The stress-strain-resistance relations of the Fe-Mn-Si alloys with different Si content have been investigated by measuring strain (ε) and resistance (△ R/R) upon tension synchronously. The results show that the str...The stress-strain-resistance relations of the Fe-Mn-Si alloys with different Si content have been investigated by measuring strain (ε) and resistance (△ R/R) upon tension synchronously. The results show that the strum induced γ→ε martensitic transfor- mation increases the strain sensitivity coeffcient of resistance (K) for the Fe-Mn-Si alloys in plastic region. There is a critical strum where dσ/dε becomes a constant value. Si increases the critical strum. A correlation between the critical strain and shape memory effect (SME) in the Fe-Mn-Si alloys is suggested.展开更多
This study proposed a new yarn-like strain sensor on the basis of the braided skin-core rope,and investigated the effect of braiding structures on the sensing properties of sensors.The morphology and electromechanical...This study proposed a new yarn-like strain sensor on the basis of the braided skin-core rope,and investigated the effect of braiding structures on the sensing properties of sensors.The morphology and electromechanical properties of the strain sensor with different braiding structures were compared and evaluated.The results show that the sensing performance of the sensor from a braided skin-core rope depends on both the number of yarns in braiding and the metallized process of braided rope.Generally,the present stretchable skin-core rope-based sensor provides a basis for the formation of a highly sensitive sensing structure.展开更多
The present work deals with the development of low cost, appreciably accurate precision electronic circuit for resistive sensor where measurement of the incremental resistance change with high degree of accuracy is es...The present work deals with the development of low cost, appreciably accurate precision electronic circuit for resistive sensor where measurement of the incremental resistance change with high degree of accuracy is essential. A linear and sensitive active half bridge circuit requiring only few components for its hardware implementation has been proposed for measuring very small resistance change due to change in physical quantity or chemical analytes. Theory of the proposed active bridge circuit has been discussed and experimental results have been compared with conventional bridge circuit. Initial measurements are made with Pt-100 Strain gauge sensor but it can be extended to other resistive sensors of practical importance. Results show that the active bridge circuit is almost four times more sensitive than conventional half bridge circuit and two times more sensitive than full Wheatstone bridge circuit. Studies have also been made to analyze the errors due to ambient temperature, connecting lead resistance and dc excitation voltage. Experimental results show that output of the circuit has negligible effect on ambient temperature and connecting lead resistance. The error due to excitation voltage has been compensated using Artificial Neural Network (ANN) based inverse modeling technique.展开更多
The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge f...The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge factor （fractional change in resistance per unit strain） of PAN-based carbon fibers is 1.38, which is lower than that of the commonly-used resistance strain gauge. These may due to that the electrical resistivity of carbon fibers decreases under tensile stress. In addition when the carbon fibers are stretched, the change of its resistance is caused by fiber physical dimension and the change of electric resistivity, and mainly caused by the change of physical dimension. The mechanical properties of carbon fiber monofilament were also measured.展开更多
The technology of continuously welded rails （CWRs） is important in modern railway track structures. To measure rail stress, resistance strain gauges are preferred due to their good stability, sensitivity, and esist...The technology of continuously welded rails （CWRs） is important in modern railway track structures. To measure rail stress, resistance strain gauges are preferred due to their good stability, sensitivity, and esistance to external interference. Based on the bi-directional strain method, we present a new method for measuring longitudinal rail stress using resistance strain gauges and develop a monitoring device for rail stress to realize long-term and multi-point measurement. Also relevant experimental verification and analysis are conducted. Results indicate that under various constraints the rail stress–strain values can be calculated just with the measured total longitudinal strain and total vertical strain. Considering the measurement error caused by sectional feature of sensors, we put forward a correction equation applicable to different stress conditions. Although the temperature values of the four full-bridge stress gauges can offset each other, the measurement error caused by rail flexural strain can also be eliminated to a certain extent at the same time, the nonuniform distribution of rail cross section temperature and unbalanced flexural strain still affect the measurement error. The experimental results also show that the developed rail-stress-monitoring sensor is suitable for measuring rail stress with reliable working performance.展开更多
Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical sti...Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical stimuli in complex ambience. Resonant tunneling diodes (RTDs) are the good candidate for such sensing applications due to the ultrafast transport process, lower tunneling current, and negative differential resistance. However, notably enhancing sensing sensitivity remains one of the greatest challenges for RTD-related strain sensors. Here, we use piezotronic effect to improve sensing performance of strain sensors in double-barrier ZnO nanowire RTDs. This strain sensor not only possesses an ultrahigh gauge factor (GF) 390 GPa^(−1), two orders of magnitude higher than these reported RTD-based strain sensors, but also can switch the sensitivity with a GF ratio of 160 by adjusting bias voltage in a small range of 0.2 V. By employing Landauer–Büttiker quantum transport theory, we uncover two primary factors governing piezotronic modulation of resonant tunneling transport, i.e., the strain-mediated polarization field for manipulation of quantized subband levels, and the interfacial polarization charges for adjustment of space charge region. These two mechanisms enable strain to induce the negative differential resistance, amplify the peak-valley current ratio, and diminish the resonant bias voltage. These performances can be engineered by the regulation of bias voltage, temperature, and device architectures. Moreover, a strain sensor capable of electrically switching sensing performance within sensitive and insensitive regimes is proposed. This study not only offers a deep insight into piezotronic modulation of resonant tunneling physics, but also advances the RTD towards highly sensitive and multifunctional sensor applications.展开更多
Karma alloy thin film strain gauges were fabricated on alumina substrates by magnetron sputtering. The electrical properties of strain gauges annealed at different temperatures were then tested. The surface morphology...Karma alloy thin film strain gauges were fabricated on alumina substrates by magnetron sputtering. The electrical properties of strain gauges annealed at different temperatures were then tested. The surface morphology and phase structure of the Karma alloy thin films were analyzed using X-ray diffraction and scanning electron microscopy. The effect of the annealing temperature on the performance of the Karma alloy thin film strain gauge was also investigated. As the annealing temperature increased, it was found that the resistivity of the thin films decreased, whereas the temperature coefficient of resistance (TCR) of the thin films increased. A Karma alloy thin film strain gauge was annealed at 200 °C, thereby obtaining a gauge factor of 1.7 and a corresponding TCR of 64.8 × 10−6 K−1. The prepared Karma alloy thin film strain gauge had a lower TCR than other strain gauges at room temperature. This result can provide a reference for the preparation and application of Karma alloy thin film strain gauges in specific scenarios.展开更多
文摘The stress-strain-resistance relations of the Fe-Mn-Si alloys with different Si content have been investigated by measuring strain (ε) and resistance (△ R/R) upon tension synchronously. The results show that the strum induced γ→ε martensitic transfor- mation increases the strain sensitivity coeffcient of resistance (K) for the Fe-Mn-Si alloys in plastic region. There is a critical strum where dσ/dε becomes a constant value. Si increases the critical strum. A correlation between the critical strain and shape memory effect (SME) in the Fe-Mn-Si alloys is suggested.
基金Biomedical Textile Material Science and Technology,China(111 Project)(No.B07024)
文摘This study proposed a new yarn-like strain sensor on the basis of the braided skin-core rope,and investigated the effect of braiding structures on the sensing properties of sensors.The morphology and electromechanical properties of the strain sensor with different braiding structures were compared and evaluated.The results show that the sensing performance of the sensor from a braided skin-core rope depends on both the number of yarns in braiding and the metallized process of braided rope.Generally,the present stretchable skin-core rope-based sensor provides a basis for the formation of a highly sensitive sensing structure.
文摘The present work deals with the development of low cost, appreciably accurate precision electronic circuit for resistive sensor where measurement of the incremental resistance change with high degree of accuracy is essential. A linear and sensitive active half bridge circuit requiring only few components for its hardware implementation has been proposed for measuring very small resistance change due to change in physical quantity or chemical analytes. Theory of the proposed active bridge circuit has been discussed and experimental results have been compared with conventional bridge circuit. Initial measurements are made with Pt-100 Strain gauge sensor but it can be extended to other resistive sensors of practical importance. Results show that the active bridge circuit is almost four times more sensitive than conventional half bridge circuit and two times more sensitive than full Wheatstone bridge circuit. Studies have also been made to analyze the errors due to ambient temperature, connecting lead resistance and dc excitation voltage. Experimental results show that output of the circuit has negligible effect on ambient temperature and connecting lead resistance. The error due to excitation voltage has been compensated using Artificial Neural Network (ANN) based inverse modeling technique.
基金Funded by the National Natural Science Foundation of China (No.10672128 and 50878170)
文摘The deformation resistance effect of polyacrylonitrile （PAN）-based carbon fibers was investigated, and the variatipn law of electrical resistivity under tensile stress was analyzed. The results show that the gauge factor （fractional change in resistance per unit strain） of PAN-based carbon fibers is 1.38, which is lower than that of the commonly-used resistance strain gauge. These may due to that the electrical resistivity of carbon fibers decreases under tensile stress. In addition when the carbon fibers are stretched, the change of its resistance is caused by fiber physical dimension and the change of electric resistivity, and mainly caused by the change of physical dimension. The mechanical properties of carbon fiber monofilament were also measured.
基金the fund support by the National Natural Science Foundation of China (No. 51425804, No. U1234201 and No. U1334203)
文摘The technology of continuously welded rails （CWRs） is important in modern railway track structures. To measure rail stress, resistance strain gauges are preferred due to their good stability, sensitivity, and esistance to external interference. Based on the bi-directional strain method, we present a new method for measuring longitudinal rail stress using resistance strain gauges and develop a monitoring device for rail stress to realize long-term and multi-point measurement. Also relevant experimental verification and analysis are conducted. Results indicate that under various constraints the rail stress–strain values can be calculated just with the measured total longitudinal strain and total vertical strain. Considering the measurement error caused by sectional feature of sensors, we put forward a correction equation applicable to different stress conditions. Although the temperature values of the four full-bridge stress gauges can offset each other, the measurement error caused by rail flexural strain can also be eliminated to a certain extent at the same time, the nonuniform distribution of rail cross section temperature and unbalanced flexural strain still affect the measurement error. The experimental results also show that the developed rail-stress-monitoring sensor is suitable for measuring rail stress with reliable working performance.
基金supported from the National Natural Science Foundation of China(No.62404125)the Hubei Provincial Natural Science Foundation of China(No.2024AFB359)+5 种基金the Yichang City Natural Science Foundation of China(No.A24-3-004)the China Three Gorges University(No.2023RCKJ0035)the Basic Research Programs of Taicang,2021(No.TC2021JC20)the China Postdoctoral Science Foundation(No.2022M722588)the Young Talent Fund of Xi’an Association for Science and Technology(No.959202313090)the Key Research and Development Projects of Shaanxi Province(No.2024GX-YBXM-029).
文摘Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical stimuli in complex ambience. Resonant tunneling diodes (RTDs) are the good candidate for such sensing applications due to the ultrafast transport process, lower tunneling current, and negative differential resistance. However, notably enhancing sensing sensitivity remains one of the greatest challenges for RTD-related strain sensors. Here, we use piezotronic effect to improve sensing performance of strain sensors in double-barrier ZnO nanowire RTDs. This strain sensor not only possesses an ultrahigh gauge factor (GF) 390 GPa^(−1), two orders of magnitude higher than these reported RTD-based strain sensors, but also can switch the sensitivity with a GF ratio of 160 by adjusting bias voltage in a small range of 0.2 V. By employing Landauer–Büttiker quantum transport theory, we uncover two primary factors governing piezotronic modulation of resonant tunneling transport, i.e., the strain-mediated polarization field for manipulation of quantized subband levels, and the interfacial polarization charges for adjustment of space charge region. These two mechanisms enable strain to induce the negative differential resistance, amplify the peak-valley current ratio, and diminish the resonant bias voltage. These performances can be engineered by the regulation of bias voltage, temperature, and device architectures. Moreover, a strain sensor capable of electrically switching sensing performance within sensitive and insensitive regimes is proposed. This study not only offers a deep insight into piezotronic modulation of resonant tunneling physics, but also advances the RTD towards highly sensitive and multifunctional sensor applications.
文摘Karma alloy thin film strain gauges were fabricated on alumina substrates by magnetron sputtering. The electrical properties of strain gauges annealed at different temperatures were then tested. The surface morphology and phase structure of the Karma alloy thin films were analyzed using X-ray diffraction and scanning electron microscopy. The effect of the annealing temperature on the performance of the Karma alloy thin film strain gauge was also investigated. As the annealing temperature increased, it was found that the resistivity of the thin films decreased, whereas the temperature coefficient of resistance (TCR) of the thin films increased. A Karma alloy thin film strain gauge was annealed at 200 °C, thereby obtaining a gauge factor of 1.7 and a corresponding TCR of 64.8 × 10−6 K−1. The prepared Karma alloy thin film strain gauge had a lower TCR than other strain gauges at room temperature. This result can provide a reference for the preparation and application of Karma alloy thin film strain gauges in specific scenarios.
