and potentially offers a reliable and cost-effective sensing option for structural health monitoring (SHM. This novel strain sensor is fabricated using a readily scalable process of coating Carbon nanotubes (CNT onto a nonwoven carrier fabric to form an electrically-isotropic conductive network. Epoxy is then infused into the CNT-modified fabric to form a free-standing nanocomposite strain sensor. By measuring the changes in the electrical properties of the sensing composite the deformation can be measured in real-time. The sensors are repeatable and linear up to 0.4% strain. Highest elastic strain gage factors of 1.9 and 4.0 have been achieved in the longitudinal and transverse direction, respectively. Although the longitudinal gage factor of the newly formed nanocomposite sensor is close to some metallic foil strain gages, the proposed sensing methodology offers spatial coverage, manufacturing customizability, distributed sensing capability as well as transverse sensitivity.

  12. Study of a high-precision SAW-MOEMS strain sensor with laser optics

    Science.gov (United States)

    Liu, Xinwei; Chen, Shufen; Li, Honglang; Zou, Zhengfeng; Fu, Lei; Meng, Yanbin

    2015-02-01

    A novel structure design of a surface acoustic wave (SAW) micro-optic-electro-mechanical-system (MOEMS) strain sensor with a light readout unit is presented in this paper. By measuring the polarization intensity ratio of the TE/TM mode outputted from the waveguide, the strain produced from an object can be measured precisely. The basic working principle of the SAW MOEMS strain sensor is introduced and the mathematical model of the strain sensor system is established. The SAW characteristics effected by the strain sensor are mathematically deduced. The coupling coefficient between the SAW modes and light modes can be calculated based on the theory of coupling modes. The conversion coefficient of polarized light modes is obtained. Due to the restrictions of the specific parameters of the device, the level of technology and the material characteristics, the sensitivity of the strain sensor system is calculated through simulation as 0.1 μɛ, with a dynamic range of 0 ~ ±50 μɛ.

  13. A novel temperature-insensitive strain sensor based on tapered fiber grating

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel temperature-insensitive strain sensor based on bandwidth demodulation of the reflected light from the tapered fiber grating is presented, which is simple and low-cost and has considerable potential particularly application for strain sensing,and with the development of the interrogation system, it can demodulate both the bandwidth and the center wavelength of the reflected light from TFG to measure strain and temperature simultaneously.

  14. Simple Creep Test For Ceramic Fibers

    Science.gov (United States)

    Dicarlo, James A.; Morscher, Gregory N.

    1994-01-01

    Simple bend-stress-relaxation test yields information on creep-related properties of polycrystalline ceramic fibers. Determination of these properties important part of efforts to develop ceramic composite materials that retain mechanical strength and resistance to creep at high temperatures. Present test measures effects of time, temperature, and applied strain on creep-related relaxation of bend stress in ceramic fiber of almost any diameter in almost any environment, without need for contact sensors. Degree of relaxation of bend stress determined from radii of curvature.

  15. Quality Factor Effect on the Wireless Range of Microstrip Patch Antenna Strain Sensors

    Directory of Open Access Journals (Sweden)

    Ali Daliri

    2014-01-01

    Full Text Available Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace and civil industries. However, the wireless interrogation range of these sensors is limited to few centimeters, which restricts their practical application. This paper presents an investigation on the effect of circular microstrip patch antenna (CMPA design on the quality factor and the maximum practical wireless reading range of the sensor. The results reveal that by using appropriate substrate materials the interrogation distance of the CMPA sensor can be increased four-fold, from the previously reported 5 to 20 cm, thus improving considerably the viability of this type of wireless sensors for strain measurement and damage detection.

  16. Fabrication of strain gauge based sensors for tactile skins

    Science.gov (United States)

    Baptist, Joshua R.; Zhang, Ruoshi; Wei, Danming; Saadatzi, Mohammad Nasser; Popa, Dan O.

    2017-05-01

    Fabricating cost effective, reliable and functional sensors for electronic skins has been a challenging undertaking for the last several decades. Application of such skins include haptic interfaces, robotic manipulation, and physical human-robot interaction. Much of our recent work has focused on producing compliant sensors that can be easily formed around objects to sense normal, tension, or shear forces. Our past designs have involved the use of flexible sensors and interconnects fabricated on Kapton substrates, and piezoresistive inks that are 3D printed using Electro Hydro Dynamic (EHD) jetting onto interdigitated electrode (IDE) structures. However, EHD print heads require a specialized nozzle and the application of a high-voltage electric field; for which, tuning process parameters can be difficult based on the choice of inks and substrates. Therefore, in this paper we explore sensor fabrication techniques using a novel wet lift-off photolithographic technique for patterning the base polymer piezoresistive material, specifically Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) or PEDOT:PSS. Fabricated sensors are electrically and thermally characterized, and temperaturecompensated designs are proposed and validated. Packaging techniques for sensors in polymer encapsulants are proposed and demonstrated to produce a tactile interface device for a robot.

  17. Inner strain determination of three-dimensional braided preforms with co-braided optical fiber sensors

    Institute of Scientific and Technical Information of China (English)

    Xianghua LI; Xiaohui LIU; Shenfang YUAN

    2008-01-01

    The experimental characterization of three-dimensional (3-D) braided composites is extremely important for their design and analysis. Because of their desirable attributes and outstanding performance, optical fiber sensors (OFSs) can be embedded to mon-itor mechanical properties of textile composites. This paper discusses two techniques to incorporate different OFSs into 3-D braided composite preforms. The oper-ating principle of various sensor systems is first con-ducted. Experiments using Michelson interferometers, FBG sensors, and micro-bend sensors are performed to verify the concept of the proposed method. Strain curves of various OFSs tests are finally compared, and they all exhibit good linearity.

  18. Design of strain tension sensor of steel wire rope used in the coal mine

    Science.gov (United States)

    Zhang, Xin; Jin, Huawei

    2016-01-01

    According to the dynamic tension testing requirements of the multi-rope winder rope, this paper designs the sensor used to measure the tension of steel wire rope directly. The sensor uses the strain shear measuring principle, and has many features with small size, big measuring range, easy to install, don't change the structure of connected devices and so on. Application of the finite element analysis software makes the structure of the sensor optimized, and then enhance the static and dynamic performance of the sensor.

  19. DEVELOPMENT OF NOVEL CERAMIC NANOFILM-FIBER INTEGRATED OPTICAL SENSORS FOR RAPID DETECTION OF COAL DERIVED SYNTHESIS GAS

    Energy Technology Data Exchange (ETDEWEB)

    Junhang Dong; Hai Xiao; Xiling Tang; Hongmin Jiang; Kurtis Remmel; Amardeep Kaur

    2012-09-30

    The overall goal of this project is to conduct fundamental studies on advanced ceramic materials and fiber optic devices for developing new types of high temperature (>500{degree}C) fiber optic chemical sensors (FOCS) for monitoring fossil (mainly coal) and biomass derived gases in power plants. The primary technical objective is to investigate and demonstrate the nanocrystalline doped-ceramic thin film enabled FOCS that possess desired stability, sensitivity and selectivity for in-situ, rapid gas detection in the syngas streams from gasification and combustion flue gases. This report summarizes research works of two integrated parts: (1) development of metal oxide solid thin films as sensing materials for detection and measurement of important gas components relevant to the coal- and biomass-derived syngas and combustion gas streams at high temperatures; and (2) development of fiber optic devices that are potentially useful for constructing FOCS in combination with the solid oxide thin films identified in this program.

  20. A distributed optical fiber bi-directional strain-displacement sensor

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A distributed optical fiber strain-displacement sensor is developed, which consists of an optical fiber gauge of strain-displacement and an optical time domain reflectometer (OTDR). The operational principle is the modulation of fiber loss in OTDR, i.e. the strain and displacement in monitoring position are obtained from the bending loss of optical fiber bonded on the optical fiber gauge of strain-displacement. After examining the strain and displacement in the cantilever and the micro displacement rack respectively, the result indicates that the distributed optical fiber gauge of strain-displacement can monitor strains or displacements in different sensitive lengths. The key technique for measuring bi-directional strain-displacement is the pretreatment of bending of the freely suspended optical fibers, which can be identified with OTDR by inserting time delay optical fiber.

  1. Study on deposition technique and properties of Pd/Ag alloy film sensor supported on ceramic substrate

    Science.gov (United States)

    Geng, Z. T.; He, Q.; Jin, C. G.

    2016-07-01

    Developing high-quality hydrogen sensitive material is the core part of hydrogen sensor, whose performance is determined by the sensitive response, reproducibility and recovery of hydrogen material etc. In order to overcome the defects of hydrogen embrittlement in previous hydrogen sensor which were based on the pure palladium, sliver as the second component added to the palladium was studied. Using photochemical etching technology to produce a bent metal mask, the mask is put on the ceramic substrate. Firstly, the thin film of Ta2O5 as a transition layer grew on the ceramic substrate. Then, a series of Pd/Ag alloy film sensors were prepared, and each performance characterization of Pd/Ag alloy film was studied. Testing results indicated that the thin film had a good linear output performance at 0∼⃒30% hydrogen concentration range, and demonstrates a high responsiveness and good repeatability. With temperature increasing, the strength of the responsive signal of the Pd/Ag alloy film decreases and its responsive time was also shortened.

  2. Fully printed, highly sensitive multifunctional artificial electronic whisker arrays integrated with strain and temperature sensors.

    Science.gov (United States)

    Harada, Shingo; Honda, Wataru; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

    2014-04-22

    Mammalian-mimicking functional electrical devices have tremendous potential in robotics, wearable and health monitoring systems, and human interfaces. The keys to achieve these devices are (1) highly sensitive sensors, (2) economically fabricated macroscale devices on flexible substrates, and (3) multifunctions beyond mammalian functions. Although highly sensitive artificial electronic devices have been reported, none have been fabricated using cost-effective macroscale printing methods and demonstrate multifunctionalities of artificial electronics. Herein we report fully printed high-sensitivity multifunctional artificial electronic whiskers (e-whisker) integrated with strain and temperature sensors using printable nanocomposite inks. Importantly, changing the composition ratio tunes the sensitivity of strain. Additionally, the printed temperature sensor array can be incorporated with the strain sensor array beyond mammalian whisker functionalities. The sensitivity for the strain sensor is impressively high (∼59%/Pa), which is the best sensitivity reported to date (>7× improvement). As the proof-of-concept for a truly printable multifunctional artificial e-whisker array, two- and three-dimensional space and temperature distribution mapping are demonstrated. This fully printable flexible sensor array should be applicable to a wide range of low-cost macroscale electrical applications.

  3. Stretchable and Flexible High-Strain Sensors Made Using Carbon Nanotubes and Graphite Films on Natural Rubber

    Science.gov (United States)

    Tadakaluru, Sreenivasulu; Thongsuwan, Wiradej; Singjai, Pisith

    2014-01-01

    Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ∼5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain). As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor) and 620% (carbon nanotube sensor) were measured; these values are respectively ∼50 and ∼120 times greater than those of conventional metallic strain sensors. PMID:24399158

  4. Fiber optic strain twin-sensor-array for smart structural health monitoring

    Institute of Scientific and Technical Information of China (English)

    赵士刚; 苑立波

    2008-01-01

    A multiplexed white light interferometric fiber optic twin-sensor-array was designed to monitor the structural health of large buildings. In this sensing system, based on a Michelson interferometer, an optical path matching technique is used to demodulate each twin-sensor. Each twin-sensor-array consists of a 2×N sensing element linked by a 3 dB coupler. When one of the twin-sensor is used to measure strain, variations caused by temperature can be compensated for by referencing the other twin-sensor. The multiplexing capacity of the sensing scheme has been analyzed and experimental results with a 2×3 twin-sensor-array are given.

  5. Embedded Electromechanical Impedance and Strain Sensors for Health Monitoring of a Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Dansheng Wang

    2015-01-01

    Full Text Available Piezoelectric lead zirconate titanate (PZT is one of the piezoelectric smart materials, which has direct and converse piezoelectric effects and can serve as an active electromechanical impedance (EMI sensor. The design and fabrication processes of EMI sensors embedded into concrete structures are presented briefly. Subsequently, finite element modeling and modal analysis of a continuous rigid frame bridge are implemented by using ANSYS and MIDAS and validated by the field test results. Uppermost, a health monitoring technique by employing the embedded EMI and strain sensors is proposed in this paper. The technique is not based on any physical model and is sensitive to incipient structural changes for its high frequency characteristics. A practical study on health monitoring of the continuous rigid frame bridge is implemented based on the EMI and strain signatures. In this study, some EMI and strain sensors are embedded into the box-sectional girders. The electrical admittances of distributed EMI active sensors and the strains of concrete are measured when the bridge is under construction or in operation. Based on the electrical admittance and strain measurements, the health statuses of the continuous rigid frame bridge are monitored and evaluated successfully in the construction and operation stages using a root-mean-square deviation (RMSD index.

  6. Deformation behavior of release agent coated glass fibre / epoxy composite using carbon nanotubes as strain sensors

    Directory of Open Access Journals (Sweden)

    Paweena Sureeyatanapas

    2013-02-01

    Full Text Available The deformation behavior of model glass fiber in epoxy composites has been studied using Raman spectroscopyproperties. Single walled carbon nanotubes (SWNTs were introduced at the glass fiber/epoxy interface as strain sensors,which can be detected by Raman Spectroscopy, to sense the strain profile of the fiber under deformation. The release agentwas applied on the fiber surface before composite fabrication. It was found that at high strain level, the behavior of a singlefiber in a composite did not follow a classical shear-lag model as shown in the fragmentation study. This is due to the interfacial failure caused by the release agent. The strain mapping result can be compared to that without release agent coating.The finding confirmed the application of SWNTs as strain sensors at the fiber/composite interface.

  7. Application of fiber optic distributed sensor for strain measurement in civil engineering

    Science.gov (United States)

    Kurashima, Toshio; Usu, Tomonori; Tanaka, Kuniaki; Nobiki, Atsushi; Sato, Masashi; Nakai, Kenji

    1997-11-01

    We report on civil engineering applications of a fiber optic distributed strain sensor. It consists of a sensing fiber and a high performance optical time domain reflectometer (OTDR), for measuring both strain and optical loss distribution along optical fibers by accessing only one end of the fiber. The OTDR can measure distributed strain with an accuracy of better than +/- 60 X 10-6 and a high spatial resolution of up to 1 m over a 10 km long fiber. In model experiments using the OTDR, we measured the strain changes in fibers attached to the surface of a concrete test beam. The performance of the fiber strain sensor was tested by measuring the strain distribution in optical fibers and comparing the results with resistance strain gage measurements for several loads. We found that the two sets of results were similar, and in addition, we demonstrated experimentally that the sensor was able to measure an induced strain change of less than 100 by 10-6, which is nearly the elastic limit of the concrete material. These results show the potential of the OTDR to extend the application of monitoring systems to such areas as large building diagnostics for civil engineering.

  8. From conventional sensors to fibre optic sensors for strain and force measurements in biomechanics applications: a review.

    Science.gov (United States)

    Roriz, Paulo; Carvalho, Lídia; Frazão, Orlando; Santos, José Luís; Simões, José António

    2014-04-11

    In vivo measurement, not only in animals but also in humans, is a demanding task and is the ultimate goal in experimental biomechanics. For that purpose, measurements in vivo must be performed, under physiological conditions, to obtain a database and contribute for the development of analytical models, used to describe human biomechanics. The knowledge and control of the mechanisms involved in biomechanics will allow the optimization of the performance in different topics like in clinical procedures and rehabilitation, medical devices and sports, among others. Strain gages were first applied to bone in a live animal in 40's and in 80's for the first time were applied fibre optic sensors to perform in vivo measurements of Achilles tendon forces in man. Fibre optic sensors proven to have advantages compare to conventional sensors and a great potential for biomechanical and biomedical applications. Compared to them, they are smaller, easier to implement, minimally invasive, with lower risk of infection, highly accurate, well correlated, inexpensive and multiplexable. The aim of this review article is to give an overview about the evolution of the experimental techniques applied in biomechanics, from conventional to fibre optic sensors. In the next sections the most relevant contributions of these sensors, for strain and force in biomechanical applications, will be presented. Emphasis was given to report of in vivo experiments and clinical applications.

  9. Flexible and printable paper-based strain sensors for wearable and large-area green electronics

    Science.gov (United States)

    Liao, Xinqin; Zhang, Zheng; Liao, Qingliang; Liang, Qijie; Ou, Yang; Xu, Minxuan; Li, Minghua; Zhang, Guangjie; Zhang, Yue

    2016-06-01

    Paper-based (PB) green electronics is an emerging and potentially game-changing technology due to ease of recycling/disposal, the economics of manufacture and the applicability to flexible electronics. Herein, new-type printable PB strain sensors (PPBSSs) from graphite glue (graphite powder and methylcellulose) have been fabricated. The graphite glue is exposed to thermal annealing to produce surface micro/nano cracks, which are very sensitive to compressive or tensile strain. The devices exhibit a gauge factor of 804.9, response time of 19.6 ms and strain resolution of 0.038%, all performance indicators attaining and even surpassing most of the recently reported strain sensors. Due to the distinctive sensing properties, flexibility and robustness, the PPBSSs are suitable for monitoring of diverse conditions such as structural strain, vibrational motion, human muscular movements and visual control.Paper-based (PB) green electronics is an emerging and potentially game-changing technology due to ease of recycling/disposal, the economics of manufacture and the applicability to flexible electronics. Herein, new-type printable PB strain sensors (PPBSSs) from graphite glue (graphite powder and methylcellulose) have been fabricated. The graphite glue is exposed to thermal annealing to produce surface micro/nano cracks, which are very sensitive to compressive or tensile strain. The devices exhibit a gauge factor of 804.9, response time of 19.6 ms and strain resolution of 0.038%, all performance indicators attaining and even surpassing most of the recently reported strain sensors. Due to the distinctive sensing properties, flexibility and robustness, the PPBSSs are suitable for monitoring of diverse conditions such as structural strain, vibrational motion, human muscular movements and visual control. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02172g

  10. Strain transfer analysis of optical fiber based sensors embedded in an asphalt pavement structure

    Science.gov (United States)

    Wang, Huaping; Xiang, Ping

    2016-07-01

    Asphalt pavement is vulnerable to random damage, such as cracking and rutting, which can be proactively identified by distributed optical fiber sensing technology. However, due to the material nature of optical fibers, a bare fiber is apt to be damaged during the construction process of pavements. Thus, a protective layer is needed for this application. Unfortunately, part of the strain of the host material is absorbed by the protective layer when transferring the strain to the sensing fiber. To account for the strain transfer error, in this paper a theoretical analysis of the strain transfer of a three-layered general model has been carried out by introducing Goodman’s hypothesis to describe the interfacial shear stress relationship. The model considers the viscoelastic behavior of the host material and protective layer. The effects of one crack in the host material and the sensing length on strain transfer relationship are been discussed. To validate the effectiveness of the strain transfer analysis, a flexible asphalt-mastic packaged distributed optical fiber sensor was designed and tested in a laboratory environment to monitor the distributed strain and appearance of cracks in an asphalt concrete beam at two different temperatures. The experimental results indicated that the developed strain transfer formula can significantly reduce the strain transfer error, and that the asphalt-mastic packaged optical fiber sensor can successfully monitor the distributed strain and identify local cracks.

  11. Interface transferring mechanism and error modification of embedded FBG strain sensors

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhi; LI Jilong; OU Jinping

    2007-01-01

    As the strain sensing element of a structural health monitoring,the study and the application of the fibre-optic bragg grating(FBG)have been widely accepted.The accuracy of the FBG sensor is highly dependent on the phyrsical and the mechanical properties of the strain interface transferring characteristics among the layers of bare optical fibre,protective coating,adhesive layer and host material.In this paper,firstly,the general expression of the multilayer interface strain transferring mechanism is derived.Secondly,based on the defined average strain,the error-modified equation of the FBG sensor is obtained.Finally,in the light of the embedded tube-packaged FBG and the fibre reinforced polymer-optical fibre bragg grating(FRP-OFBG)strain sensors.developed in the Harbin Institute of Technology (HIT),the corresponding strain transferring laws have been studied,and the corresponding error modification coefficients have also been given,which are validated by experiments.The research results provide theories for the development and application of the embedded FBG sensors.

  12. Design and Development for Capacitive Humidity Sensor Applications of Lead-Free Ca,Mg,Fe,Ti-Oxides-Based Electro-Ceramics with Improved Sensing Properties via Physisorption

    Science.gov (United States)

    Tripathy, Ashis; Pramanik, Sumit; Manna, Ayan; Bhuyan, Satyanarayan; Azrin Shah, Nabila Farhana; Radzi, Zamri; Abu Osman, Noor Azuan

    2016-01-01

    Despite the many attractive potential uses of ceramic materials as humidity sensors, some unavoidable drawbacks, including toxicity, poor biocompatibility, long response and recovery times, low sensitivity and high hysteresis have stymied the use of these materials in advanced applications. Therefore, in present investigation, we developed a capacitive humidity sensor using lead-free Ca,Mg,Fe,Ti-Oxide (CMFTO)-based electro-ceramics with perovskite structures synthesized by solid-state step-sintering. This technique helps maintain the submicron size porous morphology of the developed lead-free CMFTO electro-ceramics while providing enhanced water physisorption behaviour. In comparison with conventional capacitive humidity sensors, the presented CMFTO-based humidity sensor shows a high sensitivity of up to 3000% compared to other materials, even at lower signal frequency. The best also shows a rapid response (14.5 s) and recovery (34.27 s), and very low hysteresis (3.2%) in a 33%–95% relative humidity range which are much lower values than those of existing conventional sensors. Therefore, CMFTO nano-electro-ceramics appear to be very promising materials for fabricating high-performance capacitive humidity sensors. PMID:27455263

  13. Design and Development for Capacitive Humidity Sensor Applications of Lead-Free Ca,Mg,Fe,Ti-Oxides-Based Electro-Ceramics with Improved Sensing Properties via Physisorption

    Directory of Open Access Journals (Sweden)

    Ashis Tripathy

    2016-07-01

    Full Text Available Despite the many attractive potential uses of ceramic materials as humidity sensors, some unavoidable drawbacks, including toxicity, poor biocompatibility, long response and recovery times, low sensitivity and high hysteresis have stymied the use of these materials in advanced applications. Therefore, in present investigation, we developed a capacitive humidity sensor using lead-free Ca,Mg,Fe,Ti-Oxide (CMFTO-based electro-ceramics with perovskite structures synthesized by solid-state step-sintering. This technique helps maintain the submicron size porous morphology of the developed lead-free CMFTO electro-ceramics while providing enhanced water physisorption behaviour. In comparison with conventional capacitive humidity sensors, the presented CMFTO-based humidity sensor shows a high sensitivity of up to 3000% compared to other materials, even at lower signal frequency. The best also shows a rapid response (14.5 s and recovery (34.27 s, and very low hysteresis (3.2% in a 33%–95% relative humidity range which are much lower values than those of existing conventional sensors. Therefore, CMFTO nano-electro-ceramics appear to be very promising materials for fabricating high-performance capacitive humidity sensors.

  14. The usage of ceramics in the manufacture of the lining of temperature sensors for the oil industry; Utilizacao de ceramica para encapsulamento de sensores de temperatura na industria petrolifera

    Energy Technology Data Exchange (ETDEWEB)

    Domingues, R.O.; Yadava, Y.P.; Sanguinetti Ferreira, R.A., E-mail: rebeka.oliveira@yahoo.com.br, E-mail: yadava@ufpe.br, E-mail: ricardo.sanguinetti@pq.cnpq.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Engenharia Mecanica

    2014-07-01

    In the oil production, many types of sensors are used in order to monitor some important parameters such as temperature, pressure and flow. These sensors are subjected to harsh operating conditions. Therefore they must present an inert and stable behavior in these conditions. The temperature sensors that are more suited to the oil industry are the Temperature Detectors by Resistance (TDR), because they have high accuracy and wide temperature range. Usually these devices are built with metals as detectors of temperature by encapsulated resistance in inert ceramics. The main objective of this research is to produce new ceramics of a Ca{sub 2}AlZrO{sub 5,5} cubic complex perovskite structure for the encapsulation of temperature sensors. The stoichiometric amounts of the constituent chemicals, with a high degree of purity, are homogenized, through a solid state reaction in a high energy ball mill. They are then compacted by uniaxial pressing and calcined at 1200°C for 24 hours. Soon after, the tablet is crushed giving place to a ceramic powder and the analysis of X-ray diffraction is performed. According to the sintering behavior of the ceramic powder, the microstructure and the homogeneity are studied by the Scanning Electron Microscopy. The results are presented in terms of the potential of this ceramic for applications as components of temperature sensors. (author)

  15. Computational analysis of metallic nanowire-elastomer nanocomposite based strain sensors

    Directory of Open Access Journals (Sweden)

    Sangryun Lee

    2015-11-01

    Full Text Available Possessing a strong piezoresistivity, nanocomposites of metal nanowires and elastomer have been studied extensively for its use in highly flexible, stretchable, and sensitive sensors. In this work, we analyze the working mechanism and performance of a nanocomposite based stretchable strain sensor by calculating the conductivity of the nanowire percolation network as a function of strain. We reveal that the nonlinear piezoresistivity is attributed to the topological change of percolation network, which leads to a bottleneck in the electric path. We find that, due to enhanced percolation, the linearity of the sensor improves with increasing aspect ratio or volume fraction of the nanowires at the expense of decreasing gauge factor. In addition, we show that a wide range of gauge factors (from negative to positive can be obtained by changing the orientation distribution of nanowires. Our study suggests a way to intelligently design nanocomposite-based piezoresistive sensors for flexible and wearable devices.

  16. Large-strain Soft Sensors Using Elastomers Blended with Exfoliated/Fragmented Graphite Particles

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sungmin; Nam, Gyungmok; Kim, Jonghun; Yoon, Sang-Hee [Inha Univ., Incheon (Korea, Republic of)

    2016-09-15

    An elastic polymer (e.g., PDMS) blended with EFG particles is a promising conductive composite for fabricating soft sensors that can detect an object's deformation up to or more than 50 %. Here, we develop large-strain, sprayable soft sensors using a mixture of PDMS and EFG particles, which are used as a host elastomer and electrically conductive particles, respectively. A solution for a conductive composite mixture is prepared by the microwave-assisted graphite exfoliation, followed by ultrasonication-induced fragmentation of the exfoliated graphite and ultrasonic blending of PDMS and EFG. Using the prepared solutions for composite and pure PDMS, 1-, 2-, and 3-axis soft sensors are fabricated by airbrush stencil technique where composite mixture and pure PDMS are materials for sensing and insulating layers, respectively. We characterize the soft strain sensors after investigating the effect of PDMS/EFG wt % on mechanical compliance and electrical conductance of the conductive composite.

  17. A wearable, highly stable, strain and bending sensor based on high aspect ratio graphite nanobelts

    Science.gov (United States)

    Alaferdov, A. V.; Savu, R.; Rackauskas, T. A.; Rackauskas, S.; Canesqui, M. A.; de Lara, D. S.; Setti, G. O.; Joanni, E.; de Trindade, G. M.; Lima, U. B.; de Souza, A. S.; Moshkalev, S. A.

    2016-09-01

    A simple and scalable method was developed for the fabrication of wearable strain and bending sensors, based on high aspect ratio (length/thickness ˜103) graphite nanobelt thin films deposited by a modified Langmuir-Blodgett technique onto flexible polymer substrates. The sensing mechanism is based on the changes in contact resistance between individual nanobelts upon substrate deformation. Very high sensor response stability for more than 5000 strain-release cycles and a device power consumption as low as 1 nW were achieved. The device maximum stretchability is limited by the metal electrodes and the polymer substrate; the maximum strain that could be applied to the polymer used in this work was 40%. Bending tests carried out for various radii of curvature demonstrated distinct sensor responses for positive and negative curvatures. The graphite nanobelt thin flexible films were successfully tested for acoustic vibration and heartbeat sensing.

  18. Sheath-Core Graphite/Silk Fiber Made by Dry-Meyer-Rod-Coating for Wearable Strain Sensors.

    Science.gov (United States)

    Zhang, Mingchao; Wang, Chunya; Wang, Qi; Jian, Muqiang; Zhang, Yingying

    2016-08-17

    Recent years have witnessed the explosive development of flexible strain sensors. Nanomaterials have been widely utilized to fabricate flexible strain sensors, because of their high flexibility and electrical conductivity. However, the fabrication processes for nanomaterials and the subsequent strain sensors are generally complicated and are manufactured at high cost. In this work, we developed a facile dry-Meyer-rod-coating process to fabricate sheath-core-structured single-fiber strain sensors using ultrafine graphite flakes as the sheath and silk fibers as the core by virtue of their flexibility, high production, and low cost. The fabricated strain sensor exhibits a high sensitivity with a gauge factor of 14.5 within wide workable strain range up to 15%, and outstanding stability (up to 3000 cycles). The single-fiber-based strain sensors could be attached to a human body to detect joint motions or easily integrated into the multidirectional strain sensor for monitoring multiaxial strain, showing great potential applications as wearable strain sensors.

  19. An Experimental Study of Mortars with Recycled Ceramic Aggregates: Deduction and Prediction of the Stress-Strain

    Directory of Open Access Journals (Sweden)

    Francisca Guadalupe Cabrera-Covarrubias

    2016-12-01

    Full Text Available The difficult current environmental situation, caused by construction industry residues containing ceramic materials, could be improved by using these materials as recycled aggregates in mortars, with their processing causing a reduction in their use in landfill, contributing to recycling and also minimizing the consumption of virgin materials. Although some research is currently being carried out into recycled mortars, little is known about their stress-strain (σ-ε; therefore, this work will provide the experimental results obtained from recycled mortars with recycled ceramic aggregates (with contents of 0%, 10%, 20%, 30%, 50% and 100%, such as the density and compression strength, as well as the σ-ε curves representative of their behavior. The values obtained from the analytical process of the results in order to finally obtain, through numerical analysis, the equations to predict their behavior (related to their recycled content are those of: σ (elastic ranges and failure maximum, ε (elastic ranges and failure maximum, and Resilience and Toughness. At the end of the investigation, it is established that mortars with recycled ceramic aggregate contents of up to 20% could be assimilated just like mortars with the usual aggregates, and the obtained prediction equations could be used in cases of similar applications.

  20. Note: a high-sensitivity current sensor based on piezoelectric ceramic Pb(Zr,Ti)O3 and ferromagnetic materials.

    Science.gov (United States)

    He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Yang, Aichao; Lu, Caijiang

    2014-02-01

    An electric current sensor using piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) sandwiched between two high permeability cuboids and two NdFeB magnets is presented. The magnetic field originating from an electric wire is augmented by the high permeability cuboids. The PZT plate experiences an enhanced magnetic force and generates voltage output. When placed with a distance of d = 5.0 mm from the wire, the sensor shows a flat sensitivity of ∼5.7 mV/A in the frequency range of 30 Hz-80 Hz and an average sensitivity of 5.6 mV/A with highly linear behavior in the current range of 1 A-10 A at 50 Hz.

  1. Comparison of two novel types of sensor to monitor the strain of concrete in F-T tests

    Science.gov (United States)

    Lv, Haifeng; Liao, Kaixing; Kong, Xianglong; Li, Shengyuan; Ding, Yanbing; Sun, Changsen; Zhao, Xuefeng

    2017-04-01

    In order to monitor the strain of concrete caused by freeze-thaw (F-T) cycles, two novel types of white light interferometer (WLI) sensor are designed and tested. The first type of sensor is poured the whole saturated concrete cylinder which coiled optical fiber with epoxy for encapsulation, and the second type coat neutral silicone sealant on the surface of cylinder, where enwound with optical fiber only. Each of the type was conducted on two sensors, the sensor of the first type was named W-sensor, and the sensor of the second type was named S-sensor. The comparison of the two novel types of sensor was conducted based on the test results, and the test result showed that though all of the two types of sensor can monitor the variation of strain with the process of F-T cycles, however, the type of S-sensor is more stability and reasonable.

  2. Highly Stretchable, Hysteresis-Free Ionic Liquid-Based Strain Sensor for Precise Human Motion Monitoring.

    Science.gov (United States)

    Choi, Dong Yun; Kim, Min Hyeong; Oh, Yong Suk; Jung, Soo-Ho; Jung, Jae Hee; Sung, Hyung Jin; Lee, Hyung Woo; Lee, Hye Moon

    2017-01-18

    A highly stretchable, low-cost strain sensor was successfully prepared using an extremely cost-effective ionic liquid of ethylene glycol/sodium chloride. The hysteresis performance of the ionic-liquid-based sensor was able to be improved by introducing a wavy-shaped fluidic channel diminishing the hysteresis by the viscoelastic relaxation of elastomers. From the simulations on visco-hyperelastic behavior of the elastomeric channel, we demonstrated that the wavy structure can offer lower energy dissipation compared to a flat structure under a given deformation. The resistance response of the ionic-liquid-based wavy (ILBW) sensor was fairly deterministic with no hysteresis, and it was well-matched to the theoretically estimated curves. The ILBW sensors exhibited a low degree of hysteresis (0.15% at 250%), low overshoot (1.7% at 150% strain), and outstanding durability (3000 cycles at 300% strain). The ILBW sensor has excellent potential for use in precise and quantitative strain detections in various areas, such as human motion monitoring, healthcare, virtual reality, and smart clothes.

  3. Characterization of embedded fiber optic strain sensors into metallic structures via ultrasonic additive manufacturing

    Science.gov (United States)

    Schomer, John J.; Hehr, Adam J.; Dapino, Marcelo J.

    2016-04-01

    Fiber Bragg Grating (FBG) sensors measure deviation in a reflected wavelength of light to detect in-situ strain. These sensors are immune to electromagnetic interference, and the inclusion of multiple FBGs on the same fiber allows for a seamlessly integrated sensing network. FBGs are attractive for embedded sensing in aerospace applications due to their small noninvasive size and prospect of constant, real-time nondestructive evaluation. In this study, FBG sensors are embedded in aluminum 6061 via ultrasonic additive manufacturing (UAM), a rapid prototyping process that uses high power ultrasonic vibrations to weld similar and dissimilar metal foils together. UAM was chosen due to the desire to embed FBG sensors at low temperatures, a requirement that excludes other additive processes such as selective laser sintering or fusion deposition modeling. In this paper, the embedded FBGs are characterized in terms of birefringence losses, post embedding strain shifts, consolidation quality, and strain sensing performance. Sensors embedded into an ASTM test piece are compared against an exterior surface mounted foil strain gage at both room and elevated temperatures using cyclic tensile tests.

  4. Characterization of a soft elastomeric capacitive strain sensor for fatigue crack monitoring

    Science.gov (United States)

    Kong, Xiangxiong; Li, Jian; Laflamme, Simon; Bennett, Caroline; Matamoros, Adolfo

    2015-04-01

    Fatigue cracks have been one of the major factors for the deterioration of steel bridges. In order to maintain structural integrity, monitoring fatigue crack activities such as crack initiation and propagation is critical to prevent catastrophic failure of steel bridges due to the accumulation of fatigue damage. Measuring the strain change under cracking is an effective way of monitoring fatigue cracks. However, traditional strain sensors such as metal foil gauges are not able to capture crack development due to their small size, limited measurement range, and high failure rate under harsh environmental conditions. Recently, a newly developed soft elastomeric capacitive sensor has great promise to overcome these limitations. In this paper, crack detection capability of the capacitive sensor is demonstrated through Finite Element (FE) analysis. A nonlinear FE model of a standard ASTM compact tension specimen is created which is calibrated to experimental data to simulate its response under fatigue loading, with the goal to 1) depict the strain distribution of the specimen under the large area covered by the capacitive sensor due to cracking; 2) characterize the relationship between capacitance change and crack width; 3) quantify the minimum required resolution of data acquisition system for detecting the fatigue cracks. The minimum resolution serves as a basis for the development of a dedicated wireless data acquisition system for the capacitive strain sensor.

  5. Development of Nano-crystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hai [Missouri Univ. of Science and Technology, Rolla, MO (United States); Dong, Junhang [Univ. of Cincinnati, OH (United States); Lin, Jerry [Arizona State Univ., Tempe, AZ (United States); Romero, Van [New Mexico Institute of Mining and Technology, Socorro, NM (United States)

    2012-03-01

    This is a final technical report for the first project year from July 1, 2005 to Jan 31, 2012 for DoE/NETL funded project DE-FC26-05NT42439: Development of Nanocrystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases. This report summarizes the technical progresses and achievements towards the development of novel nanocrystalline doped ceramic material-enabled optical fiber sensors for in situ and real time monitoring the gas composition of flue or hot gas streams involved in fossil-fuel based power generation and hydrogen production.

  6. A multivariate time-warping based classifier for gesture recognition with wearable strain sensors.

    Science.gov (United States)

    Giorgino, Toni; Tormene, Paolo; Quaglini, Silvana

    2007-01-01

    Conductive elastomer elements can be industrially embedded into garments to form unobtrusive strain sensing stripes. The present article outlines the structure of a strain-sensor based gesture detection algorithm. Current sensing prototypes include several dozens of sensors; their redundancy with respect to the limb's degrees of freedom, and other artifacts implied by this measurement technique, call for the development of novel robust multivariate pattern-matching techniques. The algorithm's construction is explained, and its performances are evaluated in the context of motor rehabilitation exercises for both two-class and multi-class tasks.

  7. High-temperature Strain Sensor and Mounting Development

    Science.gov (United States)

    Williams, W. Dan; Lei, Jih-Fen; Reardon, Lawrence F.; Krake, Keith; Lemcoe, M. M.; Holmes, Harlan K.; Moore, Thomas C., Sr.

    1996-01-01

    This report describes Government Work Package Task 29 (GWP29), whose purpose was to develop advanced strain gage technology in support of the National Aerospace Plane (NASP) Program. The focus was on advanced resistance strain gages with a temperature range from room temperature to 2000 F (1095 C) and on methods for reliably attaching these gages to the various materials anticipated for use in the NASP program. Because the NASP program required first-cycle data, the installed gages were not prestabilized or heat treated on the test coupons before first-cycle data were recorded. NASA Lewis Research Center, the lead center for GWP29, continued its development of the palladium-chromium gage; NASA Langley Research Center investigated a new concept gage using Kanthal A1; and the NASA Dryden Flight Research Center chose the well-known BCL-3 iron-chromium-aluminum gage. Each center then tested all three gages. The parameters investigated were apparent strain, drift strain, and gage factor as a function of temperature, plus gage size and survival rate over the test period. Although a significant effort was made to minimize the differences in test equipment between the three test sites (e.g., the same hardware and software were used for final data processing), the center employed different data acquisition systems and furnace configurations so that some inherent differences may be evident in the final results.

  8. Characterization of Piezoelectric Ceramic-Polymer Composites for Ultrasonic Sensor Applications

    Science.gov (United States)

    Jung, Kyung Keun; Park, Sang Hyoun; Yoo, Kwang Soo; Ko, Hyun Phill; Yoon, Seok Jin

    The piezoelectric ceramic-polymer composites were prepared by Pb(Zr0.52Ti0.48)O3 (PZT)-based ceramics with high piezoelectricity and electromechanical coupling factor and the polyvinylidene fluoride (PVdF) polymer with high acoustic impedance. The composites with 0-3 connectivity type were fabricated by hot pressing and tape casting methods. Their crystallinity, microstructure, dielectric, and piezoelectric properties were systematically evaluated.

  9. Development of tube-packaged FBG strain sensor and application in the vibration experiment of submarine pipeline model

    Science.gov (United States)

    Ren, Liang; Li, Hong-Nan; Sun, Li; Li, Dong-Sheng

    2005-05-01

    Optical fiber sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. In this paper, a novel FBG (fiber Bragg grating) strain sensor, which was packaged in a 1.2mm stainless steel tube by epoxy resin, was developed. Experiments were conducted on the universal material testing machine to calibrate its strain transferring characteristics. The sensor has the advantages of small size, high precision and flexible use, and demonstrates promising potentials. Ten of tube-packaged strain FBG sensors were applied in the vibration experiment of submarine pipeline model. The strain measured by FBG sensor agrees well with the electric resistance strain sensor.

  10. Multifunctional Cement Composites Strain and Damage Sensors Applied on Reinforced Concrete (RC Structural Elements

    Directory of Open Access Journals (Sweden)

    Pedro Garcés

    2013-03-01

    Full Text Available In this research, strain-sensing and damage-sensing functional properties of cement composites have been studied on a conventional reinforced concrete (RC beam. Carbon nanofiber (CNFCC and fiber (CFCC cement composites were used as sensors on a 4 m long RC beam. Different casting conditions (in situ or attached, service location (under tension or compression and electrical contacts (embedded or superficial were compared. Both CNFCC and CFCC were suitable as strain sensors in reversible (elastic sensing condition testing. CNFCC showed higher sensitivities (gage factor up to 191.8, while CFCC only reached gage factors values of 178.9 (tension or 49.5 (compression. Furthermore, damage-sensing tests were run, increasing the applied load progressively up to the RC beam failure. In these conditions, CNFCC sensors were also strain sensitive, but no damage sensing mechanism was detected for the strain levels achieved during the tests. Hence, these cement composites could act as strain sensors, even for severe damaged structures near to their collapse.

  11. Fiber Bragg grating strain sensors to monitor and study active volcanoes

    Science.gov (United States)

    Sorrentino, Fiodor; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvo; Giacomelli, Umberto; Grassi, Renzo; Maccioni, Enrico; Morganti, Mauro

    2016-04-01

    Stress and strain changes are among the best indicators of impending volcanic activity. In volcano geodesy, borehole volumetric strain-meters are mostly utilized. However, they are not easy to install and involve high implementation costs. Advancements in opto-electronics have allowed the development of low-cost sensors, reliable, rugged and compact, thus particularly suitable for field application. In the framework of the EC FP7 MED-SUV project, we have developed strain sensors based on the fiber Bragg grating (FBG) technology. In comparison with previous implementation of the FBG technology to study rock deformations, we have designed a system that is expected to offer a significantly higher resolution and accuracy in static measurements and a smooth dynamic response up to 100 Hz, implying the possibility to observe seismic waves. The system performances are tailored to suit the requirements of volcano monitoring, with special attention to power consumption and to the trade-off between performance and cost. Preliminary field campaigns were carried out on Mt. Etna (Italy) using a prototypal single-axis FBG strain sensor, to check the system performances in out-of-the-lab conditions and in the harsh volcanic environment (lack of mains electricity for power, strong diurnal temperature changes, strong wind, erosive ash, snow and ice during the winter time). We also designed and built a FBG strain sensor featuring a multi-axial configuration which was tested and calibrated in the laboratory. This instrument is suitable for borehole installation and will be tested on Etna soon.

  12. Knitted Strain Sensor Textiles of Highly Conductive All-Polymeric Fibers.

    Science.gov (United States)

    Seyedin, Shayan; Razal, Joselito M; Innis, Peter C; Jeiranikhameneh, Ali; Beirne, Stephen; Wallace, Gordon G

    2015-09-30

    A scaled-up fiber wet-spinning production of electrically conductive and highly stretchable PU/PEDOT:PSS fibers is demonstrated for the first time. The PU/PEDOT:PSS fibers possess the mechanical properties appropriate for knitting various textile structures. The knitted textiles exhibit strain sensing properties that were dependent upon the number of PU/PEDOT:PSS fibers used in knitting. The knitted textiles show sensitivity (as measured by the gauge factor) that increases with the number of PU/PEDOT:PSS fibers deployed. A highly stable sensor response was observed when four PU/PEDOT:PSS fibers were co-knitted with a commercial Spandex yarn. The knitted textile sensor can distinguish different magnitudes of applied strain with cyclically repeatable sensor responses at applied strains of up to 160%. When used in conjunction with a commercial wireless transmitter, the knitted textile responded well to the magnitude of bending deformations, demonstrating potential for remote strain sensing applications. The feasibility of an all-polymeric knitted textile wearable strain sensor was demonstrated in a knee sleeve prototype with application in personal training and rehabilitation following injury.

  13. Surface Crack Detection in Prestressed Concrete Cylinder Pipes Using BOTDA Strain Sensors

    Directory of Open Access Journals (Sweden)

    Zhigang Xu

    2017-01-01

    Full Text Available Structural deterioration after a period of service can induce the failure of prestressed concrete cylinder pipes (PCCPs, with microcracks in the coating leading to the corrosion of the prestressed wires. In this paper, we propose the use of Brillouin optical time-domain analysis (BOTDA strain sensors for detecting the onset of microcracking in PCCP coating: the BOTDA strain sensors are mounted on the surface of the PCCP, and distributed strain measurements are employed to assess the cracks in the mortar coating and the structural state of the pipe. To validate the feasibility of the proposed approach, experimental investigations were conducted on a prototype PCCP segment, wherein the inner pressure was gradually increased to 1.6 MPa. Two types of BOTDA strain sensors—the steel wire packaged fiber optic sensor and the polyelastic packaged fiber optic sensor—were employed in the experiments. The experimental distributed measurements agreed well with the finite element computations, evidencing that the investigated strain sensors are sensitive to localized deterioration behaviors such as PCCP microcracking.

  14. Design and Fabrication of Single-Walled Carbon Nanonet Flexible Strain Sensors

    Directory of Open Access Journals (Sweden)

    Trung Kien Vu

    2012-03-01

    Full Text Available This study presents a novel flexible strain sensor for real-time strain sensing. The material for strain sensing is single-walled carbon nanonets, grown using the alcohol catalytic chemical vapor deposition method, that were encapsulated between two layers of Parylene-C, with a polyimide layer as the sensing surface. All of the micro-fabrication was compatible with the standard IC process. Experimental results indicated that the gauge factor of the proposed strain sensor was larger than 4.5, approximately 2.0 times greater than those of commercial gauges. The results also demonstrated that the gauge factor is small when the growth time of SWCNNs is lengthier, and the gauge factor is large when the line width of the serpentine pattern of SWCNNs is small.

  15. Design and analysis of MEMS MWCNT/epoxy strain sensor using COMSOL

    Science.gov (United States)

    Sapra, Gaurav; Sharma, Preetika

    2017-07-01

    The design and performance of piezoresistive MEMS-based MWCNT/epoxy composite strain sensor using COMSOL Multiphysics Toolbox has been investigated. The proposed sensor design comprises su-8 based U-shaped cantilever beam with MWCNT/epoxy composite film as an active sensing element. A point load in microscale has been applied at the tip of the cantilever beam to observe its deflection in the proposed design. Analytical simulations have been performed to optimize various design parameters of the proposed sensor, which will be helpful at the time of fabrication.

  16. A Table-Shaped Tactile Sensor for Detecting Triaxial Force on the Basis of Strain Distribution

    Science.gov (United States)

    Lee, Jeong Il; Kim, Min-Gyu; Shikida, Mitsuhiro; Sato, Kazuo

    2013-01-01

    A slim and flexible tactile sensor applicable to the interaction of human and intelligent robots is presented. In particular, a simple sensing principle for decoupling of three-dimensional force is proposed. Sensitivity of the proposed tactile sensor is tested experimentally. To improve the sensitivity of the sensor, a table-shaped sensing element was designed. Table-shaped structure can convert an external acting force into concentrated internal stress. A “triaxial force decoupling algorithm” was developed by combining two-dimensional mapping data calculated by finite element analysis. The sensor was calibrated under normal and tangential forces. The external loads applied to the sensor could be decoupled independently as a function of the strain-gauge responses. PMID:24287546

  17. Development and application of optical fibre strain and pressure sensors for in-flight measurements

    Science.gov (United States)

    Lawson, N. J.; Correia, R.; James, S. W.; Partridge, M.; Staines, S. E.; Gautrey, J. E.; Garry, K. P.; Holt, J. C.; Tatam, R. P.

    2016-10-01

    Fibre optic based sensors are becoming increasingly viable as replacements for traditional flight test sensors. Here we present laboratory, wind tunnel and flight test results of fibre Bragg gratings (FBG) used to measure surface strain and an extrinsic fibre Fabry-Perot interferometric (EFFPI) sensor used to measure unsteady pressure. The calibrated full scale resolution and bandwidth of the FBG and EFFPI sensors were shown to be 0.29% at 2.5 kHz up to 600 μɛ and 0.15% at up to 10 kHz respectively up to 400 Pa. The wind tunnel tests, completed on a 30% scale model, allowed the EFFPI sensor to be developed before incorporation with the FBG system into a Bulldog aerobatic light aircraft. The aircraft was modified and certified based on Certification Standards 23 (CS-23) and flight tested with steady and dynamic manoeuvres. Aerobatic dynamic manoeuvres were performed in flight including a spin over a g-range  -1g to  +4g and demonstrated both the FBG and the EFFPI instruments to have sufficient resolution to analyse the wing strain and fuselage unsteady pressure characteristics. The steady manoeuvres from the EFFPI sensor matched the wind tunnel data to within experimental error while comparisons of the flight test and wind tunnel EFFPI results with a Kulite pressure sensor showed significant discrepancies between the two sets of data, greater than experimental error. This issue is discussed further in the paper.

  18. High-resolution absolute frequency referenced fiber optic sensor for quasi-static strain sensing

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Timothy T.-Y.; Chow, Jong H.; Shaddock, Daniel A.; Littler, Ian C. M.; Gagliardi, Gianluca; Gray, Malcolm B.; McClelland, David E.

    2010-07-20

    We present a quasi-static fiber optic strain sensing system capable of resolving signals below nanostrain from 20 mHz. A telecom-grade distributed feedback CW diode laser is locked to a fiber Fabry-Perot sensor, transferring the detected signals onto the laser. An H{sup 13}C{sup 14}N absorption line is then used as a frequency reference to extract accurate low-frequency strain signals from the locked system.

  19. Graphene–polymer coating for the realization of strain sensors

    Directory of Open Access Journals (Sweden)

    Carmela Bonavolontà

    2017-01-01

    Full Text Available In this work we present a novel route to produce a graphene-based film on a polymer substrate. A transparent graphite colloidal suspension was applied to a slat of poly(methyl methacrylate (PMMA. The good adhesion to the PMMA surface, combined with the shear stress, allows a uniform and continuous spreading of the graphite nanocrystals, resulting in a very uniform graphene multilayer coating on the substrate surface. The fabrication process is simple and yields thin coatings characterized by high optical transparency and large electrical piezoresitivity. Such properties envisage potential applications of this polymer-supported coating for use in strain sensing. The electrical and mechanical properties of these PMMA/graphene coatings were characterized by bending tests. The electrical transport was investigated as a function of the applied stress. The structural and strain properties of the polymer composite material were studied under stress by infrared thermography and micro-Raman spectroscopy.

  20. FeGa based tunneling magnetoresistance junctions and strain sensors

    OpenAIRE

    Thajudin, Ahmed Fazir

    2012-01-01

    Tunnel magnetoresistance (TMR) and inverse magnetostriction based strain gauges have gained immense importance due to their high spatial resolution and extremely high gauge factors. A TMR junction comprises of two ferromagnetic electrodes separated by an insulating barrier layer. One of the ferromagnetic layer is soft magnetic which is free to rotate its magnetization under external magnetic field, the other ferromagnet is hard magnetic and is stable under the same external field. An intentio...

  1. A piezoelectric-based infinite stiffness generation method for strain-type load sensors

    Science.gov (United States)

    Zhang, Shuwen; Shao, Shubao; Chen, Jie; Xu, Minglong

    2015-11-01

    Under certain application conditions like nanoindentation technology and the mechanical property measurement of soft materials, the elastic deformation of strain-type load sensors affects their displacement measurement accuracy. In this work, a piezoelectric-based infinite stiffness generation method for strain-type load sensors that compensates for this elastic deformation is presented. The piezoelectric material-based deformation compensation method is proposed. An Hottinger Baldwin Messtechnik GmbH (HBM) Z30A/50N load sensor acts as the foundation of the method presented in this work. The piezoelectric stack is selected based on its size, maximum deformation value, blocking force and stiffness. Then, a clamping and fixing structure is designed to integrate the HBM sensor with the piezoelectric stack. The clamping and fixing structure, piezoelectric stack and HBM load sensor comprise the sensing part of the enhanced load sensor. The load-deformation curve and the voltage-deformation curve of the enhanced load sensor are then investigated experimentally. Because a hysteresis effect exists in the piezoelectric structure, the relationship between the control signal and the deformation value of the piezoelectric material is nonlinear. The hysteresis characteristic in a quasi-static condition is studied and fitted using a quadratic polynomial, and its coefficients are analyzed to enable control signal prediction. Applied arithmetic based on current theory and the fitted data is developed to predict the control signal. Finally, the experimental effects of the proposed method are presented. It is shown that when a quasi-static load is exerted on this enhanced strain-type load sensor, the deformation is reduced and the equivalent stiffness appears to be almost infinite.

  2. High-Temperature, Thin-Film Ceramic Thermocouples Developed

    Science.gov (United States)

    Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2005-01-01

    To enable long-duration, more distant human and robotic missions for the Vision for Space Exploration, as well as safer, lighter, quieter, and more fuel efficient vehicles for aeronautics and space transportation, NASA is developing instrumentation and material technologies. The high-temperature capabilities of thin-film ceramic thermocouples are being explored at the NASA Glenn Research Center by the Sensors and Electronics Branch and the Ceramics Branch in partnership with Case Western Reserve University (CWRU). Glenn s Sensors and Electronics Branch is developing thin-film sensors for surface measurement of strain, temperature, heat flux, and surface flow in propulsion system research. Glenn s Ceramics Branch, in conjunction with CWRU, is developing structural and functional ceramic technology for aeropropulsion and space propulsion.

  3. An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments.

    Science.gov (United States)

    Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

    2015-08-31

    Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively.

  4. Internal Strain Measurement in 3D Braided Composites Using Co-braided Optical Fiber Sensors

    Institute of Scientific and Technical Information of China (English)

    Shenfang YUAN; Rui HUANG; Yunjiang RAO

    2004-01-01

    3D braided composite technology has stimulated a great deal of interest in the world at large. But due to the threedimensional nature of these kinds of composites, coupled with the shortcomings of currently-adopted experimental test methods, it is difficult to measure the internal parameters of this materials, hence causes it difficult to understand the material performance. A new method is introduced herein to measure the internal strain of braided composite materials using co-braided fiber optic sensors. Two kinds of fiber optic sensors are co-braided into 3D braided composites to measure internal strain. One of these is the Fabry-Parrot (F-P) fiber optic sensor; the other is the polarimetric fiber optic sensor. Experiments are conducted to measure internal strain under tension, bending and thermal environments in the 3D carbon fiber braided composite specimens, both locally and globally. Experimental results show that multiple fiber optic sensors can be braided into the 3D braided composites to measure the internal parameters, providing a more accurate measurement method and leading to a better understanding of these materials.

  5. RANCANG BANGUN SENSOR VISKOSITAS CAIRAN MENGGUNAKAN STRAIN GAUGE DENGAN PRINSIP SILINDER KONSENTRIS

    Directory of Open Access Journals (Sweden)

    Farid Hananto Hananto

    2013-05-01

    Full Text Available Viskositas   adalah salah satu sifat penting suatu cairan. Pengukuran viskositas kebanyakan dilakukan dengan cara mekanik dan manual. Untuk memudahkan pengukuran dan digitalisasi pengukuran viskositas diperlukan sensor yang bisa mengubah besaran viskositas menjadi besaran listrik. Dalam penelitian ini telah di rancang sensor viskostas cairan menggunakan strain gauge menggunakan prinsip silinder konsentris. Silinder dalam menggunakan diameter 3 cm sedangkan silinder luar yang juga berfungsi sebagai tempat cairan sampel berdiameter 4 cm. Silinder dalam dihubungkan dengan pelat pegas oleh sebuah as yang mana pada pegas tersebut dilekatkan sensor strain gauge. Silinder luar sebagai tempat sampel cairan dihubungkan ke sebuah motor yang dapat berputar konstan. Putaran silinder luar ini akan membuat cairan ikut berputar dan juga akan menyeret silinder dalam bergeser memutar. Gaya yang diterima oleh silinder dalam ini salah satunya tergantung pada viskositas dari cairan ini yang nantinya bisa dibaca oleh sensor strain gage yang dilekatkan pada pegas silinder dalam. Dari hasil penelitian didapatkan data bahwa tegangan keluaran rata-rata untuk sensor ini didapatkan sebesar 1,2 mvolt/cPois. Yang ini berarti setiap 1 cPois viskostas cairan akan menghasilkan tegangan sebesar 1,2 mili volt.

  6. Fiber-optic Fabry-Pérot strain sensor based on graded-index multimode fiber

    Institute of Scientific and Technical Information of China (English)

    Tian Zhao; Yuan Gong; Yunjiang Rao; Yu Wu; Zengling Ran; Huijuan Wu

    2011-01-01

    By using a graded-index multimode fiber (GI-MMF) with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry-Pérot interferometric (MEFPI) strain sensor is fabricated through chemical etching and fusion splicing. Higher reflectance of the microcavity is obtained due to the less-curved inner wall in the center of the fiber core after etching and higher index contrast between the GI-MMF core and air. The maximum reflection of the sensor is enhanced 12 dB than that obtained by etching of the Er- or B-doped fibers. High fringe contrast of 22 dB is obtained. The strain and temperature responses of the MEFPI sensors are investigated in this experiment. Good linearity and high sensitivity axe achieved, with wavelength-strain and wavelength-temperature sensitivities of 7.82 pm/μεand 5.01 pm/℃, respectively.%@@ By using a graded-index multimode fiber (GI-MMF) with a relatively flat index profile and high refractive index of the fiber core, a microextrinsic fiber-optic Fabry-Pérot interferometric (MEFPI) strain sensor is fabricated through chemical etching and fusion splicing.Higher reflectance of the microcavity is obtained due to the less-curved inner wall in the center of the fiber core after etching and higher index contrast between the GI-MMF core and air.

  7. Sensitivity of photonic crystal fiber grating sensors: biosensing, refractive index, strain, and temperature sensing

    DEFF Research Database (Denmark)

    Rindorf, Lars Henning; Bang, Ole

    2008-01-01

    We study the sensitivity of fiber grating sensors in the applications of strain, temperature, internal label-free biosensing, and internal refractive index sensing. New analytical expressions for the sensitivities, valid for photonic crystal fibers are rigorously derived. These are generally valid...

  8. A Novel Extrinsic Fiber-Optic Fabry-Perot Strain Sensor System Based on Optical Amplification

    Institute of Scientific and Technical Information of China (English)

    Yun-Jiang Rao; Jian Jiang; Zheng-Lin Ran

    2003-01-01

    A novel extrinsic fiber-optic Fabry-Perot interferometric strain sensor system is demonstrated based on the simultaneous use of the amplified spontaneous emission and optical amplification. The improvement of 3~4 orders of magnitude in signal level can be achieved.

  9. A skin-integrated transparent and stretchable strain sensor with interactive color-changing electrochromic displays.

    Science.gov (United States)

    Park, Heun; Kim, Dong Sik; Hong, Soo Yeong; Kim, Chulmin; Yun, Jun Yeong; Oh, Seung Yun; Jin, Sang Woo; Jeong, Yu Ra; Kim, Gyu Tae; Ha, Jeong Sook

    2017-06-08

    In this study, we report on the development of a stretchable, transparent, and skin-attachable strain sensor integrated with a flexible electrochromic device as a human skin-inspired interactive color-changing system. The strain sensor consists of a spin-coated conductive nanocomposite film of poly(vinyl alcohol)/multi-walled carbon nanotube/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) on a polydimethylsiloxane substrate. The sensor exhibits excellent performance of high sensitivity, high durability, fast response, and high transparency. An electrochromic device (ECD) made of electrochemically synthesized polyaniline nanofibers and V2O5 on an indium-tin-oxide-coated polyethylene terephthalate film experiences a change in color from yellow to dark blue on application of voltage. The strain sensor and ECD are integrated on skin via an Arduino circuit for an interactive color change with the variation of the applied strain, which enables a real-time visual display of body motion. This integrated system demonstrates high potential for use in interactive wearable devices, military applications, and smart robots.

  10. A Novel Extrinsic Fiber-Optic Fabry-Perot Strain Sensor System Based on Optical Amplification

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel extrinsic fiber-optic Fabry-Perot interferometric strain sensor system is demonstrated based on the simultaneous use of the amplified spontaneous emission and optical amplification. The improvement of 3~4 orders of magnitude in signal level can be achieved.

  11. A high sensitive fiber Bragg grating strain sensor with automatic temperature compensation

    Institute of Scientific and Technical Information of China (English)

    Kuo Li; Zhen'an Zhou

    2009-01-01

    A high sensitive fiber Bragg grating (FBG) strain sensor with automatic temperature compensation is demonstrated. FBG is axially linked with a stick and their free ends are fixed to the measured object. When the measured strain changes, the stick does not change in length, but the FBG does. When the temperature changes, the stick changes in length to pull the FBG to realize temperature compensation. In experiments, 1.45 times strain sensitivity of bare FBG with temperature compensation of less than 0.1 nm Bragg wavelength drift over 100℃ shift is achieved.

  12. D-Shaped Polarization Maintaining Fiber Sensor for Strain and Temperature Monitoring

    Science.gov (United States)

    Qazi, Hummad Habib; Mohammad, Abu Bakar; Ahmad, Harith; Zulkifli, Mohd Zamani

    2016-01-01

    A D-shaped polarization-maintaining fiber (PMF) as fiber optic sensor for the simultaneous monitoring of strain and the surrounding temperature is presented. A mechanical end and edge polishing system with aluminum oxide polishing film is utilized to perform sequential polishing on one side (lengthwise) of the PMF in order to fabricate a D-shaped cross-section. Experimental results show that the proposed sensor has high sensitivity of 46 pm/µε and 130 pm/°C for strain and temperature, respectively, which is significantly higher than other recently reported work (mainly from 2013) related to fiber optic sensors. The easy fabrication method, high sensitivity, and good linearity make this sensing device applicable in various applications such as health monitoring and spatial analysis of engineering structures. PMID:27649195

  13. Laser-engraved carbon nanotube paper for instilling high sensitivity, high stretchability, and high linearity in strain sensors

    KAUST Repository

    Xin, Yangyang

    2017-06-29

    There is an increasing demand for strain sensors with high sensitivity and high stretchability for new applications such as robotics or wearable electronics. However, for the available technologies, the sensitivity of the sensors varies widely. These sensors are also highly nonlinear, making reliable measurement challenging. Here we introduce a new family of sensors composed of a laser-engraved carbon nanotube paper embedded in an elastomer. A roll-to-roll pressing of these sensors activates a pre-defined fragmentation process, which results in a well-controlled, fragmented microstructure. Such sensors are reproducible and durable and can attain ultrahigh sensitivity and high stretchability (with a gauge factor of over 4.2 × 10(4) at 150% strain). Moreover, they can attain high linearity from 0% to 15% and from 22% to 150% strain. They are good candidates for stretchable electronic applications that require high sensitivity and linearity at large strains.

  14. Highly stretchable strain sensor based on SWCNTs/CB synergistic conductive network for wearable human-activity monitoring and recognition

    Science.gov (United States)

    Guo, Xiaohui; Huang, Ying; Zhao, Yunong; Mao, Leidong; Gao, Le; Pan, Weidong; Zhang, Yugang; Liu, Ping

    2017-09-01

    Flexible, stretchable, and wearable strain sensors have attracted significant attention for their potential applications in human movement detection and recognition. Here, we report a highly stretchable and flexible strain sensor based on a single-walled carbon nanotube (SWCNTs)/carbon black (CB) synergistic conductive network. The fabrication, synergistic conductive mechanism, and characterization of the sandwich-structured strain sensor were investigated. The experimental results show that the device exhibits high stretchability (120%), excellent flexibility, fast response (∼60 ms), temperature independence, and superior stability and reproducibility during ∼1100 stretching/releasing cycles. Furthermore, human activities such as the bending of a finger or elbow and gestures were monitored and recognized based on the strain sensor, indicating that the stretchable strain sensor based on the SWCNTs/CB synergistic conductive network could have promising applications in flexible and wearable devices for human motion monitoring.

  15. Strain measurements on concrete beam and carbon fiber cable with distributed optical fiber Bragg grating sensors

    Science.gov (United States)

    Nellen, Philipp M.; Bronnimann, Rolf; Sennhauser, Urs J.; Askins, Charles G.; Putnam, Martin A.

    1996-09-01

    We report on civil engineering applications of wavelength multiplexed optical fiber Bragg grating arrays directly produced on the draw tower for testing and surveying advanced structures and materials such as carbon fiber reinforced concrete elements and prestressing cables. We equipped a 6 by 0.9 by 0.5 m concrete beam, which was reinforced with carbon fiber reinforced epoxy laminates, and a 7-m long prestressing carbon fiber cable made of seven twisted strands, with optical fiber Bragg grating sensors. Static strains up to 8000 micrometers/m and dynamic strains up to 1200 micrometers/m were measured with a Michelson interferometer used as Fourier spectrometer with a resolution of about 10 micrometers/m for all sensors. Comparative measurements with electrical resistance strain gauges were in good agreement with the fiber optical results. We installed the fiber sensors in two different arrangements: some Bragg grating array elements measured local strain while others were applied in an extensometric configuration to measure moderate strain over a base length of 0.1 to 1 m.

  16. Error analysis and measurement uncertainty for a fiber grating strain-temperature sensor.

    Science.gov (United States)

    Tang, Jaw-Luen; Wang, Jian-Neng

    2010-01-01

    A fiber grating sensor capable of distinguishing between temperature and strain, using a reference and a dual-wavelength fiber Bragg grating, is presented. Error analysis and measurement uncertainty for this sensor are studied theoretically and experimentally. The measured root mean squared errors for temperature T and strain ε were estimated to be 0.13 °C and 6 με, respectively. The maximum errors for temperature and strain were calculated as 0.00155 T + 2.90 × 10(-6) ε and 3.59 × 10(-5) ε + 0.01887 T, respectively. Using the estimation of expanded uncertainty at 95% confidence level with a coverage factor of k = 2.205, temperature and strain measurement uncertainties were evaluated as 2.60 °C and 32.05 με, respectively. For the first time, to our knowledge, we have demonstrated the feasibility of estimating the measurement uncertainty for simultaneous strain-temperature sensing with such a fiber grating sensor.

  17. Analysis of time-domain signals of piezoelectric strain sensors on slow spinning planetary gearboxes

    Science.gov (United States)

    Noll, Martin-Christopher; Godfrey, Julian William; Schelenz, Ralf; Jacobs, Georg

    2016-05-01

    Currently, condition monitoring of gearboxes mainly relies on signals of mechanical vibrations (mostly acceleration; fewer velocity and distance) or very high-frequency acoustic emissions as well as oil particle and temperature data. Strains are rarely used, since the common measuring technique employing strain gauges can cause problems in harsh environmental conditions. In the following, time-domain signals of robust piezoelectric strain sensors applied on the surface of the ring gear of a gearbox are analyzed regarding their mechanical basics, measurement chains and inferable information. The gearbox specimen is a main gearbox of a wind energy converter (WEC), which is deployed on a WEC system test rig. It can be shown that the surface strain on fixed ring gears in tangential direction is mainly influenced by the transferred tooth forces between planets and ring gear but also by the stiffnesses and geometries of the ring gear itself and the supporting gearbox structure. A direct comparison of sensor connection in AC- and DC-coupling shows that with the utilized piezoelectric sensors in DC-coupling surface strain signals with very low frequencies down to 0.002 Hz can be obtained. The acquired signals show a very high signal-to-noise-ratio and high repeatability even at very low revolution speeds. Furthermore a direct correlation to the dynamic torque, which is transferred by the gearbox, and to the planetary load sharing is found.

  18. A Spray-On Carbon Nanotube Artificial Neuron Strain Sensor for Composite Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Gyeongrak Choi

    2016-07-01

    Full Text Available We present a nanocomposite strain sensor (NCSS to develop a novel structural health monitoring (SHM sensor that can be easily installed in a composite structure. An NCSS made of a multi-walled carbon nanotubes (MWCNT/epoxy composite was installed on a target structure with facile processing. We attempted to evaluate the NCSS sensing characteristics and benchmark compared to those of a conventional foil strain gauge. The response of the NCSS was fairly good and the result was nearly identical to the strain gauge. A neuron, which is a biomimetic long continuous NCSS, was also developed, and its vibration response was investigated for structural damage detection of a composite cantilever. The vibration response for damage detection was measured by tracking the first natural frequency, which demonstrated good result that matched the finite element (FE analysis.

  19. A Spray-On Carbon Nanotube Artificial Neuron Strain Sensor for Composite Structural Health Monitoring.

    Science.gov (United States)

    Choi, Gyeongrak; Lee, Jong Won; Cha, Ju Young; Kim, Young-Ju; Choi, Yeon-Sun; Schulz, Mark J; Moon, Chang Kwon; Lim, Kwon Tack; Kim, Sung Yong; Kang, Inpil

    2016-07-26

    We present a nanocomposite strain sensor (NCSS) to develop a novel structural health monitoring (SHM) sensor that can be easily installed in a composite structure. An NCSS made of a multi-walled carbon nanotubes (MWCNT)/epoxy composite was installed on a target structure with facile processing. We attempted to evaluate the NCSS sensing characteristics and benchmark compared to those of a conventional foil strain gauge. The response of the NCSS was fairly good and the result was nearly identical to the strain gauge. A neuron, which is a biomimetic long continuous NCSS, was also developed, and its vibration response was investigated for structural damage detection of a composite cantilever. The vibration response for damage detection was measured by tracking the first natural frequency, which demonstrated good result that matched the finite element (FE) analysis.

  20. A Spray-On Carbon Nanotube Artificial Neuron Strain Sensor for Composite Structural Health Monitoring

    Science.gov (United States)

    Choi, Gyeongrak; Lee, Jong Won; Cha, Ju Young; Kim, Young-Ju; Choi, Yeon-Sun; Schulz, Mark J.; Moon, Chang Kwon; Lim, Kwon Tack; Kim, Sung Yong; Kang, Inpil

    2016-01-01

    We present a nanocomposite strain sensor (NCSS) to develop a novel structural health monitoring (SHM) sensor that can be easily installed in a composite structure. An NCSS made of a multi-walled carbon nanotubes (MWCNT)/epoxy composite was installed on a target structure with facile processing. We attempted to evaluate the NCSS sensing characteristics and benchmark compared to those of a conventional foil strain gauge. The response of the NCSS was fairly good and the result was nearly identical to the strain gauge. A neuron, which is a biomimetic long continuous NCSS, was also developed, and its vibration response was investigated for structural damage detection of a composite cantilever. The vibration response for damage detection was measured by tracking the first natural frequency, which demonstrated good result that matched the finite element (FE) analysis. PMID:27472332

  1. Enhanced green upconversion by controlled ceramization of Er{sup 3+}–Yb{sup 3+} co-doped sodium niobium tellurite glass–ceramics for low temperature sensors

    Energy Technology Data Exchange (ETDEWEB)

    Suresh Kumar, J., E-mail: suresh@ua.pt; Pavani, K.; Graça, M.P.F.; Soares, M.J.

    2014-12-25

    Highlights: • Upconversion luminescence improved in glass–ceramics compared to host glass. • Judd–Ofelt and radiative parameters calculated. • NIR decay curve results concur the results of improved luminescence. • Temperature dependent upconversion support the use of materials for sensors. - Abstract: Tellurite based glasses are well-known for their upconversion properties besides having a disadvantage of low mechanical strength dragging them away from practical applications. The present work deals with preparation of sodium niobium tellurite (SNT) glasses using melt quenching method, in which small quantities of boron and silicon in the form of oxides are added to improve their mechanical properties. Controlled heat treatment is performed to ceramize the prepared glasses based on the thermal data given by DTA. XRD and SEM profiles of the glass–ceramics which confirmed the formation of crystalline monoclinic Sodium Tellurium Niobium Oxide (Na{sub 1.4}Nb{sub 3}Te{sub 4.9}O{sub 18}) phase (JCPDS card No. 04–011-7556). Upconversion measurements in the visible region were made for the prepared Er{sup 3+}–Yb{sup 3+} co-doped glasses and glass–ceramics with 980 nm laser excitation varying the laser power and concentration of Er{sup 3+} ions. Results showed that the upconversion luminescence intensity was enhanced by ten times in SNT glass–ceramics compared to that in the SNT glasses. Decay curves give evidence of high performance of glass–ceramics compared to glasses due to ceramization and structural changes. Temperature dependent visible upconversion was performed to test the ability of efficient SNT glass–ceramic at low temperatures and variation of upconversion intensities was studied.

  2. Piezoelectric and dielectric properties of polymer-ceramic composites for sensors

    NARCIS (Netherlands)

    James, N.K.

    2015-01-01

    The main objective of this PhD thesis is to develop new routes and concepts for manufacturing piezoelectric ceramic-polymer composites with adequate piezoelectric properties while retaining ease of manufacturing and mechanical flexibility and explore new possibilities to maximize especially the volt

  3. Durability Evaluation of a Thin Film Sensor System With Enhanced Lead Wire Attachments on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Lei, Jih-Fen; Kiser, J. Douglas; Singh, Mrityunjay; Cuy, Mike; Blaha, Charles A.; Androjna, Drago

    2000-01-01

    An advanced thin film sensor system instrumented on silicon carbide (SiC) fiber reinforced SiC matrix ceramic matrix composites (SiC/SiC CMCs), was evaluated in a Mach 0.3 burner rig in order to determine its durability to monitor material/component surface temperature in harsh environments. The sensor system included thermocouples in a thin film form (5 microns thick), fine lead wires (75 microns diameter), and the bonds between these wires and the thin films. Other critical components of the overall system were the heavy, swaged lead wire cable (500 microns diameter) that contained the fine lead wires and was connected to the temperature readout, and ceramic attachments which were bonded onto the CMCs for the purpose of securing the lead wire cables, The newly developed ceramic attachment features a combination of hoops made of monolithic SiC or SiC/SiC CMC (which are joined to the test article) and high temperature ceramic cement. Two instrumented CMC panels were tested in a burner rig for a total of 40 cycles to 1150 C (2100 F). A cycle consisted of rapid heating to 1150 C (2100 F), a 5 minute hold at 1150 C (2100 F), and then cooling down to room temperature in 2 minutes. The thin film sensor systems provided repeatable temperature measurements for a maximum of 25 thermal cycles. Two of the monolithic SiC hoops debonded during the sensor fabrication process and two of the SiC/SiC CMC hoops failed during testing. The hoops filled with ceramic cement, however, showed no sign of detachment after 40 thermal cycle test. The primary failure mechanism of this sensor system was the loss of the fine lead wire-to-thin film connection, which either due to detachment of the fine lead wires from the thin film thermocouples or breakage of the fine wire.

  4. Fully integrated carbon nanotube composite thin film strain sensors on flexible substrates for structural health monitoring

    Science.gov (United States)

    Burton, A. R.; Lynch, J. P.; Kurata, M.; Law, K. H.

    2017-09-01

    Multifunctional thin film materials have opened many opportunities for novel sensing strategies for structural health monitoring. While past work has established methods of optimizing multifunctional materials to exhibit sensing properties, comparatively less work has focused on their integration into fully functional sensing systems capable of being deployed in the field. This study focuses on the advancement of a scalable fabrication process for the integration of multifunctional thin films into a fully integrated sensing system. This is achieved through the development of an optimized fabrication process that can create a broad range of sensing systems using multifunctional materials. A layer-by-layer deposited multifunctional composite consisting of single walled carbon nanotubes (SWNT) in a polyvinyl alcohol and polysodium-4-styrene sulfonate matrix are incorporated with a lithography process to produce a fully integrated sensing system deposited on a flexible substrate. To illustrate the process, a strain sensing platform consisting of a patterned SWNT-composite thin film as a strain-sensitive element within an amplified Wheatstone bridge sensing circuit is presented. Strain sensing is selected because it presents many of the design and processing challenges that are core to patterning multifunctional thin film materials into sensing systems. Strain sensors fabricated on a flexible polyimide substrate are experimentally tested under cyclic loading using standard four-point bending coupons and a partial-scale steel frame assembly under lateral loading. The study reveals the material process is highly repeatable to produce fully integrated strain sensors with linearity and sensitivity exceeding 0.99 and 5 {{V}}/{ε }, respectively. The thin film strain sensors are robust and are capable of high strain measurements beyond 3000 μ {ε }.

  5. Microfabricated photoplastic cantilever with integrated photoplastic/carbon based piezoresistive strain sensor

    DEFF Research Database (Denmark)

    Gammelgaard, Lauge; Rasmussen, Peter Andreas; Calleja, M.;

    2006-01-01

    We present an SU-8 micrometer sized cantilever strain sensor with an integrated piezoresistor made of a conductive composite of SU-8 polymer and carbon black particles. The composite has been developed using ultrasonic mixing. Cleanroom processing of the polymer composite has been investigated an...... silicon and the gauge factor of the composite material is relatively high, this polymer based strain sensor is more sensitive than a similar silicon based cantilever sensor. (c) 2006 American Institute of Physics.......We present an SU-8 micrometer sized cantilever strain sensor with an integrated piezoresistor made of a conductive composite of SU-8 polymer and carbon black particles. The composite has been developed using ultrasonic mixing. Cleanroom processing of the polymer composite has been investigated...... and it has been shown that it is possible to pattern the composite by standard UV photolithography. The composite material has been integrated into an SU-8 microcantilever and the polymer composite has been demonstrated to be piezoresistive with gauge factors around 15-20. Since SU-8 is much softer than...

  6. Three-axial Fiber Bragg Grating Strain Sensor for Volcano Monitoring

    Science.gov (United States)

    Giacomelli, Umberto; Beverini, Nicolò; Carbone, Daniele; Carelli, Giorgio; Francesconi, Francesco; Gambino, Salvatore; Maccioni, Enrico; Morganti, Mauro; Orazi, Massimo; Peluso, Rosario; Sorrentino, Fiodor

    2017-04-01

    Fiber optic and FBGs sensors have attained a large diffusion in the last years as cost-effective monitoring and diagnostic devices in civil engineering. However, in spite of their potential impact, these instruments have found very limited application in geophysics. In order to study earthquakes and volcanoes, the measurement of crustal deformation is of crucial importance. Stress and strain behaviour is among the best indicators of changes in the activity of volcanoes .. Deep bore-hole dilatometers and strainmeters have been employed for volcano monitoring. These instruments are very sensitive and reliable, but are not cost-effective and their installation requires a large effort. Fiber optic based devices offer low cost, small size, wide frequency band, easier deployment and even the possibility of creating a local network with several sensors linked in an array. We present the realization, installation and first results of a shallow-borehole (8,5 meters depth) three-axial Fiber Bragg Grating (FBG) strain sensor prototype. This sensor has been developed in the framework of the MED-SUV project and installed on Etna volcano, in the facilities of the Serra La Nave astrophysical observatory. The installation siteis about 7 Km South-West of the summit craters, at an elevation of about 1740 m. The main goal of our work is the realization of a three-axial device having a high resolution and accuracy in static and dynamic strain measurements, with special attention to the trade-off among resolution, cost and power consumption. The sensor structure and its read-out system are innovative and offer practical advantages in comparison with traditional strain meters. Here we present data collected during the first five months of operation. In particular, the very clear signals recorded in the occurrence of the Central Italy seismic event of October 30th demonstrate the performances of our device.

  7. Carbon nanotube thin film strain sensors: comparison between experimental tests and numerical simulations

    Science.gov (United States)

    Lee, Bo Mi; Loh, Kenneth J.

    2017-04-01

    Carbon nanotubes can be randomly deposited in polymer thin film matrices to form nanocomposite strain sensors. However, a computational framework that enables the direct design of these nanocomposite thin films is still lacking. The objective of this study is to derive an experimentally validated and two-dimensional numerical model of carbon nanotube-based thin film strain sensors. This study consisted of two parts. First, multi-walled carbon nanotube (MWCNT)-Pluronic strain sensors were fabricated using vacuum filtration, and their physical, electrical, and electromechanical properties were evaluated. Second, scanning electron microscope images of the films were used for identifying topological features of the percolated MWCNT network, where the information obtained was then utilized for developing the numerical model. Validation of the numerical model was achieved by ensuring that the area ratios (of MWCNTs relative to the polymer matrix) were equivalent for both the experimental and modeled cases. Strain sensing behavior of the percolation-based model was simulated and then compared to experimental test results.

  8. Oil pipeline geohazard monitoring using optical fiber FBG strain sensors (Conference Presentation)

    Science.gov (United States)

    Salazar-Ferro, Andres; Mendez, Alexis

    2016-04-01

    Pipelines are naturally vulnerable to operational, environmental and man-made effects such as internal erosion and corrosion; mechanical deformation due to geophysical risks and ground movements; leaks from neglect and vandalism; as well as encroachments from nearby excavations or illegal intrusions. The actual detection and localization of incipient and advanced faults in pipelines is a very difficult, expensive and inexact task. Anything that operators can do to mitigate the effects of these faults will provide increased reliability, reduced downtime and maintenance costs, as well as increased revenues. This talk will review the on-line monitoring of an extensive network of oil pipelines in service in Colombia using optical fiber Bragg grating (FBG) strain sensors for the measurement of strains and bending caused by geohazard risks such as soil movements, landslides, settlements, flooding and seismic activity. The FBG sensors were mounted on the outside of the pipelines at discrete locations where geohazard risk was expected. The system has been in service for the past 3 years with over 1,000 strain sensors mounted. The technique has been reliable and effective in giving advanced warning of accumulated pipeline strains as well as possible ruptures.

  9. Dynamic Strain Sensing in a Long-Span Suspension Bridge Using Fiber Bragg Grating Sensors

    Science.gov (United States)

    Zhu, Yinian; Zhu, Yan-Jin; Balogun, Oluwaseyi; Zhu, Songye; Xu, You-Lin; Krishnaswamy, Sridhar

    2011-06-01

    Optical fiber sensors are ideal for monitoring continuous deterioration conditions of civil infrastructure, especially of long-span bridges. Typically, a network of sensors is used to measure the strains or low frequency vibrational response of the structure. In this work, we demonstrate dynamic spectral demodulation of fiber Bragg grating (FBG) sensor responses with a stabilized Michelson interferometer for monitoring mechanical strains in a model of long-span bridge. A series of experiments has been performed, including the measurements of the natural resonant modes of the model bridge, impact response of a bridge member and acoustic emissions in a fractured aluminum bar. The experimental results not only reveal that dynamic spectral demodulation of FBG strain responses at frequencies extending up to about 3.5 MHz is possible, but also suggest that the method may be suitable for monitoring high frequency mechanical strains in civil structures that result from cracking or impact loading, thus providing a tool for local detection of structural damage.

  10. Integration of graphene sensor with electrochromic device on modulus-gradient polymer for instantaneous strain visualization

    Science.gov (United States)

    Yang, Tingting; Zhong, Yujia; Tao, Dashuai; Li, Xinming; Zang, Xiaobei; Lin, Shuyuan; Jiang, Xin; Li, Zhihong; Zhu, Hongwei

    2017-09-01

    In nature, some animals change their deceptive coloration for camouflage, temperature preservation or communication. This astonishing function has inspired scientists to replicate the color changing abilities of animals with artificial skin. Recently, some studies have focused on the smart materials and devices with reversible color changing or light-emitting properties for instantaneous strain visualization. However, most of these works only show eye-detectable appearance change when subjected to large mechanical deformation (100%-500% strain), and conspicuous color change at small strain remains rarely explored. In the present study, we developed a user-interactive electronic skin with human-readable optical output by assembling a highly sensitive resistive strain sensor with a stretchable organic electrochromic device (ECD) together. We explored the substrate effect on the electromechanical behavior of graphene and designed a strategy of modulus-gradient structure to employ graphene as both the highly sensitive strain sensing element and the insensitive stretchable electrode of the ECD layer. Subtle strain (0-10%) was enough to evoke an obvious color change, and the RGB value of the color quantified the magnitude of the applied strain. Such high sensitivity to smaller strains (0-10%) with color changing capability will potentially enhance the function of wearable devices, robots and prosthetics in the future.

  11. Mechanical stress measurement by an achromatic optical digital speckle pattern interferometry strain sensor with radial in-plane sensitivity: experimental comparison with electrical strain gauges

    Energy Technology Data Exchange (ETDEWEB)

    Viotti, Matias R.; Armando Albertazzi, G. Jr.; Kapp, Walter A.

    2011-03-01

    This paper shows the optical setup of a radial in-plane digital speckle pattern interferometer which uses an axis-symmetrical diffractive optical element (DOE) to obtain double illumination. The application of the DOE gives in-plane sensitivity which only depends on the grating period of the DOE instead of the wavelength of the laser used as illumination source. A compact optical layout was built in order to have a portable optical strain sensor with a circular measurement area of about 5 mm in diameter. In order to compare its performance with electrical strain sensors (strain gauges), mechanical loading was generated by a four-point bending device and simultaneously monitored by the optical strain sensor and by two-element strain gauge rosettes. Several mechanical stress levels were measured showing a good agreement between both sensors. Results showed that the optical sensor could measure applied mechanical strains with a mean uncertainty of about 5% and 4% for the maximum and minimum principal strains, respectively.

  12. Highly sensitive strain sensor based on helical structure combined with Mach-Zehnder interferometer in multicore fiber.

    Science.gov (United States)

    Zhang, Hailiang; Wu, Zhifang; Shum, Perry Ping; Dinh, Xuan Quyen; Low, Chun Wah; Xu, Zhilin; Wang, Ruoxu; Shao, Xuguang; Fu, Songnian; Tong, Weijun; Tang, Ming

    2017-04-18

    Optical fiber sensors for strain measurement have been playing important roles in structural health monitoring for buildings, tunnels, pipelines, aircrafts, and so on. A highly sensitive strain sensor based on helical structures (HSs) assisted Mach-Zehnder interference in an all-solid heterogeneous multicore fiber (MCF) is proposed and experimentally demonstrated. Due to the HSs, a maximum strain sensitivity as high as -61.8 pm/με was experimentally achieved. This is the highest sensitivity among interferometer-based strain sensors reported so far, to the best of our knowledge. Moreover, the proposed sensor has the ability to discriminate axial strain and temperature, and offers several advantages such as repeatability of fabrication, robust structure and compact size, which further benefits its practical sensing applications.

  13. PLZT ferroelectric ceramics on the morphotropic boundary phase. Study as possible pyroelectric sensors

    Energy Technology Data Exchange (ETDEWEB)

    Pelaiz Barranco, A.; Perez Martinez, O. [Univ. de La Habana (Cuba). Inst. de Materiales y Reactivos; Calderon Pinar, F. [Univ. de La Habana (Cuba). Inst. de Materiales y Reactivos; Centro de Investigaciones en Ciencia Aplicada y Tecnologia de Avanzada (CICATA), Altamira, Tamps (Mexico)

    2001-08-16

    PLZT compositions near the morphotropic boundary phase (Zr/Ti = 53/47) were studied changing the lanthanum fraction from 0.5 to 14 at%. The grain size and the porosity due to the lanthanum addition showed an important influence on the dielectric properties of the samples. Dielectric and pyroelectric studies show that the ceramics of lower lanthanum concentrations are suitable materials for practical applications. The ceramic's response subjected to light radiation was investigated. The radiation is absorbed near the material surface and its temperature rises leading to a change in the electrical polarization of the bulk material. This phenomenon is analyzed and correlated with the absorbed light on the surface of the material. (orig.)

  14. Highly Stretchable, Ultrasensitive, and Wearable Strain Sensors Based on Facilely Prepared Reduced Graphene Oxide Woven Fabrics in an Ethanol Flame.

    Science.gov (United States)

    Yin, Biao; Wen, Yanwei; Hong, Tao; Xie, Zhongshuai; Yuan, Guoliang; Ji, Qingmin; Jia, Hongbing

    2017-09-11

    The recent booming development of wearable electronics urgently calls for high-performance flexible strain sensors. To date, it is still a challenge to manufacture flexible strain sensors with superb sensitivity and a large workable strain range simultaneously. Herein, a facile, quick, cost-effective, and scalable strategy is adopted to fabricate novel strain sensors based on reduced graphene oxide woven fabrics (GWF). By pyrolyzing commercial cotton bandages coated with graphene oxide (GO) sheets in an ethanol flame, the reduction of GO and the pyrolysis of the cotton bandage template can be synchronously completed in tens of seconds. Due to the unique hierarchical structure of the GWF, the strain sensor based on GWF exhibits large stretchability (57% strain) with high sensitivity, inconspicuous drift, and durability. The GWF strain sensor is successfully used to monitor full-range (both subtle and vigorous) human activities or physical vibrational signals of the local environment. The present work offers an effective strategy to rapidly prepare low-cost flexible strain sensors with potential applications in the fields of wearable electronics, artificial intelligence devices, and so forth.

  15. Strain Sensing Characteristics of Rubbery Carbon Nanotube Composite for Flexible Sensors.

    Science.gov (United States)

    Choi, Gyong Rak; Park, Hyung-ki; Huh, Hoon; Kim, Young-Ju; Ham, Heon; Kim, Hyoun Woo; Lim, Kwon Taek; Kim, Sung Yong; Kang, Inpil

    2016-02-01

    In this study, the piezoresistive properties of CNT (Carbon Nanotube)/EPDM composite are characterized for the applications of a flexible sensor. The CNT/EPDM composites were prepared by using a Brabender mixer with MWCNT (Multi-walled Carbon Nanotube) and organoclay. The static and quasi-dynamic voltage output responses of the composite sensor were also experimentally studied and were compared with those of a conventional foil strain gage. The voltage output by using a signal processing system was fairly stable and it shows somehow linear responses at both of loading and unloading cases with hysteresis. The voltage output was distorted under a quasi-dynamic test due to its unsymmetrical piezoresistive characteristics. The CNT/EPDM sensor showed quite tardy response to its settling time test under static deflections and that would be a hurdle for its real time applications. Furthermore, since the CNT/EPDM sensor does not have directional voltage output to tension and compression, it only could be utilized as a mono-directional force sensor such as a compressive touch sensor.

  16. Feature extraction for ultrasonic sensor based defect detection in ceramic components

    Science.gov (United States)

    Kesharaju, Manasa; Nagarajah, Romesh

    2014-02-01

    High density silicon carbide materials are commonly used as the ceramic element of hard armour inserts used in traditional body armour systems to reduce their weight, while providing improved hardness, strength and elastic response to stress. Currently, armour ceramic tiles are inspected visually offline using an X-ray technique that is time consuming and very expensive. In addition, from X-rays multiple defects are also misinterpreted as single defects. Therefore, to address these problems the ultrasonic non-destructive approach is being investigated. Ultrasound based inspection would be far more cost effective and reliable as the methodology is applicable for on-line quality control including implementation of accept/reject criteria. This paper describes a recently developed methodology to detect, locate and classify various manufacturing defects in ceramic tiles using sub band coding of ultrasonic test signals. The wavelet transform is applied to the ultrasonic signal and wavelet coefficients in the different frequency bands are extracted and used as input features to an artificial neural network (ANN) for purposes of signal classification. Two different classifiers, using artificial neural networks (supervised) and clustering (un-supervised) are supplied with features selected using Principal Component Analysis(PCA) and their classification performance compared. This investigation establishes experimentally that Principal Component Analysis(PCA) can be effectively used as a feature selection method that provides superior results for classifying various defects in the context of ultrasonic inspection in comparison with the X-ray technique.

  17. Carbon nanotube thin film strain sensor models assembled using nano- and micro-scale imaging

    Science.gov (United States)

    Lee, Bo Mi; Loh, Kenneth J.; Yang, Yuan-Sen

    2017-02-01

    Nanomaterial-based thin films, particularly those based on carbon nanotubes (CNT), have brought forth tremendous opportunities for designing next-generation strain sensors. However, their strain sensing properties can vary depending on fabrication method, post-processing treatment, and types of CNTs and polymers employed. The objective of this study was to derive a CNT-based thin film strain sensor model using inputs from nano-/micro-scale experimental measurements of nanotube physical properties. This study began with fabricating ultra-low-concentration CNT-polymer thin films, followed by imaging them using atomic force microscopy. Image processing was employed for characterizing CNT dispersed shapes, lengths, and other physical attributes, and results were used for building five different types of thin film percolation-based models. Numerical simulations were conducted to assess how the morphology of dispersed CNTs in its 2D matrix affected bulk film electrical and electromechanical (strain sensing) properties. The simulation results showed that CNT morphology had a significant impact on strain sensing performance.

  18. Carbon nanotube thin film strain sensor models assembled using nano- and micro-scale imaging

    Science.gov (United States)

    Lee, Bo Mi; Loh, Kenneth J.; Yang, Yuan-Sen

    2017-07-01

    Nanomaterial-based thin films, particularly those based on carbon nanotubes (CNT), have brought forth tremendous opportunities for designing next-generation strain sensors. However, their strain sensing properties can vary depending on fabrication method, post-processing treatment, and types of CNTs and polymers employed. The objective of this study was to derive a CNT-based thin film strain sensor model using inputs from nano-/micro-scale experimental measurements of nanotube physical properties. This study began with fabricating ultra-low-concentration CNT-polymer thin films, followed by imaging them using atomic force microscopy. Image processing was employed for characterizing CNT dispersed shapes, lengths, and other physical attributes, and results were used for building five different types of thin film percolation-based models. Numerical simulations were conducted to assess how the morphology of dispersed CNTs in its 2D matrix affected bulk film electrical and electromechanical (strain sensing) properties. The simulation results showed that CNT morphology had a significant impact on strain sensing performance.

  19. Modal macro-strain vector based damage detection methodology with long-gauge FBG sensors

    Science.gov (United States)

    Xu, Bin; Liu, Chongwu W.; Masri, Sami F.

    2009-07-01

    Advances in optic fiber sensing technology provide easy and reliable way for the vibration-based strain measurement of engineering structures. As a typical optic fiber sensing techniques with high accuracy and resolution, long-gauge Fiber Bragg Grating (FBG) sensors have been widely employed in health monitoring of civil engineering structures. Therefore, the development of macro strain-based identification methods is crucial for damage detection and structural condition evaluation. In the previous study by the authors, a damage detection algorithm for a beam structure with the direct use of vibration-based macro-strain measurement time history with neural networks had been proposed and validated with experimental measurements. In this paper, a damage locating and quantifying method was proposed using modal macrostrain vectors (MMSVs) which can be extracted from vibration induced macro-strain response measurement time series from long-gage FBG sensors. The performance of the proposed methodology for damage detection of a beam with different damage scenario was studied with numerical simulation firstly. Then, dynamic tests on a simply-supported steel beam with different damage scenarios were carried out and macro-strain measurements were employed to detect the damage severity. Results show that the proposed MMSV based structural identification and damage detection methodology can locate and identify the structural damage severity with acceptable accuracy.

  20. A Polypyrrole-based Strain Sensor Dedicated to Measure Bladder Volume in Patients with Urinary Dysfunction

    Directory of Open Access Journals (Sweden)

    Vamsy P. Chodavarapu

    2008-08-01

    Full Text Available This paper describes a new technique to measure urine volume in patients with urinary bladder dysfunction. Polypyrrole – an electronically conducting polymer - is chemically deposited on a highly elastic fabric. This fabric, when placed around a phantom bladder, produced a reproducible change in electrical resistance on stretching. The resistance response to stretching is linear in 20%-40% strain variation. This change in resistance is influenced by chemical fabrication conditions. We also demonstrate the dynamic mechanical testing of the patterned polypyrrole on fabric in order to show the feasibility of passive interrogation of the strain sensor for biomedical sensing applications.

  1. Simultaneous and quasi-independent strain and temperature sensor based on microstructured optical fiber

    Science.gov (United States)

    Lopez-Aldaba, A.; Auguste, J.-L.; Jamier, R.; Roy, P.; Lopez-Amo, M.

    2017-04-01

    In this paper, a new sensor system for simultaneous and quasi-independent strain and temperature measurements is presented. The interrogation of the sensing head has been carried out by monitoring the FFT phase variations of two of the microstructured optical fiber (MOF) cavity interference frequencies. This method is independent of the signal amplitude and also avoids the need to track the wavelength evolution in the spectrum, which can be a handicap when there are multiple interference frequency components with different sensitivities. The sensor is operated within a range of temperature of 30°C-75°C, and 380μɛ of maximum strain were applied; being the sensitivities achieved of 127.5pm/°C and -19.1pm/μɛ respectively. Because the system uses an optical interrogator as unique active element, the system presents a cost-effective feature.

  2. Monitoring of hardening and hygroscopic induced strains in a calcium phosphate bone cement using FBG sensor.

    Science.gov (United States)

    Bimis, A; Karalekas, D; Bouropoulos, N; Mouzakis, D; Zaoutsos, S

    2016-07-01

    This study initially deals with the investigation of the induced strains during hardening stage of a self-setting calcium phosphate bone cement using fiber-Bragg grating (FBG) optical sensors. A complementary Scanning Electron Microscopy (SEM) investigation was also conducted at different time intervals of the hardening period and its findings were related to the FBG recordings. From the obtained results, it is demonstrated that the FBG response is affected by the microstructural changes taking place when the bone cement is immersed into the hardening liquid media. Subsequently, the FBG sensor was used to monitor the absorption process and hygroscopic response of the hardened and dried biocement when exposed to a liquid/humid environment. From the FBG-based calculated hygric strains as a function of moisture concentration, the coefficient of moisture expansion (CME) of the examined bone cement was obtained, exhibiting two distinct linear regions.

  3. Strain Sharing Assessment in Woven Fiber Reinforced Concrete Beams Using Fiber Bragg Grating Sensors.

    Science.gov (United States)

    Montanini, Roberto; Recupero, Antonino; De Domenico, Fabrizio; Freni, Fabrizio

    2016-09-22

    Embedded fiber Bragg grating sensors have been extensively used worldwide for health monitoring of smart structures. In civil engineering, they provide a powerful method for monitoring the performance of composite reinforcements used for concrete structure rehabilitation and retrofitting. This paper discusses the problem of investigating the strain transfer mechanism in composite strengthened concrete beams subjected to three-point bending tests. Fiber Bragg grating sensors were embedded both in the concrete tensioned surface and in the woven fiber reinforcement. It has been shown that, if interface decoupling occurs, strain in the concrete can be up to 3.8 times higher than that developed in the reinforcement. A zero friction slipping model was developed which fitted very well the experimental data.

  4. Package analysis of 3D-printed piezoresistive strain gauge sensors

    Science.gov (United States)

    Das, Sumit Kumar; Baptist, Joshua R.; Sahasrabuddhe, Ritvij; Lee, Woo H.; Popa, Dan O.

    2016-05-01

    Poly(3,4-ethyle- nedioxythiophene)-poly(styrenesulfonate) or PEDOT:PSS is a flexible polymer which exhibits piezo-resistive properties when subjected to structural deformation. PEDOT:PSS has a high conductivity and thermal stability which makes it an ideal candidate for use as a pressure sensor. Applications of this technology includes whole body robot skin that can increase the safety and physical collaboration of robots in close proximity to humans. In this paper, we present a finite element model of strain gauge touch sensors which have been 3D-printed onto Kapton and silicone substrates using Electro-Hydro-Dynamic ink-jetting. Simulations of the piezoresistive and structural model for the entire packaged sensor was carried out using COMSOLR , and compared with experimental results for validation. The model will be useful in designing future robot skin with predictable performances.

  5. Split-Ring Resonator-Based Strain Sensor on Flexible Substrates for Glaucoma Detection

    Science.gov (United States)

    Ekinci, Gizem; Deniz Yalcinkaya, Arda; Dundar, Gunhan; Torun, Hamdi

    2016-10-01

    This paper presents split-ring resonator-based strain sensors designed and characterized for glaucoma detection application. The geometry of the sensor is optimized such that it can be embedded in a contact lens. Silver conductive paint is to form the sensors realized on flexible substrates made of cellulose acetate and latex rubber. The devices are excited and interrogated using a pair of monopole antennas and the characteristics of devices with different curvature profiles are obtained. The sensitivity of the device, i.e. the change in resonant frequency for a unit change in radius of curvature, on acetate film is calculated as -4.73 MHz/mm and the sensitivity of the device on latex is 33.2 MHz/mm. The results indicate that the demonstrated device is suitable for glaucoma diagnosis.

  6. Tensile strain measurements of ceramic fibers using scanning laser acoustic microscopy

    Science.gov (United States)

    Kent, Renee M.; Vary, Alex

    1992-01-01

    A noncontacting technique using scanning laser acoustic microscopy for making in situ tensile strain measurements of small diameter fibers was implemented for the tensile strain analysis of individual Nicalon SiC fibers (nominal diameter 15 microns). Stress vs strain curves for the fibers were plotted from the experimental data. The mean elastic modulus of the fibers was determined to be 185.3 GPa. Similar measurements were made for Carborundum SiC fibers (nominal diameter 28 microns) and Saphikon sapphire fibers (nominal diameter 140 microns).

  7. Fully integrated patterned carbon nanotube strain sensors on flexible sensing skin substrates for structural health monitoring

    Science.gov (United States)

    Burton, Andrew R.; Kurata, Masahiro; Nishino, Hiromichi; Lynch, Jerome P.

    2016-04-01

    New advances in nanotechnology and material processing is creating opportunities for the design and fabrication of a new generation of thin film sensors that can used to assess structural health. In particular, thin film sensors attached to large areas of the structure surface has the potential to provide spatially rich data on the performance and health of a structure. This study focuses on the development of a fully integrated strain sensor that is fabricated on a flexible substrate for potentially use in sensing skins. This is completed using a carbon nanotube-polymer composite material that is patterned on a flexible polyimide substrate using optical lithography. The piezoresistive carbon nanotube elements are integrated into a complete sensing system by patterning copper electrodes and integrating off-the-shelf electrical components on the flexible film for expanded functionality. This diverse material utilization is realized in a versatile process flow to illustrate a powerful toolbox for sensing severity, location, and failure mode of damage on structural components. The fully integrated patterned carbon nanotube strain sensor is tested on a quarter-scale, composite beam column connection. The results and implications for future structural damage detection are discussed.

  8. Field validation of road roughness evaluation using in-pavement strain sensors

    Science.gov (United States)

    Zhang, Z.; Deng, F.; Huang, Y.; Bridgelall, R.

    2016-04-01

    Most transportation agencies now collect pavement roughness data using the inertial profilers, which requires instrumented vehicles and technicians with specialized training to interpret the results. The extensive labor requirements of the profiling activities limit data collection for portions of the national highway system to at most once per year, resulting in outdated roughness data for decision making of maintenance needs. In this paper, a real-time roughness evaluation method was developed by linking the output of durable in-pavement strain sensors to road roughness level. The durable in-pavement sensors will continuously provide information of road roughness in real time after they are installed and calibrated during the road construction until the service life of the associated pavement. Field tests validated the developed strain method by comparison with standard inertial profiling method and the connected-vehicle method. The comparison of the results from the field tests approves the effectiveness of the developed road roughness evaluation method using in-pavement strain sensors, which can be further applied practically for needed concrete pavements.

  9. Accuracy of a Wearable Sensor for Measures of Head Kinematics and Calculation of Brain Tissue Strain.

    Science.gov (United States)

    Knowles, Brooklynn M; Yu, Henry; Dennison, Christopher R

    2017-02-01

    Wearable kinematic sensors can be used to study head injury biomechanics based on kinematics and, more recently, based on tissue strain metrics using kinematics-driven brain models. These sensors require in-situ calibration and there is currently no data conveying wearable ability to estimate tissue strain. We simulated head impact (n = 871) to a 50th percentile Hybrid III (H-III) head wearing a hockey helmet instrumented with wearable GForceTracker (GFT) sensors measuring linear acceleration and angular velocity. A GFT was also fixed within the H-III head to establish a lower boundary on systematic errors. We quantified GFT errors relative to H-III measures based on peak kinematics and cumulative strain damage measure (CSDM). The smallest mean errors were 12% (peak resultant linear acceleration) and 15% (peak resultant angular velocity) for the GFT within the H-III. Errors for GFTs on the helmet were on average 54% (peak resultant linear acceleration) and 21% (peak resultant angular velocity). On average, the GFT inside the helmet overestimated CSDM by 0.15.

  10. Characteristics of strain transfer and the reflected spectrum of a metal-coated fiber Bragg grating sensor

    Science.gov (United States)

    Kim, Sang-Woo

    2017-09-01

    Previous researchers have simulated strain transfer and spectrum of normal fiber Bragg grating (FBG) sensors with a polymer coating bonded on the structure. They only considered the shear stress in a polymer coating for the simulation. However, for metal-coated FBG sensors, not only shear stress but also axial stress in the metal coating should be reflected into the calculation because its axial stiffness is no longer negligible. Thus, the author investigated the strain transfer and reflected spectra of metal-coated FBG sensors by considering both shear stress and axial stress. The strain transfer analysis involved evaluating the strain profiles along the sensor by plotting an analytical solution, and validating the evaluated profiles with the results obtained by a finite element analysis (FEA). The solution was also verified by the experiments that used aluminum-coated FBG sensors bonded on a carbon fiber reinforced polymer (CFRP) composite specimen. A transfer-matrix (T-matrix) formulation and coupled mode theory were used to simulate the reflected spectra of metal-coated FBG sensors for the evaluated strain profile. In addition, the effect of mechanical and geometric parameters of the sensor was examined. The findings revealed that the strain transfer characteristics and reflected spectra deteriorated with increases in the thickness and Young's modulus of the metal coating due to the consideration of axial stress. It is the opposite results for the normal FBG sensor with a polymer coating. Furthermore, the results also indicated that the decrease in bonding thickness resulted in improved strain transfer and signal characteristics. Moreover, a bonding length of 14 mm was suitable in suppressing an asymmetric shape of the reflected spectrum and in achieving an accurate measurement. The results of the parametric study are expected to contribute to improve the measurement accuracy of metal-coated FBG sensors in actual applications. The analytical methodology can be

  11. Development of a high-sensitivity strain measurement system based on a SH SAW sensor

    Science.gov (United States)

    Oh, Haekwan; Lee, Keekeun; Eun, Kyoungtae; Choa, Sung-Hoon; Yang, Sang Sik

    2012-02-01

    A strain measurement system based on a shear horizontal surface acoustic wave (SH SAW) was developed. The developed system is composed of a SAW microsensor, a printed circuit board (PCB), an adhesive and a strain gauge. When a compression force is applied to the PCB by the strain gauge, the PCB is bent so that external strain energy can be evenly delivered to the microsensor without any detachment of the sensor from the board. When a stretching force is applied to the PCB under the condition that one side of the PCB is fixed and the other side is modulated, the actual length of the SAW delay line between the two interdigital transducers (IDTs) is increased. The increase in the delay line length causes a change in the time for the propagating SAW to reach the output IDT. If strain energy is applied to the piezoelectric substrate, the substrate density is changed, which then changes the propagation velocity of the SAW. Coupling-of-modes modeling was conducted prior to fabrication to determine the optimal device parameters. Depending on the strain, the frequency difference was linearly modulated. The obtained sensitivity for stretching was 17.3 kHz/% for the SH wave mode and split electrode. And the obtained sensitivity for bending was 46.1 kHz/% for the SH wave mode and split electrode. The SH wave showed about 15% higher sensitivity than the Rayleigh wave, and the dog-bone PCB showed about 8% higher sensitivity than the rectangular PCB. The obtained sensitivity was about five times higher than that of existing SAW-based strain sensors.

  12. Application of FOX-TEK sensors to measure strains in steel pipe with wall thinning defects under internal pressure

    Energy Technology Data Exchange (ETDEWEB)

    Tennyson, R.C.; Lin, W.; Doiron, A. [Natural Resources Canada, Ottawa, ON (Canada)

    2002-06-30

    A project was undertaken as part of the ISPIR program to investigate the application of fiber optic sensing to monitor pipelines. This report discussed the application of FOX-TEK (FT) sensors to measure strains in steel pipe with wall thinning defects under internal pressure. Sensor installation and pipe test results were both discussed. Several illustrations were offered, including the geometry of pipes with internal defects and location of FT sensors; smoothing of the pipe surface prior to bonding sensors; close-up views of 2 FT sensors bonded over defect areas of the steel pipe; an overview of steel pipe with 3 FT sensors; and an internal pressure test of steel pipe with 4 FT sensors connected to an FTI 3300 instrument. FT sensor strain results were plotted for 2 different sized cutouts and a finite element analysis was conducted to calculate the circumferential strain distribution for 24 inch and 4 inch cutouts, with and without the weld seams present. It was concluded that the FT sensors can accurately detect the hoop strains for uniform wall sections, circumferential defect areas and large regions of wall thinning for a pipe under internal pressure. 1 tab., 8 figs.

  13. A POF-based distributed strain sensor for detecting deformation of wooden structures

    Science.gov (United States)

    Fukumoto, Takuji; Nakamura, Kentaro; Ueha, Sadayuki

    2008-04-01

    This report presents a feasibility test of the distributed strain sensor based on plastic optical fiber (POF) for detecting deformation of wooden structures. First, a simple method to fix POF cable onto wooden structures is developed, where the dimensions of the fixing plate are determined so as to minimize the OTDR responses due to the fixing tool as well as the slip between the POF cable and the structure. Second, the authors focus on a new function "memory effect" of the POF-based strain sensor. The strain once applied to the POF cable is memorized through the plastic deformation of the core material, and can be read out using OTDR even after the event. The characteristics of the memory effect and its life are discussed experimentally for tensile strain. Third, in this report, we showed that a 5-point measurement with the spatial resolution of around 5 m was possible for the axial elongation imposed on the POF. Then, we apply the present method for detection of deformations of wooden frame structures. We try to detect the direction and magnitude of deformations at four corners of a rectangular wooden frame using a POF cable and OTDR. The availability of the memory effect in multipoint measurements on wooden structures is also discussed.

  14. Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes

    Science.gov (United States)

    Lipomi, Darren J.; Vosgueritchian, Michael; Tee, Benjamin C.-K.; Hellstrom, Sondra L.; Lee, Jennifer A.; Fox, Courtney H.; Bao, Zhenan

    2011-12-01

    Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics, implantable medical devices and robotic systems with human-like sensing capabilities. The availability of conducting thin films with these properties could lead to the development of skin-like sensors that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays and solar cells, and also wrap around non-planar and biological surfaces such as skin and organs, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm-1 in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.

  15. Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes.

    Science.gov (United States)

    Lipomi, Darren J; Vosgueritchian, Michael; Tee, Benjamin C-K; Hellstrom, Sondra L; Lee, Jennifer A; Fox, Courtney H; Bao, Zhenan

    2011-10-23

    Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics, implantable medical devices and robotic systems with human-like sensing capabilities. The availability of conducting thin films with these properties could lead to the development of skin-like sensors that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays and solar cells, and also wrap around non-planar and biological surfaces such as skin and organs, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm(-1) in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.

  16. In-Situ Three-Dimensional Shape Rendering from Strain Values Obtained Through Optical Fiber Sensors

    Science.gov (United States)

    Chan, Hon Man (Inventor); Parker, Jr., Allen R. (Inventor)

    2015-01-01

    A method and system for rendering the shape of a multi-core optical fiber or multi-fiber bundle in three-dimensional space in real time based on measured fiber strain data. Three optical fiber cores arc arranged in parallel at 120.degree. intervals about a central axis. A series of longitudinally co-located strain sensor triplets, typically fiber Bragg gratings, are positioned along the length of each fiber at known intervals. A tunable laser interrogates the sensors to detect strain on the fiber cores. Software determines the strain magnitude (.DELTA.L/L) for each fiber at a given triplet, but then applies beam theory to calculate curvature, beading angle and torsion of the fiber bundle, and from there it determines the shape of the fiber in s Cartesian coordinate system by solving a series of ordinary differential equations expanded from the Frenet-Serrat equations. This approach eliminates the need for computationally time-intensive curve-tilting and allows the three-dimensional shape of the optical fiber assembly to be displayed in real-time.

  17. Experimental research on the effect of Young's modulus on optical fiber microbend strain sensor

    Science.gov (United States)

    Tao, Ruichen; Li, Min

    2010-11-01

    By investigation of the theoretical model of fiber microbend sensor, and derivative of the basic function of microbend with respect to applied external force F then Young's modulus E, we get an expression of sensor's output signal as a function of E which shows that the output of the microbend sensor decreases with the Young's modulus of the gripper increasing, and the change is nonlinear. To verify the accuracy of the theoretical derivation, we design and make four optical fiber microbend grippers of different materials, including stainless steel, Polyvinyl Chloride (PVC), polypropylene (PPR) and bamboo, with the same geometric parameters of grippers such as a mechanical period derived for the maximal sensitivity from the well-known microbend interval equation, and carry out the demonstration experiments under the same initial testing conditions. The initial testing condition has been adjusted during the process of manufacturing and installing the fiber microbend gripper. The experimental data based on our design testing systems showed that the outputs of the microbend sensors match our theoretical simulation curves well to the applied external force F. The conclusion might be useful for future reference of microbend strain sensors design.

  18. Tunable Polymer Fiber Bragg Grating (FBG) Inscription: Fabrication of Dual-FBG Temperature Compensated Polymer Optical Fiber Strain Sensors

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2012-01-01

    We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning...... of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm....

  19. A flexible strain sensor based on a Conductive Polymer Composite for in situ measurement of parachute canopy deformation.

    Science.gov (United States)

    Cochrane, Cédric; Lewandowski, Maryline; Koncar, Vladan

    2010-01-01

    A sensor based on a Conductive Polymer Composite (CPC), fully compatible with a textile substrate and its general properties, has been developed in our laboratory, and its electromechanical characterization is presented herein. In particular the effects of strain rate (from 10 to 1,000 mm/min) and of repeated elongation cycles on the sensor behaviour are investigated. The results show that strain rate seems to have little influence on sensor response. When submitted to repeated tensile cycles, the CPC sensor is able to detect accurately fabric deformations over each whole cycle, taking into account the mechanical behaviour of the textile substrate. Complementary information is given concerning the non-effect of aging on the global resistivity of the CPC sensor. Finally, our sensor was tested on a parachute canopy during a real drop test: the canopy fabric deformation during the critical inflation phase was successfully measured, and was found to be less than 9%.

  20. Design and modeling of an all-optical frequency modulated MEMS strain sensor using nanoscale Bragg gratings

    DEFF Research Database (Denmark)

    Reck, Kasper; Almind, Ninia Sejersen; Mar, Mikkel Dysseholm;

    2009-01-01

    We present modeling and design of an all-optical MEMS Bragg grating (half-pitch of 125 nm) strain sensor for single-fiber distributed sensing. Low optical loss and the use of frequency modulation rather than amplitude modulation, makes this sensor better suited for distributed systems than...... mechanical amplification can be obtained if using an angled double beam micrometer scale MEMS structure, compared to conventional fiber Bragg grating sensors. An optimized design and fabrication process is presented....

  1. Patterned, highly stretchable and conductive nanofibrous PANI/PVDF strain sensors based on electrospinning and in situ polymerization

    Science.gov (United States)

    Yu, Gui-Feng; Yan, Xu; Yu, Miao; Jia, Meng-Yang; Pan, Wei; He, Xiao-Xiao; Han, Wen-Peng; Zhang, Zhi-Ming; Yu, Liang-Min; Long, Yun-Ze

    2016-01-01

    A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10 000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger motion. The results demonstrate promising application of the patterned nanofibrous membrane in flexible electronic fields.A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10 000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger

  2. Soft Nanocomposite Based Multi-point, Multi-directional Strain Mapping Sensor Using Anisotropic Electrical Impedance Tomography

    Science.gov (United States)

    Lee, Hyosang; Kwon, Donguk; Cho, Haedo; Park, Inkyu; Kim, Jung

    2017-01-01

    The practical utilization of soft nanocomposites as a strain mapping sensor in tactile sensors and artificial skins requires robustness for various contact conditions as well as low-cost fabrication process for large three dimensional surfaces. In this work, we propose a multi-point and multi-directional strain mapping sensor based on multiwall carbon nanotube (MWCNT)-silicone elastomer nanocomposites and anisotropic electrical impedance tomography (aEIT). Based on the anisotropic resistivity of the sensor, aEIT technique can reconstruct anisotropic resistivity distributions using electrodes around the sensor boundary. This strain mapping sensor successfully estimated stretch displacements (error of 0.54 ± 0.53 mm), surface normal forces (error of 0.61 ± 0.62 N), and multi-point contact locations (error of 1.88 ± 0.95 mm in 30 mm × 30 mm area for a planar shaped sensor and error of 4.80 ± 3.05 mm in 40 mm × 110 mm area for a three dimensional contoured sensor). In addition, the direction of lateral stretch was also identified by reconstructing anisotropic distributions of electrical resistivity. Finally, a soft human-machine interface device was demonstrated as a practical application of the developed sensor. PMID:28120886

  3. Synergistic Effects of Stress-Rupture and Cyclic Loading on Strain Response of Fiber-Reinforced Ceramic-Matrix Composites at Elevated Temperature in Oxidizing Atmosphere

    Directory of Open Access Journals (Sweden)

    Longbiao Li

    2017-02-01

    Full Text Available In this paper, the synergistic effects of stress rupture and cyclic loading on the strain response of fiber-reinforced ceramic-matrix composites (CMCs at elevated temperature in air have been investigated. The stress-strain relationships considering interface wear and interface oxidation in the interface debonded region under stress rupture and cyclic loading have been developed to establish the relationship between the peak strain, the interface debonded length, the interface oxidation length and the interface slip lengths. The effects of the stress rupture time, stress levels, matrix crack spacing, fiber volume fraction and oxidation temperature on the peak strain and the interface slip lengths have been investigated. The experimental fatigue hysteresis loops, interface slip lengths, peak strain and interface oxidation length of cross-ply SiC/MAS (magnesium alumino-silicate, MAS composite under cyclic fatigue and stress rupture at 566 and 1093 °C in air have been predicted.

  4. Sensorically and antimicrobially active metabolite production of Lactobacillus strains on Jerusalem artichoke juice.

    Science.gov (United States)

    Zalán, Zsolt; Hudáček, Jaroslav; Tóth-Markus, Marianna; Husová, Eva; Solichová, Kateřina; Hegyi, Ferenc; Plocková, Milada; Chumchalová, Jana; Halász, Anna

    2011-03-15

    In the tubers of Jerusalem artichoke (Helianthus tuberosus L.) the main carbohydrate is the well-known prebiotic inulin, which is a good growth substrate for gut microorganisms. Jerusalem artichoke tuber is traditionally consumed boiled or pickled rather than in fermented form. Lactic acid bacteria are traditionally used in the production of fermented foods; nevertheless their behavior and metabolite production are considerably influenced by the substrate. The purpose of this study was to investigate the growth and production of the most important sensorically and antimicrobially active metabolites of different Lactobacillus strains on Jerusalem artichoke juice. All investigated strains grew well (in the range 10(9) cfu mL(-1) ) in the media. The organic acids (lactic acid, 110-337 mmol L(-1) ; acetic acid, 0-180 mmol L(-1) ; and succinic acid, 0-79 mmol L(-1) ), hydrogen peroxide (0.25-1.77 mg L(-1) ), mannitol (0.06-3.24 g L(-1) ), acetoin and diacetyl production of strains varies not only according to the species but also from strain to strain, which will be demonstrated and discussed in the paper. Our results showed that lactobacilli can be used for the fermentation of Jerusalem artichoke, which in this form could be used, alone or mixed with other raw food material, as a new synbiotic functional food. Copyright © 2011 Society of Chemical Industry.

  5. Deflection determination of concrete structures considering nonlinearity based on long-gauge strain sensors

    Science.gov (United States)

    Hong, Wan; Lv, Kui; Li, Bing; Jiang, Yuchen; Hu, Xiamin; Qu, Qizhong

    2017-10-01

    Deflection determination of concrete structures using distributed long-gauge strain sensors is investigated in this paper. Firstly, the relationship between deflection and distributed long-gauge strain of concrete beams is presented, and the method is independent of external load and takes account of structural nonlinearity. The deflection distribution along the span of a beam-like structure can be predicted from strain response for the whole process of loading (elastic stage, concrete cracking stage and steel yielding stage). Secondly, experiment of a reinforced concrete beam has been conducted to verify the accuracy of the method. Experimental results show that the relative error between the estimated and actual deflection can be controlled within about 5% while the error can reach up to about 70% if structural nonlinearity is not considered. Finally, the influence of error of material parameters and sensor gauge length on deflection estimation has been analyzed. The error of concrete compression strength has a limited influence on deflection prediction while the contribution of tensile concrete should be considered before concrete cracking. The error of area of tensile bars will affect the deflection accuracy after concrete cracking.

  6. Miniaturized platform with on-chip strain sensors for compression testing of arrayed materials.

    Science.gov (United States)

    MacQueen, Luke; Chebotarev, Oleg; Simmons, Craig A; Sun, Yu

    2012-10-21

    We report a microfabricated mechanical testing platform with on-chip strain sensors for in situ mechanical characterization of arrayed materials. The device is based on deformable elastomeric membranes that are actuated by pressure that is delivered through an underlying channel network. The bulging membranes compress material samples that are confined between the membranes and a rigid top-plate. Carbon nanotube-based strain sensors that exhibit strain-dependent electrical resistivity were integrated within the membranes to provide continuous read-out of membrane deflection amplitude. We used this platform to study the cyclic compression of several different silicone samples and thereby measured their elastic moduli. The results obtained using our miniaturized platform were in excellent agreement with those obtained using a commercially available mechanical testing platform and clearly demonstrated the utility of our platform for the mechanical testing of small samples in parallel. The miniaturized platform can significantly increase mechanical testing efficiency, particularly when testing of iterative sample formulations is required.

  7. High electrostrictive strain induced by defect dipoles in acceptor-doped (K0.5Na0.5)NbO3 ceramics

    Science.gov (United States)

    Dai, Ye-Jing; Zhao, Yong-Jie; Zhao, Zhe; Zhao, Zhi-Hao; Zhou, Qi-Wu; Zhang, Xiao-Wen

    2016-07-01

    Acceptor doping is an efficient method to improve ferroelectric material performance through the formation of defect dipoles. Here, a high electrostrictive strain of 0.16-0.19%, and large d33\\ast of  >300 pm V-1 are obtained in CuO-doped (K0.5Na0.5)NbO3 ceramics. We analyzed the orientation relationship and the interaction between defect dipole polarization (P d) along orientation and spontaneous polarization (P s) parallel to in orthorhombic (K0.5Na0.5)NbO3. Thus, a ‘coupling effect’ mechanism was suggested to explain how the P d and P s can work together to contribute to the electrostrictive strains in this lead-free piezoelectric ceramic.

  8. Method of correlation function for analyzing cross-sensitivity of strain and temperature in fiber grating sensors

    Institute of Scientific and Technical Information of China (English)

    HAN Gui-hua; ZHANG Wei-gang

    2007-01-01

    A novel method of correlation function for analyzing cross-sensitivity between strain and temperature is reported for the first time in this paper. Using the new method, the correlative characteristics between strain and temperature of fiber Bragg grating sensors are studied both theoretically and experimentally The experimental results accord with the theoretical calculations.

  9. A Stretchable Radio-Frequency Strain Sensor Using Screen Printing Technology

    Directory of Open Access Journals (Sweden)

    Heijun Jeong

    2016-11-01

    Full Text Available In this paper, we propose a stretchable radio-frequency (RF strain sensor fabricated with screen printing technology. The RF sensor is designed using a half-wavelength patch that resonates at 3.7 GHz. The resonant frequency is determined by the length of the patch, and it therefore changes when the patch is stretched. Polydimethylsiloxane (PDMS is used to create the substrate, because of its stretchable and screen-printable surface. In addition, Dupont PE872 (Dupont, NC, American silver conductive ink is used to create the stretchable conductive patterns. The sensor performance is demonstrated both with full-wave simulations and with measurements carried out on a fabricated sample. When the length of the patch sensor is increased by a 7.8% stretch, the resonant frequency decreases from 3.7 GHz to 3.43 GHz, evidencing a sensitivity of 3.43 × 107 Hz/%. Stretching the patch along its width does not change the resonant frequency.

  10. Strengthening of Back Muscles Using a Module of Flexible Strain Sensors

    Directory of Open Access Journals (Sweden)

    Wan-Chun Chuang

    2015-02-01

    Full Text Available This research aims at developing a flexible strain module applied to the strengthening of back muscles. Silver films were sputtered onto flexible substrates to produce a flexible sensor. Assuming that back muscle elongation is positively correlated with the variations in skin surface length, real-time resistance changes exhibited by the sensor during simulated training sessions were measured. The results were used to identify the relationship between resistance change of sensors and skin surface stretch. In addition, muscle length changes from ultrasound images were used to determine the feasibility of a proof of concept sensor. Furthermore, this module is capable of detecting large muscle contractions, some of which may be undesirable for the prescribed training strategy. Therefore, the developed module can facilitate real-time assessments of the movement accuracy of users during training, and the results are instantly displayed on a screen. People using the developed training system can immediately adjust their posture to the appropriate position. Thus, the training mechanism can be constructed to help user improve the efficiency of back muscle strengthening.

  11. Static and Dynamic Strain Monitoring of Reinforced Concrete Components through Embedded Carbon Nanotube Cement-Based Sensors

    Directory of Open Access Journals (Sweden)

    Antonella D’Alessandro

    2017-01-01

    Full Text Available The paper presents a study on the use of cement-based sensors doped with carbon nanotubes as embedded smart sensors for static and dynamic strain monitoring of reinforced concrete (RC elements. Such novel sensors can be used for the monitoring of civil infrastructures. Because they are fabricated from a structural material and are easy to utilize, these sensors can be integrated into structural elements for monitoring of different types of constructions during their service life. Despite the scientific attention that such sensors have received in recent years, further research is needed to understand (i the repeatability and accuracy of sensors’ behavior over a meaningful number of sensors, (ii testing configurations and calibration methods, and (iii the sensors’ ability to provide static and dynamic strain measurements when actually embedded in RC elements. To address these research needs, this paper presents a preliminary characterization of the self-sensing capabilities and the dynamic properties of a meaningful number of cement-based sensors and studies their application as embedded sensors in a full-scale RC beam. Results from electrical and electromechanical tests conducted on small and full-scale specimens using different electrical measurement methods confirm that smart cement-based sensors show promise for both static and vibration-based structural health monitoring applications of concrete elements but that calibration of each sensor seems to be necessary.

  12. Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials

    Directory of Open Access Journals (Sweden)

    Manjusha Ramakrishnan

    2016-01-01

    Full Text Available This paper provides an overview of the different types of fiber optic sensors (FOS that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements.

  13. Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials.

    Science.gov (United States)

    Ramakrishnan, Manjusha; Rajan, Ginu; Semenova, Yuliya; Farrell, Gerald

    2016-01-15

    This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements.

  14. Piezoresistive Properties of Suspended Graphene Membranes under Uniaxial and Biaxial Strain in Nanoelectromechanical Pressure Sensors

    Science.gov (United States)

    2016-01-01

    Graphene membranes act as highly sensitive transducers in nanoelectromechanical devices due to their ultimate thinness. Previously, the piezoresistive effect has been experimentally verified in graphene using uniaxial strain in graphene. Here, we report experimental and theoretical data on the uni- and biaxial piezoresistive properties of suspended graphene membranes applied to piezoresistive pressure sensors. A detailed model that utilizes a linearized Boltzman transport equation describes accurately the charge-carrier density and mobility in strained graphene and, hence, the gauge factor. The gauge factor is found to be practically independent of the doping concentration and crystallographic orientation of the graphene films. These investigations provide deeper insight into the piezoresistive behavior of graphene membranes. PMID:27797484

  15. Optical fiber strain sensor using fiber resonator based on frequency comb Vernier spectroscopy

    DEFF Research Database (Denmark)

    Zhang, Liang; Lu, Ping; Chen, Li;

    2012-01-01

    A novel (to our best knowledge) optical fiber strain sensor using a fiber ring resonator based on frequency comb Vernier spectroscopy is proposed and demonstrated. A passively mode-locked optical fiber laser is employed to generate a phased-locked frequency comb. Strain applied to the optical fiber...... be proportionally improved by increasing the length of the optical fiber ring resonator....... of the fiber ring resonator can be measured with the transmission spectrum. A good linearity is obtained between displacement and the inverse of wavelength spacing with an R2 of 0.9989, and high sensitivities better than 40  pm/με within the range of 0 to 10  με are achieved. The sensitivity can...

  16. Full scale strain monitoring of a suspension bridge using high performance distributed fiber optic sensors

    Science.gov (United States)

    Xu, Jinlong; Dong, Yongkang; Zhang, Zhaohui; Li, Shunlong; He, Shaoyang; Li, Hui

    2016-12-01

    This paper investigated field monitoring of a 1108 m suspension bridge during an assessment load test, using integrated distributed fibre-optic sensors (DFOSs). In addition to the conventional Brillouin time domain analysis system, a high spatial resolution Brillouin system using the differential pulse-width pair (DPP) technique was adopted. Temperature compensation was achieved using a Raman distributed temperature sensing system. This is the first full scale field application of DFOSs using the Brillouin time domain analysis technique in a thousand-meter-scale suspension bridge. Measured strain distributions along the whole length of the bridge were presented. The interaction between the main cables and the steel-box-girder was highlighted. The Brillouin fibre-optic monitoring systems exhibited great facility for the purposes of long distance distributed strain monitoring, with up to 0.05 m spatial resolution, and 0.01 m/point sampling interval. The performance of the Brillouin system using DPP technique was discussed. The measured data was also employed for assessing bridge design and for the assessment of structural condition. The results show that the symmetrical design assumptions were consistent with the actual bridge, and that the strain values along the whole bridge were within the safety range. This trial field study serves as an example, demonstrating the feasibility of highly dense strain and temperature measurement for large scale civil infrastructures using integrated DFOSs.

  17. Wireless Open-Circuit In-Plane Strain and Displacement Sensor Requiring No Electrical Connections

    Science.gov (United States)

    Woodard, Stanley E. (Inventor)

    2014-01-01

    A wireless in-plane strain and displacement sensor includes an electrical conductor fixedly coupled to a substrate subject to strain conditions. The electrical conductor is shaped between its ends for storage of an electric field and a magnetic field, and remains electrically unconnected to define an unconnected open-circuit having inductance and capacitance. In the presence of a time-varying magnetic field, the electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses. The sensor also includes at least one electrically unconnected electrode having an end and a free portion extending from the end thereof. The end of each electrode is fixedly coupled to the substrate and the free portion thereof remains unencumbered and spaced apart from a portion of the electrical conductor so-shaped. More specifically, at least some of the free portion is disposed at a location lying within the magnetic field response generated by the electrical conductor. A motion guidance structure is slidingly engaged with each electrode's free portion in order to maintain each free portion parallel to the electrical conductor so-shaped.

  18. A transgenic sensor strain for monitoring the RNAi pathway in the yellow fever mosquito, Aedes aegypti.

    Science.gov (United States)

    Adelman, Zach N; Anderson, Michelle A E; Morazzani, Elaine M; Myles, Kevin M

    2008-07-01

    The RNA interference pathway functions as an antiviral defense in invertebrates. In order to generate a phenotypic marker which "senses" the status of the RNAi pathway in Aedes aegypti, transgenic strains were developed to express EGFP and DsRED marker genes in the eye, as well as double-stranded RNA homologous to a portion of the EGFP gene. Transgenic "sensor" mosquitoes exhibited robust eye-specific DsRED expression with little EGFP, indicating RNAi-based silencing. Cloning and high-throughput sequencing of small RNAs confirmed that the inverted-repeat transgene was successfully processed into short-interfering RNAs by the mosquito RNAi pathway. When the A. aegypti homologues of the genes DCR-2 or AGO-2 were knocked down, a clear increase in EGFP fluorescence was observed in the mosquito eyes. Knockdown of DCR-2 was also associated with an increase in EGFP mRNA levels, as determined by Northern blot and real-time PCR. Knockdown of AGO-3, a gene involved in the germline-specific piRNA pathway, did not restore EGFP expression at either the mRNA or protein level. This transgenic sensor strain can now be used to identify other components of the mosquito RNAi pathway and has the potential to be used in the identification of arboviral suppressors of RNAi.

  19. Maximising electro-mechanical response by minimising grain-scale strain heterogeneity in phase-change actuator ceramics

    DEFF Research Database (Denmark)

    Oddershede, Jette; Hossain, Mohammad Jahangir; Daniels, John E.

    2016-01-01

    Phase-change actuator ceramics directly couple electrical and mechanical energies through an electric-field-induced phase transformation. These materials are promising for the replacement of the most common electro-mechanical ceramic, lead zirconate titanate, which has environmental concerns. Her...

  20. A packaged, low-cost, robust optical fiber strain sensor based on small cladding fiber sandwiched within periodic polymer grating.

    Science.gov (United States)

    Chiang, Chia-Chin; Li, Chein-Hsing

    2014-06-02

    In the present study, a novel packaged long-period fiber grating (PLPFG) strain sensor is first presented. The MEMS process was utilized to fabricate the packaged optical fiber strain sensor. The sensor structure consisted of etched optical fiber sandwiched between two layers of thick photoresist SU-8 3050 and then packaged with poly (dimethylsiloxane) (PDMS) polymer material to construct the PLPFG strain sensor. The PDMS packaging material was used to prevent the glue effect, wherein glue flows into the LPFG structure and reduces coupling strength, in the surface bonding process. Because the fiber grating was packaged with PDMS material, it was effectively protected and made robust. The resonance attenuation dip of PLPFG grows when it is loading. This study explored the size effect of the grating period and fiber diameter of PLPFG via tensile testing. The experimental results found that the best strain sensitivity of the PLPFG strain sensor was -0.0342 dB/με, and that an R2 value of 0.963 was reached.

  1. In-fiber rectangular air fabry-perot strain sensor based on high-precision fiber cutting platform

    Science.gov (United States)

    Zhao, Yong; Chen, Mao-qing; Lv, Ri-qing; Xia, Feng

    2017-02-01

    An in-fiber rectangular air Fabry-Perot (FP) strain sensor based on a high-precision fiber cutting platform (HFCP) is proposed. The HFCP consisting of a CCD notation system, a micro-displacement platform, and an optical fiber cleaver can be used to precisely control the length of FP cavity. The microcavity of FP (even only tens of microns) with smooth reflective surface can be realized easily by using this system. The FP structures with different cavity lengths have been fabricated in this paper. Simulation and experimental results prove that the shorter length the cavity has, the higher strain sensitivity and the larger free spectral range (FSR) the sensor obtains. The strain sensitivity and FSR of in-fiber rectangular air FP sensor with a cavity length of 35 μm can be up to 2.23 pm/με and 28.5 nm respectively. Moreover, the proposed FP strain sensor has a negligible temperature sensitivity in the range of 25-75 °C. It is anticipated that such easy making, compact and low-cost fiber-optic strain sensors could find important applications in practice.

  2. Synthesis and Characterizations of Novel Ca-Mg-Ti-Fe-Oxides Based Ceramic Nanocrystals and Flexible Film of Polydimethylsiloxane Composite with Improved Mechanical and Dielectric Properties for Sensors

    Science.gov (United States)

    Tripathy, Ashis; Pramanik, Sumit; Manna, Ayan; Azrin Shah, Nabila Farhana; Shasmin, Hanie Nadia; Radzi, Zamri; Abu Osman, Noor Azuan

    2016-01-01

    Armalcolite, a rare ceramic mineral and normally found in the lunar earth, was synthesized by solid-state step-sintering. The in situ phase-changed novel ceramic nanocrystals of Ca-Mg-Ti-Fe based oxide (CMTFOx), their chemical reactions and bonding with polydimethylsiloxane (PDMS) were determined by X-ray diffraction, infrared spectroscopy, and microscopy. Water absorption of all the CMTFOx was high. The lower dielectric loss tangent value (0.155 at 1 MHz) was obtained for the ceramic sintered at 1050 °C (S1050) and it became lowest for the S1050/PDMS nanocomposite (0.002 at 1 MHz) film, which was made by spin coating at 3000 rpm. The excellent flexibility (static modulus ≈ 0.27 MPa and elongation > 90%), viscoelastic property (tanδ = E″/E′: 0.225) and glass transition temperature (Tg: −58.5 °C) were obtained for S1050/PDMS film. Parallel-plate capacitive and flexible resistive humidity sensors have been developed successfully. The best sensing performance of the present S1050 (3000%) and its flexible S1050/PDMS composite film (306%) based humidity sensors was found to be at 100 Hz, better than conventional materials. PMID:26927116

  3. Synthesis and Characterizations of Novel Ca-Mg-Ti-Fe-Oxides Based Ceramic Nanocrystals and Flexible Film of Polydimethylsiloxane Composite with Improved Mechanical and Dielectric Properties for Sensors

    Directory of Open Access Journals (Sweden)

    Ashis Tripathy

    2016-02-01

    Full Text Available Armalcolite, a rare ceramic mineral and normally found in the lunar earth, was synthesized by solid-state step-sintering. The in situ phase-changed novel ceramic nanocrystals of Ca-Mg-Ti-Fe based oxide (CMTFOx, their chemical reactions and bonding with polydimethylsiloxane (PDMS were determined by X-ray diffraction, infrared spectroscopy, and microscopy. Water absorption of all the CMTFOx was high. The lower dielectric loss tangent value (0.155 at 1 MHz was obtained for the ceramic sintered at 1050 °C (S1050 and it became lowest for the S1050/PDMS nanocomposite (0.002 at 1 MHz film, which was made by spin coating at 3000 rpm. The excellent flexibility (static modulus ≈ 0.27 MPa and elongation > 90%, viscoelastic property (tanδ = E″/E′: 0.225 and glass transition temperature (Tg: −58.5 °C were obtained for S1050/PDMS film. Parallel-plate capacitive and flexible resistive humidity sensors have been developed successfully. The best sensing performance of the present S1050 (3000% and its flexible S1050/PDMS composite film (306% based humidity sensors was found to be at 100 Hz, better than conventional materials.

  4. Simultaneous, inherently temperature and strain insensitive bio-sensors based on dual-resonance long-period gratings

    CERN Document Server

    Tripathi, Saurabh Mani; Bock, Wojtek J; Mikulic, Predrag

    2016-01-01

    Addressing the temperature and strain induced cross-talks simultaneously, we propose an inherently strain and temperature insensitive fiber-optic bio-sensor. The insensitivity has been achieved by properly adjusting the dopants and their concentrations in the optical fiber core region, and by optimizing the grating period and the strength of concatenated dual-resonance long-period-gratings. The simulations have been carried out using the same fiber parameters as used in our earlier experimental studies, which matched excellently with the experimental results. The proposed sensor has a theoretical refractive-index sensitivity of 4607 nm/RIU, which can be used to detect changes as small as 2.2 x10^-7 in ambient refractive indices using a detection system with spectral resolution of 1 pm. Our work finds application in developing precision biosensors with inherent insensitivity towards temperature and axial strain fluctuations. The sensor is currently under fabrication at our lab.

  5. Flexible strain sensors with high performance based on metallic glass thin film

    Science.gov (United States)

    Xian, H. J.; Cao, C. R.; Shi, J. A.; Zhu, X. S.; Hu, Y. C.; Huang, Y. F.; Meng, S.; Gu, L.; Liu, Y. H.; Bai, H. Y.; Wang, W. H.

    2017-09-01

    Searching strain sensitive materials for electronic skin is of crucial significance because of the restrictions of current materials such as poor electrical conductivity, large energy consumption, complex manufacturing process, and high cost. Here, we report a flexible strain sensor based on the Zr55Cu30Ni5Al10 metallic glass thin film which we name metallic glass skin. The metallic glass skin, synthesized by ion beam deposition, exhibits piezoresistance effects with a gauge factor of around 2.86, a large detectable strain range (˜1% or 180° bending angle), and good conductivity. Compared to other e-skin materials, the temperature coefficient of resistance of the metallic glass skin is extremely low (9.04 × 10-6 K-1), which is essential for the reduction in thermal drift. In addition, the metallic glass skin exhibits distinct antibacterial behavior desired for medical applications, also excellent reproducibility and repeatability (over 1000 times), nearly perfect linearity, low manufacturing cost, and negligible energy consumption, all of which are required for electronic skin for practical applications.

  6. Prediction of dynamic strains on a monopile offshore wind turbine using virtual sensors

    Science.gov (United States)

    Iliopoulos, A. N.; Weijtjens, W.; Van Hemelrijck, D.; Devriendt, C.

    2015-07-01

    The monitoring of the condition of the offshore wind turbine during its operational states offers the possibility of performing accurate assessments of the remaining life-time as well as supporting maintenance decisions during its entire life. The efficacy of structural monitoring in the case of the offshore wind turbine, though, is undermined by the practical limitations connected to the measurement system in terms of cost, weight and feasibility of sensor mounting (e.g. at muddline level 30m below the water level). This limitation is overcome by reconstructing the full-field response of the structure based on the limited number of measured accelerations and a calibrated Finite Element Model of the system. A modal decomposition and expansion approach is used for reconstructing the responses at all degrees of freedom of the finite element model. The paper will demonstrate the possibility to predict dynamic strains from acceleration measurements based on the aforementioned methodology. These virtual dynamic strains will then be evaluated and validated based on actual strain measurements obtained from a monitoring campaign on an offshore Vestas V90 3 MW wind turbine on a monopile foundation.

  7. Contribution to the large and stable electric field induced strain for textured Pb(Mg1/3Nb2/3)0.675Ti0.325O3 ceramics

    Science.gov (United States)

    Zeng, Jiangtao; Zhao, Kunyu; Ruan, Wei; Ruan, Xuezheng; Zheng, Liaoying; Li, Guorong

    2016-08-01

    Textured Pb(Mg1/3Nb2/3)0.675Ti0.325O3 (PMN-PT) ceramics were prepared by the templated grain growth method with 3% plate-like BaTiO3 as templates. The degree of grain orientation was about 81% by calculating from the XRD pattern. Temperature dependence of electric field induced strain was measured for both untextured and textured PMN-PT ceramics. The results show that the electric field induced strain for textured PMN-PT ceramics is much larger and more stable than that for untextured PMN-PT ceramics in a wide temperature range. The contribution from the piezoelectric effect and electrostrictive effect to the strain was analyzed, and it was found that textured PMN-PT ceramics exhibited electrostrictive coefficient Q33 as high as 5.19 × 10-2 m4 C-2 and it was comparable to that of PMN-PT single crystals. The electrostrictive effect contributed the main part of the enhancement of electric field induced strain for textured PMN-PT ceramics.

  8. A high sensitive fiber-optic strain sensor with tunable temperature sensitivity for temperature-compensation measurement

    Science.gov (United States)

    Hu, Jie; Huang, Hui; Bai, Min; Zhan, Tingting; Yang, Zhibo; Yu, Yan; Qu, Bo

    2017-02-01

    A high sensitive fiber-optic strain sensor, which consists of a cantilever, a tandem rod and a fiber collimator, was proposed. The tandem rod, which transfer the applied strain to the cantilever, was used for tuning the temperature sensitivity from ‑0.15 to 0.19 dB/°C via changing the length ratio of the rods. Moreover, due to the small beam divergence of the collimator, high strain sensitivity can be realized via incident-angle sensitive detection-mechanism. A strain detection-range of 1.1 × 103 με (with a sensing length of 21.5 mm), a detection limit of 5.7 × 10‑3 με, and a maximum operating frequency of 1.18 KHz were demonstrated. This sensor is promising for compensating the thermal-expansion of various target objects.

  9. Carbon Nanotube Coatings as Used in Strain Sensors for Composite Tanks

    Science.gov (United States)

    Trigwell, Steve; Snyder, Sarah; Hatfield, Walt; Dervishi, Enkeleda; Biris, Alexandru S.

    2011-01-01

    The next generation of cryogenic fuel tanks, crew habitats and other components for future spacecraft will focus on the usc of lightweight carbon fiber composite materials. A critical issue in the design and optimization of such tanks and structures will bc in structural health monitoring, however, current strain sensors have limitations. In this study, a novel carbon nanotube thin film was applied to carbon fiber composites for structural monitoring. Applying a load using a 3-point bend test to simulate bowing of a tank wall, induced significant increases in the film's electrical resistance at small deflections. Upon release of the load, the resistance returned to its approximate start value and was reproducible over multiple tests. The results show that a carbon nanotube thin film has great potential for the health monitoring of composite structures.

  10. Lightweight, Superelastic, and Mechanically Flexible Graphene/Polyimide Nanocomposite Foam for Strain Sensor Application.

    Science.gov (United States)

    Qin, Yuyang; Peng, Qingyu; Ding, Yujie; Lin, Zaishan; Wang, Chunhui; Li, Ying; Xu, Fan; Li, Jianjun; Yuan, Ye; He, Xiaodong; Li, Yibin

    2015-09-22

    The creation of superelastic, flexible three-dimensional (3D) graphene-based architectures is still a great challenge due to structure collapse or significant plastic deformation. Herein, we report a facile approach of transforming the mechanically fragile reduced graphene oxide (rGO) aerogel into superflexible 3D architectures by introducing water-soluble polyimide (PI). The rGO/PI nanocomposites are fabricated using strategies of freeze casting and thermal annealing. The resulting monoliths exhibit low density, excellent flexibility, superelasticity with high recovery rate, and extraordinary reversible compressibility. The synergistic effect between rGO and PI endows the elastomer with desirable electrical conductivity, remarkable compression sensitivity, and excellent durable stability. The rGO/PI nanocomposites show potential applications in multifunctional strain sensors under the deformations of compression, bending, stretching, and torsion.

  11. Coaxial printing method for directly writing stretchable cable as strain sensor

    Science.gov (United States)

    Yan, Hai-liang; Chen, Yan-qiu; Deng, Yong-qiang; Zhang, Li-long; Hong, Xiao; Lau, Woon-ming; Mei, Jun; Hui, David; Yan, Hui; Liu, Yu

    2016-08-01

    Through applying the liquid metal and elastomer as the core and shell materials, respectively, a coaxial printing method is being developed in this work for preparing a stretchable and conductive cable. When liquid metal alloy eutectic Gallium-Indium is embedded into the elastomer matrix under optimized control, the cable demonstrates well-posed extreme mechanic performance, under stretching for more than 350%. Under developed compression test, the fabricated cable also demonstrates the ability for recovering original properties due to the high flowability of the liquid metal and super elasticity of the elastomeric shell. The written cable presents high cycling reliability regarding its stretchability and conductivity, two properties which can be clearly predicted in theoretical calculation. This work can be further investigated as a strain sensor for monitoring motion status including frequency and amplitude of a curved object, with extensive applications in wearable devices, soft robots, electronic skins, and wireless communication.

  12. A portable optical DSPI strain sensor with radial sensitivity using an axis-symmetrical DOE

    Science.gov (United States)

    Viotti, Matias R.; Kapp, Walter A.; Albertazzi Gonçalves, Armando, Jr.

    2010-09-01

    This paper presents the optical setup of a radial in-plane digital speckle pattern interferometer (DSPI) which uses an axissymmetrical diffractive optical element to obtain double illumination. The application of the DOE gives true in-plane sensitivity that is independent on the wavelength of the laser used as illumination source. Furthermore, it only depends on the grating period of the DOE. A new optical layout was introduced in order to obtain a circular measurement area of about 5 mm in diameter. A brief description of the DOE and the portable strain sensor are presented. A detailed explanation of the clamping system is presented showing its ability to deal with rigid body displacements. Finally, some experimental results are shown enlightening that it is able to measure mechanical stress fields from only one difference phase map.

  13. An Euler-Bernoulli second strain gradient beam theory for cantilever sensors

    Science.gov (United States)

    Amiot, F.

    2013-04-01

    This paper derives an Euler-Bernoulli beam theory for isotropic elastic materials based on a second strain gradient description. As such a description has been proved to allow for the definition of surface tension for solids, the equations satisfied by a beam featuring a through-thickness cohesion modulus gradient are established in order to describe the behaviour of micro cantilever sensors. Closed-form solutions are given for mechanical and chemical loadings. It is then shown that the involved material parameters seem virtually identifiable from full-field measurements and that the shape of the displacement field resulting from a chemical loading depends on the cantilever's thickness as well as on the material parameters. This makes such a theory potentially able to explain some of the experimental results found in the literature.

  14. Coaxial printing method for directly writing stretchable cable as strain sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Hai-liang [College of Material Science and Engineering, Beijing University of Technology, 100124 Beijing (China); Chengdu Green Energy and Green Manufacturing Technology R& D Center, 610299 Chengdu (China); Chen, Yan-qiu, E-mail: yu.liu@vip.163.com, E-mail: cyqleaf@qq.com, E-mail: hyan@but.ac.cn; Deng, Yong-qiang; Zhang, Li-long; Lau, Woon-ming; Mei, Jun; Liu, Yu, E-mail: yu.liu@vip.163.com, E-mail: cyqleaf@qq.com, E-mail: hyan@but.ac.cn [Chengdu Green Energy and Green Manufacturing Technology R& D Center, 610299 Chengdu (China); Hong, Xiao [Chengdu Green Energy and Green Manufacturing Technology R& D Center, 610299 Chengdu (China); College of Computer Science, Sichuan University, Chengdu 610207 (China); Hui, David [Department of Mechanical Engineering, University of New Orleans, New Orleans, Louisiana 70148 (United States); Yan, Hui, E-mail: yu.liu@vip.163.com, E-mail: cyqleaf@qq.com, E-mail: hyan@but.ac.cn [College of Material Science and Engineering, Beijing University of Technology, 100124 Beijing (China)

    2016-08-22

    Through applying the liquid metal and elastomer as the core and shell materials, respectively, a coaxial printing method is being developed in this work for preparing a stretchable and conductive cable. When liquid metal alloy eutectic Gallium-Indium is embedded into the elastomer matrix under optimized control, the cable demonstrates well–posed extreme mechanic performance, under stretching for more than 350%. Under developed compression test, the fabricated cable also demonstrates the ability for recovering original properties due to the high flowability of the liquid metal and super elasticity of the elastomeric shell. The written cable presents high cycling reliability regarding its stretchability and conductivity, two properties which can be clearly predicted in theoretical calculation. This work can be further investigated as a strain sensor for monitoring motion status including frequency and amplitude of a curved object, with extensive applications in wearable devices, soft robots, electronic skins, and wireless communication.

  15. Review of Trackside Monitoring Solutions: From Strain Gages to Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Georges Kouroussis

    2015-08-01

    Full Text Available A review of recent research on structural monitoring in railway industry is proposed in this paper, with a special focus on stress-based solutions. After a brief analysis of the mechanical behaviour of ballasted railway tracks, an overview of the most common monitoring techniques is presented. A special attention is paid on strain gages and accelerometers for which the accurate mounting position on the track is requisite. These types of solution are then compared to another modern approach based on the use of optical fibres. Besides, an in-depth discussion is made on the evolution of numerical models that investigate the interaction between railway vehicles and tracks. These models are used to validate experimental devices and to predict the best location(s of the sensors. It is hoped that this review article will stimulate further research activities in this continuously expanding field.

  16. Characterization of zeolite-trench-embedded microcantilevers with CMOS strain gauge for integrated gas sensor applications

    Science.gov (United States)

    Inoue, Shu; Denoual, Matthieu; Awala, Hussein; Grand, Julien; Mintova, Sveltana; Tixier-Mita, Agnès; Mita, Yoshio

    2016-04-01

    Custom-synthesized zeolite is coated and fixed into microcantilevers with microtrenches of 1 to 5 µm width. Zeolite is a porous material that absorbs chemical substances; thus, it is expected to work as a sensitive chemical-sensing head. The total mass increases with gas absorption, and the cantilever resonance frequency decreases accordingly. In this paper, a thick zeolite cantilever sensor array system for high sensitivity and selectivity is proposed. The system is composed of an array of microcantilevers with silicon deep trenches. The cantilevers are integrated with CMOS-made polysilicon strain gauges for frequency response electrical measurement. The post-process fabrication of such an integrated array out of a foundry-made CMOS chip is successful. On the cantilevers, three types of custom zeolite (FAU-X, LTL, and MFI) are integrated by dip and heating methods. The preliminary measurement has shown a clear shift of resonance frequency by the chemical absorbance of ethanol gas.

  17. A High-Performance LC Wireless Passive Pressure Sensor Fabricated Using Low-Temperature Co-Fired Ceramic (LTCC) Technology

    OpenAIRE

    Chen Li; Qiulin Tan; Chenyang Xue; Wendong Zhang; Yunzhi Li; Jijun Xiong

    2014-01-01

    An LC resonant pressure sensor with improved performance is presented in this paper. The sensor is designed with a buried structure, which protects the electrical components from contact with harsh environments and reduces the resonant-frequency drift of the sensor in high-temperature environments. The pressure-sensitive membrane of the sensor is optimized according to small-deflection-plate theory, which allows the sensor to operate in high-pressure environments. The sensor is fabricated usi...

  18. Tailoring percolating conductive networks of natural rubber composites for flexible strain sensors via a cellulose nanocrystal templated assembly.

    Science.gov (United States)

    Wang, Shuman; Zhang, Xinxing; Wu, Xiaodong; Lu, Canhui

    2016-01-21

    Conductive polymer composites (CPCs) just above the percolation threshold exhibit a unique strain-reversible electric response upon application of tensile strain, which can be used to prepare strain sensors. However, it is difficult to balance the electric conductivity which is fundamental to a stable output signal and the strain sensing sensitivity due to the relatively dense conductive pathways of the traditional CPCs. Constructing a "brittle" but effective conductive network structure in CPCs is the essential foundation of a desirable sensing material. Here, we demonstrate for the first time that highly flexible, stretchable, sensitive, and reversible strain sensors can be fabricated by a facile latex assembly approach, in which nontoxic, sustainable and biodegradable cellulose nanocrystals played a key role in tailoring the percolating network of conductive natural rubber (NR)/carbon nanotube (CNT) composites. The resulting nanocomposites with a continuous 3D conductive structure exhibited a very low electrical conductivity percolation threshold (4-fold lower than that of the conventional NR/CNT composites), high resistivity and sensitivity (gauge factor ≈ 43.5) and meanwhile good reproducibility of up to 100% strain. The proposed materials and principles in this study open up a novel practical approach to design high performance flexible sensors for a broad range of multifunctional applications.

  19. Resonance line shape, strain and electric potential distributions of composite magnetoelectric sensors

    Directory of Open Access Journals (Sweden)

    Martina Gerken

    2013-06-01

    Full Text Available Multiferroic composite magnetoelectric (ME sensors are based on the elastic coupling of a magnetostrictive phase and a piezoelectric phase. A deformation of the magnetostrictive phase causes strain in the piezoelectric phase and thus an induced voltage. Such sensors may be applied both for static as well as for dynamic magnetic field measurements. Particularly high sensitivities are achieved for operation at a mechanical resonance. Here, the resonance line shape of layered (2-2 composite cantilever ME sensors at the first bending-mode resonance is investigated theoretically. Finite element method (FEM simulations using a linear material model reveal an asymmetric resonance profile and a zero-response frequency for the ME coefficient. Frequency-dependent strain and electric potential distributions inside the magnetoelectric composite are studied for the case of a magnetostrictive-piezoelectric bilayer. It is demonstrated that a positive or a negative voltage may be induced across the piezoelectric layer depending on the position of the neutral plane. The frequency-dependent induced electric potential is investigated for structured cantilevers that exhibit magnetostriction only at specific positions. For static operation an induced voltage is obtained locally at positions with magnetostriction. In addition to this direct effect a resonance-assisted effect is observed for dynamic operation. Magnetostriction in a limited area of the cantilever causes a global vibration of the cantilever. Thus, deformation of the piezoelectric layer and an induced electric potential also occur in areas of the cantilever without magnetostriction. The direct and the resonance-assisted pathway may induce voltages of equal or of opposite sign. The net induced voltage results from the superposition of the two effects. As the resonance-assisted induced voltage changes sign upon passing the resonance frequency, while the direct component is constant, an asymmetric line

  20. Resonance line shape, strain and electric potential distributions of composite magnetoelectric sensors

    Science.gov (United States)

    Gerken, Martina

    2013-06-01

    Multiferroic composite magnetoelectric (ME) sensors are based on the elastic coupling of a magnetostrictive phase and a piezoelectric phase. A deformation of the magnetostrictive phase causes strain in the piezoelectric phase and thus an induced voltage. Such sensors may be applied both for static as well as for dynamic magnetic field measurements. Particularly high sensitivities are achieved for operation at a mechanical resonance. Here, the resonance line shape of layered (2-2 composite) cantilever ME sensors at the first bending-mode resonance is investigated theoretically. Finite element method (FEM) simulations using a linear material model reveal an asymmetric resonance profile and a zero-response frequency for the ME coefficient. Frequency-dependent strain and electric potential distributions inside the magnetoelectric composite are studied for the case of a magnetostrictive-piezoelectric bilayer. It is demonstrated that a positive or a negative voltage may be induced across the piezoelectric layer depending on the position of the neutral plane. The frequency-dependent induced electric potential is investigated for structured cantilevers that exhibit magnetostriction only at specific positions. For static operation an induced voltage is obtained locally at positions with magnetostriction. In addition to this direct effect a resonance-assisted effect is observed for dynamic operation. Magnetostriction in a limited area of the cantilever causes a global vibration of the cantilever. Thus, deformation of the piezoelectric layer and an induced electric potential also occur in areas of the cantilever without magnetostriction. The direct and the resonance-assisted pathway may induce voltages of equal or of opposite sign. The net induced voltage results from the superposition of the two effects. As the resonance-assisted induced voltage changes sign upon passing the resonance frequency, while the direct component is constant, an asymmetric line shape and a zero

  1. A fruitful demonstration in sensors based on upconversion luminescence of Yb3+/Er3+codoped Sb2O3-WO3-Li2O (SWL) glass-ceramic

    Science.gov (United States)

    Prasad Sukul, Prasenjit; Kumar, Kaushal

    2016-07-01

    In this article, erbium and ytterbium doped lithium tungsten antimonate (Yb3+/Er3+:Sb2O3-WO3-Li2O) glass-ceramics (GC) is synthesized and its novel applications in temperature sensing and detection of latent fingerprints is studied. It is also estimated that this material could be useful as a solar cell concentrator. The upconversion emission studies on Yb3+/Er3+:SWL glass-ceramics have shown intense green emission at 525 nm (2H11/2 → 4I15/2) & 545 nm (4s3/2 → 4I15/2). The variation of UC intensities with external temperature have shown a well-fashioned pattern, which suggests that the 2H11/2 and 4S3/2 levels of Er3+ ion are thermally coupled and can act as a temperature sensor in the 300-500 K temperature range. Dry powder of Yb3+/Er3+:SWL glass-ceramic is used to develop latent fingerprint with high contrast in green color on glass slide.

  2. Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Høgh, Jacob Herold

    2013-01-01

    failure. The internal process-induced strain development is investigated through use of different cure schedules and tool/part interactions. The fibre Bragg grating sensors successfully monitor resin flow front progression during infusion, and strain development during curing, representative...... of the different cure temperatures and tool/part interfaces used. Substantial internal process-induced strains develop in the transverse fibre direction, which should be taken into consideration when designing fibre-reinforced polymer laminates. Flexure tests indicate no significant difference in the mechanical...

  3. Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

    DEFF Research Database (Denmark)

    Kerrouche, Abdelfateh; Boyle, William J.O.; Sun, Tong

    2009-01-01

    Results are reported from a study carried out using a series of Bragg grating based optical fiber sensors written into a very short length (60mm) optical fiber net work and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures...... from the calibrated force applied by the pulling machine and from a conventional resistive strain gauge mounted on the rod itself is obtained. Calculations from strain to shear stress show a relatively uniform stress distribution along the bar anchor used. The results give confidence to results from...... various methods of insitu monitoring of strains on such CFRP rods when used in different engineering structures....

  4. Design and Development of a Flexible Strain Sensor for Textile Structures Based on a Conductive Polymer Composite

    Directory of Open Access Journals (Sweden)

    Claude Dufour

    2007-04-01

    Full Text Available The aim of this work is to develop a smart flexible sensor adapted to textile structures, able to measure their strain deformations. The sensors are “smart” because of their capacity to adapt to the specific mechanical properties of textile structures that are lightweight, highly flexible, stretchable, elastic, etc. Because of these properties, textile structures are continuously in movement and easily deformed, even under very low stresses. It is therefore important that the integration of a sensor does not modify their general behavior. The material used for the sensor is based on a thermoplastic elastomer (Evoprene/carbon black nanoparticle composite, and presents general mechanical properties strongly compatible with the textile substrate. Two preparation techniques are investigated: the conventional melt-mixing process, and the solvent process which is found to be more adapted for this particular application. The preparation procedure is fully described, namely the optimization of the process in terms of filler concentration in which the percolation theory aspects have to be considered. The sensor is then integrated on a thin, lightweight Nylon fabric, and the electromechanical characterization is performed to demonstrate the adaptability and the correct functioning of the sensor as a strain gauge on the fabric. A normalized relative resistance is defined in order to characterize the electrical response of the sensor. Finally, the influence of environmental factors, such as temperature and atmospheric humidity, on the sensor performance is investigated. The results show that the sensor’s electrical resistance is particularly affected by humidity. This behavior is discussed in terms of the sensitivity of the carbon black filler particles to the presence of water.

  5. A fully integrated GaAs-based three-axis Hall magnetic sensor exploiting self-positioned strain released structures

    Science.gov (United States)

    Todaro, Maria T.; Sileo, Leonardo; Epifani, Gianmichele; Tasco, Vittorianna; Cingolani, Roberto; De Vittorio, Massimo; Passaseo, Adriana

    2010-10-01

    In this work, we demonstrate a fully integrated three-axis Hall magnetic sensor by exploiting microfabrication technologies applied to a GaAs-based heterostructure. This allows us to obtain, by the same process, three mutually orthogonal sensors: an in-plane Hall sensor and two out-of-plane Hall sensors. The micromachined devices consist of a two-dimensional electron gas AlGaAs/InGaAs/GaAs multilayer which represents the sensing structure, grown on the top of an InGaAs/GaAs strained bilayer. After the release from the substrate, the strained bilayer acts as a hinge for the multilayered structure allowing the out-of-plane self-positioning of devices. Both the in-plane and out-of-plane Hall sensors show a linear response versus the magnetic field with a sensitivity for current-biased devices higher than 1000 V A-1 T-1, corresponding to an absolute sensitivity more than 0.05 V T-1 at 50 µA. Moreover, Hall voltage measurements, as a function of the mechanical angle for both in-plane and out-of-plane sensors, demonstrate the potential of such a device for measurements of the three vector components of a magnetic field.

  6. Circuit Design of Surface Acoustic Wave Based Micro Force Sensor

    Directory of Open Access Journals (Sweden)

    Yuanyuan Li

    2014-01-01

    Full Text Available Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established to analyze the frequency, and a peripheral circuit is designed to measure the micro force. The SAW based micro force sensor is tested to show the reasonable design of detection circuit and the stability of frequency and amplitude.

  7. Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

    Institute of Scientific and Technical Information of China (English)

    DONG Wu-qin; JIA Zhen-hong

    2008-01-01

    The relation between the power of the Brillouin signal and the swain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Brillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of thep arameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.

  8. Piezoelectric Ceramic Characteristics Using Fiber Grating Sensor%用光纤光栅传感器研究压电陶瓷的特性

    Institute of Scientific and Technical Information of China (English)

    余有龙; 谭玲; 邹李刚; 王浩

    2011-01-01

    提出了一种利用光纤光栅传感器研究压电陶瓷特性的新方法.该方法采用非平衡Michelson扫描干涉仪对光纤光栅传感信号进行相位解调,通过观测波长漂移引起的相移,从而获得压电陶瓷的位移量与所加电压间的关系.实验分析了迟滞特性和蠕变现象,得到了压电陶瓷的电压-位移特性曲线以及蠕变特性曲线.实验表明,光源功率的波动对压电陶瓷迟滞特性不能造成影响且压电陶瓷的蠕变特性与电压方向无关.%A method for characteristics of piezoelectric ceramics was presented using a fiber Bragg grating sensor. An unbalanced Michelson interferometer was utilized to demodulate the fiber Bragg grating sensor signals. The relationship between the displacement of piezoelectric ceramic and the applied voltage was shown by observing the phase-shift induced by wavelength-shift. The hysteretic and creep properties of the piezoelectric ceramic were demonstrated experimentally,and the applied voltage-displacement curve and the creep curve were obtained. The results show that the fluctuations of light power had no effect on hysteretic,and the voltage direction has nothing with creep.

  9. Performance assessment of indigenously developed FBG strain sensors under short-term and long-term loadings

    Indian Academy of Sciences (India)

    K Kesavan; B Arun Sundaram; A K Farvaze Ahmed; S Parivallal; P Biswas; S Bandyopadhyay; K Ravisankar; Umesh Tiwari

    2015-04-01

    Fibre Bragg Grating (FBG) sensors are the most recent type of fibre optic sensors, which are gaining importance in the field of structural health monitoring of civil infrastructure. These are proven to be more versatile due to their distinct advantages such as high sensitivity, immunity to electromagnetic interference, ease of multiplexing and remote sensing. These are suitable for the short-term and longterm monitoring of the structures. Multiple Fibre Bragg Grating (FBG) sensors can be surface mounted and/or embedded in structures to measure strain, temperature, cracks and vibrations. Use of FBG sensors for real time health monitoring of various civil engineering structures is well-established in western world since last decade, whereas in the Indian context this technology is still in a nascent stage. In this paper, performance assessment of indigenously developed FBG sensors for the application of health monitoring of civil engineering structures by conducting short-term and long-term studies is presented. Brief details of the laboratory studies carried out on indigenously developed FBG sensors are covered in this paper. From the laboratory studies it is found that, these FBG sensors are suitable in health monitoring of civil engineering structures.

  10. Strain distribution and crack detection in thin unbonded concrete pavement overlays with fully distributed fiber optic sensors

    Science.gov (United States)

    Bao, Yi; Chen, Genda

    2016-01-01

    This study aims at evaluating the feasibility of strain measurement and crack detection in thin unbonded concrete pavement overlays with pulse prepump Brillouin optical time domain analysis. Single-mode optical fibers with two-layer and three-layer coatings, respectively, were applied as fully distributed sensors, their performances were compared with analytical predictions. They were successfully protected from damage during concrete casting of three full-scale concrete panels when 5 to 10-cm-thick protective mortar covers had been set for 2 h. Experimental results from three-point loading tests of the panels indicated that the strain distributions measured from the two types of sensors were in good agreement, and cracks can be detected at sharp peaks of the measured strain distributions. The two-layer and three-layer coated fibers can be used to measure strains up to 2.33% and 2.42% with a corresponding sensitivity of 5.43×10-5 and 4.66×10-5 GHz/μɛ, respectively. Two cracks as close as 7 to 9 cm can be clearly detected. The measured strains in optical fiber were lower than the analytical prediction by 10% to 25%. Their difference likely resulted from strain transfer through various coatings, idealized point loading, varying optical fiber embedment, and concrete heterogeneity.

  11. Design and Development of a Flexible Strain Sensor for Textile Structures Based on a Conductive Polymer Composite

    OpenAIRE

    Claude Dufour; Maryline Lewandowski; Vladan Koncar; Cédric Cochrane

    2007-01-01

    The aim of this work is to develop a smart flexible sensor adapted to textile structures, able to measure their strain deformations. The sensors are “smart†because of their capacity to adapt to the specific mechanical properties of textile structures that are lightweight, highly flexible, stretchable, elastic, etc. Because of these properties, textile structures are continuously in movement and easily deformed, even under very low stresses. It is therefore important that the integra...

  12. Load sensor

    NARCIS (Netherlands)

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder for

  13. Pressure-sensitive strain sensor based on a single percolated Ag nanowire layer embedded in colorless polyimide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chan-Jae [Display Materials & Components Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816 (Korea, Republic of); Jun, Sungwoo [Display Materials & Components Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816 (Korea, Republic of); Display and Nanosystem Laboratory, College of Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Ju, Byeong-Kwon [Display and Nanosystem Laboratory, College of Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Jong-Woong, E-mail: wyjd@keti.re.kr [Display Materials & Components Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816 (Korea, Republic of)

    2017-06-01

    This paper presents the fabrication of an elastomer-free, transparent, pressure-sensitive strain sensor consisting of a specially designed silver nanowire (AgNW) pattern and colorless polyimide (cPI). A percolated AgNW network was patterned with a simple tandem compound circuit, which was then embedded in the surface of the cPI via inverted layer processing. The resulting film-type sensor was highly transparent (~93.5% transmittance at 550 nm) and mechanically stable (capable of resisting 10000 cycles of bending to a 500 µm radius of curvature). We demonstrated that a thin, transparent, and mechanically stable electrode can be produced using a combination of AgNWs and cPI, and used to produce a system sensitive to pressure-induced bending. The capacitance of the AgNW tandem compound electrode pattern grew via fringing, which increased with the pressure-induced bending applied to the surface of the sensor. The sensitivity was four times higher than that of an elastomeric pressure sensor made with the same design. Finally, we demonstrated a skin-like pressure sensor attached to the inside wrist of a human arm. - Highlights: • A thin, transparent pressure sensor was fabricated from AgNWs and cPI. • An AgNW network was patterned with a simple circuit, and then embedded into cPI. • The resulting film-type sensor was highly transparent and mechanically stable. • The sensor sensitivity was 4x higher than that of an elastomeric pressure sensor.

  14. Optical Fiber Sensors for Infrasonic Wind Noise Reduction and Earth Strain Measurement

    Science.gov (United States)

    DeWolf, Scott

    Fiber-based interferometers provide the means to sense very small displacements over long baselines, and have the advantage of being nearly completely passive in their operation, making them particularly well suited for geophysical applications. This work presents the development and results from four new systems: one in atmospheric acoustics and three in Earth strain. Turbulent pressure fluctuations (wind noise) are a significant limiting factor in low-frequency atmospheric acoustic measurements. The Optical Fiber Infrasound Sensor (OFIS) provides an alternative to traditional infrasonic wind noise reduction (WNR) techniques by providing an instantaneous average over a large spatial extent. This study shows that linear OFISs ranging in length from 30 to 270 m provide a WNR of up to 30 dB in winds up to 5 m/s, in good agreement with a new analytical model. Arrays of optical fiber strainmeters were deployed to measure sediment compaction at two sites in Bangladesh. One array at Jamalganj (in the north) consists of 20, 40, 60, and 100 m long strainmeters, while the second near Khulna (in the south) also includes lengths of 80 and 300 m. Two years of weekly measurements show a clear seasonal signal and subsidence at both sites that is in reasonable agreement with collocated GPS receivers. A new 250-meter, interferometric vertical borehole strainmeter has been developed based completely on passive optical components. Details of the prototyping, design, and deployment at the Pinon Flat Observatory (PFO) are presented. Power spectra show an intertidal noise level of -130 dB (re. 1 epsilon/Hz), consistent within 1-3 dB between redundant components. Examination of its response to Earth tides and earthquakes relative to the areal strain recorded by an orthogonal pair of collocated, 730 m horizontal laser strainmeters yield a Poisson's ratio of 0.26. Two prototype horizontal strainmeters were also developed to explore the use of similar interferometric optical fiber

  15. A novel fiber-laser-based fiber Bragg grating strain sensor with high-birefringence Sagnac fiber loop mirror

    Institute of Scientific and Technical Information of China (English)

    Ou Xu; Shaohua Lu; Suchun Feng; Shuisheng Jian

    2008-01-01

    A novel fiber-laser-based strain sensor is proposed and experimentally demonstrated. The laser cavity is composed of a high-birefringence Sagnac fiber loop mirror (HiBi-SFLM) and a fiher Bragg grating (FBG) which also acts as a strain-sensing element. In the linear region of the HiBi-SFI,M reflection spectrum, when the strain applied on the FBG makes the Bragg grating wavelength shift,, the laser output power changes due to reflectivity variation of the HiBi-SFLM. Experimental results show that the laser output power varies ahnost linearly with the applied strain. The measurement of the output power can be performed by a conventional photo-detector.

  16. Highly Sensitive, Stretchable, and Wash-Durable Strain Sensor Based on Ultrathin Conductive Layer@Polyurethane Yarn for Tiny Motion Monitoring.

    Science.gov (United States)

    Wu, Xiaodong; Han, Yangyang; Zhang, Xinxing; Lu, Canhui

    2016-04-20

    Strain sensors play an important role in the next generation of artificially intelligent products. However, it is difficult to achieve a good balance between the desirable performance and the easy-to-produce requirement of strain sensors. In this work, we proposed a simple, cost-efficient, and large-area compliant strategy for fabricating highly sensitive strain sensor by coating a polyurethane (PU) yarn with an ultrathin, elastic, and robust conductive polymer composite (CPC) layer consisting of carbon black and natural rubber. This CPC@PU yarn strain sensor exhibited high sensitivity with a gauge factor of 39 and detection limit of 0.1% strain. The elasticity and robustness of the CPC layer endowed the sensor with good reproducibility over 10,000 cycles and excellent wash- and corrosion-resistance. We confirmed the applicability of our strain sensor in monitoring tiny human motions. The results indicated that tiny normal physiological activities (including pronunciation, pulse, expression, swallowing, coughing, etc.) could be monitored using this CPC@PU sensor in real time. In particular, the pronunciation could be well parsed from the recorded delicate speech patterns, and the emotions of laughing and crying could be detected and distinguished using this sensor. Moreover, this CPC@PU strain-sensitive yarn could be woven into textiles to produce functional electronic fabrics. The high sensitivity and washing durability of this CPC@PU yarn strain sensor, together with its low-cost, simplicity, and environmental friendliness in fabrication, open up new opportunities for cost-efficient fabrication of high performance strain sensing devices.

  17. Fast Estimation of Strains for Cross-Beams Six-Axis Force/Torque Sensors by Mechanical Modeling

    Directory of Open Access Journals (Sweden)

    Junqing Ma

    2013-05-01

    Full Text Available Strain distributions are crucial criteria of cross-beams six-axis force/torque sensors. The conventional method for calculating the criteria is to utilize Finite Element Analysis (FEA to get numerical solutions. This paper aims to obtain analytical solutions of strains under the effect of external force/torque in each dimension. Genetic mechanical models for cross-beams six-axis force/torque sensors are proposed, in which deformable cross elastic beams and compliant beams are modeled as quasi-static Timoshenko beam. A detailed description of model assumptions, model idealizations, application scope and model establishment is presented. The results are validated by both numerical FEA simulations and calibration experiments, and test results are found to be compatible with each other for a wide range of geometric properties. The proposed analytical solutions are demonstrated to be an accurate estimation algorithm with higher efficiency.

  18. Simulation and experimental characterization of polymer/carbon nanotubes composites for strain sensor applications

    Science.gov (United States)

    De Vivo, B.; Lamberti, P.; Spinelli, G.; Tucci, V.; Vertuccio, L.; Vittoria, V.

    2014-08-01

    In this paper, a numerical model is presented in order to analyze the electrical characteristics of polymer composites filled by carbon nanotubes (CNTs) subject to tensile stress and investigate the possible usage of such materials as innovative sensors for small values of strain. The simulated mechano-electrical response of the nanocomposite is obtained through a multi-step approach which, through different modeling stages, provides a simple and effective tool for material analysis and design. In particular, at first, the morphological structures of the composites are numerically simulated by adopting a previously presented model based on a Monte Carlo procedure in which uniform distributions of the CNTs, approximated as of solid cylinders and ensuring some physical constraints, are dispersed inside a cubic volume representing the polymer matrix. Second, a geometrical analysis allows to obtain the percolation paths detected in the simulated structures. Suitable electrical networks composed by resistors and capacitors associated to the complex charge transport and polarization mechanisms occurring in the percolation paths are then identified. Finally, the variations of these circuit parameters, which are differently affected by the mechanical stresses applied to the composites, are considered to analyze the electromechanical characteristics of the composites and hence their performances as stress sensors. The proposed approach is used to investigate the impact on the electro-mechanical response of some physical properties of the base materials, such as the type of carbon nanotube, the height of energy barrier of polymer resin, as well as characteristics of the composite, i.e., the volume fraction of the filler. The tunneling effect between neighboring nanotubes is found to play a dominant role in determining the composite sensitivity to mechanical stresses. The simulation results are also compared with the experimental data obtained by performing stress tests on

  19. Enhanced FBG sensor-based system performance assessment for monitoring strain along a prestressed CFRP rod in structural monitoring

    DEFF Research Database (Denmark)

    Kerrouche, A.; Boyle, W.J.O.; Sun, T.

    2009-01-01

    Fiber Bragg grating (FBG) sensor-based systems have been widely used for many engineering applications including most recently a number of applications in structural health monitoring. It is well known that strain and temperature both affect the FBG spectrum which in the interrogation system...... of the existing FBG-based system and the evaluation of the software developed to be compatible with a resolution reaching as high as +/- 0.15 mu epsilon is presented. The system has been tested under particular conditions where a prestressed CFRP (carbon fiber reinforced polymer) rod to which a FBG sensor...... will be converted to a conventional electronic signal. This procedure provides the means for the FBG-based sensor system to be used for several monitoring applications. The aim of this research is to improve an existing monitoring system which has been used for several Held test inspections. A brief description...

  20. SDIO Workshop on Piezoelectric Ceramic Actuators for Space Applications Held in Alexandria, Virginia on 25 February 1992

    Science.gov (United States)

    1992-06-01

    Advanced Piezoelectric Ceramic Actuator Materials for Space Applications Appendix D-- ACESA, ACTEX and AMASS PZT Material Needs Appendix E-- High Strain...with Embedded Sensors and Actuators ACTEX Advanced Control Technology Experiment Ag silver AMASS Advanced Materials Application to Space Structures...ACESA), Advanced Control Technology Experiment ( ACTEX ), and Advanced Materials Application to Space Structures (AMASS). The ACESA struts, 16 feet long

  1. A Wireless Sensor Network with Enhanced Power Efficiency and Embedded Strain Cycle Identification for Fatigue Monitoring of Railway Bridges

    Directory of Open Access Journals (Sweden)

    Glauco Feltrin

    2016-01-01

    Full Text Available Wireless sensor networks have been shown to be a cost-effective monitoring tool for many applications on civil structures. Strain cycle monitoring for fatigue life assessment of railway bridges, however, is still a challenge since it is data intensive and requires a reliable operation for several weeks or months. In addition, sensing with electrical resistance strain gauges is expensive in terms of energy consumption. The induced reduction of battery lifetime of sensor nodes increases the maintenance costs and reduces the competitiveness of wireless sensor networks. To overcome this drawback, a signal conditioning hardware was designed that is able to significantly reduce the energy consumption. Furthermore, the communication overhead is reduced to a sustainable level by using an embedded data processing algorithm that extracts the strain cycles from the raw data. Finally, a simple software triggering mechanism that identifies events enabled the discrimination of useful measurements from idle data, thus increasing the efficiency of data processing. The wireless monitoring system was tested on a railway bridge for two weeks. The monitoring system demonstrated a good reliability and provided high quality data.

  2. Electric field-induced giant strain and photoluminescence-enhancement effect in rare-earth modified lead-free piezoelectric ceramics.

    Science.gov (United States)

    Yao, Qirong; Wang, Feifei; Xu, Feng; Leung, Chung Ming; Wang, Tao; Tang, Yanxue; Ye, Xiang; Xie, Yiqun; Sun, Dazhi; Shi, Wangzhou

    2015-03-11

    In this work, an electric field-induced giant strain response and excellent photoluminescence-enhancement effect was obtained in a rare-earth ion modified lead-free piezoelectric system. Pr(3+)-modified 0.93(Bi0.5Na0.5)TiO3-0.07BaTiO3 ceramics were designed and fabricated by a conventional fabrication process. The ferroelectric, dielectric, piezoelectric, and photoluminescence performances were systematically studied, and a schematic phase diagram was constructed. It was found the Pr(3+) substitution induced a transition from ferroelectric a long-range order structure to a relaxor pseudocubic phase with short-range coherence structure. Around a critical composition of 0.8 mol % Pr(3+), a giant reversible strain of ∼0.43% with a normalized strain Smax/Emax of up to 770 pm/V was obtained at ∼5 kV/mm. Furthermore, the in situ electric field enhanced the photoluminescence intensity by ∼40% in the proposed system. These findings have great potential for actuator and multifunctional device applications, which may also open up a range of new applications.

  3. Portfolio: Ceramics.

    Science.gov (United States)

    Hardy, Jane; And Others

    1982-01-01

    Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

  4. Portfolio: Ceramics.

    Science.gov (United States)

    Hardy, Jane; And Others

    1982-01-01

    Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

  5. Eraser-based eco-friendly fabrication of a skin-like large-area matrix of flexible carbon nanotube strain and pressure sensors

    Science.gov (United States)

    Sahatiya, Parikshit; Badhulika, Sushmee

    2017-03-01

    This paper reports a new type of electronic, recoverable skin-like pressure and strain sensor, produced on a flexible, biodegradable pencil-eraser substrate and fabricated using a solvent-free, low-cost and energy efficient process. Multi-walled carbon nanotube (MWCNT) film, the strain sensing element, was patterned on pencil eraser with a rolling pin and a pre-compaction mechanical press. This induces high interfacial bonding between the MWCNTs and the eraser substrate, which enables the sensor to achieve recoverability under ambient conditions. The eraser serves as a substrate for strain sensing, as well as acting as a dielectric for capacitive pressure sensing, thereby eliminating the dielectric deposition step, which is crucial in capacitive-based pressure sensors. The strain sensing transduction mechanism is attributed to the tunneling effect, caused by the elastic behavior of the MWCNTs and the strong mechanical interlock between MWCNTs and the eraser substrate, which restricts slippage of MWCNTs on the eraser thereby minimizing hysteresis. The gauge factor of the strain sensor was calculated to be 2.4, which is comparable to and even better than most of the strain and pressure sensors fabricated with more complex designs and architectures. The sensitivity of the capacitive pressure sensor was found to be 0.135 MPa‑1.To demonstrate the applicability of the sensor as artificial electronic skin, the sensor was assembled on various parts of the human body and corresponding movements and touch sensation were monitored. The entire fabrication process is scalable and can be integrated into large areas to map spatial pressure distributions. This low-cost, easily scalable MWCNT pin-rolled eraser-based pressure and strain sensor has huge potential in applications such as artificial e-skin in flexible electronics and medical diagnostics, in particular in surgery as it provides high spatial resolution without a complex nanostructure architecture.

  6. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  7. Composite Cure Process Modeling and Simulations using COMPRO(Registered Trademark) and Validation of Residual Strains using Fiber Optics Sensors

    Science.gov (United States)

    Sreekantamurthy, Thammaiah; Hudson, Tyler B.; Hou, Tan-Hung; Grimsley, Brian W.

    2016-01-01

    Composite cure process induced residual strains and warping deformations in composite components present significant challenges in the manufacturing of advanced composite structure. As a part of the Manufacturing Process and Simulation initiative of the NASA Advanced Composite Project (ACP), research is being conducted on the composite cure process by developing an understanding of the fundamental mechanisms by which the process induced factors influence the residual responses. In this regard, analytical studies have been conducted on the cure process modeling of composite structural parts with varied physical, thermal, and resin flow process characteristics. The cure process simulation results were analyzed to interpret the cure response predictions based on the underlying physics incorporated into the modeling tool. In the cure-kinetic analysis, the model predictions on the degree of cure, resin viscosity and modulus were interpreted with reference to the temperature distribution in the composite panel part and tool setup during autoclave or hot-press curing cycles. In the fiber-bed compaction simulation, the pore pressure and resin flow velocity in the porous media models, and the compaction strain responses under applied pressure were studied to interpret the fiber volume fraction distribution predictions. In the structural simulation, the effect of temperature on the resin and ply modulus, and thermal coefficient changes during curing on predicted mechanical strains and chemical cure shrinkage strains were studied to understand the residual strains and stress response predictions. In addition to computational analysis, experimental studies were conducted to measure strains during the curing of laminated panels by means of optical fiber Bragg grating sensors (FBGs) embedded in the resin impregnated panels. The residual strain measurements from laboratory tests were then compared with the analytical model predictions. The paper describes the cure process

  8. Design and performance investigation of a highly accurate apodized fiber Bragg grating-based strain sensor in single and quasi-distributed systems.

    Science.gov (United States)

    Ali, Taha A; Shehata, Mohamed I; Mohamed, Nazmi A

    2015-06-01

    In this work, fiber Bragg grating (FBG) strain sensors in single and quasi-distributed systems are investigated, seeking high-accuracy measurement. Since FBG-based strain sensors of small lengths are preferred in medical applications, and that causes the full width at half-maximum (FWHM) to be larger, a new apodization profile is introduced for the first time, to the best of our knowledge, with a remarkable FWHM at small sensor lengths compared to the Gaussian and Nuttall profiles, in addition to a higher mainlobe slope at these lengths. A careful selection of apodization profiles with detailed investigation is performed-using sidelobe analysis and the FWHM, which are primary judgment factors especially in a quasi-distributed configuration. A comparison between the elite selection of apodization profiles (extracted from related literature) and the proposed new profile is carried out covering the reflectivity peak, FWHM, and sidelobe analysis. The optimization process concludes that the proposed new profile with a chosen small length (L) of 10 mm and Δnac of 1.4×10-4 is the optimum choice for single stage and quasi-distributed strain-sensor networks, even better than the Gaussian profile at small sensor lengths. The proposed profile achieves the smallest FWHM of 15 GHz (suitable for UDWDM), and the highest mainlobe slope of 130 dB/nm. For the quasi-distributed scenario, a noteworthy high isolation of 6.953 dB is achieved while applying a high strain value of 1500 μstrain (με) for a five-stage strain-sensing network. Further investigation was undertaken, proving that consistency in choosing the apodization profile in the quasi-distributed network is mandatory. A test was made of the inclusion of a uniform apodized sensor among other apodized sensors with the proposed profile in an FBG strain-sensor network.

  9. Measurement of Temperature and Residual Strain during Fatigue of a CFRP Composite Using Fiber Bragg Grating Sensors

    Institute of Scientific and Technical Information of China (English)

    SHEN Xiaoyan; LIN Yuchi; WANG Wei

    2009-01-01

    Fatigue behaviour has important implications for engineering composite structures in sectors ranging from automotive to aerospace. Optical sensing technology displays excellent performance in these fields for monitoring. In this paper, temperature and residual strain during fatigue of a carbon fiber reinforced polymer(CFRP) are investigated. Four autoclaved CFRP beam specimens, with fiber Bragg grating(FBG) sensors and thermocouples embedded at selected locations, are subjected to three-point bending cyclic loading on the BOSE testing machine for fatigue testing. Thermocouples are used to measure the temperature while FBGs can sense the temperature and strain as well. Seven tests in total are conducted at different frequencies, and each test lasts for several days. From the experimental results, transient steep peaks of temperature increases (up to 2.3 ℃) are discovered at the beginning of the load. The following constant temperature increments are around 1.0 ℃, which is not relevant to frequencies from 0.1 Hz to 20 Hz and suspected due to fatigue. Residual strains of 1×10-5-2×10-5 during fatigue, fading away rapidly when unloading, are also reported. Embedded FBGs here are validated to sense temperature and strains in composite structures, which demonstrates promising potentials in structure monitoring fields. CFRP are verified to have an excellent performance during fatigue with low temperature increase and residual strain.

  10. Electric circuit model for MgO-doped ZrO2-TiO2 ceramic humidity sensor

    Science.gov (United States)

    Jain, M. K.; Bhatnagar, M. C.; Sharma, G. L.

    1998-12-01

    The MgO-doped ZrO2-TiO2 ceramic pellets were studied for its humidity-sensitive electrical conduction. An equivalent circuit model has been proposed to define the humidity-sensitive electrical properties. This model is in agreement with the experimental findings. The electrical conduction is largely controlled by the intergranular impedance except at very high humidities. The impedance of the pellets showed inductive behavior in high-humidity region. This behavior can be attributed to the spherical paths adopted by charge carrier because conduction is mainly through the spherical grain surface.

  11. Composite cavity based fiber optic Fabry Perot strain sensors demodulated by an unbalanced fiber optic Michelson interferometer with an electrical scanning mirror

    Science.gov (United States)

    Zhang, Jianzhong; Yang, Jun; Sun, Weimin; Jin, Wencai; Yuan, Libo; Peng, G. D.

    2008-08-01

    A composite cavity based fiber optic Fabry-Perot strain sensor system, interrogated by a white light source and demodulated by an unbalanced fiber optic Michelson interferometer with an electrical scanning mirror, is proposed and demonstrated. Comparing with the traditional extrinsic fiber optic Fabry-Perot strain sensor, the potential multiplexing capability and the dynamic measurement range are improved simultaneously. At the same time, the measurement stability of the electrical scanning mirror system is improved by the self-referenced signal of the sensor structure.

  12. Stretchable Complementary Split Ring Resonator (CSRR-Based Radio Frequency (RF Sensor for Strain Direction and Level Detection

    Directory of Open Access Journals (Sweden)

    Seunghyun Eom

    2016-10-01

    Full Text Available In this paper, we proposed a stretchable radio frequency (RF sensor to detect strain direction and level. The stretchable sensor is composed of two complementary split ring resonators (CSRR with microfluidic channels. In order to achieve stretchability, liquid metal (eutectic gallium-indium, EGaIn and Ecoflex substrate are used. Microfluidic channels are built by Ecoflex elastomer and microfluidic channel frames. A three-dimensional (3D printer is used for fabrication of microfluidic channel frames. Two CSRR resonators are designed to resonate 2.03 GHz and 3.68 GHz. When the proposed sensor is stretched from 0 to 8 mm along the +x direction, the resonant frequency is shifted from 3.68 GHz to 3.13 GHz. When the proposed sensor is stretched from 0 to 8 mm along the −x direction, the resonant frequency is shifted from 2.03 GHz to 1.78 GHz. Therefore, we can detect stretched length and direction from independent variation of two resonant frequencies.

  13. Printed strain sensor with temperature compensation and its evaluation with an example of applications in structural health monitoring

    Science.gov (United States)

    Zymelka, Daniel; Yamashita, Takahiro; Takamatsu, Seiichi; Itoh, Toshihiro; Kobayashi, Takeshi

    2017-05-01

    In this paper, we describe the development of a flexible printed strain sensor and its evaluation with an example of its applications to structural health monitoring. The sensor was fabricated on a thin poly(ethylene naphthalate) (PEN) substrate using the screen printing method. In order to ensure compensation for temperature variations, a full-Wheatstone-bridge circuit was integrated into the sensor’s structure. For this reason, the sensor’s shape was specially designed in such a way that only one symmetrical structure was enough to build the full-Wheatstone-bridge. The developed device was evaluated by various laboratory tests as well as by measurements carried out on a highway bridge. The collected results demonstrate its potential suitability for application to dynamic load tests within the framework of structural health monitoring.

  14. Gallium-Based Room Temperature Liquid Metals and its Application to Single Channel Two-Liquid Hyperelastic Capacitive Strain Sensors

    Science.gov (United States)

    Liu, Shanliangzi

    Gallium-based liquid metals are of interest for a variety of applications including flexible electronics, soft robotics, and biomedical devices. Still, nano- to microscale device fabrication with these materials is challenging because of their strong adhesion to a majority of substrates. This unusual high adhesion is attributed to the formation of a thin oxide shell; however, its role in the adhesion process has not yet been established. In the first part of the thesis, we described a multiscale study aiming at understanding the fundamental mechanisms governing wetting and adhesion of gallium-based liquid metals. In particular, macroscale dynamic contact angle measurements were coupled with Scanning Electron Microscope (SEM) imaging to relate macroscopic drop adhesion to morphology of the liquid metal-surface interface. In addition, room temperature liquid-metal microfluidic devices are also attractive systems for hyperelastic strain sensing. Currently two types of liquid metal-based strain sensors exist for inplane measurements: single-microchannel resistive and two-microchannel capacitive devices. However, with a winding serpentine channel geometry, these sensors typically have a footprint of about a square centimeter, limiting the number of sensors that can be embedded into. In the second part of the thesis, firstly, simulations and an experimental setup consisting of two GaInSn filled tubes submerged within a dielectric liquid bath are used to quantify the effects of the cylindrical electrode geometry including diameter, spacing, and meniscus shape as well as dielectric constant of the insulating liquid and the presence of tubing on the overall system's capacitance. Furthermore, a procedure for fabricating the two-liquid capacitor within a single straight polydiemethylsiloxane channel is developed. Lastly, capacitance and response of this compact device to strain and operational issues arising from complex hydrodynamics near liquid-liquid and liquid

  15. Design and proposal of dual line-of-defense perimeter watchdog incorporating optimally designed FBG based accelerometers and strain sensors using single optical fiber

    Science.gov (United States)

    Khan, Mohd. Mansoor; Sonkar, Ramesh Kumar

    2015-06-01

    Paper presents Opto-Mechanical intrusion sensor fence with FBGs attached to mechanical accelerometers and strain sensors, optimized on SolidWorks 2013 for desired frequency to 35 Hz, picking up accelerations/ strains and its deployment for perimeter security. The accelerometer structure consists of inertial mass supported by an L-shaped modified cantilever beam having non-uniform cross section area connected to base by a thin neck element which acts as strain concentrated centre hence an optimum zone for FBG sensors placement. Bragg wavelength shifts were obtained on Optigrating software for the obtained strain values on mechanical assembly of fence. CFD wind analysis is performed on the assembly to obtain the spot for accelerometer's placement to avoid false alarms up to wind velocities of 20 m/s.

  16. Distributed fiber Brillouin strain and temperature sensor with centimeter spatial resolution by coherent probe-pump technique

    Science.gov (United States)

    Zou, Lufan; Bao, Xiaoyi; Wan, Yidun; Ravet, Fabien; Chen, Liang

    2005-05-01

    We present a sensing principle of the distributed fiber Brillouin strain and temperature sensor by coherent probe-pump technique that offers a new method to achieve centimeter spatial resolution with high frequency resolution. A combination of continuous wave (cw) and pulse source as the probe (Stokes) beam and cw laser as the pump beam have resulted in stronger Brillouin interaction of Stokes and pump inside the pulse-length in the form of cw-pump and pulse-pump interactions. We find that the coherent portion inside the pulse-length of these two interactions due to the same phase has a very high Brillouin amplification. The Brillouin profile originating from the coherent interaction of pulse-pump with cw-pump results in high temperature and strain accuracy with centimeter resolution, which has been verified by successfully detecting 1.5 cm out-layer crack on an optical ground wire (OPGW) cable.

  17. Deformable trailing edge flaps for modern megawatt wind turbine controllers using strain gauge sensors

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn; Henriksen, Lars Christian; Gaunaa, Mac

    2010-01-01

    . By enabling the trailing edge to move independently and quickly along the spanwise position of the blade, local small flutuations in the aerodynamic forces can be alleviated by deformation of the airfoil flap. Strain gauges are used as input for the flap controller, and the effect of placing strain gauges...

  18. Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

    Science.gov (United States)

    Dukic, Maja; Winhold, Marcel; Schwalb, Christian H.; Adams, Jonathan D.; Stavrov, Vladimir; Huth, Michael; Fantner, Georg E.

    2016-01-01

    The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors' conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy. PMID:27666316

  19. Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

    Science.gov (United States)

    Dukic, Maja; Winhold, Marcel; Schwalb, Christian H.; Adams, Jonathan D.; Stavrov, Vladimir; Huth, Michael; Fantner, Georg E.

    2016-09-01

    The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors' conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy.

  20. Advances in Fiber Optic Sensors Technology Development for temperature and strain measurements in Superconducting magnets and devices

    CERN Document Server

    Chiuchiolo, A.; Bajko, M.; Bottura, L.; Consales, M.; Cusano, A.; Giordano, M.; Perez, J. C.

    2016-01-01

    The luminosity upgrade of the Large Hadron Collider (HL-LHC) requires the development of a new generation of superconducting magnets based on Nb3Sn technology. In order to monitor the magnet thermo-mechanical behaviour during its service life, from the coil fabrication to the magnet operation, reliable sensing systems need to be implemented. In the framework of the FP7 European project EUCARD, Nb3Sn racetrack coils are developed as test beds for the fabrication validation, the cable characterization and the instrumentation development. Fiber optic sensors (FOS) based on Fiber Bragg Grating (FBG) technology have been embedded in the coils of the Short Model Coil (SMC) magnet. The FBG sensitivity to both temperature and strain required the development of a solution able to separate the mechanical and temperature effects. This work presents the feasibility study of the implementation of embedded FBG sensors for the temperature and strain monitoring of the 11 T type conductor. We aim to monitor and register these...

  1. Numerical simulation and experimental validation of a large-area capacitive strain sensor for fatigue crack monitoring

    Science.gov (United States)

    Kong, Xiangxiong; Li, Jian; Bennett, Caroline; Collins, William; Laflamme, Simon

    2016-12-01

    A large-area electronics in the form of a soft elastomeric capacitor (SEC) has shown great promise as a strain sensor for fatigue crack monitoring in steel structures. The SEC sensors are inexpensive, easy to fabricate, highly stretchable, and mechanically robust. It is a highly scalable technology, capable of monitoring deformations on mesoscale systems. Preliminary experiments verified the SEC sensor’s capability in detecting, localizing, and monitoring crack growth in a compact specimen. Here, a numerical simulation method is proposed to simulate accurately the sensor’s performance under fatigue cracks. Such a method would provide a direct link between the SEC’s signal and fatigue crack geometry, extending the SEC’s capability to dense network applications on mesoscale structural components. The proposed numerical procedure consists of two parts: (1) a finite element (FE) analysis for the target structure to simulate crack growth based on an element deletion method; (2) an algorithm to compute the sensor’s capacitance response using the FE analysis results. The proposed simulation method is validated based on test data from a compact specimen. Results from the numerical simulation show good agreement with the SEC’s response from the laboratory tests as a function of the crack size. Using these findings, a parametric study is performed to investigate how the SEC would perform under different geometries. Results from the parametric study can be used to optimize the design of a dense sensor network of SECs for fatigue crack detection and localization.

  2. Strain-driven and ultrasensitive resistive sensor/switch based on conductive alginate/nitrogen-doped carbon-nanotube-supported Ag hybrid aerogels with pyramid design.

    Science.gov (United States)

    Zhao, Songfang; Zhang, Guoping; Gao, Yongju; Deng, Libo; Li, Jinhui; Sun, Rong; Wong, Ching-Ping

    2014-12-24

    Flexible strain-driven sensor is an essential component in the flexible electronics. Especially, high durability and sensitivity to strain are required. Here, we present an efficient and low-cost fabrication strategy to construct a highly sensitive and flexible pressure sensor based on a conductive, elastic aerogel with pyramid design. When pressure is loaded, the contact area between the interfaces of the conductive aerogel and the copper electrode as well as among the building blocks of the nitrogen-doped carbon-nanotube-supported Ag (N-CNTs/Ag) aerogel monoliths, changes in reversible and directional manners. This contact resistance mechanism enables the hybrid aerogels to act as strain-driven sensors with high sensitivity and excellent on/off swithching behavior, and the gauge factor (GF) is ∼15 under strain of 3%, which is superior to those reported for other aerogels. In addition, robust, elastomeric and conductive nanocomposites can be fabricated by injecting polydimethylsiloxane (PDMS) into alginate/N-CNTs/Ag aerogels. Importantly, the building blocks forming the aerogels retain their initial contact and percolation after undergoing large-strain deformation, PDMS infiltration, and cross-linking of PDMS, suggesting their potential applications as strain sensors.

  3. Effect of Prior Exposure at Elevated Temperatures on Tensile Properties and Stress-Strain Behavior of Three Oxide/Oxide Ceramic Matrix Composites

    Science.gov (United States)

    2015-03-26

    aerospace , and military designs. One of the largest drawbacks to monolithic ceramics is low fracture toughness and susceptibility to catastrophic...Laboratory, Wright-Patterson AFB, OH, 2005. [30] G. Fair, " Ceramic Composites for Structural Aerospace Applications: Processing and Properties," Air...OF THREE OXIDE/OXIDE CERAMIC MATRIX COMPOSITES THESIS Christopher J. Hull, Captain, USAF AFIT-ENY-MS-15-M-228 DEPARTMENT OF THE AIR FORCE

  4. Role of the interface between distributed fibre optic strain sensor and soil in ground deformation measurement

    Science.gov (United States)

    Zhang, Cheng-Cheng; Zhu, Hong-Hu; Shi, Bin

    2016-11-01

    Recently the distributed fibre optic strain sensing (DFOSS) technique has been applied to monitor deformations of various earth structures. However, the reliability of soil deformation measurements remains unclear. Here we present an integrated DFOSS- and photogrammetry-based test study on the deformation behaviour of a soil foundation model to highlight the role of strain sensing fibre–soil interface in DFOSS-based geotechnical monitoring. Then we investigate how the fibre–soil interfacial behaviour is influenced by environmental changes, and how the strain distribution along the fibre evolves during progressive interface failure. We observe that the fibre–soil interfacial bond is tightened and the measurement range of the fibre is extended under high densities or low water contents of soil. The plastic zone gradually occupies the whole fibre length when the soil deformation accumulates. Consequently, we derive a theoretical model to simulate the fibre–soil interfacial behaviour throughout the progressive failure process, which accords well with the experimental results. On this basis, we further propose that the reliability of measured strain can be determined by estimating the stress state of the fibre–soil interface. These findings may have important implications for interpreting and evaluating fibre optic strain measurements, and implementing reliable DFOSS-based geotechnical instrumentation.

  5. FBG传感器和电阻应变仪的振动监测特性%Vibration detection characteristics of FBG sensor and resistance strain gauge

    Institute of Scientific and Technical Information of China (English)

    龚华平; 杨效; 屠于梦; 宋海峰; 董新永

    2013-01-01

    Fiber Bragg grating (FBG) sensor and resistance strain gauge sensor were fixed on the uniform strength beam. Vibration detection characteristics of two kinds of sensors were investigated. The advantage and disadvantage of two kinds of sensors were compared. Vibration was caused by a motor which was fixed at the end of uniform strength beam. The vibration signal in time domain was measured, which was monitored by FBG sensor and resistance strain gauge sensor simultaneously, and the frequency spectrum was analyzed from the vibration curve through FFT. The results show that the vibration graph monitored by FBG sensor is consistent with the vibration graph monitored by resistance strain gauge sensor. But the frequency spectrum monitored by FBG sensor has second harmonic and third harmonic obviously. The frequency spectrum monitored by resistance strain gauge sensor has weak subharmonic. The experiment investigation also indicates that the vibration signal can not be monitored by resistance strain gauge under the electromagnetic interference conditions, but can be monitored by FBG sensor.%  将光纤布拉格光栅(FBG)传感器和电阻应变片固定在等强度梁上,研究了两种传感器的振动监测性能,总结比较了其优缺点。通过固定在等强度梁末端的电机来产生振动,测试了FBG传感器和电阻应变片监测到随时间变化的振动信号,并分析了振动信号经傅里变换(FFT)的频谱图。实验结果表明,FBG传感器和电阻应变片监测到振动信号的时图基本一致,但是FBG传感器监测到振动信号经FFT变换的频谱图出现较明显的二次谐波和三次谐波,电阻应变仪监测到的频谱图出现的谐波较弱。在实验中还观察到,在有电磁干扰情况下,电阻应变仪监测不到振动信号,而FBG传感器正常工作,不受电磁干扰。

  6. Electric field induced lattice strain in pseudocubic Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-modified BaTiO{sub 3}-BiFeO{sub 3} piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Ichiro, E-mail: ifujii@rins.ryukoku.ac.jp [Department of Materials Chemistry, Ryukoku University, Otsu, Shiga 520-2194 (Japan); Iizuka, Ryo; Ueno, Shintaro; Nakashima, Kouichi; Wada, Satoshi [Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi, Kofu, Yamanashi 400-8510 (Japan); Nakahira, Yuki; Sunada, Yuya; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro [Department of Physical Science, Hiroshima University, Higashihiroshima, Hiroshima 739-8526 (Japan)

    2016-04-25

    Contributions to the piezoelectric response in pseudocubic 0.3BaTiO{sub 3}-0.1Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-0.6BiFeO{sub 3} ceramics were investigated by synchrotron X-ray diffraction under electric fields. All of the lattice strain determined from the 110, 111, and 200 pseudocubic diffraction peaks showed similar lattice strain hysteresis that was comparable to the bulk butterfly-like strain curve. It was suggested that the hysteresis of the lattice strain and the lack of anisotropy were related to the complex domain structure and the phase boundary composition.

  7. Hierarchical and Multifunctional Three-dimensional Network of Carbon Nanotubes for Supercapacitor and Strain Sensor Applications

    Science.gov (United States)

    2016-05-19

    Mailing address: Department of Chemistry , Hanyang University, 17 Haengdang- dong, Seongdong-gu, Seoul 133-791, Korea - Phone: +82-2-2220-0945...irrecoverable loss of junctions among CNTs when repetitive strain is applied to the film. Furthermore, various surfactants , mixing parameters, and CNT volume

  8. Temperature-Strain Discrimination Sensor Using a WDM Chirped in-Fibre Bragg Grating and an Extrinsic Fabry-Pérot

    Institute of Scientific and Technical Information of China (English)

    RAO Yun-Jiang; ZENG Xiang-Kai; ZHU Yong; WANG Yi-Ping; ZHU Tao; RAN Zeng-Ling; ZHANG Lin; IAN Bennion

    2001-01-01

    A novel fibre-optic sensing system used for temperature-strain discrimination is presented. This system consists of an extrinsic Fabry-Pérot interferometric sensor (EFPI) and a chirped in-fibre Bragg grating (CFBG) in series.The EFPI and the CFBG are wavelength-division-multiplexed (WDM) to provide strain and temperature infor mation, respectively. The wavelength-shift of the CFBG induced by temperature change in the 1.55 μm region is interrogated with an intensity-based scheme, allowing fast measurement of temperature. The cavity length change of the EFPI is measured in the 1.3μm region, allowing strain to be measured without cross-talk from the temperature sensor, i.e. the CFBG. Experimental results show that the achieved accuracies for strain and temperature measurement are ±20 × 10-6 and ±2°C, respectively.

  9. Multiplexed fibre Fizeau interferometer and fibre Bragg grating sensor system for simultaneous measurement of quasi-static strain and temperature using discrete wavelet transform

    Science.gov (United States)

    Wong, Allan C. L.; Childs, Paul A.; Peng, Gang-Ding

    2006-02-01

    We present a multiplexed fibre Fizeau interferometer (FFI) and fibre Bragg grating (FBG) sensor system for simultaneous measurement of quasi-static strain and temperature. A combined spatial-frequency and wavelength- division multiplexing scheme is employed to multiplex the FFI and FBG sensors. A demodulation technique based on the discrete wavelet transform with signal processing enhancements is used to determine the measurand- induced physical changes of the sensors. The noise associated with the sensor signal is reduced by the block-level-thresholding wavelet denoising method, which is applied via the demodulation technique. This sensor system yields a high accuracy and resolution, and low crosstalk. It is well suited for long-term quasi-static measurements, especially for the structural health monitoring of large-scale structures.

  10. Rheology of Superplastic Ceramics

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Constitutive equation of rheglogy describing a phenomenological level of superplastic deformation as functional correlation between tensor components of stress and strain rate has been analyzed for the case of superplastic ceramic flow. Rheological properties of material are taken into account by means of scalar rheological coefficients of shear and volume viscosity, which are functions of temperature, effective stress (or strain rate) and density of material.

  11. Electrospun Aligned Fibrous Arrays and Twisted Ropes: Fabrication, Mechanical and Electrical Properties, and Application in Strain Sensors

    Science.gov (United States)

    Zheng, Jie; Yan, Xu; Li, Meng-Meng; Yu, Gui-Feng; Zhang, Hong-Di; Pisula, Wojciech; He, Xiao-Xiao; Duvail, Jean-Luc; Long, Yun-Ze

    2015-12-01

    Electrospinning (e-spinning) is a versatile technique to fabricate ultrathin fibers from a rich variety of functional materials. In this paper, a modified e-spinning setup with two-frame collector is proposed for the fabrication of highly aligned arrays of polystyrene (PS) and polyvinylidene fluoride (PVDF) nanofibers, as well as PVDF/carbon nanotube (PVDF/CNT) composite fibers. Especially, it is capable of producing fibrous arrays with excellent orientation over a large area (more than 14 cm × 12 cm). The as-spun fibers are suspended and can be easily transferred to other rigid or flexible substrates. Based on the aligned fibrous arrays, twisted long ropes are also prepared. Compared with the aligned arrays, twisted PVDF/CNT fiber ropes show enhanced mechanical and electrical properties and have potential application in microscale strain sensors.

  12. On Ceramics.

    Science.gov (United States)

    School Arts, 1982

    1982-01-01

    Presents four ceramics activities for secondary-level art classes. Included are directions for primitive kiln construction and glaze making. Two ceramics design activities are described in which students make bizarrely-shaped lidded jars, feet, and footwear. (AM)

  13. Amperometric NOx-sensor for Combustion Exhaust Gas Control. Studies on transport properties and catalytic activity of oxygen permeable ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Romer, E.W.J.

    2001-04-27

    , the two materials must be co-firable and, hence, match in thermal, chemical and mechanical behaviour. A number of studies on different mixed oxygen ion/electron conducting materials is described in this thesis. Emphasis is put on the demands of the targeted sensor application, in which these materials are used as mixed conducting dense ceramic membranes. In Chapter 2, a series of perovskite materials is studied. The general composition is ABO{sub 3-{delta}} (A = Gd, Pr, Y; B = Mn, Cr, Fe), being partially doped with Ca{sup 2+} and Sr{sup 2+} on the A-site to create mobile oxygen vacancies. The main focus of the work presented is on the measurement of catalytic activities towards NOx and the ionic conductivities of the selected materials. In Chapter 3, the preparation and characterisation of a material with the overall composition of Gd{sub 0.7}Ca{sub 0.3}CoO{sub x} is described. Dual phase composite membranes are the subject of investigations presented in Chapters 4-7. The main advantage of these type of materials is that their properties can be tailored to meet the demands imposed by the sensor design. Emphasis is on the preparation of the materials, characterisation by SEM-EDX, XRD, catalytic activity and measurement of ionic/electronic conductivities. In Chapter 4, dual phase composites of composition Gd{sub 0.7}Ca{sub 0.3}CoO{sub x}/Ce{sub 0.8}Gd{sub 0.2}O{sub 2-} are studied. Composites ZrO{sub 2}/In{sub 2}O{sub 3} and ZrO{sub 2}/ITO are subject to the investigations reported in Chapters 5 and 6, respectively. Finally, in Chapter 7, composite Au/YSZ and Au/Ce{sub 0.8}Gd{sub 0.2}O{sub 2-} membranes are studied. Finally, in Chapter 8 a summary of the results is given together with recommendations for future research.

  14. Real-time In-Flight Strain and Deflection Monitoring with Fiber Optic Sensors

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Ko, William L.; Piazza, Anthony

    2008-01-01

    This viewgraph presentation reviews Dryden's efforts to develop in-flight monitoring based on Fiber Optics. One of the motivating factors for this development was the breakup of the Helios aircraft. On Ikhana the use of fiber optics for wing shape sensing is being developed. They are being used to flight validate fiber optic sensor measurements and real-time wing shape sensing predictions on NASA's Ikhana vehicle; validate fiber optic mathematical models and design tools; Assess technical viability and, if applicable, develop methodology and approach to incorporate wing shape measurements within the vehicle flight control system, and develop and flight validate advanced approaches to perform active wing shape control.

  15. Fiber Bragg-grating strain sensor interrogation using laser radio-frequency modulation.

    Science.gov (United States)

    Gagliardi, G; Salza, M; Ferraro, P; De Natale, P

    2005-04-04

    We demonstrate the possibility of using radio-frequency modulation spectroscopic techniques for interrogation of fiber Bragg-grating (FBG) structures. Sidebands at 2 GHz are superimposed onto the output spectrum of a 1560-nm DFB diode laser. The power reflected by an FBG is demodulated at multiples of the sideband frequency. The sideband-to-carrier beat signal is shown to be extremely sensitive to Bragg wavelength shifts due to mechanical stress. Using this method, both static and dynamic strain measurements can be performed, with a noise-equivalent sensitivity of the order of 150 nepsilon/ radicalHz, in the quasi-static domain (2 Hz), and 1.6 nepsilon/ radicalHz at higher frequencies (1 kHz). The measured frequency response is presently limited at 20 kHz only by the test device bandwidth. A long-term reproducibility in strain measurements within 100 nepsilon is estimated from laser frequency drift referred to molecular absorption lines.

  16. Temperature-dependent strain and temperature sensitivities of fused silica single mode fiber sensors with pulse pre-pump Brillouin optical time domain analysis

    Science.gov (United States)

    Bao, Yi; Chen, Genda

    2016-06-01

    This paper reports a distributed temperature and strain sensor based on pulse pre-pump Brillouin optical time domain analysis. An uncoated, telecom-grade fused silica single-mode fiber as a distributed sensor was calibrated for its sensitivity coefficients under various strains and temperatures up to 800 °C. The Brillouin frequency of fiber samples changed nonlinearly with temperature and linearly with strain. The temperature sensitivity decreased from 1.113 to 0.830 MHz /°C in the range of 22-800 °C. The strain sensitivity was reduced from 0.054 to 0.042 MHz /μɛ as the temperature increased from 22 to 700 °C and became unstable at higher temperatures due to creep effect. The strain measurement range was reduced from 19 100 to 6000 μɛ in the temperature range of 22-800 °C due to fused silica’s degradation. The calibrated fiber optic sensor demonstrated adequate accuracy and precision for strain and temperature measurements and stable performance in heating-cooling cycles. It was validated in an application setting.

  17. Simplified sensor design for temperature-strain discrimination using fiber Bragg gratings embedded in laminated composites

    Science.gov (United States)

    Rodriguez-Cobo, L.; Marques, A. T.; Lopez-Higuera, J. M.; Santos, J. L.; Frazão, O.

    2013-05-01

    Several easy-to-manufacture designs based on a pair of Fiber Bragg Gratings structure embedded in Carbon Fiber Reinforced Plastic (CFRP) have been explored. These smart composites can be used for strain and temperature discrimination. A Finite Elements Analysis and Matlab software were used to study the mechanical responses and its optical behaviors. The results exhibited different sensitivity and using a matrix method it is possible to compensate the thermal drift in a real application keeping a simple manufacture process.

  18. Sampling optimization for high-speed weigh-in-motion measurements using in-pavement strain-based sensors

    Science.gov (United States)

    Zhang, Zhiming; Huang, Ying; Bridgelall, Raj; Palek, Leonard; Strommen, Robert

    2015-06-01

    Weigh-in-motion (WIM) measurement has been widely used for weight enforcement, pavement design, freight management, and intelligent transportation systems to monitor traffic in real-time. However, to use such sensors effectively, vehicles must exit the traffic stream and slow down to match their current capabilities. Hence, agencies need devices with higher vehicle passing speed capabilities to enable continuous weight measurements at mainline speeds. The current practices for data acquisition at such high speeds are fragmented. Deployment configurations and settings depend mainly on the experiences of operation engineers. To assure adequate data, most practitioners use very high frequency measurements that result in redundant samples, thereby diminishing the potential for real-time processing. The larger data memory requirements from higher sample rates also increase storage and processing costs. The field lacks a sampling design or standard to guide appropriate data acquisition of high-speed WIM measurements. This study develops the appropriate sample rate requirements as a function of the vehicle speed. Simulations and field experiments validate the methods developed. The results will serve as guidelines for future high-speed WIM measurements using in-pavement strain-based sensors.

  19. Electromagnetic functionalized micro-ribbons and ropes for strain sensors via UV-assisted solvent-free electrospinning

    Science.gov (United States)

    He, Xiao-Xiao; Yu, Gui-Feng; Wang, Xiao-Xiong; Zhang, Jun; Zheng, Jie; Yu, Miao; Ning, Xin; Long, Yun-Ze

    2017-10-01

    Electromagnetic functionalized polyaniline/polyurethane acrylate/Fe3O4 (PANI/PUA/Fe3O4) micro-ribbons have been fabricated by UV-assisted solvent-free electrospinning. Herein, two strategies are used to fabricate the composite. One involves the direct electrospinning of PANI/PUA/Fe3O4 ribbons (the one-step method), the other involves electrospinning the PUA/Fe3O4 ribbons first, followed by the in situ polymerization of PANI on the surface of the PUA/Fe3O4 ribbons (the two-step method). The conductivity of the PANI/PUA/Fe3O4 composite produced via the two-step method can reach 2.04  ×  10‑3 S·cm‑1, which is 7.5  ×  102 times higher than that of the composite made via the one-step method. In particular, strain sensors based on PANI/PUA/Fe3O4 micro-ropes show a linear response to the applied strain from 0% to 199.9%, as well as a quick and repeatable response to pressure and finger motion. Meanwhile, the electromagnetic functionalized ribbons exhibit superparamagnetic behavior at 300 K. This work will provide an efficient and eco-friendly approach to fabricating multi-functional composites and devices.

  20. Ceramic MEMS Designed for Wireless Pressure Monitoring in the Industrial Environment

    Directory of Open Access Journals (Sweden)

    Marko Pavlin

    2011-12-01

    Full Text Available This paper presents the design of a wireless pressure-monitoring system for harsh-environment applications. Two types of ceramic pressure sensors made with a low-temperature cofired ceramic (LTCC were considered. The first type is a piezoresistive strain gauge pressure sensor. The second type is a capacitive pressure sensor, which is based on changes of the capacitance values between two electrodes: one electrode is fixed and the other is movable under an applied pressure. The design was primarily focused on low power consumption. Reliable operation in the presence of disturbances, like electromagnetic interference, parasitic capacitances, etc., proved to be contradictory constraints. A piezoresistive ceramic pressure sensor with a high bridge impedance was chosen for use in a wireless pressure-monitoring system and an acceptable solution using energy-harvesting techniques has been achieved. The described solution allows for the integration of a sensor element with an energy harvester that has a printed thick-film battery and complete electronics in a single substrate packaged inside a compact housing.

  1. A transgenic sensor strain for monitoring the RNAi pathway in the yellow fever mosquito, Aedes aegypti

    OpenAIRE

    Adelman, Zach N.; Anderson, Michelle A. E.; Morazzani, Elaine M.; Kevin M. Myles

    2008-01-01

    The RNA interference pathway functions as an antiviral defense in invertebrates. In order to generate a phenotypic marker which “senses” the status of the RNAi pathway in Aedes aegypti, transgenic strains were developed to express EGFP and DsRED marker genes in the eye, as well as double-stranded RNA homologous to a portion of the EGFP gene. Transgenic “sensor” mosquitoes exhibited robust eye-specific DsRED expression with little EGFP, indicating RNAi-based silencing. Cloning and high-through...

  2. Mushroom body miscellanea: transgenic Drosophila strains expressing anatomical and physiological sensor proteins in Kenyon cells.

    Science.gov (United States)

    Pech, Ulrike; Dipt, Shubham; Barth, Jonas; Singh, Priyanka; Jauch, Mandy; Thum, Andreas S; Fiala, André; Riemensperger, Thomas

    2013-01-01

    The fruit fly Drosophila melanogaster represents a key model organism for analyzing how neuronal circuits regulate behavior. The mushroom body in the central brain is a particularly prominent brain region that has been intensely studied in several insect species and been implicated in a variety of behaviors, e.g., associative learning, locomotor activity, and sleep. Drosophila melanogaster offers the advantage that transgenes can be easily expressed in neuronal subpopulations, e.g., in intrinsic mushroom body neurons (Kenyon cells). A number of transgenes has been described and engineered to visualize the anatomy of neurons, to monitor physiological parameters of neuronal activity, and to manipulate neuronal function artificially. To target the expression of these transgenes selectively to specific neurons several sophisticated bi- or even multipartite transcription systems have been invented. However, the number of transgenes that can be combined in the genome of an individual fly is limited in practice. To facilitate the analysis of the mushroom body we provide a compilation of transgenic fruit flies that express transgenes under direct control of the Kenyon-cell specific promoter, mb247. The transgenes expressed are fluorescence reporters to analyze neuroanatomical aspects of the mushroom body, proteins to restrict ectopic gene expression to mushroom bodies, or fluorescent sensors to monitor physiological parameters of neuronal activity of Kenyon cells. Some of the transgenic animals compiled here have been published already, whereas others are novel and characterized here for the first time. Overall, the collection of transgenic flies expressing sensor and reporter genes in Kenyon cells facilitates combinations with binary transcription systems and might, ultimately, advance the physiological analysis of mushroom body function.

  3. Can a wearable strain sensor based on a carbon nanotube network be an alternative to an isokinetic dynamometer for the measurement of knee-extensor muscle strength?

    Science.gov (United States)

    Benlikaya, Ruhan; Ege, Yavuz; Pündük, Zekine; Slobodian, Petr; Meriç, Gökhan

    2017-04-01

    This study aimed to find out whether a wearable strain sensor including thermoplastic polyurethane composite with a multi-walled carbon nanotube network could be a viable alternative to an isokinetic dynamometer for the measurement of knee-extensor muscle strength. For the first time, the voltage-torque and angle–time relations of the sensor were determined to allow a comparison between the angle-dependent torque changes of the dynamometer and the sensor. This comparison suggested that the torque–angle relations of the dynamometer and the sensor did not have the same characteristics. In this regard, the sensor may be used in the torque measurements due to the moderate correlation between the torque values determined via the isokinetic dynamometer and the sensor and due to the significant difference between low and high torque values of the sensor. By the same token, the torque-angle graph of the sensor may be more informative than that of the dynamometer in evaluation of knee problems.

  4. Truly Distributed Optical Fiber Sensors for Structural Health Monitoring: From the Telecommunication Optical Fiber Drawling Tower to Water Leakage Detection in Dikes and Concrete Structure Strain Monitoring

    Directory of Open Access Journals (Sweden)

    Jean-Marie Henault

    2010-01-01

    Full Text Available Although optical fiber sensors have been developed for 30 years, there is a gap between lab experiments and field applications. This article focuses on specific methods developed to evaluate the whole sensing chain, with an emphasis on (i commercially-available optoelectronic instruments and (ii sensing cable. A number of additional considerations for a successful pairing of these two must be taken into account for successful field applications. These considerations are further developed within this article and illustrated with practical applications of water leakage detection in dikes and concrete structures monitoring, making use of distributed temperature and strain sensing based on Rayleigh, Raman, and Brillouin scattering in optical fibers. They include an adequate choice of working wavelengths, dedicated localization processes, choices of connector type, and further include a useful selection of traditional reference sensors to be installed nearby the optical fiber sensors, as well as temperature compensation in case of strain sensing.

  5. Performance of low-cost few-mode fiber Bragg grating sensor systems: polarization sensitivity and linearity of temperature and strain response

    DEFF Research Database (Denmark)

    Ganziy, Denis; Rose, Bjarke; Bang, Ole

    2016-01-01

    We evaluate whether 850 nm fiber Bragg grating (FBG) sensor systems can use low-cost 1550 nm telecom fibers; in other words, how detrimental the influence of higher-order modes is to the polarization stability and linearity of the strain and temperature response. We do this by comparing...... polarization sensitivity of a few-mode 850 nm FBG sensor to a strictly single-mode 850 nm FBG sensor system using 850 nm single-mode fibers. We also compare the performance of the FBGs in strain and temperature tests. Our results show that the polarization stability and the linearity of the response degrade...... due to the presence of the higher-order modes. We demonstrate that, by using simple coiling of the 1550 nm fiber, one can regain the performance of the few-mode system and make it usable for high precision measurements....

  6. Ultra-high density out-of-plane strain sensor 3D architecture based on sub-20 nm PMOS FinFET

    KAUST Repository

    Ghoneim, Mohamed T.

    2016-02-03

    Future wearable electronics require not only flexibility but also preservation of the perks associated with today\\'s high-performance, traditional silicon electronics. In this work we demonstrate a state-of-the-art fin-shaped field-effect transistor (FinFET)-based, out-of-plane strain sensor on flexible silicon through transforming the bulk device in a transfer-less process. The device preserves the functionality and high performance associated with its bulk, inflexible state. Furthermore, gate leakage current shows sufficient dependence on the value of the applied out-of-plane strain that enables permits use of the flexible device as a switching device as well as a strain sensor.

  7. Evaluation of the applicability of optical fiber strain sensors for monitoring rock deformation caused by ocean tide -a case study at the Aburatsubo site, Japan-

    Science.gov (United States)

    Matsui, H.; Kashiwai, Y.; Sano, O.; Tokunaga, T.; He, Z.; Mogi, K.; Wang, H. F.

    2009-12-01

    Monitoring rock deformation with high resolution is one of the essential factors for crustal deformation studies. Extensometers with several tens of meters long and inclinometer with similar length have been used as conventional monitoring methods. Because these large scale sensors require vast space for monitoring, it is difficult to distribute many monitoring points with high density. It is also difficult to conduct spatially high resolution monitoring. These limits on present monitoring methods make it difficult to evaluate the effects of heterogeneity of the rock masses and of the existence of fractures on the measured behavior of rock masses. In other words, scale dependency of rock deformation has not yet been studied through in-situ data. Thus, the small sensors with high resolution are required. We are planning to develop an ultra-high resolution sensor based on the optical fiber sensing technology in the three-year period. The optical fiber sensor has advantages against conventional electric sensors; long term stability, flexibility of incorporating many types of sensors on a single data acquisition cable, and a future promise for the methods to become even better, cheaper, and faster. The Fiber Bragg Grating (FBG) sensing technology is chosen as a potential method out of many kinds of optical fiber sensing methods, and a pair of commercially available FBG sensors were deployed in the Aburatsubo Earthquake Observation Center, the Earthquake Research Institute, University of Tokyo, for verifying their resolution and stability. According to the strain measurements by conventional extensometers at the Aburatsubo site, deformation on the order of 10-7 strain caused by ocean tides is observed. Purpose of the first stage of this developing work is to evaluate the commercially available FBG sensor and to study the feasibility for developing the precise small sensor for rock mechanics study. The FBG sensor successfully monitored the deformations caused by ocean

  8. Constructing of cure monitoring system with piezoelectric ceramics for composite laminate

    Science.gov (United States)

    Oshima, Nobuo; Inoue, Kouichi; Motogi, Shinya; Fukuda, Takehito

    2003-08-01

    The cure monitoring system with piezoelectric ceramics is constructed. An embedded type piezoelectric ceramics sensor with flat lead wires is developed. And the piezoelectric ceramics is embedded into composite laminate. A dummy piezoelectric ceramics is set in the autoclave oven. The impedance of the piezoelectric ceramics which is embedded in the composite laminate and that of the dummy piezoelectric ceramics are measured by a LCR meter. The piezoelectric ceramics have strong temperature dependency. The temperature dependency of the impedance of piezoelectric ceramics is corrected by the information from the dummy piezoelectric ceramics. A dielectric sensor is also embedded in the composite laminate as a reference sensor for the degree of cure. The change in calculated cure index shows good correspondence with change in the log ion viscosity which is measured by the dielectric cure monitoring sensor.

  9. Ceramic joining

    Energy Technology Data Exchange (ETDEWEB)

    Loehman, R.E. [Sandia National Lab., Albuquerque, NM (United States)

    1996-04-01

    This paper describes the relation between reactions at ceramic-metal interfaces and the development of strong interfacial bonds in ceramic joining. Studies on a number of systems are described, including silicon nitrides, aluminium nitrides, mullite, and aluminium oxides. Joints can be weakened by stresses such as thermal expansion mismatch. Ceramic joining is used in a variety of applications such as solid oxide fuel cells.

  10. Ceramic Processing

    Energy Technology Data Exchange (ETDEWEB)

    EWSUK,KEVIN G.

    1999-11-24

    Ceramics represent a unique class of materials that are distinguished from common metals and plastics by their: (1) high hardness, stiffness, and good wear properties (i.e., abrasion resistance); (2) ability to withstand high temperatures (i.e., refractoriness); (3) chemical durability; and (4) electrical properties that allow them to be electrical insulators, semiconductors, or ionic conductors. Ceramics can be broken down into two general categories, traditional and advanced ceramics. Traditional ceramics include common household products such as clay pots, tiles, pipe, and bricks, porcelain china, sinks, and electrical insulators, and thermally insulating refractory bricks for ovens and fireplaces. Advanced ceramics, also referred to as ''high-tech'' ceramics, include products such as spark plug bodies, piston rings, catalyst supports, and water pump seals for automobiles, thermally insulating tiles for the space shuttle, sodium vapor lamp tubes in streetlights, and the capacitors, resistors, transducers, and varistors in the solid-state electronics we use daily. The major differences between traditional and advanced ceramics are in the processing tolerances and cost. Traditional ceramics are manufactured with inexpensive raw materials, are relatively tolerant of minor process deviations, and are relatively inexpensive. Advanced ceramics are typically made with more refined raw materials and processing to optimize a given property or combination of properties (e.g., mechanical, electrical, dielectric, optical, thermal, physical, and/or magnetic) for a given application. Advanced ceramics generally have improved performance and reliability over traditional ceramics, but are typically more expensive. Additionally, advanced ceramics are typically more sensitive to the chemical and physical defects present in the starting raw materials, or those that are introduced during manufacturing.

  11. 基于高温烧结氧化铝陶瓷的无线无源温度传感器%Wireless Passive Temperature Sensor Based on High Temperature Sintering Alumina Ceramic

    Institute of Scientific and Technical Information of China (English)

    任重; 谭秋林; 李晨; 郑庭丽; 蔡婷; 熊继军

    2014-01-01

    A wireless passive temperature sensor based on Alumina ceramic is designed and fabricated,where the alumina ceramic substrate is obtained with the overall size of 28 mmí28 mmí0 . 47 mm through high temperature sintering technology,and passive LC series resonant circuit is printed on the substrate by thick film technology. A wireless test on the sensor is achieved under the temperature from 18 ℃ to 300 ℃. The results show that the temperature sensor demonstrates good linear characteristics, large linear range and low non-linear error. The sensitivity of the sensor on resonant frequency to temperature is about 2 . 75 kHz/℃. It can be applied to detect high temperature in harsh environments.%通过高温烧结技术获得了总体尺寸为28 mm×28 mm×0.47 mm的氧化铝陶瓷基板,结合厚膜技术在该基板上印刷无源LC串联谐振电路,设计并制备了一种基于氧化铝陶瓷的无线无源温度传感器。在18℃~300℃的温度范围内实现了传感器的无线测试,测试结果表明该温度传感器呈现出了良好的线性特征,线性范围大且非线性误差小,其谐振频率对温度的灵敏度约为2.75 kHz/℃,可应用于高温恶劣环境下的温度检测。

  12. Primate drum kit: a system for studying acoustic pattern production by non-human primates using acceleration and strain sensors.

    Science.gov (United States)

    Ravignani, Andrea; Matellán Olivera, Vicente; Gingras, Bruno; Hofer, Riccardo; Rodríguez Hernández, Carlos; Sonnweber, Ruth-Sophie; Fitch, W Tecumseh

    2013-07-31

    The possibility of achieving experimentally controlled, non-vocal acoustic production in non-human primates is a key step to enable the testing of a number of hypotheses on primate behavior and cognition. However, no device or solution is currently available, with the use of sensors in non-human animals being almost exclusively devoted to applications in food industry and animal surveillance. Specifically, no device exists which simultaneously allows: (i) spontaneous production of sound or music by non-human animals via object manipulation, (ii) systematical recording of data sensed from these movements, (iii) the possibility to alter the acoustic feedback properties of the object using remote control. We present two prototypes we developed for application with chimpanzees (Pan troglodytes) which, while fulfilling the aforementioned requirements, allow to arbitrarily associate sounds to physical object movements. The prototypes differ in sensing technology, costs, intended use and construction requirements. One prototype uses four piezoelectric elements embedded between layers of Plexiglas and foam. Strain data is sent to a computer running Python through an Arduino board. A second prototype consists in a modified Wii Remote contained in a gum toy. Acceleration data is sent via Bluetooth to a computer running Max/MSP. We successfully pilot tested the first device with a group of chimpanzees. We foresee using these devices for a range of cognitive experiments.

  13. Primate Drum Kit: A System for Studying Acoustic Pattern Production by Non-Human Primates Using Acceleration and Strain Sensors

    Directory of Open Access Journals (Sweden)

    W. Tecumseh Fitch

    2013-07-01

    Full Text Available The possibility of achieving experimentally controlled, non-vocal acoustic production in non-human primates is a key step to enable the testing of a number of hypotheses on primate behavior and cognition. However, no device or solution is currently available, with the use of sensors in non-human animals being almost exclusively devoted to applications in food industry and animal surveillance. Specifically, no device exists which simultaneously allows: (i spontaneous production of sound or music by non-human animals via object manipulation, (ii systematical recording of data sensed from these movements, (iii the possibility to alter the acoustic feedback properties of the object using remote control. We present two prototypes we developed for application with chimpanzees (Pan troglodytes which, while fulfilling the aforementioned requirements, allow to arbitrarily associate sounds to physical object movements. The prototypes differ in sensing technology, costs, intended use and construction requirements. One prototype uses four piezoelectric elements embedded between layers of Plexiglas and foam. Strain data is sent to a computer running Python through an Arduino board. A second prototype consists in a modified Wii Remote contained in a gum toy. Acceleration data is sent via Bluetooth to a computer running Max/MSP. We successfully pilot tested the first device with a group of chimpanzees. We foresee using these devices for a range of cognitive experiments.

  14. An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Yun Tu

    2017-02-01

    Full Text Available Local strain measurements are considered as an effective method for structural health monitoring of high-temperature components, which require accurate, reliable and durable sensors. To develop strain sensors that can be used in higher temperature environments, an improved metal-packaged strain sensor based on a regenerated fiber Bragg grating (RFBG fabricated in hydrogen (H2-loaded boron–germanium (B–Ge co-doped photosensitive fiber is developed using the process of combining magnetron sputtering and electroplating, addressing the limitation of mechanical strength degradation of silica optical fibers after annealing at a high temperature for regeneration. The regeneration characteristics of the RFBGs and the strain characteristics of the sensor are evaluated. Numerical simulation of the sensor is conducted using a three-dimensional finite element model. Anomalous decay behavior of two regeneration regimes is observed for the FBGs written in H2-loaded B–Ge co-doped fiber. The strain sensor exhibits good linearity, stability and repeatability when exposed to constant high temperatures of up to 540 °C. A satisfactory agreement is obtained between the experimental and numerical results in strain sensitivity. The results demonstrate that the improved metal-packaged strain sensors based on RFBGs in H2-loaded B–Ge co-doped fiber provide great potential for high-temperature applications by addressing the issues of mechanical integrity and packaging.

  15. An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

    Science.gov (United States)

    Tu, Yun; Ye, Lin; Zhou, Shao-Ping; Tu, Shan-Tung

    2017-01-01

    Local strain measurements are considered as an effective method for structural health monitoring of high-temperature components, which require accurate, reliable and durable sensors. To develop strain sensors that can be used in higher temperature environments, an improved metal-packaged strain sensor based on a regenerated fiber Bragg grating (RFBG) fabricated in hydrogen (H2)-loaded boron–germanium (B–Ge) co-doped photosensitive fiber is developed using the process of combining magnetron sputtering and electroplating, addressing the limitation of mechanical strength degradation of silica optical fibers after annealing at a high temperature for regeneration. The regeneration characteristics of the RFBGs and the strain characteristics of the sensor are evaluated. Numerical simulation of the sensor is conducted using a three-dimensional finite element model. Anomalous decay behavior of two regeneration regimes is observed for the FBGs written in H2-loaded B–Ge co-doped fiber. The strain sensor exhibits good linearity, stability and repeatability when exposed to constant high temperatures of up to 540 °C. A satisfactory agreement is obtained between the experimental and numerical results in strain sensitivity. The results demonstrate that the improved metal-packaged strain sensors based on RFBGs in H2-loaded B–Ge co-doped fiber provide great potential for high-temperature applications by addressing the issues of mechanical integrity and packaging. PMID:28241465

  16. Experimental Method of Temperature and Strain Discrimination in Polymer Composite Material by Embedded Fiber-Optic Sensors Based on Femtosecond-Inscribed FBGs

    Directory of Open Access Journals (Sweden)

    Victor V. Shishkin

    2016-01-01

    Full Text Available Experimental method of temperature and strain discrimination with fiber Bragg gratings (FBGs sensors embedded in carbon fiber-reinforced plastic is proposed. The method is based on two-fiber technique, when two FBGs inscribed in different fibers with different sensitivities to strain and/or temperature are placed close to each other and act as a single sensing element. The nonlinear polynomial approximation of Bragg wavelength shift as a function of temperature and strain is presented for this method. The FBGs were inscribed with femtosecond laser by point-by-point inscription technique through polymer cladding of the fiber. The comparison of linear and nonlinear approximation accuracies for array of embedded sensors is performed. It is shown that the use of nonlinear approximation gives 1.5–2 times better accuracy. The obtained accuracies of temperature and strain measurements are 2.6–3.8°C and 50–83 με in temperature and strain range of 30–120°C and 0–400 με, respectively.

  17. Multi-point strain and displacement sensor based on intensity-modulated light and two-photon absorption process in Si-avalanche photodiode

    Science.gov (United States)

    Miyazawa, Hiromasa; Nemoto, Masaya; Yamada, Yoshiki; Tanaka, Yosuke; Kurokawa, Takashi

    2017-04-01

    We propose a system for precise measurement of multi-point displacement and strain using fiber Bragg grating (FBG) sensors along with intensity-modulated light and two-photon absorption process in a Si-avalanche photodiode (Si-APD). This method sweeps both the optical wavelength and the phase difference between the two modulation signals. The FBGs' reflection spectra and their change due to strain are successfully observed at the same time with the precision measurement of the FBG's displacement, where the relative measurement uncertainty is 10-4. This fiber sensing system is especially suitable for structural health monitoring.

  18. 基于氧化铝陶瓷的电容式高温压力传感器%A Capacitive High Temperature Pressure Sensor Based on Alumina Ceramic

    Institute of Scientific and Technical Information of China (English)

    李晨; 谭秋林; 张文栋; 薛晨阳; 贾平岗; 李运芝; 熊继军

    2014-01-01

    氧化铝陶瓷因其稳定的机械性能和高温鲁棒性得到了广泛的应用。文章以LC谐振电路为技术背景,提出了一种基于氧化铝陶瓷的电容式高温压力传感器,并通过厚膜集成工艺技术将一个定值电感与一个可变电容集成在氧化铝陶瓷基板上实现了传感器的制备。对传感器进行高温环境下的压力测试,实验结果表明:传感器能够完成600℃高温环境下1到5 bar范围内压力的原位测试,且在600℃高温环境下传感器的重复性误差,迟滞性误差和零点漂移分别为8.3%,5.05%和3.7%。%Alumina ceramic has wide applications with its stable mechanical toughness and high temperature robust-ness. In the technical background of LC resonance circuit,this paper presents a capacitance high temperature pres-sure sensor based on alumina ceramics.A fixed inductance and a varied capacitance were integrated on the ceramic substrate through the thick film integrated technology.The sensor was tested in high temperature and pressure envi-ronments,and the experimental results shown that:the sensor can complete the pressure situ test at 600 ℃in range of 1 to 5 bar,and the repeatability error,hysteresis error and zero drift of the sensor were approximately 8. 3%,5�05% and 3.7%,respectively.

  19. 基于陶瓷微热板的高温气体传感器研究%Study of high-temperature gas sensor based on ceramic micro-hot-plate

    Institute of Scientific and Technical Information of China (English)

    薛严冰; 唐祯安

    2011-01-01

    针对目前商用陶瓷气体传感器功耗大、封装困难等缺点,提出一种陶瓷微加工微热板式气体传感器的结构和无内引线封装的方式。通过光刻剥离的方法,在氧化铝陶瓷基底上制作出Pt微加热器及接触电极。采用激光微细加工技术,制作出不同结构参数的陶瓷微热板器件。从温度同加热功率的关系、热响应时间和微加热器稳定性等方面对微热板进行了测试和评价。结果表明,陶瓷微热板具有较低功耗和高温工作的优势,可稳定工作的温度达到600℃。作为热板的高温应用之一,研制了CH4气体传感器,在500℃的工作条件下,对CH4气有很好响应灵敏度,且对CO%A novel gas sensor based on micro-machined ceramic hot-plate and wire-free bonding is presented to overcome the shortcomings of high power consumption and packaging difficulty existing in the current commercial ceramic gas sensors.The Pt heater and contact electrodes were sputtered on alumina substrate by controlled lift-off processing.The devices with different parameters were fabricated using the laser micro-machining technique.The performance of the hot-plate was tested and evaluated from the following aspects:the relationship between temperature and heating power,thermal response time and the stability of the heater.The results show that the ceramic hot plates have advantages of lower power consumption and higher working temperature,and they can steadily work at temperature of 600 ℃.As one of the applications of the hot-plate working in high temperature,CH4 gas sensors were developed.The sensors have high sensitivity to CH4 under 500 ℃,and basically have no response to the interfering gas of CO.

  20. [Ceramic posts].

    Science.gov (United States)

    Mainjot, Amélie; Legros, Caroline; Vanheusden, Alain

    2006-01-01

    As a result of ceramics and all-ceram technologies development esthetic inlay core and abutments flooded the market. Their tooth-colored appearance enhances restoration biomimetism principally on the marginal gingiva area. This article reviews indications and types of cores designed for natural teeth and implants.

  1. Ceramic Methyltrioxorhenium

    CERN Document Server

    Herrmann, R; Eickerling, G; Helbig, C; Hauf, C; Miller, R; Mayr, F; Krug von Nidda, H A; Scheidt, E W; Scherer, W; Herrmann, Rudolf; Troester, Klaus; Eickerling, Georg; Helbig, Christian; Hauf, Christoph; Miller, Robert; Mayr, Franz; Nidda, Hans-Albrecht Krug von; Scheidt, Ernst-Wilhelm; Scherer, Wolfgang

    2006-01-01

    The metal oxide polymeric methyltrioxorhenium [(CH3)xReO3] is an unique epresentative of a layered inherent conducting organometallic polymer which adopts the structural motifs of classical perovskites in two dimensions (2D) in form of methyl-deficient, corner-sharing ReO5(CH3) octahedra. In order to improve the characteristics of polymeric methyltrioxorhenium with respect to its physical properties and potential usage as an inherentconducting polymer we tried to optimise the synthetic routes of polymeric modifications of 1 to obtain a sintered ceramic material, denoted ceramic MTO. Ceramic MTO formed in a solvent-free synthesis via auto-polymerisation and subsequent sintering processing displays clearly different mechanical and physical properties from polymeric MTO synthesised in aqueous solution. Ceramic MTO is shown to display activated Re-C and Re=O bonds relative to MTO. These electronic and structural characteristics of ceramic MTO are also reflected by a different chemical reactivity compared with its...

  2. High-Temperature Performance of Wireless Passive Pressure Sensor Based on Alumina Ceramic%氧化铝陶瓷基无线无源压力传感器的高温性能研究

    Institute of Scientific and Technical Information of China (English)

    任重; 蔡婷; 谭秋林; 李晨; 郑庭丽; 熊继军

    2014-01-01

    利用高温烧结陶瓷技术制备了一种基于氧化铝陶瓷的LC谐振式无线无源压力传感器,并通过合理地设计圆柱螺旋天线以及隔热结构,实现了该传感器在高温环境中的无线耦合测试。研究了传感器在不同温度下的阻抗频率特性,分析并探讨了传感器的高温性能。测试结果表明,在29℃(室温)至700℃的温度范围内,测试天线端的最高瞬时温度为188.4℃,保证了传感器高温测试的可靠性。谐振频率对温度的平均变化量为1.314 kHz/℃,两次重复性测试的相对变化量为3.81%,重复性较好。该压力传感器可应用于高温恶劣环境下的压力测试,其高温性能的研究为压力信号的准确读取奠定了良好的基础。%A wireless passive LC resonant pressure sensor based on alumina ceramic is fabricated by the high tem-perature sintering ceramic process,and cylindrical helical antenna and a structure of insulation material are designed to realize the wireless coupling test for the sensor in high temperature environment. The high temperature perform-ance of the sensor is analyzed and discussed by studying the impedance-frequency characteristics under different temperatures. The results show that the highest instantaneous temperature of the terminal of the test antenna is 188.4℃ when the temperature is ranged from 29℃( room temperature) to 700℃,which ensures the reliability of the test on the sensor under high temperature. The average change of resonant frequency to temperature is 1.314 kHz/℃, and the relative change of the twice tests is 3.81%,with good reproducibility. The pressure sensor can be used to measure the pressure under high temperature and harsh environment,and the study of the high temperature perform-ance of the sensor laid a good basis for accurately reading the pressure signal.

  3. Compressive properties of open-cell ceramic foams

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-yan; FU Yi-ming; ZENG Xiao-ming

    2006-01-01

    The compressive experiments of two kinds of ceramic foams were completed. The results show that the behavior of ceramic foams made by organic filling method is anisotropic. The stress-strain responses of ceramic foams made by sponge-replication show isotropy and strain rate dependence. The struts brittle breaking of net structure of this ceramic foam arises at the weakest defects of framework or at the part of framework,which causes the initiation and expanding of cracks. The compressive strength of ceramic foam is dependent on the strut size and relative density of foams.

  4. Performance of a Distributed Simultaneous Strain and Temperature Sensor Based on a Fabry-Perot Laser Diode and a Dual-Stage FBG Optical Demultiplexer

    Directory of Open Access Journals (Sweden)

    Shinwon Kang

    2013-11-01

    Full Text Available A simultaneous strain and temperature measurement method using a Fabry-Perot laser diode (FP-LD and a dual-stage fiber Bragg grating (FBG optical demultiplexer was applied to a distributed sensor system based on Brillouin optical time domain reflectometry (BOTDR. By using a Kalman filter, we improved the performance of the FP-LD based OTDR, and decreased the noise using the dual-stage FBG optical demultiplexer. Applying the two developed components to the BOTDR system and using a temperature compensating algorithm, we successfully demonstrated the simultaneous measurement of strain and temperature distributions under various experimental conditions. The observed errors in the temperature and strain measured using the developed sensing system were 0.6 °C and 50 με, and the spatial resolution was 1 m, respectively.

  5. Dynamic Strain Measurements on Automotive and Aeronautic Composite Components by Means of Embedded Fiber Bragg Grating Sensors

    OpenAIRE

    Alfredo Lamberti; Gabriele Chiesura; Geert Luyckx; Joris Degrieck; Markus Kaufmann; Steve Vanlanduit

    2015-01-01

    The measurement of the internal deformations occurring in real-life composite components is a very challenging task, especially for those components that are rather difficult to access. Optical fiber sensors can overcome such a problem, since they can be embedded in the composite materials and serve as in situ sensors. In this article, embedded optical fiber Bragg grating (FBG) sensors are used to analyze the vibration characteristics of two real-life composite components. The first component...

  6. Engineering ceramics

    CERN Document Server

    Bengisu, Murat

    2001-01-01

    This is a comprehensive book applying especially to junior and senior engineering students pursuing Materials Science/ Engineering, Ceramic Engineering and Mechanical Engineering degrees. It is also a reference book for other disciplines such as Chemical Engineering, Biomedical Engineering, Nuclear Engineering and Environmental Engineering. Important properties of most engineering ceramics are given in detailed tables. Many current and possible applications of engineering ceramics are described, which can be used as a guide for materials selection and for potential future research. While covering all relevant information regarding raw materials, processing properties, characterization and applications of engineering ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

  7. Structural Ceramics Database

    Science.gov (United States)

    SRD 30 NIST Structural Ceramics Database (Web, free access)   The NIST Structural Ceramics Database (WebSCD) provides evaluated materials property data for a wide range of advanced ceramics known variously as structural ceramics, engineering ceramics, and fine ceramics.

  8. Comparative determination of physical stress and strain on milkers in milking parlours on dairy farms in Upper Austria, using ECG, an activity sensor and spirometer

    Directory of Open Access Journals (Sweden)

    Magdalena Mayrhofer

    2017-05-01

    Full Text Available To-date, the impact of modern milking parlors in dairy farming on physical strain has not been the subject of many studies. Therefore, this case study aims to record and evaluate the physical strain during the entire milking process, including the oxygen consumption (VO2, heart rate (HR and metabolic rate (WkJ, Watt of milkers. The recording was conducted with a portable respiratory gas analysis system and an ECG and activity sensor on 4 dairy farms in Austria. Eight subjects aged from 45–52 years, with a mean age 50±2.4 SD, participated and the data were recorded during the milking process in 2 types of milking parlours. For assessment, the entire milking process was divided into preparation, milking and follow-up work. The entire milking process was performed with an average oxygen consumption of 46.5 l/h and a heart rate of 98 bpm, which is below the anaerobic threshold; whereas in the preparation and follow-up work, this threshold was exceeded. Generally, during the milking process, a moderate physical strain (32.4% and a balanced metabolic rate (143 watt/m2 were determined. The physical strain in female milkers was 9.2% higher than in male milkers throughout the entire process. Reduction of physical strain can be achieved through additional breaks, reduced work speed, division of labour and technical devices.

  9. Serotype- and strain- dependent contribution of the sensor kinase CovS of the CovRS two-component system to Streptococcus pyogenes pathogenesis

    Directory of Open Access Journals (Sweden)

    Podbielski Andreas

    2010-02-01

    Full Text Available Abstract Background The Streptococcus pyogenes (group A streptococci, GAS two-component signal transduction system CovRS has been described to be important for pathogenesis of this exclusively human bacterial species. If this system acts uniquely in all serotypes is currently unclear. Presence of serotype- or strain-dependent regulatory circuits and polarity is an emerging scheme in Streptococcus pyogenes pathogenesis. Thus, the contribution of the sensor kinase (CovS of the global regulatory two-component signal transduction system CovRS on pathogenesis of several M serotypes was investigated. Results CovS mutation uniformly repressed capsule expression and hampered keratinocyte adherence in all tested serotypes. However, a serotype- and even strain-dependent contribution on survival in whole human blood and biofilm formation was noted, respectively. Conclusions These data provide new information on the action of the CovS sensor kinase and revealed that its activity on capsule expression and keratinocyte adherence is uniform across serotypes, whereas the influence on biofilm formation and blood survival is serotype or even strain dependent. This adds the CovRS system to a growing list of serotype-specific acting regulatory loci in S. pyogenes.

  10. Ultra-Precision Measurement and Control of Angle Motion in Piezo-Based Platforms Using Strain Gauge Sensors and a Robust Composite Controller

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Wu

    2013-07-01

    Full Text Available The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS error of 0.21 μrad, which is approximately equal to the noise level.

  11. Ultra-precision measurement and control of angle motion in piezo-based platforms using strain gauge sensors and a robust composite controller.

    Science.gov (United States)

    Liu, Lei; Bai, Yu-Guang; Zhang, Da-Li; Wu, Zhi-Gang

    2013-07-15

    The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS) and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS) error of 0.21 μrad, which is approximately equal to the noise level.

  12. Qualification of a distributed optical fiber sensor bonded to the surface of a concrete structure: a methodology to obtain quantitative strain measurements

    Science.gov (United States)

    Billon, Astrid; Hénault, Jean-Marie; Quiertant, Marc; Taillade, Frédéric; Khadour, Aghiad; Martin, Renaud-Pierre; Benzarti, Karim

    2015-11-01

    Distributed optical fiber systems (DOFSs) are an emerging and innovative technology that allows long-range and continuous strain/temperature monitoring with a high resolution. Sensing cables are either surface-mounted or embedded into civil engineering structures to ensure long-term structural monitoring and early crack detection. However, strain profiles measured in the optical fiber (OF) may differ from the actual strain in the structure due to the shear transfer through the intermediate material layers between the OF and the host material (i.e., in the protective coating of the sensing cable and in the adhesive). Therefore, OF sensors need to be qualified to provide accurate quantitative strain measurements. This study presents a methodology for the qualification of a DOFS. This qualification is achieved through the calculation of the so-called mechanical transfer function (MTF), which relates the strain profile in the OF to the actual strain profile in the structure. It is proposed to establish a numerical modeling of the system, in which the mechanical parameters are calibrated from experiments. A specific surface-mounted sensing cable connected to an optical frequency domain reflectometry interrogator is considered as a case study. It was found that (i) tensile and pull-out tests can provide detailed information about materials and interfaces of the numerical model; (ii) the calibrated model made it possible to compute strain profiles along the OF and therefore to calculate the MTF of the system; (iii) the results proved to be consistent with experimental data collected on a cracked concrete beam during a four-point bending test. This paper is organized as follows: first, the technical background related to DOFSs and interrogators is briefly recalled, the MTF is defined and the above-mentioned methodology is presented. In the second part, the methodology is applied to a specific cable. Finally, a comparison with experimental evidence validates the proposed

  13. Temperature-independent strain sensor based on a tapered Bragg fibre fabricated using a CO2 laser

    Science.gov (United States)

    Martins, T. J. M.; Marques, M. B.; Roy, P.; Jamier, R.; Février, S.; Frazão, O.

    2016-05-01

    Temperature-independent strain measurement is achieved resorting to a taper fabricated on a Bragg fibre using a CO2 laser. The characteristic bimodal interference of an untapered Bragg fibre is rendered multimode after taper fabrication and the resulting transmission spectra are analysed as temperature and strain change. The intrinsic strain sensitivity exhibited by the Bragg fibre is increased 15 fold after tapering and reaches 22.68 pm/μepsilon. The difference in wavelength shift promoted by variations in temperature and strain for the two fringes studied is examined and strain sensing with little temperature sensitivity is achieved, presenting a sensitivity of 2.86 pm/μepsilon, for strain values up to 400 μepsilon.

  14. 机器人指端应变式触觉传感器%The Robotic Fingertip Tactile Sensor Based on Strain-gauge

    Institute of Scientific and Technical Information of China (English)

    戴士杰; 岳宏; 李慨; 李铁军

    2001-01-01

    叙述了机器人指端应变式触觉传感器的原理、分类和发展,介绍几种典型 的机器人指端应变式触觉传感器,同时提出一种新型的机器人指端应变式触觉传 感器,并对其工作原理进行详细说明.在传感器结构设计中采用合理结构,使被 抓物体的横截面尺寸不受弹性薄板薄板尺寸限制;当超过测量范围时,保证金属 薄板不受破坏,同时实现了柔顺抓握.%The principle、classification and development of robotic fin gertip tactile sensor which use strain-gauge is discussed in details. Several typical robotic fingertip tactile sensors based on strain-gaug e is introduced, meanwhile a new kind robotic fingertip tactile sensor based on strain-gauge is presented, and its work principle is explain ed thoroughly.Using proper construction,the size of the object's cros s section,which is grasped bu the gripper, isn't limited by the size o f the taetile thin metal plate; if the object overweight,then the thin metal plate is insured against damage,meauwhile,the more stable and c ompliant grasp can be realized

  15. Technology of strain measurement based on Fabry-Perot optical fiber sensor in monitoring of civil engineering%土木工程健康监测用F-P光纤应变测量技术

    Institute of Scientific and Technical Information of China (English)

    周智; 边玉明; 田石柱

    2001-01-01

    介绍了基于白光干涉的光纤F-P应变传感器原理,对其用于土木工程健康监测的安装工艺、温度补偿技术进行了研究,提出了工程应用中尚存的问题。%The theory of optical fiber Febry-Perot strain sensor based on white light interferometer is introduced. Then, the technics of installation of F-P strain sensor in civil engineering and the compensating of temperature strain are studied. Finally, some problems are brought forward.

  16. On the optimization of fiber Bragg grating optical sensor using genetic algorithm to monitor the strain of civil structure with high sensitivity

    Science.gov (United States)

    Kaur, Gurpreet; Kaler, Rajinder Singh; Kwatra, Naveen

    2016-08-01

    The effect of strain on civil structures is experimentally studied using fiber Bragg grating (FBG). The genetic algorithm is implemented to optimize the multiple parameters (Poisson's ratio, photoelastic coefficient P11, and photoelastic coefficient P12) of the proposed sensor. The optimized results helped in increasing the sensitivity in terms of wavelength shift. It is observed that the proposed FBG provides maximum wavelength shift of 38.16 nm with Poisson's ratio of 1.94, photoelastic coefficient P11 of 1.994, and photoelastic coefficient P12 of 1.8103.

  17. Low-power hardware implementation of artificial neural network strain detection for extrinsic Fabry-Pérot interferometric sensors under sinusoidal excitation

    Science.gov (United States)

    Mitchell, Kyle; Ebel, William J.; Watkins, Steve E.

    2009-11-01

    Artificial neural networks are studied for use in estimating strain in extrinsic Fabry-Pérot interferometric sensors. These networks can require large memory spaces and a large number of calculations for implementation. We describe a modified neural network solution that is suitable for implementation on relatively low cost, low-power hardware. Moreover, we give strain estimates resulting from an implementation of the artificial neural network algorithm on an 8-bit 8051 processor with 64 kbytes of memory. For example, one of our results shows that for 2048 samples of the transmittance signal, the presented neural network algorithm requires around 24,622 floating point multiplies and 35,835 adds, and where the data and algorithm fit within the 64-kbyte memory.

  18. Distributed fiber strain and vibration sensor based on Brillouin optical time-domain reflectometry and polarization optical time-domain reflectometry.

    Science.gov (United States)

    Wang, Feng; Zhang, Xuping; Wang, Xiangchuan; Chen, Haisheng

    2013-07-15

    A distributed fiber strain and vibration sensor which effectively combines Brillouin optical time-domain reflectometry and polarization optical time-domain reflectometry is proposed. Two reference beams with orthogonal polarization states are, respectively, used to perform the measurement. By using the signal obtained from either reference beam, the vibration of fiber can be measured from the polarization effect. After combining the signals obtained by both reference beams, the strain can be measured from the Brillouin effect. In the experiment, 10 m spatial resolution, 0.6 kHz frequency measurement range, 2.5 Hz frequency resolution, and 0.2 MHz uncertainty of Brillouin frequency measurement are realized for a 4 km sensing distance.

  19. Damage accumulation in cyclically-loaded glass-ceramic matrix composites monitored by acoustic emission.

    Science.gov (United States)

    Aggelis, D G; Dassios, K G; Kordatos, E Z; Matikas, T E

    2013-01-01

    Barium osumilite (BMAS) ceramic matrix composites reinforced with SiC-Tyranno fibers are tested in a cyclic loading protocol. Broadband acoustic emission (AE) sensors are used for monitoring the occurrence of different possible damage mechanisms. Improved use of AE indices is proposed by excluding low-severity signals based on waveform parameters, rather than only threshold criteria. The application of such improvements enhances the accuracy of the indices as accumulated damage descriptors. RA-value, duration, and signal energy follow the extension cycles indicating moments of maximum or minimum strain, while the frequency content of the AE signals proves very sensitive to the pull-out mechanism.

  20. Damage Accumulation in Cyclically-Loaded Glass-Ceramic Matrix Composites Monitored by Acoustic Emission

    Directory of Open Access Journals (Sweden)

    D. G. Aggelis

    2013-01-01

    Full Text Available Barium osumilite (BMAS ceramic matrix composites reinforced with SiC-Tyranno fibers are tested in a cyclic loading protocol. Broadband acoustic emission (AE sensors are used for monitoring the occurrence of different possible damage mechanisms. Improved use of AE indices is proposed by excluding low-severity signals based on waveform parameters, rather than only threshold criteria. The application of such improvements enhances the accuracy of the indices as accumulated damage descriptors. RA-value, duration, and signal energy follow the extension cycles indicating moments of maximum or minimum strain, while the frequency content of the AE signals proves very sensitive to the pull-out mechanism.

  1. Gas sensor array based on ceramic micro-hotplate for flammable gas detection%陶瓷微热板阵列式可燃气体传感器

    Institute of Scientific and Technical Information of China (English)

    薛严冰; 唐祯安

    2012-01-01

    设计了基于陶瓷基底的悬桥式微热板结构以解决硅微热板高温稳定性差的问题.分析了微热板的传热过程,并通过有限元工具对其稳态热响应特性及微加热器电极结构进行了模拟.采用常规微电子技术结合激光微加工技术,实际制作了基底厚度为100 μm,桥宽度为2 mm的微结构,并对结构的加热功率-温度关系进行了测试.结果表明:热板具有较好的高温稳定性,1.5W加热功率可使板上平均温度达到630℃.将桥式微热板作为阵列传感器的加热平台,Pd掺杂原子数百分比为0.2%和10%的SnO2纳米材料分别作为阵列中两只传感器的敏感膜材料,设计并制作了阵列式气体传感器.传感器在恒电压加热方式下可实现CO或CH4单一模式气体检测;阵列传感器在高、低温脉冲电压加热模式下可实现对CO和CH4两种混合气体的定量检测.%A ceramic hotplate with the structure of suspending bridge was designed to improve the thermal stability of silicon micro hotplates. The heat transfer process of the hotplate was analyzed and the characteristics of steady-state thermal response and the electrode structure of a heater were simulated by using the finite element method. Combined the conventional microelectronic technology and laser micro processing technology, the microstructures with thickness of 100 μm and bridge width of 2 mm were produced actually and the property of power assumption verses the temperature was measured. The results show that the hotplate has good stability at high temperature, and the average temperature on the ceramic hot-plate can reach 630℃ when a 1. 5 W heating power is applied. By taking the ceramic hotplate as heating platform and nano-scale SnO2 materials with Pd doping concentration of 0. 2 % and 10 %(atom number percentage) as sensitive membrane materials, respectively, the array with two sensors was designed and fabricated. Experiments show that when the sensor array

  2. Transmission of Er:YAG laser through different dental ceramics.

    Science.gov (United States)

    Sari, Tugrul; Tuncel, Ilkin; Usumez, Aslihan; Gutknecht, Norbert

    2014-01-01

    The aim of this study was to determine the erbium-doped yttrium aluminum garnet (Er:YAG) laser transmission ratio through different dental ceramics with different thicknesses. Laser debonding procedure of adhesively luted all-ceramic restorations is based on the transmission of laser energy through the ceramic and the ablation of resin cement, because of the transmitted laser energy. Five different dental ceramics were evaluated in this study: sintered zirconium-oxide core ceramic, monolithic zirconium-oxide ceramic, feldspathic ceramic, leucite-reinforced glass ceramic, and lithium disilicate-reinforced glass ceramic. Two ceramic discs with different thicknesses (0.5 and 1 mm) were fabricated for each group. Ceramic discs were placed between the sensor membrane of the laser power meter and the tip of the contact handpiece of an Er:YAG laser device with the aid of a custom- made acrylic holder. The transmission ratio of Er:YAG laser energy (500 mJ, 2 Hz, 1 W, 1000 μs) through different ceramic discs was measured with the power meter. Ten measurements were made for each group and the results were analyzed with two way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests. The highest transmission ratio was determined for lithium disilicate-reinforced ceramic with 0.5 mm thickness (88%) and the lowest was determined for feldspathic ceramic with 1 mm thickness (44%). The differences among the different ceramics and between the different thicknesses were significant (pCeramic type and thickness should be taken into consideration to adjust the laser irradiation parameters during laser debonding of adhesively luted all-ceramic restorations.

  3. Ceramic Seal.

    Energy Technology Data Exchange (ETDEWEB)

    Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Juan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Custer, Joyce Olsen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hymel, Ross W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Krementz, Dan [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gobin, Derek [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Harpring, Larry [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martinez-Rodriguez, Michael [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Varble, Don [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); DiMaio, Jeff [Tetramer Technologies, Pendleton, SC (United States); Hudson, Stephen [Tetramer Technologies, Pendleton, SC (United States)

    2016-11-01

    Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

  4. Renewable-surface sol-gel derived carbon ceramic electrode fabricated by [Ru(bpy)(tpy)Cl]PF6 and its application as an amperometric sensor for sulfide and sulfur oxoanions.

    Science.gov (United States)

    Salimi, Abdollah; Pourbeyram, Sima; Amini, Mohamad Kazem

    2002-12-01

    A highly sensitive and fast responding sensor for the determination of thiosulfate, sulfite, sulfide and dithionite is described. It consists of a chemically modified carbon ceramic composite electrode (CCE) containing [Ru(bpy)(tpy)Cl]PF6 complex that was constructed by the sol-gel technique. A reversible redox couple of Ru(II)/Ru(III) was observed as a solute in acetonitrile solution and as a component of carbon based conducting composite electrode. Electrochemical behavior and stability of modified CCE were investigated by cyclic voltametry, the apparent electron transfer rate constant (kappa(S)) and transfer coefficient (a) were determined by cyclic voltametry which were about 28 s(-1) and 0.43 respectively. Electrocatalytic oxidation of S(2-), SO3(2-), S2O4(2-) and S2O3(2-) were effective at the modified electrode at significantly reduced overpotentials and in the pH range 1-11. Optimum pH values for amperometric detection of thiosulfate, dithionite, sulfide and sulfite are 7, 9, 2 and 2. Under the optimized conditions the calibration curves are linear in the concentration ranges 1-500, 3-80, 2-90 and 1-100 microM for S2O3(2-), SO3(2-), S2- and S2O4(2-) determination. The detection limit (signal to noise is 3) and sensitivity are 0.5 and 12, 2.8 and 6, 1.6 and 8, and 0.65 microM and 80 nA microM(-1) for thiosulfate, sulfite, sulfide and dithionite detection. The modified carbon ceramic electrode doped with Ru-complex shows good reproducibility, a short response time (t 6 month) and especially good surface renewability by simple mechanical polishing (RSD for eight successive polishing is 2%). The advantages of this sulfur compound amperometric detector based on ruthenium doped CCE are high sensitivity, inherent stability at a broader pH range, excellent catalytic activity, less expense and simplicity of preparation in comparison with recently published papers. This sensor can be used as a chromatographic detector for analysis of sulfur derivatives.

  5. Dynamic Strain Measurements on Automotive and Aeronautic Composite Components by Means of Embedded Fiber Bragg Grating Sensors.

    Science.gov (United States)

    Lamberti, Alfredo; Chiesura, Gabriele; Luyckx, Geert; Degrieck, Joris; Kaufmann, Markus; Vanlanduit, Steve

    2015-10-26

    The measurement of the internal deformations occurring in real-life composite components is a very challenging task, especially for those components that are rather difficult to access. Optical fiber sensors can overcome such a problem, since they can be embedded in the composite materials and serve as in situ sensors. In this article, embedded optical fiber Bragg grating (FBG) sensors are used to analyze the vibration characteristics of two real-life composite components. The first component is a carbon fiber-reinforced polymer automotive control arm; the second is a glass fiber-reinforced polymer aeronautic hinge arm. The modal parameters of both components were estimated by processing the FBG signals with two interrogation techniques: the maximum detection and fast phase correlation algorithms were employed for the demodulation of the FBG signals; the Peak-Picking and PolyMax techniques were instead used for the parameter estimation. To validate the FBG outcomes, reference measurements were performed by means of a laser Doppler vibrometer. Sensors 2015, 15 27175 The analysis of the results showed that the FBG sensing capabilities were enhanced when the recently-introduced fast phase correlation algorithm was combined with the state-of-the-art PolyMax estimator curve fitting method. In this case, the FBGs provided the most accurate results, i.e. it was possible to fully characterize the vibration behavior of both composite components. When using more traditional interrogation algorithms (maximum detection) and modal parameter estimation techniques (Peak-Picking), some of the modes were not successfully identified.

  6. Dynamic Strain Measurements on Automotive and Aeronautic Composite Components by Means of Embedded Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Alfredo Lamberti

    2015-10-01

    Full Text Available The measurement of the internal deformations occurring in real-life composite components is a very challenging task, especially for those components that are rather difficult to access. Optical fiber sensors can overcome such a problem, since they can be embedded in the composite materials and serve as in situ sensors. In this article, embedded optical fiber Bragg grating (FBG sensors are used to analyze the vibration characteristics of two real-life composite components. The first component is a carbon fiber-reinforced polymer automotive control arm; the second is a glass fiber-reinforced polymer aeronautic hinge arm. The modal parameters of both components were estimated by processing the FBG signals with two interrogation techniques: the maximum detection and fast phase correlation algorithms were employed for the demodulation of the FBG signals; the Peak-Picking and PolyMax techniques were instead used for the parameter estimation. To validate the FBG outcomes, reference measurements were performed by means of a laser Doppler vibrometer. Sensors 2015, 15 27175 The analysis of the results showed that the FBG sensing capabilities were enhanced when the recently-introduced fast phase correlation algorithm was combined with the state-of-the-art PolyMax estimator curve fitting method. In this case, the FBGs provided the most accurate results, i.e. it was possible to fully characterize the vibration behavior of both composite components. When using more traditional interrogation algorithms (maximum detection and modal parameter estimation techniques (Peak-Picking, some of the modes were not successfully identified.

  7. Structure Optimization of Fiber Bragg Grating Strain Sensors%光纤布喇格光栅应变传感器结构优化研究

    Institute of Scientific and Technical Information of China (English)

    袁子琳; 龚元; 马耀远; 杜磊; 吴宇; 饶云江; 吴慧娟; 王浚璞; 万夫

    2012-01-01

    提出了一种改进的光纤光栅应变传感器结构,用有限元分析软件对其进行建模和静力仿真,得到其应力分布和光栅区域的应变情况.在整体宽度与厚度相等的情况下,此结构的灵敏度约为传统“工”字型结构的600倍.进一步分析了其关键区域的6个结构参量对应变灵敏度及量程的影响.筛选、设计并加工出不同尺寸的两种应变片,分别用UV胶与玻璃焊料对光栅进行封装,得到灵敏度分别为:249 pm/N、330 pm/N和1.1 pm/N.比较分析表明,本文提供的分析方法与数据,可为不同工程应用场合的最优结构设计提供依据.%The dependence of a fiber Bragg grating strain sensor on the improved structure parameters was investigated both numerically and experimentally. The stress distribution and the strain of the grating region was obtained. In the case of the overall width and thickness are equal, the sensitivity of this structure is about 600 times higher than the traditional I-shaped structure. The influence of the 6 key structure parameters on the strain sensitivity and the measurement range was analyzed in detail. Experimental results were also given compared with the numerical simulated results. The gratings were packaged respectively with UV glue and glass solder to get the sensitivities were: 249 pm/N, 330 pm/N and 1. 1 pm/N. The analysis method and data provided a basis for structural optimum design of fiber Bragg grating strain sensors in different applications.

  8. Quorum sensing signal profile of Acinetobacter strains from nosocomial and environmental sources Perfil de sensores de quórum en cepas nosocomiales y ambientales de Acinetobacter

    Directory of Open Access Journals (Sweden)

    R. H. González

    2009-06-01

    Full Text Available A set of 43 strains corresponding to 20 classified and unclassified genomic Acinetobacter species was analyzed for the production of typical N-acyl homoserine lactone quorum sensing molecules in culture broths. A large percentage of the strains (74% displayed quorum sensing signals that could be separated into three statistically significantly different chromatographic groups (p Rf2 > Rf1. None of the three signals could be specifically assigned to a particular species in the genus; furthermore, no distinction could be made between the quorum sensing signals secreted by typical opportunistic strains of the A. calcoaceticus-A. baumannii complex, isolated from patients, with respect to the other species of the genus, except for the Rf1 signal which was present in all the QS positive strains belonging to this complex and DNA group 13 TU. In conclusion, quorum sensors in Acinetobacter are not homogenously distributed among species and one of them is present in most of the A. calcoaceticus-baumannii complex.Se analizó la producción de moléculas típicas de N-acil homoserina lactona con actividad de quorum sensing en cultivos líquidos de un grupo de 43 cepas correspondientes a 20 especies genómicas clasificadas y no clasificadas de Acinetobacter. Un porcentaje alto de las cepas (74% mostraron señales de quorum sensing que pudieron ser separadas en tres grupos cromatográficos significativamente diferentes entre sí (p Rf2 > Rf1. Ninguna de las tres señales pudo ser asignada a una especie en particular dentro del género; es más, no se encontró diferencia entre las señales producidas por las cepas típicamente oportunistas (complejo A. calcoaceticus-A. baumannii aisladas de pacientes respecto de las producidas por otras cepas del mismo género, excepto para el caso de Rf1, que se encontró presente en todos los aislamientos quorum sensing positivos del mencionado complejo y en las cepas del grupo de DNA 13TU. En conclusión, los sensores de

  9. 基于电阻应变片式传感器的电子秤设计%Design of electronic scales based resistance strain gauge sensor

    Institute of Scientific and Technical Information of China (English)

    王来志; 王小平

    2014-01-01

    给出了采用AT89S52单片机作为微控制器,结合电阻应变片式传感器、A/D转换器、键盘/开关、LCD显示器、报警电路等部分设计的一种智能自动称量电子秤的实现方法。本电子称具有体积小、成本低、精确度和可靠性高等特点。%An intelligent automatic weighing electronic scale is provided which uses AT89S52 as microcontroller, combines with resistance strain gauge sensor, A/D converter, keyboard/switches, LCD displayer, alarm circuit and so on. The electronic scale has the features of small size, low cost, high accuracy and high reliability.

  10. Vibrissa Sensor

    Science.gov (United States)

    2016-09-30

    Docket No. 300119 1 of 11 VIBRISSA SENSOR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention provides a... measured as strain. [0009] Thus, there is a need for a sensor utilizing a vibrissa that can detect dynamic and high frequency movement of the

  11. Robotic compliant fingertips possessing strain typed tactile sensor%具有应变式触觉传感器的机器人柔顺指端

    Institute of Scientific and Technical Information of China (English)

    戴士杰; 岳宏; 王仲民; 李德仲

    2001-01-01

    Aimed at the operation of grasping a uniform sectioned and even massed bar by a robot situated in gravitational field this paper put forward a kind of structure of robot′s compliant fingertips,possessing strain typed tactile sensor.In the gripper of robot's parallel grasping the perception on length and mass of an object is realized by utilizing metal elastic sheet as elastic element and using strain slice as tactile sensor.The electrorheologic fluids are sealed in the fingertips to achieve soft and hard grasping.Moreover,the sensory principle of grasping system is being discussed emphatically.The experimental results indicated that the fingertips of this kind of robot possess good discriminative ability and stable grasping capability.%针对机器人抓握处于重力场中的等截面均质杆件操作,提出一种具有应变式触觉传感器的机器人柔顺指端的结构。在机器人平行抓握手爪中,利用金属弹性薄板做弹性元件,应变片做触觉敏感单元,实现对物体的长度和质量的感知;在指端的表面封装电流变流体实现软/硬抓握。另外,着重讨论了抓握系统的传感原理。试验表明,这种机器人指端具有良好的识别能力和稳定抓握能力。

  12. Michelson optical fiber strain sensor%高分辨率麦克尔逊光纤应变传感器

    Institute of Scientific and Technical Information of China (English)

    毕卫红

    2000-01-01

    运用麦克尔逊干涉结构,采用氦氖激光、单模光纤、光纤耦合器等器件构成光纤应变传感器, 利用除法器消除光源幅度干扰,提高系统的分辨率。本文采用在光纤端面镀反射膜的方法提 高抗干扰能力;输入、输出在同一侧便于使用;实验结果表明所设计的传感器是正确和可行的 。%The Michelson interferometer is used for fiber-optical strain sensor, which is consisted of He-Ne laser, single-Mode optical fiber and optical fiber coupler. The divider is used to eliminate the attitude fluctuation from the laser and to get high resolution. The growing mirror on the end of optical fiber is used to increa se the ability in anti-disturbance. The input and output signals are on the s ame side, which make the sensor easily applied.

  13. Dental composite resins: measuring the polymerization shrinkage using optical fiber Bragg grating sensors

    Science.gov (United States)

    Ottevaere, H.; Tabak, M.; Chah, K.; Mégret, P.; Thienpont, H.

    2012-04-01

    Polymerization shrinkage of dental composite materials is recognized as one of the main reasons for the development of marginal leakage between a tooth and filling material. As an alternative to conventional measurement methods, we propose optical fiber Bragg grating (FBG) based sensors to perform real-time strain and shrinkage measurements during the curing process of dental resin cements. We introduce a fully automated set-up to measure the Bragg wavelength shift of the FBG strain sensors and to accurately monitor the linear strain and shrinkage of dental resins during curing. Three different dental resin materials were studied in this work: matrix-filled BisGMA-based resins, glass ionomers and organic modified ceramics.

  14. Pb(Ni1/3Sb2/3O3-PbZrTiO3 Ceramic Sensors for Underwater Transducer Application

    Directory of Open Access Journals (Sweden)

    C. M. Lonkar

    2012-07-01

    Full Text Available Cymbal is a class-V flextensional transducer that consists of thickness poled ceramic disc sandwiched between the two metal end caps which acts as a mechanical transformer. Cymbal transducers were fabricated using piezoceramic discs of compositions Pb0.988(Zr0.52Ti0.48 0.976Nb0.024O3 (PZT type 5A and Pb0.98La0.02 (NiSb0.05[(Zr0.52 Ti0.480.995]0.95O3 (PNS-PZT. Piezoelectric and hydrostatic constants for PNS-PZT composition were on higher side. End capswere made up of brass sheet having thickness 0.5 mm. Underwater testing of the polyurethane moulded cymbal hydrophones were carried out in acoustic tank and compared. The resonance frequency for both the hydrophones was 10.1 kHz. PNS-PZT hydrophone shows higher sensitivity (-183.2 dB re 1V/μPa compared to PZT type 5A (-191.2 dB re 1V/μPa at resonance frequency. Directivity pattern observed for PNS-PZT is omni-directional near resonance frequency.Defence Science Journal, 2012, 62(4, pp.269-273, DOI:http://dx.doi.org/10.14429/dsj.62.1718

  15. Health monitoring of a continuous rigid frame bridge based on PZT impedance and strain measurements

    Science.gov (United States)

    Zhang, Junbing; Zhu, Hongping; Wang, Dansheng; He, Bo; Zhou, Huaqiang

    2009-07-01

    Critical civil infrastructures such as bridges, dams, and pipelines present a major investment and their safety and security affect the life of citizens and national economic development. So it is very important for engineers and researchers to monitor their integrity while in operation and throughout. In recent years, the piezoelectric-ceramic (PZT) patches, which serve both as impedance sensors and actuators, have been increasingly used for structural health monitoring. This paper presents an impedance-based method, which utilizes the electro-mechanical coupling property of PZT sensors. There are a lot of advantages of this method, such as not based on any physical models, sensitive to tiny damage for its high frequency characteristics. An engineering application of this method for health monitoring of a continuous rigid frame bridge is implemented in this study. Some PZT active sensors are embedded into critical sections of the continuous rigid-frame box beam. The electrical admittances of these distributed PZT sensors are measured when the bridge is constructing or suffering from operational loads. For comparison, strain gauges are arranged in adjacent regions of these PZT sensors to obtain the strains of concrete around them at the same time. Based on the admittance sigatures obtained form PZT sensors and the strain measurements of concrete around them, the health status of the bridge is monitored and evaluated successfully.

  16. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    Directory of Open Access Journals (Sweden)

    D. Belavic

    2012-04-01

    Full Text Available The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s, mixer(s, reformer and combustor. Low-temperature co-fired ceramic (LTCC technology was used to fabricate the ceramic structures with buried cavities and channels, and thick-film technology was used to make electrical heaters, temperature sensors and pressure sensors. The final 3D ceramic structure consists of 45 LTCC tapes. The dimensions of the structure are 75 × 41 × 9 mm3 and the weight is about 73 g.

  17. Optical Fiber Strain Sensor Application in Safety Inspection Under Dynamic Loading%光纤应变传感器在振动检测和安全评估中的应用

    Institute of Scientific and Technical Information of China (English)

    孙雨; 吴江; 李旭强

    2012-01-01

    介绍了一种利用光纤应变传感器进行动载作用下构件安全性检测的方法,以国内某过山车基础支撑为例,介绍了光纤应变传感器的安装和使用方法,并通过对传感器采集到的应变数据进行分析,结合其他现场检测数据,对受测构件安全性给出了评价.%The method of using fiber optic strain sensors for safety inspection of structural elements under dynamic loading is introduced. In the study with fiber optic strain sensor in an in-situ test of the structural supporting system of a roller coaster, the method of installation and operation of fiber optic strain sensors is elaborated. In the comparison of the data collected from the fiber optic strain sensors and other test method, analysis is carried out to estimate the safety of the structural system.

  18. Test Structures Applied to the Rapid Prototyping of Sensors

    Science.gov (United States)

    Buehler, M.; Chang, L-J.; Martin, D.

    1997-01-01

    Recently, test structures were used to aid in the rapid development of a gas sensor and pressure sensor. These sensors were fabricated using co-fired ceramic technology and a multiproject approach. This talk will describe results obtained from a ceramic substrate which contained 36 chips with six variants including the sensors, process control monitors, and an interconnect chip. As far as the authors know, this is the first implementation of multi-projects in co-fired ceramic substrate. The gas sensor is being developed for the Space Shuttle and the pressure gage is being developed as a Martian barometer.

  19. Flexible tensile strain sensor based on lead-free 0.5Ba (Ti0.8Zr0.2) O3-0.5(Ba0.7Ca0.3) TiO3 piezoelectric nanofibers

    Science.gov (United States)

    Xing, Lindong; Zhu, Ruijian; Wang, Zengmei; Wang, Fengxia; Kimura, Hideo

    2017-09-01

    Here, we report our study results of a flexible piezoelectric tensile strain sensor which is fabricated by synthesizing 0.5Ba (Zr0.2Ti0.8) O3-0.5(Ba0.7Ca0.3) TiO3 (0.5BZT-0.5BCT) nanofibers via an electrospinning process. Our nanofibers show an ultrahigh d33 of 275 pm V-1. 0.5BZT-0.5BCT nanofibers and MW-CNTs are dispersed in polydimethylsiloxane (PDMS) to fabricate a highly stretchable and flexible tensile sensor, and the multiple roles of the MW-CNTs are probed and demonstrated. This nanofiber-based piezoelectric tensile strain sensor shows great resolution and sensitivity under external mechanical deformation. It is suitable for applications in complex environments.

  20. Integral Textile Ceramic Structures

    Science.gov (United States)

    Marshall, David B.; Cox, Brian N.

    2008-08-01

    A new paradigm for ceramic composite structural components enables functionality in heat exchange, transpiration, detailed shape, and thermal strain management that significantly exceeds the prior art. The paradigm is based on the use of three-dimensional fiber reinforcement that is tailored to the specific shape, stress, and thermal requirements of a structural application and therefore generally requires innovative textile methods for each realization. Key features include the attainment of thin skins (less than 1 mm) that are nevertheless structurally robust, transpiration holes formed without cutting fibers, double curvature, compliant integral attachment to other structures that avoids thermal stress buildup, and microcomposite ceramic matrices that minimize spalling and allow the formation of smooth surfaces. All these features can be combined into structures of very varied gross shape and function, using a wide range of materials such as all-oxide systems and SiC and carbon fibers in SiC matrices. Illustrations are drawn from rocket nozzles, thermal protection systems, and gas turbine engines. The new design challenges that arise for such material/structure systems are being met by specialized computational modeling that departs significantly in the representation of materials behavior from that used in conventional finite element methods.

  1. The development overview of strain sensor based on suspension graphene%基于悬浮式石墨烯的应变传感器发展概述

    Institute of Scientific and Technical Information of China (English)

    张玮峰; 李晓莉; 张子生; 尚雅轩; 李晓苇

    2016-01-01

    Graphene materials with unique mechanical and electrical properties, so quickly became a focus of research. Based on graphene strain sensor can not only enrich the sensor construction materials, and with the help of graphene characteristic, can develop more excellent performance than silicon stress sensor. This paper introduces the design of suspension graphene strain sensors in recent years with the development of manufacturing technology. The structure and principle of the sensor are described, such as sensitivity performance. This paper expounds the structure and performance of the sensor was improved and optimized process. Strain sensor based on suspension graphene, can be applied to nano electromechanical systems (NEMS), in the field of medical and biological nanometer, has great application potential.%石墨烯材料具有独特的机械与电学性质,迅速成为当前科研的热点。基于石墨烯构建应变传感器,不仅可以丰富传感器的构建材料,而且借助石墨烯特有的性质,可以研制出比硅性能更优异的应力传感器。本文介绍了近些年来悬浮式石墨烯应变传感器的设计与制造技术的发展,介绍了传感器的结构、原理、灵敏度等性能,阐述了对传感器的结构和性能进行改进和优化的过程。基于悬浮式石墨烯的应变传感器可应用于纳机电系统(NEMS),在医学、生物等纳米领域具有巨大的应用潜力。

  2. Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Stajanca, Pavol;

    2016-01-01

    Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C....... We also characterize the mPOF optically and mechanically, and further test the sensitivity of the PC FBG to strain and temperature. We demonstrate that the PC FBG can bear temperatures as high as 125°C without malfunctioning. In contrast, polymethyl methacrylate-based FBG technology is generally...

  3. Study of 1-3 PZT fibre/epoxy composite force sensor

    Science.gov (United States)

    Choy, S. H.; Chan, H. L. W.; Ng, M. W.; Liu, P. C. K.

    2005-09-01

    Lead zirconate titanate (PZT) fibres were prepared by a powder-based extrusion method. Pre-sintered PZT powder mixed with poly(acrylic acid) was spun in a spinnerette to produce fibres. The fibre of ˜400 μm diameter was used to fabricate 1-3 PZT fibre/epoxy composite discs with different volume fractions (ϕ) of PZT. Since the ceramic fibres are rather brittle, their elastic properties cannot be measured directly. In order to determine the properties of the ceramic fibres, effective properties of the fibres/epoxy 1-3 composite were measured. By using a modified series and parallel model, the properties of 1-3 composites can be calculated. Then, the elastic coefficient s33,fibreE, relative permittivity ɛ33,fibreT and piezoelectric strain coefficient d33,fibre of the ceramic fibre could be found. Ring-shaped PZT fibre/epoxy materials composites with different ϕ were fabricated to be used as the sensing material in force sensor applications. The ring-shape composite with ϕ=0.5 was installed into a housing and the sensor was calibrated by different methods and its sensitivity was found to be 144 pC/N within the frequency range of 0.5 6.4 kHz which is much higher than that of a quartz force sensor with a similar structure.

  4. Ceramic Matrix Composites .

    Directory of Open Access Journals (Sweden)

    J. Mukerji

    1993-10-01

    Full Text Available The present state of the knowledge of ceramic-matrix composites have been reviewed. The fracture toughness of present structural ceramics are not enough to permit design of high performance machines with ceramic parts. They also fail by catastrophic brittle fracture. It is generally believed that further improvement of fracture toughness is only possible by making composites of ceramics with ceramic fibre, particulate or platelets. Only ceramic-matrix composites capable of working above 1000 degree centigrade has been dealt with keeping reinforced plastics and metal-reinforced ceramics outside the purview. The author has discussed the basic mechanisms of toughening and fabrication of composites and the difficulties involved. Properties of available fibres and whiskers have been given. The best results obtained so far have been indicated. The limitations of improvement in properties of ceramic-matrix composites have been discussed.

  5. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  6. Ceramic Laser Materials

    Science.gov (United States)

    Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

  7. Dramatic influence of Dy{sup 3+} doping on strain and domain structure in lead-free piezoelectric 0.935(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}−0.065BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Li, C. Q.; Zhang, J. Z.; Hu, Z. G., E-mail: zghu@ee.ecnu.edu.cn; Chu, J. H. [Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Yao, Q. R.; Wang, F. F.; Liu, A. Y.; Shi, W. Z. [Department of Physics, Shanghai Normal University, Shanghai 200234 (China)

    2015-12-15

    An electric-field induced giant strain response and doping level dependent domain structural variations have been studied in the dysprosium (Dy{sup 3+})-modified 0.935(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}-0.065BaTiO{sub 3}(xDy : NBBT) ceramics with the doping levels of 0%, 0.5%, 1%, and 2%. X-ray diffraction and Raman spectroscopy analyses not only demonstrates the change in ionic configurations induced by Dy{sup 3+} doping, but also shows the local crystal symmetry for x ≥ 0.5% doping levels to deviate from the idealized cubic structure. Piezoresponse force microscopy measurement exhibits the presence of an intermediate phase with orthorhombic symmetry at the critical Dy{sup 3+} doping level of 2%. Moreover, at this doping level, a giant recoverable nonlinear strain of ∼0.44% can be observed with high normalized strain (S{sub max}/E{sub max}) of 728 pm/V. At the same applied field, the strain exhibits a 175% increase than that of NBBT ceramic. Such a large strain stems from the varying coherence lengths of polar nanoregions (PNRs) and an unusual reversible 90° domain switching caused by the symmetry conforming property of point defects, where the restoring force is provided by unswitchable defects. The mechanism reveals a new possibility to achieve large electric-field strain effect for a wide range of ferroelectric systems, which can lead to applications in novel “on-off” actuators.

  8. Ceramic art in sculpture

    OpenAIRE

    Rokavec, Eva

    2014-01-01

    Diploma seminar speaks of ceramics as a field of artistic expression and not just as pottery craft. I presented short overview of developing ceramic sculpture and its changing role. Clay inspires design and touch more than other sculpture media. It starts as early as in prehistory. Although it sometimes seems that was sculptural ceramics neglected in art history overview, it was not so in actual praxis. There is a rich tradition of ceramics in the East and also in Europe during the renaissanc...

  9. Ceramic to metal seal

    Energy Technology Data Exchange (ETDEWEB)

    Snow, Gary S. (Albuquerque, NM); Wilcox, Paul D. (Albuquerque, NM)

    1976-01-01

    Providing a high strength, hermetic ceramic to metal seal by essentially heating a wire-like metal gasket and a ceramic member, which have been chemically cleaned, while simultaneously deforming from about 50 to 95 percent the metal gasket against the ceramic member at a temperature of about 30 to 75 percent of the melting temperature of the metal gasket.

  10. Light element ceramics

    OpenAIRE

    Rao, KJ; Varma, KBR; Raju, AR

    1988-01-01

    An overview of a few structually important light element ceramics is presented. Included in the overview are silicon nitide, sialon, aluminium nitride, boron carbide and silicon carbide. Methods of preparation, characterization and industrial applications of these ceramics are summarized. Mechanical properties, industrial production techniques and principal uses of these ceramics are emphasized.

  11. A state-the-art report on the development of the piezoelectric accelerometer sensor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jee Yun; Oh, Suk Jin; Kim, Kyung Hoh; Kim, Sun Jae; Kang, Dae Kab [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-12-01

    A state-of-the art surveys on the application and the manufacturing technology of a piezoelectric accelerometer sensor. An accelerometer sensor is applied to the monitoring of acoustic leak, reactor coolant pump vibration and loose parts in the reactor, and the measurement of vibration and stress of large equipments such as pump, tubes, etc.. The performance of an accelerometer consisted of piezoelectric ceramic, mass, base, case and cable is depend on the characteristics of each component and the assembling method. Sensitivity, linearity and dynamic range, transverse sensitivity, phase response, transient temperature response, frequency response, base strain sensitivity, magnetic sensitivity, acoustic sensitivity, humidity effect and radiation effect must be measured and evaluated for conforming quality of the developed accelerometer sensor. 35 figs., 29 tabs., 38 refs. (Author).

  12. Integrated thick-film nanostructures based on spinel ceramics.

    Science.gov (United States)

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-03-26

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications.

  13. Forming of superplastic ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Lesuer, D.R.; Wadsworth, J.; Nieh, T.G.

    1994-05-01

    Superplasticity in ceramics has now advanced to the stage that technologically viable superplastic deformation processing can be performed. In this paper, examples of superplastic forming and diffusion bonding of ceramic components are given. Recent work in biaxial gas-pressure forming of several ceramics is provided. These include yttria-stabilized, tetragonal zirconia (YTZP), a 20% alumina/YTZP composite, and silicon. In addition, the concurrent superplastic forming and diffusion bonding of a hybrid ceramic-metal structure are presented. These forming processes offer technological advantages of greater dimensional control and increased variety and complexity of shapes than is possible with conventional ceramic shaping technology.

  14. Ceramic gas turbine shroud

    Science.gov (United States)

    Shi, Jun; Green, Kevin E.

    2014-07-22

    An example gas turbine engine shroud includes a first annular ceramic wall having an inner side for resisting high temperature turbine engine gasses and an outer side with a plurality of radial slots. A second annular metallic wall is positioned radially outwardly of and enclosing the first annular ceramic wall and has a plurality of tabs in communication with the slot of the first annular ceramic wall. The tabs of the second annular metallic wall and slots of the first annular ceramic wall are in communication such that the first annular ceramic wall and second annular metallic wall are affixed.

  15. Creep in ceramics

    CERN Document Server

    Pelleg, Joshua

    2017-01-01

    This textbook is one of its kind, since there are no other books on Creep in Ceramics. The book consist of two parts: A and B. In part A general knowledge of creep in ceramics is considered, while part B specifies creep in technologically important ceramics. Part B covers creep in oxide ceramics, carnides and nitrides. While covering all relevant information regarding raw materials and characterization of creep in ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

  16. Fracture Toughness Prediction for MWCNT Reinforced Ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Nguyen, Ba Nghiep

    2013-09-01

    This report describes the development of a micromechanics model to predict fracture toughness of multiwall carbon nanotube (MWCNT) reinforced ceramic composites to guide future experimental work for this project. The modeling work described in this report includes (i) prediction of elastic properties, (ii) development of a mechanistic damage model accounting for matrix cracking to predict the composite nonlinear stress/strain response to tensile loading to failure, and (iii) application of this damage model in a modified boundary layer (MBL) analysis using ABAQUS to predict fracture toughness and crack resistance behavior (R-curves) for ceramic materials containing MWCNTs at various volume fractions.

  17. Ultralight, scalable, and high-temperature–resilient ceramic nanofiber sponges

    Science.gov (United States)

    Wang, Haolun; Zhang, Xuan; Wang, Ning; Li, Yan; Feng, Xue; Huang, Ya; Zhao, Chunsong; Liu, Zhenglian; Fang, Minghao; Ou, Gang; Gao, Huajian; Li, Xiaoyan; Wu, Hui

    2017-01-01

    Ultralight and resilient porous nanostructures have been fabricated in various material forms, including carbon, polymers, and metals. However, the development of ultralight and high-temperature resilient structures still remains extremely challenging. Ceramics exhibit good mechanical and chemical stability at high temperatures, but their brittleness and sensitivity to flaws significantly complicate the fabrication of resilient porous ceramic nanostructures. We report the manufacturing of large-scale, lightweight, high-temperature resilient, three-dimensional sponges based on a variety of oxide ceramic (for example, TiO2, ZrO2, yttria-stabilized ZrO2, and BaTiO3) nanofibers through an efficient solution blow-spinning process. The ceramic sponges consist of numerous tangled ceramic nanofibers, with densities varying from 8 to 40 mg/cm3. In situ uniaxial compression in a scanning electron microscope showed that the TiO2 nanofiber sponge exhibits high energy absorption (for example, dissipation of up to 29.6 mJ/cm3 in energy density at 50% strain) and recovers rapidly after compression in excess of 20% strain at both room temperature and 400°C. The sponge exhibits excellent resilience with residual strains of only ~1% at 800°C after 10 cycles of 10% compression strain and maintains good recoverability after compression at ~1300°C. We show that ceramic nanofiber sponges can serve multiple functions, such as elasticity-dependent electrical resistance, photocatalytic activity, and thermal insulation. PMID:28630915

  18. The friction and wear of ceramic/ceramic and ceramic/metal combinations in sliding contact

    Science.gov (United States)

    Sliney, Harold E.; Dellacorte, Christopher

    1994-01-01

    The tribological characteristics of ceramics sliding on ceramics are compared to those of ceramics sliding on a nickel-based turbine alloy. The friction and wear of oxide ceramics and silicon-based ceramics in air at temperatures from room ambient to 900 C (in a few cases to 1200 C) were measured for a hemispherically-tipped pin on a flat sliding contact geometry. In general, especially at high temperature, friction and wear were lower for ceramic/metal combinations than for ceramic/ceramic combinations. The better tribological performance for ceramic/metal combinations is attributed primarily to the lubricious nature of the oxidized surface of the metal.

  19. 基于ZMD31050的一体化应变式传感器设计方法%Design Method for ZMD31050-based Integrated Strain Sensor

    Institute of Scientific and Technical Information of China (English)

    何宸; 李明富; 李莉; 刘明鑫

    2014-01-01

    In order to solve the compensation and signal regulation problem of the traditional strain sensor, this article introduced a design method for ZMD31050-based integrated strain sensor. By the particular design of sensor structure, signal regulation circuit and compensation system, the problem above-mentioned is effectively solved which enable of the non-linear compensation and correction of zero-point and full-scale output. And the test result shows that this design simplified the regulation circuit, realized the integrated sensor design, can provide reference for the related integrated sensor design.%针对传统应变式传感器补偿和信号调理方法等方面存在的问题,介绍一种基于ZMD31050芯片的一体化应变式传感器的设计方法。通过设计专用的传感器结构、信号调理电路以及补偿校准系统,有效解决了传统应变式传感器补偿和信号调理中的问题,实现了对传感器零点和满量程输出以及满量程输出非线性的补偿和校准。实践结果表明:该传感器简化了调理电路,实现了一体化传感器的设计,可为相关一体化应变式传感器研制提供参考。

  20. Metallic and intermetallic-bonded ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Plucknett, K.P.; Tiegs, T.N.; Alexander, K.B. [Oak Ridge National Laboratory, TN (United States)] [and others

    1995-05-01

    The purpose of this task is to establish a framework for the development and fabrication of metallic-phase-reinforced ceramic matrix composites with improved fracture toughness and damage resistance. The incorporation of metallic phases that plastically deform in the crack tip region, and thus dissipate strain energy, will result in an increase in the fracture toughness of the composite as compared to the monolithic ceramic. It is intended that these reinforced ceramic matrix composites will be used over a temperature range from 20{degrees}C to 800-1200{degrees}C for advanced applications in the industrial sector. In order to systematically develop these materials, a combination of experimental and theoretical studies must be undertaken.

  1. Sensor probe for rectal manometry

    Energy Technology Data Exchange (ETDEWEB)

    Blechschmidt, R.A.; Hohlfeld, O.; Mueller, R.; Werthschuetzky, R. [Technische Univ. Darmstadt (Germany). Inst. fuer Elektromechanische Konstruktionen

    2001-07-01

    In this paper a pressure sensor probe is presented that is suitable for assessing dynamic rectal pressure profiles. It consists of ten piezoresistive sensors, mounted on low temperature co-fired ceramics. The sensors are coated with a bio-compatible silicone elastomer. It was possible to reduce the size of the ceramic to 4.5 x 5.5 mm with a height of 1.4 mm. The whole probe has a diameter of 9 mm and a length of 20 cm. One healthy test person underwent rectal manometry. The experimental data and the analysis of linearity, hysteresis, temperature stability, and reproducibility are discussed. The presented sensor probe extends the classical anorectal manometry, particularly in view of quantifying disorders of the rectal motility. (orig.)

  2. Analyses of fine paste ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sabloff, J A [ed.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  3. Ceramic laser materials

    Science.gov (United States)

    Ikesue, Akio; Aung, Yan Lin

    2008-12-01

    The word 'ceramics' is derived from the Greek keramos, meaning pottery and porcelain. The opaque and translucent cement and clay often used in tableware are not appropriate for optical applications because of the high content of optical scattering sources, that is, defects. Recently, scientists have shown that by eliminating the defects, a new, refined ceramic material - polycrystalline ceramic - can be produced. This advanced ceramic material offers practical laser generation and is anticipated to be a highly attractive alternative to conventional glass and single-crystal laser technologies in the future. Here we review the history of the development of ceramic lasers, the principle of laser generation based on this material, some typical results achieved with ceramic lasers so far, and discuss the potential future outlook for the field.

  4. Antibacterial ceramic for sandbox. Sunabayo kokin ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, K. (Ishizuka Glass Co. Ltd. Nagoya (Japan))

    1993-10-01

    Sands in sandboxes in parks have been called into question of being contaminated by colon bacilli and spawns from ascarides. This paper introduces an antibacterial ceramic for sandbox developed as a new material effective to help reduce the contamination. The ceramic uses natural sand as the main raw material, which is added with borax and silver to contain silver ions that have bacteria and fungus resistance and deodorizing effect. The ceramic has an average grain size ranging from 0.5 mm to 0.7 mm, and is so devised as to match specific gravity, grain size and shape of the sand, hence no separation and segregation can occur. The result of weatherability and antibacterial strength tests on sand for a sandbox mixed with the ceramic at 1% suggests that its efficacy lasts for about three years. Its actual use is under observation. Its efficacy has been verified in a test that measures a survival factor of spawns from dog ascardides contacted with aqueous solution containing the ceramic at 1%. Safety and sanitation tests have proved the ceramic a highly safe product that conforms to the food sanitation law. 5 refs., 3 figs., 3 tabs.

  5. 几种可应用于电动助力转向系统的应变式扭矩传感器%Some Strain Type Torque Sensors That Can be Applied to Electric Power Steering Systems

    Institute of Scientific and Technical Information of China (English)

    李春阳

    2015-01-01

    A torque sensor is a key component of an auto electric power Steering system (EPS) , and its output characteristics has a direct effect on the accuracy and stability of EPS output. The application principle, characteristics and use scope of sev-eral typical kinds of strain type torque sensors are introduced. Coupled with the research situation at home and abroad, the development trend of strain type torque sensors applied to EPS system is induced.%扭矩传感器是汽车电动助力转向系统(Electric Power Steering,EPS)的关键部件之一,其输出特性直接影响EPS的输出准确性和稳定性。介绍了几种典型应变式扭矩传感器的应用原理、特点和使用范围,结合国内外的研究概况,归纳出应用于EPS系统应变式扭矩传感器的发展趋势。

  6. Continuous Fiber Ceramic Composites

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  7. Defect production in ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Kinoshita, C. [Kyushu Univ. (Japan)

    1997-08-01

    A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si{sub 3}N{sub 4}), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed.

  8. JPRS Report, Science & Technology, Japan, 28th Ceramics Science Discussion

    Science.gov (United States)

    2007-11-02

    Hiroshi Asakura, Hiroshi Yamamura] .............................. 59 Microstructure, Dielectric Properties of Tungsten Bronze -Type Ceramics [Yoji Ueda...of Strain 60 Microstructure, Dielectric Properties of Tungsten Bronze -Type Ceramics 906C7512 Tokyo SERAMIKKUSU KISO KAGAKU TORONKAI in Japanese 24 Jan...with different microstructures were produced for an oxide of the tungsten bronze type, Ba 0 . 5 Sr 0 . 5 Nb 20 6 , by varying the particle size and

  9. Metallic-fibre-reinforced ceramic-matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, F.; Schnedecker, G.; Boncoeur, M.

    1994-12-31

    A refractory metal wire cloth is embedded in an oxide ceramic matrix, using a plasma spraying technology, in order to elaborate composite plates. When mechanically tested, the composite fails with a pseudo-ductile fracture mode whereas the ceramic alone is originally brittle. It exhibits a higher fracture strength, and remains in the form of a single piece even when straining is important. No further heat treatment is needed after the original processing to reach these characteristics. (authors). 2 figs., 2 refs.

  10. An Embedded FBG Strain Sensor for Bridge Cable Tension Measurement%光纤光栅的缆索锚固区索力测量传感器设计

    Institute of Scientific and Technical Information of China (English)

    刘立; 陈伟民; 章鹏; 吴俊; 刘浩

    2012-01-01

    A Fiber Bragg Grating (FBG) embedded strain sensor is put forward. This method can make sure the survival of the sensor and solve the problem of over range measurement. It is mounted into the bridge anchor zone to detect the decay strain derived from cable body. Based on the analysis of bridge cable, design requests of this sensor are known as package structure, modulus of elasticity of package which must be matched up with the anchor material. Finally, epoxy glue with micro silicon is used as the package layer. To make sure the performance of the sensor, tensile tests are conducted by tensile testing machine, the results show that the linearity of sensor is 0.999 74, and the sensitivity is 2.74 pm/N, good in repeatability. And then the sensors arc put into the cable anchor, tensile test of the cable is implemented, and the sensor is good at linearity and repeatability.%在光纤光栅传感器测量缆索索力的应用中,为了保证传感器的存活率以及解决超量程测量的问题,设计了一种桥梁缆索锚固区植入式光纤光栅应变传感器.通过对桥梁缆索特性分析,对该传感器的封装结构、封装材料的弹性模量提出设计要求,并选择环氧树脂添加微细硅粉作为传感器封装层材料.利用拉力试验机对植入式应变传感器进行力学传感器性能实验,其线性度R2为0.999 74,灵敏度为2.74 pm/N,重复性好.把植入式传感器植入缆索锚固区,进行缆索张力实验.实验数据具有良好的线性度和重复性.

  11. Capacitive pressure sensor in post-processing on LTCC substrates

    NARCIS (Netherlands)

    Meijerink, M.G.H.; Nieuwkoop, E.; Veninga, E.P.; Meuwissen, M.H.H.; Tijdink, M.W.W.J.

    2005-01-01

    A capacitive pressure sensor was realized by means of a post-processing step on a low temperature co-fired ceramics (LTCC) substrate. The new sensor fabrication technology allows for integration of the sensor with interface circuitry and possibly also wireless transmission circuits on LTCC substrate

  12. Ceramic Technology Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The Ceramic Technology Project was developed by the USDOE Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the USDOE and NASA advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. A five-year project plan was developed with extensive input from private industry. In July 1990 the original plan was updated through the estimated completion of development in 1993. The objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities.

  13. Large Field-Induced Strain Properties of Sr(K0.25Nb0.75) O3-Modified Bi1/2(Na0.82K0.18)1/2TiO3 Lead-Free Piezoelectric Ceramics

    Science.gov (United States)

    Tran, Vu Diem Ngoc; Ullah, Aman; Dinh, Thi Hinh; Lee, Jae-Shin

    2016-05-01

    Lead-free piezoelectric ceramics with compositions of (1 - x)Bi1/2(Na0.82 K0.18)1/2TiO3 + xSr(K0.25Nb0.75)O3, which are abbreviated as (1 - x)BNKT- xSKN with x = 0, 0.01, 0.02, 0.03, 0.04, and 0.05, were synthesized using a conventional solid-state reaction method. The effects of SKN addition on the BNKT system were examined in terms of the phase transition, strain behavior, and ferroelectric and dielectric properties. X-ray diffraction revealed a single perovskite phase for all compositions. The results showed that with increasing SKN content, BNKT-SKN underwent a phase transition from the coexistence of rhombohedral and tetragonal phases to a tetragonal phase. The addition of SKN shifted the depolarization temperature, T d, to a lower temperature and enhanced the diffuseness of the dielectric peaks. The polarization and bipolar strain hysteresis loops of BNKT-SKN showed that the addition of SKN induced a ferroelectric to ergodic relaxor phase transition with a disruption of the ferroelectric order of pure BNKT. As a result, the strain of BNKT-SKN improved significantly with increasing SKN content and reached the highest value of a normalized strain, S max/ E max, of 557 pm/V, when modified with 3 mol.% SKN.

  14. Effect of Lanthanum Doping on Ferroelectric and Strain Properties of 0.96Bi1/2(Na0.84K0.16)1/2TiO3-0.04SrTiO3 Lead-Free Ceramics

    Science.gov (United States)

    Tran, Vu Diem Ngoc; Ullah, Aman; Dinh, Thi Hinh; Lee, Jae-Shin

    2016-05-01

    Lead-free 0.96[Bi1/2(Na0.84K0.16)1/2](1- x)La x TiO3-0.04SrTiO3 (BNKTLa x-ST, with x = 0.00, 0.01, 0.02, 0.03, 0.04, and 0.05) ceramics have been synthesized using a conventional solid-state reaction method and their phase transition, dielectric, ferroelectric, and strain properties investigated. X-ray diffraction patterns revealed formation of pure perovskite phase. A phase transition from coexistence of rhombohedral and tetragonal to a pseudocubic phase was observed at x = 0.02. Polarization and bipolar strain hysteresis loops indicated that the ferroelectric order (FE) of BNKT-ST is significantly disrupted by lanthanum doping. The destabilization of the FE order results in degradation of the remanent polarization, coercive field, depolarization temperature ( T d), electromechanical coupling factor ( k p), and static d 33, accompanied by large electric-field-induced strain of 0.34% at 60 kV/cm with normalized strain of d 33 * = S max/ E max = 600 pm/V at a critical composition of around x = 0.02.

  15. Proton conducting cerate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Coffey, G.W.; Pederson, L.R.; Armstrong, T.R.; Bates, J.L.; Weber, W.J. [Pacific Northwest Lab., Richland, WA (United States)

    1995-08-01

    Cerate perovskites of the general formula AM{sub x}Ce{sub 1-x}O{sub 3-{delta}}, where A = Sr or Ba and where M = Gd, Nd, Y, Yb or other rare earth dopant, are known to conduct a protonic current. Such materials may be useful as the electrolyte in a solid oxide fuel cell operating at intermediate temperatures, as an electrochemical hydrogen separation membrane, or as a hydrogen sensor. Conduction mechanisms in these materials were evaluated using dc cyclic voltammetry and mass spectrometry, allowing currents and activation energies for proton, electron, and oxygen ion contributions to the total current to be determined. For SrYb{sub 0.05}Ce{sub 0.95}O{sub 3-{delta}}, one of the best and most environmentally stable compositions, proton conduction followed two different mechanisms: a low temperature process, characterized by an activation energy of 0.42{+-}0.04 eV, and a high temperature process, characterized by an activation energy of 1.38{+-}0.13 eV. It is believed that the low temperature process is dominated by grain boundary conduction while bulk conduction is responsible for the high temperature process. The activation energy for oxygen ion conduction (0.97{+-}0.10 eV) agrees well with other oxygen conductors, while that for electronic conduction, 0.90{+-}0.09 eV, is affected by a temperature-dependent electron carrier concentration. Evaluated by direct measurement of mass flux through a dense ceramic with an applied dc field, oxygen ions were determined to be the majority charge carrier except at the lowest temperatures, followed by electrons and then protons.

  16. Final Report for Award DE-SC0005403. Improved Electrochemical Performance of Strained Lattice Electrolytes via Modulated Doping

    Energy Technology Data Exchange (ETDEWEB)

    Hertz, Joshua L. [Univ. of Delaware, Newark, DE (United States); Prasad, Ajay K. [Univ. of Delaware, Newark, DE (United States)

    2015-09-06

    The enclosed document provides a final report to document the research performed at the University of Delaware under Grant DE-SC0005403: Improved Electrochemical Performance of Strained Lattice Electrolytes via Modulated Doping. The ultimate goal of this project was to learn how to systematically strain the inter-atomic distance in thin ceramic films and how to use this newfound control to improve the ease by which oxygen ions can conduct through the films. Increasing the ionic conductivity of ceramics holds the promise of drastic improvements in the performance of solid oxide fuel cells, chemical sensors, gas permeation membranes, and related devices. Before this work, the experimental evidence advocating for strain-based techniques was often controversial and poorly characterized. Enabling much of this work was a new method to quickly create a very wide range of ceramic nanostructures that was established during the first phase of the project. Following this initial phase, we created a variety of promising nanostructured epitaxial films and multilayers with systematic variations in lattice mismatch and dopant content. Over the course of the work, a positive effect of tensile atomic strain on the oxygen conductivity was conclusively found using a few different forms of samples and experimental techniques. The samples were built by sputtering, an industrially scalable technique, and thus the technological implementation of these results may be economically feasible. Still, two other results consistently achieved over multiple efforts in this work give pause. The first of these results was that very specific, pristine surfaces upon which to build the nanostructures were strictly required in order to achieve measurable results. The second of these results was that compressively strained films with concomitant reductions in oxygen conductivity are much easier to obtain relative to tensile-strained films with increased conductivity.

  17. Industrial Ceramics: Secondary Schools.

    Science.gov (United States)

    New York City Board of Education, Brooklyn, NY. Bureau of Curriculum Development.

    The expanding use of ceramic products in today's world can be seen in the areas of communications, construction, aerospace, textiles, metallurgy, atomic energy, and electronics. The demands of science have brought ceramics from an art to an industry using mass production and automated processes which requires the services of great numbers as the…

  18. Verification of ceramic structures

    NARCIS (Netherlands)

    Behar-Lafenetre, S.; Cornillon, L.; Rancurel, M.; Graaf, D. de; Hartmann, P.; Coe, G.; Laine, B.

    2012-01-01

    In the framework of the "Mechanical Design and Verification Methodologies for Ceramic Structures" contract [1] awarded by ESA, Thales Alenia Space has investigated literature and practices in affiliated industries to propose a methodological guideline for verification of ceramic spacecraft and instr

  19. Relaxor-PT Single Crystal Piezoelectric Sensors

    OpenAIRE

    Xiaoning Jiang; Jinwook Kim; Kyugrim Kim

    2014-01-01

    Relaxor-PbTiO3 piezoelectric single crystals have been widely used in a broad range of electromechanical devices, including piezoelectric sensors, actuators, and transducers. This paper reviews the unique properties of these single crystals for piezoelectric sensors. Design, fabrication and characterization of various relaxor-PT single crystal piezoelectric sensors and their applications are presented and compared with their piezoelectric ceramic counterparts. Newly applicable fields and futu...

  20. [Study on the axial strain sensor of birefringence photonic crystal fiber loop mirror based on the absolute integral of the monitoring peak].

    Science.gov (United States)

    Jiang, Ying; Zeng, Jie; Liang, Da-Kai; Wang, Xue-Liang; Ni, Xiao-Yu; Zhang, Xiao-Yan; Li, Ji-Feng; Luo, Wen-Yong

    2013-12-01

    In the present paper, the theoretical expression of the wavelength change and the axial strain of birefringence fiber loop mirror is developed. The theoretical result shows that the axial strain sensitivity of birefringence photonic crystal fiber loop mirror is much lower than conventional birefringence fiber loop mirror. It is difficult to measure the axial strain by monitoring the wavelength change of birefringence photonic crystal fiber loop mirror, and it is easy to cause the measurement error because the output spectrum is not perfectly smooth. The different strain spectrum of birefringence photonic crystal fiber loop mirror was measured experimentally by an optical spectrum analyzer. The measured spectrum was analysed. The results show that the absolute integral of the monitoring peak decreases with increasing strain and the absolute integral is linear versus strain. Based on the above results, it is proposed that the axial strain can be measured by monitoring the absolute integral of the monitoring peak in this paper. The absolute integral of the monitoring peak is a comprehensive index which can indicate the light intensity of different wavelength. This method of monitoring the absolute integral of the monitoring peak to measure the axial strain can not only overcome the difficulty of monitoring the wavelength change of birefringence photonic crystal fiber loop mirror, but also reduce the measurement error caused by the unsmooth output spectrum.

  1. Ceramics As Materials Of Construction

    OpenAIRE

    Zaki, A.; Eteiba, M. B.; Abdelmonem, N.M.

    1988-01-01

    This paper attempts to review the limitations for using the important ceramics in contact with corrosive media. Different types of ceramics are included. Corrosion properties of ceramics and their electrical properties are mentioned. Recommendations are suggested for using ceramics in different media.

  2. Structural health monitoring with fiber optic sensors

    Institute of Scientific and Technical Information of China (English)

    F.ANSARI

    2009-01-01

    Optical fiber sensors have been successfully implemented in aeronautics, mechanical systems, and medical applications. Civil structures pose further challenges in monitoring mainly due to their large dimensions, diversity and heterogeneity of materials involved, and hostile construction environment. This article provides a summary of basic principles pertaining to practical health monitoring of civil engineering structures with optical fiber sensors. The issues discussed include basic sensor principles, strain transfer mechanism, sensor packaging, sensor placement in construction environment, and reliability and survivability of the sensors.

  3. Morphotropic NaNbO{sub 3}-BaTiO{sub 3}-CaZrO{sub 3} lead-free ceramics with temperature-insensitive piezoelectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Ruzhong, E-mail: piezolab@hfut.edu.cn, E-mail: rzzuo@hotmail.com; Qi, He; Fu, Jian [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009 (China)

    2016-07-11

    A morphotropic NaNbO{sub 3}-based lead-free ceramic was reported to have temperature-insensitive piezoelectric and electromechanical properties (d{sub 33} = 231 pC/N, k{sub p} = 35%, T{sub c} = 148 °C, and low-hysteresis strain ∼0.15%) in a relatively wide temperature range. This was fundamentally ascribed to the finding of a composition-axis vertical morphotropic phase boundary in which coexisting ferroelectric phases are only compositionally driven and thermally insensitive. Both phase coexistence and nano-scaled domain morphology deserved well enhanced electrical properties, as evidenced by means of synchrotron x-ray diffraction and transmission electron microscopy. Our study suggests that the current lead-free ceramic would be a very promising piezoelectric material for actuator and sensor applications.

  4. High pressure ceramic joint

    Science.gov (United States)

    Ward, Michael E.; Harkins, Bruce D.

    1993-01-01

    Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

  5. The APS ceramic chambers

    Energy Technology Data Exchange (ETDEWEB)

    Milton, S.; Warner, D.

    1994-07-01

    Ceramics chambers are used in the Advanced Photon Source (APS) machines at the locations of the pulsed kicker and bumper magnets. The ceramic will be coated internally with a resistive paste. The resistance is chosen to allow the low frequency pulsed magnet field to penetrate but not the high frequency components of the circulating beam. Another design goal was to keep the power density experienced by the resistive coating to a minimum. These ceramics, their associated hardware, the coating process, and our recent experiences with them are described.

  6. Interfacing design and making of Ceramics

    DEFF Research Database (Denmark)

    Hansen, Flemming Tvede

    2014-01-01

    allow capturing spatial hand gestures and body movement in real-time. Where technology often seems to take us away from material this approach enables the designers body to be once again involved in the making. This approach builds on McCullough’s (1998) idea about a close connection between digital...... investigates the idea of an interactive digital design tool for designing wall like composition with 3d ceramics and is working on two levels. One which has to do with a digital interactive system that responds on the movement of the hands; at a certain distance the user’s hands appear on a monitor screen...... and Aesthetics in the conference. Digital technology as 3D printing with ceramic allows to bridge from the digital design environment to fabrication. At the same time novel digital means can create new interfaces between the human, space and the material. Here advances in 3d motion capture technology and sensors...

  7. Advanced Ceramics Property Measurements

    Science.gov (United States)

    Salem, Jonathan; Helfinstine, John; Quinn, George; Gonczy, Stephen

    2013-01-01

    Mechanical and physical properties of ceramic bodies can be difficult to measure correctly unless the proper techniques are used. The Advanced Ceramics Committee of ASTM, C-28, has developed dozens of consensus test standards and practices to measure various properties of a ceramic monolith, composite, or coating. The standards give the "what, how, how not, and why" for measurement of many mechanical, physical, thermal, and performance properties. Using these standards will provide accurate, reliable, and complete data for rigorous comparisons with other test results from your test lab, or another. The C-28 Committee has involved academics, producers, and users of ceramics to write and continually update more than 45 standards since the committee's inception in 1986. Included in this poster is a pictogram of the C-28 standards and information on how to obtain individual copies with full details or the complete collection of standards in one volume.

  8. Ceramic fiber filter technology

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, B.L.; Janney, M.A.

    1996-06-01

    Fibrous filters have been used for centuries to protect individuals from dust, disease, smoke, and other gases or particulates. In the 1970s and 1980s ceramic filters were developed for filtration of hot exhaust gases from diesel engines. Tubular, or candle, filters have been made to remove particles from gases in pressurized fluidized-bed combustion and gasification-combined-cycle power plants. Very efficient filtration is necessary in power plants to protect the turbine blades. The limited lifespan of ceramic candle filters has been a major obstacle in their development. The present work is focused on forming fibrous ceramic filters using a papermaking technique. These filters are highly porous and therefore very lightweight. The papermaking process consists of filtering a slurry of ceramic fibers through a steel screen to form paper. Papermaking and the selection of materials will be discussed, as well as preliminary results describing the geometry of papers and relative strengths.

  9. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

    This article describes how to make a clay camera. This idea of creating functional cameras from clay allows students to experience ceramics, photography, and painting all in one unit. (Contains 1 resource and 3 online resources.)

  10. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

    This article describes how to make a clay camera. This idea of creating functional cameras from clay allows students to experience ceramics, photography, and painting all in one unit. (Contains 1 resource and 3 online resources.)

  11. Glass and glass-ceramic photonic systems

    Science.gov (United States)

    Zur, Lidia; Thi Ngoc Tran, Lam; Meneghetti, Marcello; Varas, Stefano; Armellini, Cristina; Ristic, Davor; Chiasera, Alessandro; Scotognella, Francesco; Pelli, Stefano; Nunzi Conti, Gualtiero; Boulard, Brigitte; Zonta, Daniele; Dorosz, Dominik; Lukowiak, Anna; Righini, Giancarlo C.; Ramponi, Roberta; Ferrari, Maurizio

    2017-02-01

    The development of optically confined structure is a major topic in both basic and applied physics not solely ICT oriented but also concerning lighting, laser, sensing, energy, environment, biological and medical sciences, and quantum optics. Glasses and glass-ceramics activated by rare earth ions are the bricks of such structures. Glass-ceramics are nanocomposite systems that exhibit specific morphologic, structural and spectroscopic properties allowing developing new physical concepts, for instance the mechanism related to the transparency, as well as novel photonic devices based on the enhancement of the luminescence. The dependence of the final product on the specific parent glass and on the fabrication protocol still remain an important task of the research in material science. Looking to application, the enhanced spectroscopic properties typical of glass ceramic in respect to those of the amorphous structures constitute an important point for the development of integrated optics devices, including optical amplifiers, monolithic waveguide laser, novel sensors, coating of spherical microresonators, and up and down converters. This paper presents some results obtained by our consortium regarding glass-based photonics systems. We will comment the energy transfer mechanism in transparent glass ceramics taking as examples the up and down conversion systems and the role of SnO2 nanocrystals as sensitizers. Coating of spherical resonators by glass ceramics, 1D-Photonic Crystals for luminescence enhancement, laser action and disordered 1-D photonic structures will be also discussed. Finally, RF-Sputtered rare earth doped P2O5- SiO2-Al2O3-Na2O-Er2O3 planar waveguides, will be presented.

  12. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-07-01

    This is the fourth quarterly report on a new study to develop a ceramic membrane/metal joint. The first experiments using the La-Sr-Fe-O ceramic are reported. Some of the analysis performed on the samples obtained are commented upon. A set of experiments to characterize the mechanical strength and thermal fatigue properties of the joints has been designed and begun. Finite element models of joints used to model residual stresses are described.

  13. The effect of flexoelectricity on the dielectric properties of inhomogeneously strained ferroelectric thin films

    NARCIS (Netherlands)

    Catalan, G; Sinnamon, LJ; Gregg, JM

    2004-01-01

    Recent experimental measurements of large flexoelectric coefficients in ferroelectric ceramics suggest that strain gradients can affect the polarization and permittivity behaviour of inhomogeneously strained ferroelectrics. Here we present a phenomenological model of the effect of flexoelectricity o

  14. 应变片倾斜角度对称重传感器偏载误差的影响%Influence of strain gauge tilt angle on eccentric error of load sensor

    Institute of Scientific and Technical Information of China (English)

    尹继武; 龙姝明

    2014-01-01

    基于双孔平行梁作为弹性元件的称重传感器,分析应变计粘贴时的倾斜角度对称重传感器偏载误差的影响。研究表明:偏载误差与载荷作用点偏移距离成线性关系;一般情况下,纵向偏载误差小于横向偏载误差;减小因为应变片粘贴倾斜角引起的偏载误差的办法是,改进应变片粘贴工艺,使应变片倾斜角相等且尽量小。%Based on double-hole parallel beams as the elastic element ,the paper analyzed the influence of strain gauge tilt angle on eccentric error of load sensor .The result showed that eccentric load error is in pro-portion to the offset distance of load position .Generally,longitudinal eccentric load error is far less than hori-zontal eccentric load error .The fundamental method ,which can reduce error caused by strain gauge tilt angle , is to improve the pasting process ,and to make tilt angle of every strain gauge equal and as small as possible .

  15. Degradability of dental ceramics.

    Science.gov (United States)

    Anusavice, K J

    1992-09-01

    The degradation of dental ceramics generally occurs because of mechanical forces or chemical attack. The possible physiological side-effects of ceramics are their tendency to abrade opposing dental structures, the emission of radiation from radioactive components, the roughening of their surfaces by chemical attack with a corresponding increase in plaque retention, and the release of potentially unsafe concentrations of elements as a result of abrasion and dissolution. The chemical durability of dental ceramics is excellent. With the exception of the excessive exposure to acidulated fluoride, ammonium bifluoride, or hydrofluoric acid, there is little risk of surface degradation of virtually all current dental ceramics. Extensive exposure to acidulated fluoride is a possible problem for individuals with head and/or neck cancer who have received large doses of radiation. Such fluoride treatment is necessary to minimize tooth demineralization when saliva flow rates have been reduced because of radiation exposure to salivary glands. Porcelain surface stains are also lost occasionally when abraded by prophylaxis pastes and/or acidulated fluoride. In each case, the solutes are usually not ingested. Further research that uses standardized testing procedures is needed on the chemical durability of dental ceramics. Accelerated durability tests are desirable to minimize the time required for such measurements. The influence of chemical durability on surface roughness and the subsequent effect of roughness on wear of the ceramic restorations as well as of opposing structures should also be explored on a standardized basis.

  16. Poole-frenkel piezoconductive element and sensor

    Science.gov (United States)

    Habermehl, Scott D.

    2004-08-03

    A new class of highly sensitive piezoconductive strain sensor elements and sensors has been invented. The new elements function under conditions such that electrical conductivity is dominated by Poole-Frenkel transport. A substantial piezoconductive effect appears in this regime, allowing the new sensors to exhibit sensitivity to applied strain as much as two orders of magnitude in excess of prior art sensors based on doped silicon.

  17. Clinical application of bio ceramics

    Science.gov (United States)

    Anu, Sharma; Gayatri, Sharma

    2016-05-01

    Ceramics are the inorganic crystalline material. These are used in various field such as biomedical, electrical, electronics, aerospace, automotive and optical etc. Bio ceramics are the one of the most active areas of research. Bio ceramics are the ceramics which are biocompatible. The unique properties of bio ceramics make them an attractive option for medical applications and offer some potential advantages over other materials. During the past three decades, a number of major advances have been made in the field of bio ceramics. This review focuses on the use of these materials in variety of clinical scenarios.

  18. Development of ceramic-reinforced photopolymers for SLA 3D printing technology

    Science.gov (United States)

    Yun, Ji Sun; Park, Tae-Wan; Jeong, Young Hun; Cho, Jeong Ho

    2016-06-01

    Al2O3 ceramic-reinforced photopolymer samples for SLA 3D printing technology were prepared using a silane coupling agent (VTES, vinyltriethoxysilane). Depending on the method used to coat the VTES onto the ceramic surface, the dispersion of ceramic particles in the photopolymer solution was remarkably improved. SEM, TEM and element mapping images showed Al2O3 particles well wrapped with VTES along with well-distributed Al2O3 particles overall on the cross-sectional surfaces of 3D-printed objects. The tensile properties (stress-strain curves) of 3D-printed objects of the ceramic-reinforced photopolymer were investigated as a function of the Al2O3 ceramic content when it ranged from 0 to 20 wt%. The results demonstrate that an Al2O3 ceramic content of 15 wt% resulted in enhanced tensile characteristics.

  19. Thin-Film Ceramic Thermocouples Fabricated and Tested

    Science.gov (United States)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Gregory, Otto J.; Blaha, Charles A.

    2004-01-01

    The Sensors and Electronics Technology Branch of the NASA Glenn Research Center is developing thin-film-based sensors for surface measurement in propulsion system research. Thin-film sensors do not require special machining of the components on which they are mounted, and they are considerably thinner than wire- or foil-based sensors. One type of sensor being advanced is the thin-film thermocouple, specifically for applications in high-temperature combustion environments. Ceramics are being demonstrated as having the potential to meet the demands of thin-film thermocouples in advanced aerospace environments. The maximum-use temperature of noble metal thin-film thermocouples, 1500 C (2700 F), may not be adequate for components used in the increasingly harsh conditions of advanced aircraft and next-generation launch vehicles. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically in the form of bulky rods or probes. As part of ASTP, Glenn's Sensors and Electronics Technology Branch is leading an in-house effort to apply ceramics as thin-film thermocouples for extremely high-temperature applications as part of ASTP. Since the purity of the ceramics is crucial for the stability of the thermocouples, Glenn's Ceramics Branch and Case Western Reserve University are developing high-purity ceramic sputtering targets for fabricating high-temperature sensors. Glenn's Microsystems Fabrication Laboratory, supported by the Akima Corporation, is using these targets to fabricate thermocouple samples for testing. The first of the materials used were chromium silicide (CrSi) and tantalum carbide (TaC). These refractory materials are expected to survive temperatures in excess of 1500 C. Preliminary results indicate that the thermoelectric voltage output of a thin-film CrSi versus TaC thermocouple is 15 times that of the standard type R (platinum-rhodium versus platinum) thermocouple, producing 20 mV with a 200

  20. FOREWORD: Focus on innovation in ceramics research in East Asia Focus on innovation in ceramics research in East Asia

    Science.gov (United States)

    Kato, Akio; Hishita, Shunichi; Osada, Minoru; Haneda, Hajime

    2010-10-01

    Ceramics, as broadly defined, include all materials other than organic substances and metals, either crystalline or amorphous. They have been used by humans since early history and have contributed considerably to improving the quality of our life. In most cases, however, high-temperature treatment is necessary to prepare ceramics. This burdens the environment and there is therefore a great need for new ceramics processing methods. Recent technologically advanced ceramics are often composed of nanocrystallites, which have great potential for innovation in terms of exploring practical applications of nanomaterials and, consequently, reducing the environmental load. The ceramics industry had long flourished in Asia, particularly in East Asia, and even today, this region is leading the development of related materials. In line with these traditions, Japanese and Korean ceramics societies have been co-sponsoring seminars on ceramics since the 1980s. Having become more international in scope and context, a series of these seminars is now known as the International Japan-Korea Seminar on Ceramics. This focus issue contains eight key articles presented at the 26th International Japan-Korea Seminar on Ceramics held on 24-26 November 2010 at the Tsukuba International Congress Center. In particular, Fabbri et al review electrode materials for protonic solid-oxide fuel cells, and Kamiya et al outline the present situation and future prospects for transparent transistors, particularly those based on amorphous In-Ga-Zn-O films. Eitel et al discuss the progress in engineering high-strain lead-free piezoelectric ceramics. Kim and Kumar review a simple processing method for producing porous ceramics using polysiloxane precursors, Kamiya and Iijima focus on surface modification and characterization of nanomaterials, and Wan et al briefly review the strategy of reducing lattice thermal conductivity of thermoelectric materials and propose new materials for thermoelectric devices