Resistance Bridge Research Articles

Method of metrological self-checking of a strain gauge pressure sensor

Existing methods of metrological self-monitoring of measuring sensors for temperature and pressure of technological industries are considered. The analysis of methods of metrological self-checking of strain gauge pressure sensors is carried out. Method is proposed based on measuring the supply voltage and voltage on the measuring diagonal of the bridge. The temperature of the strain gauge bridge is determined using a semiconductor thermistor installed near the bridge. This allows you to adjust the measured value of the total resistance of the bridge from the temperature of the bridge. With aging and exposure to external conditions, a change in the overall resistance of the bridge can be used to judge the error of the sensor. An experimental sample of the sensor was made. The failure of the strain gage bridge is simulated by parallel connection of an additional resistor to one of the shoulders of the bridge. Experimental studies have shown that modern technical means make it possible to assess the effect of changes in the total bridge resistance on the sensor error.

Способ метрологического самоконтроля тензорезистивного датчика давления

Existing methods of metrological self-monitoring of measuring sensors for temperature and pressure of technological industries are considered. The analysis of methods of metrological self-checking of strain gauge pressure sensors is carried out. Method is proposed based on measuring the supply voltage and voltage on the measuring diagonal of the bridge. The temperature of the strain gauge bridge is determined using a semiconductor thermistor installed near the bridge. This allows you to adjust the measured value of the total resistance of the bridge from the temperature of the bridge. With aging and exposure to external conditions, a change in the overall resistance of the bridge can be used to judge the error of the sensor. An experimental sample of the sensor was made. The failure of the strain gage bridge is simulated by parallel connection of an additional resistor to one of the shoulders of the bridge. Experimental studies have shown that modern technical means make it possible to assess the effect of changes in the total bridge resistance on the sensor error.

Dynamical edge effect factor determination for building components thermal characterization under outdoor test conditions in a PASLINK test cell: A methodological proposal

The thermal characterization of building components in dynamic exterior conditions is crucial for understanding their real performance, particularly if they are passive or active solar elements. In this respect, the PASLINK methodology has stood out as an effective technique for outdoor testing due to its level of development and precision. It is based on the use of a calibrated test cell with interior walls covered by heat flow meters. The accurate determination of the heat flow through the envelope of the cell is essential for the subsequent thermal analysis of the passive/active solar component being tested.Although the walls of a PASLINK cell have a high thermal resistance and minimal thermal bridges, a higher heat flux is inevitable near the inner corners because of the edge effects. This variation is partially detected by heat flow meters, requiring correction factors accordingly named ‘edge effect factors’. Additional heat flow meters strategically arranged in some interior corners are used to determine these factors in a calibration test. The factors thus calculated are used as invariable values in subsequent cell tests. However, the skill and knowledge of the staff conducting the calibration test are fundamental, as human errors can affect this process.This proposal outlines a more objective and reliable new methodology to determine edge effect correction factors. It is based on applying correlations of instantaneous readings of heat flow meters. These correlations are obtained in an initial PASLINK calibration test, but are valid for all subsequent tests. The factors calculated in this way depend on instantaneous test readings and, for this reason, they are dynamic values perfectly adapted to each test.The calibration test of the cell called EGUZKI, located in Vitoria-Gasteiz (Northern Spain), is used to demonstrate the validity of the proposed method. With the current PASLINK calibration test methodology, the calibrated cell obtains a measurement error of 13%, while the proposed new dynamic methodology reduces this error to 6%.Although this new methodology is determined in the context of a PASLINK test cell, it is an extensive method applicable to the correction of heat flow measurements affected by edge effects in general.

Fully Differential Chopper-Stabilized Multipath Current-Feedback Instrumentation Amplifier with R-2R DAC Offset Adjustment for Resistive Bridge Sensors

A fully differential multipath current-feedback instrumentation amplifier (CFIA) for a resistive bridge sensor readout integrated circuit (IC) is proposed. To reduce the CFIA’s own offset and 1/f noise, a chopper stabilization technique is implemented. To attenuate the output ripple caused by chopper up-modulation, a ripple reduction loop (RRL) is employed. A multipath architecture is implemented to compensate for the notch in the chopping frequency band of the transfer function. To prevent performance degradation resulting from external offset, a 12-bit R-2R digital-to-analog converter (DAC) is employed. The proposed CFIA has an adjustable gain of 16–44 dB with 5-bit programmable resistors. The proposed resistive sensor readout IC is implemented in a 0.18 μm complementary metal-oxide-semiconductor (CMOS) process. The CFIA draws 169 μA currents from a 3.3 V supply. The simulated input-referred noise and noise efficiency factor (NEF) are 28.3 nV/√Hz and 14.2, respectively. The simulated common-mode rejection ratio (CMRR) is 162 dB, and the power supply rejection ratio (PSRR) is 112 dB.

Fatigue resistance of metal-free cantilever bridges supported by labial laminate veneers

Fatigue resistance of metal-free cantilever bridges supported by labial laminate veneers

Geometric Construction and Static Analysis on Timber-Arched Structural System of Shouning Timber-Arched Lounge Bridge

Due to the disrepair, many timber-arched lounge bridges have structural safety hazards and require protection. This paper analyzed the structural composition as well as the composition principle of of Shouning timber-arched lounge bridge. It is found that the timber-arched bridge structure belongs to highly indeterminate. The ANSYS finite element simulation analysis of timber-arched lounge bridge shows that three-node and five-node seedlings are the components which are mainly subjected to axial force. Their shear stress is only 12% of the axial stress. Three-node and five-node seedlings make full use of the tensile and compressive properties of wood. At the same time, the portal framed bent, horse leg also play an important part in the structure. The double bridging is the important component to guarantee the wind resistance, earthquake resistance and transverse stability of bridges. The results of this paper have academic guidance meaning for the maintenance and reinforcement of timber-arched lounge bridge.

Development of a voltage controlled resistor for use in a self-balancing resistance bridge.

We report on a simple design for a voltage controlled resistor that can operate in a continuous range from ∼50 Ω to over ∼100 kΩ. The device consists of a light emitting diode (LED) placed near a photocell. Varying the voltage across the LED changes its brightness, which, in turn, changes the resistance of the photocell. The resistance of the photoresistor is measured by calibrating the output of a nearby phototransistor against the photoresistor resistance, allowing for an independent measurement of the resistance. The performance of the device is tested in the context of a temperature measuring system involving a Wheatstone bridge.

Monitoring and Evaluation of Overturning Resistance of Box Girder Bridges Based on Time-Varying Reliability Analysis

AbstractIn recent years, overturning accidents of box girder bridges have occurred frequently, causing widespread concern among researchers. From the perspective of bridge structure monitoring, thi...

A flexible and compact electronic system for the bolometric diagnostic with on-line calibration capability

At ENEA Frascati laboratories an updated electronic system for the bolometric diagnostic is under development. The system is based on the most recent electronic technology and it is able to manage a large number of channels. It is flexible, reliable and compact in order to be suitable for applications on large fusion experimental machines or reactors. The system has been conceived to be applied to bolometric detectors based on a resistive bridge, it is mainly based on the digital signal processing technology to guarantee high accuracy, large dynamic range and a high signal to noise ratio. It is also able to manage a large offset of the bridges. A further important feature of the system is the embedded calibration capability of the sensor detectors that allows for the calibration of each channel in parallel and in a very short time with the bolometer heads installed and without any manual intervention on the lay-out, thus also allowing for calibration just shortly before the plasma experiment. A further fast embedded on-line calibration capability allows for the estimation of the sensor temperature and of the temperature gradient in the bolometer head, inside the bolometer measurement temporal window. The paper describes the main concepts, the general architecture of the system and in detail the calibration and the on-line calibration functionalities.

Railroad bridge fatigue life estimation using the probabilistic method and new fatigue resistance for riveted details

Existing fatigue life evaluation procedures are often over-simplified and do not account accurately for the uncertainty in applied load and fatigue resistance of steel railway bridges. Simplified calculations and conservative assumptions often lead to significant reductions in estimated life that indicate older structures ceased to be functional decades ago. Fitness for service assessments that utilise probabilistic methods and that are informed by and consistent with detailed physical inspections of the structures provide a more accurate assessment of the expected life of bridges and can be used to establish improved bridge inspection programmes. This paper focuses on development of probabilistic, risk-based methods and models for assessing steel bridge Fitness for Service (FFS) and remaining life. The fatigue resistance models developed in this project are calibrated, validated, and verified against all available and relevant fatigue test results. For some bridge types, these models provide remaining fatigue life estimates that are double and sometimes even triple those obtained by using existing simplified methods. In this paper, a probabilistic method is demonstrated on two, riveted deck plate girder spans that exceed 100 years of service and are currently located at the Facility for Accelerated Service Testing (FAST) near Pueblo, CO.

From magnetoresistor element to in-plane sensitive Hall device

This paper contributes to the development of in-plane sensitive Hall-effect configurations based on a new sensor concept. An original coupling of pairs of identical two-contact (2C) magnetoresistors transduce an in-plane magnetic field, i.e., parallel to the silicon chip surface into a Hall voltages by means of four-contact (4C) and eight-contact (8C) devices. Two different arrangements are accomplished – hybrid realization with a discrete resistor bridge and fully integrated implementation. The pair’s ohmic contacts of the magnetoresistors are cross-coupled and parallel connected. These configurations has linear and odd output signal as a function of the magnetic field and supply current. The quadratic and even magnetoresistance of innovative solutions is completely suppressed, which ensures high measurement accuracy alongside with identification of the magnetic field polarity. The experimental prototypes feature simplified technological fabrication, sensitivity about 100 V/AT, low output temperature drift and high linearity. The lowest detected magnetic induction at current of 3 mA over frequency range 5 Hz ÷ 500 Hz at a signal-to-noise ratio equal to unity is around 10–12 μT. A benchmarking of the characteristics was performed with both new configurations as well as with an in-plane sensitive four-contact Hall element with closed design. It is established that the new arrangements have advantage and confirms the innovativeness of the proposed concept. The complete electrical, temperature and technological matching of proposed Hall devices is very promising for many practical applications.

A low-cost concurrent TSV test architecture with lossless test output compression scheme.

As the traditional IC design migrates to three-dimensional integrated circuits (3D-ICs) design, new challenges need to be considered carefully to solve its reliability and yield issues. 3D-ICs using through-silicon-vias (TSVs) can have latent defects such as resistive open and bridge defects, which are caused by the thermal stress during the fabrication process. These latent defects lead to the deterioration of the electrical performance of TSVs caused by an undesired increase in the resistance-capacitance (RC) delay. For this reason, various post-bond test methodologies have been studied to improve the reliability of 3D-ICs. Cost reduction in these TSV test architectures is also currently being studied by decreasing various factors such as hardware overhead, test time, and the peak current consumption. Usually, a single test-clock-period is required to determine whether the test result contains the defective TSV. When the test result of any TSVs fails, we use another single test-clock-period to classify its defect type. In this paper, we propose a new TSV test architecture to transfer the combined test output of the test result and the specific defect type to the pad during the single test-clock-period. Our proposed test architecture also provides a reliable block-based concurrent testing to optimize the test time by dividing the die into concurrent blocks. The experimental results showed that our proposed test architecture could reduce the test time and the hardware overhead substantially by ensuring that the reasonable peak power consumption for mass production was reasonable without the test quality being adversely affected.

Experimental characterization and constitutive modeling of polyurethanes for structural applications, accounting for damage, hysteresis, loading rate and long term effects

Polymers are highly customizable materials that present high potential for applications in the development of damage-resistant structural systems. Out of the various polymeric materials, polyurethanes combining high strength (2–3 times that of normal concrete) with high deformation capacity (~0.04 strain at yielding) have been recently considered in the development of damage resistant bridge columns. However, development of structural systems incorporating polyurethanes requires fundamental understanding of their mechanical properties under various loading conditions, as well as development of versatile constitutive models describing such responses. Compared to conventional structural materials, the response properties of polyurethanes include hysteresis, damage (softening), and rate dependence (viscosity) in the elastic and inelastic range. To address this challenge, this study: (i) conducts an experimental program to characterize the mechanical behavior of an amorphous thermoset polyurethane which has been (and is currently being) considered in structural applications, (ii) develops a softening viscoelastic viscoplastic uniaxial material model to simulate the observed response under various loading conditions, and (iii) develops a heuristic systematic procedure to estimate model parameters from test data. The loading conditions of the experimental program include: (a) monotonic/cyclic compression-only and tension-only loading at strain rates up to 0.1/s, (b) multi-step strain-controlled monotonic loading including constant deformation segments to quantify relaxation and capture the so-called equilibrium path, (c) cyclic combined tension-compression uniaxial loading, and (d) relaxation and creep compressive tests. The test results showed nonlinear rate dependence, asymmetric response in tension and compression, monotonic/cyclic damage, and hysteresis.

Reconfigurable Spintronics Wheatstone Bridge Sensors With Offset Voltage Compensation at Wafer Level

Industrial requirements are continuously pushing the sensor limits toward higher signal-to-noise ratio under harsh environments, without compromising production costs by additional electronics. Non-full resistive Wheatstone bridge architectures arise as a compact and cheaper alternative to full-bridge measurement schemes, despite a lower output, linearity, and immunity to thermal drifts promoted by the replacement of the out-of-phase sensing elements by passive elements. However, the combination of state-of-the-art magnetoresistive (MR) sensors with thermally compatible materials used as tunable thin-film resistor at wafer level can lead to competitive prototypes for applications with high constraints. Therefore, the resistivity and the temperature coefficient of resistance (TCR) of Cr, Ti, and TiW thin films were evaluated as potential candidates for a thermal and electrical stable non-full MR bridge. Within a TCR around 1059 ± 12 ppm/°C for a spin-valve sensor lying between the values observed for a Ti thickness range of 300 A up to 500 A (571.9 ± 8.3 and 1347 ± 69 ppm/°C, respectively), a sin/cos magnetic encoder was prototyped in a non-full-bridge architecture with a thermal offset drift of 51.48 ± 0.25 nV/Vcc/°C and an offset voltage of 16 mV/Vcc.

Experimental research on the time-varying law of performance for natural rubber laminated bearings subjected to seawater dry-wet cycles

Natural rubber laminated bearings (NRBs) in sea-crossing or offshore bridges are extremely vulnerable to seawater dry-wet cycles due to weather conditions, wind, waves, and other factors in coastal areas. Seawater dry-wet cycles test was conducted on 20 NRBs and 63 rubber sheets for 60 days to investigate the influence of seawater dry-wet cycles on basic NRB performance. The change laws that govern the NRBs’ horizontal and vertical stiffness were obtained via seawater dry-wet cycles test. In addition, the proposed constitutive parameters of the rubber material were used to establish a finite-element model of the NRBs to simulate and analyze the bearings’ performance and time-varying law. The test results were then compared with the fitted and simulated results. Finally, the performance deterioration law of the NRBs was predicted over a 120-year lifespan based on the extrapolation of the 60-day test results, and the finite element analysis of the performance for NRB within 120-year service life was done to verify the reliable of the prediction result. The 60 days test results show that the NRBs’ horizontal and vertical stiffness increased by 23% and 7%, respectively, after test for 60 days, and horizontal and vertical stiffness increased linearly as the seawater dry-wet cycles test time increased. The findings presented in this paper lay a foundation for further research on the performance of NRBs and will play an important role in the study of the seismic resistance and life-cycle performance of sea-crossing bridges and other structures subjected to seawater dry-wet cycles.

Fire Resistance of Steel Bridge Considering Damage of Marine Environment

ABSTRACT Li, Y. and Dong, F., 2018. Fire resistance of steel bridge considering damage of marine environment. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 442–447. Coconut Creek (Florida), I SSN 0749-0208. The traditional method does not consider the fire resistance of steel bridges subjected to chloride ion corrosion. Therefore, a method for studying the fire resistance of steel bridges under consideration of the damage of marine environment is proposed. First of all, the thermal and mechanical properties of steel bridges at high temperature are analyzed. Then, the corrosion mechanism of steel bridges considering the damage of marine environment is analyzed. Finally, the maximum width of initial crack generated by chloride erosion is acted as the damage index for rapid chloride corrosion test, and then the fire test is performed for components of different damage degree. The experimental results show that the c...

Security and fault tolerance evaluation of TMR–QDI circuits

The authors report the results of a study on the impact of resistive bridging faults on triple modular redundancy (TMR)-based quasi-delay-insensitive (QDI) asynchronous countermeasures, which is used to provide a secure circuit against power analyses. They have carried out the present study on CADENCE using a resistive bridges fault model. They show that the resistive bridge faults can have serious impacts on the security of integrated circuits and it is possible to discover the secret data. Based on the bridges resistance value, there are three operating intervals of secure circuits, in which TMR-based QDI may or may not function correctly in the presence of two resistive bridge faults depending on the interval of the resistance value.

Non-Linear Control for Variable Resistive Bridge Type Fault Current Limiter in AC-DC Systems

This paper proposes a non-linear control-based variable resistive bridge type fault current limiter (VR-BFCL) as a prospective solution to ease the effect of disturbances on voltage source converter-based high voltage DC (VSC-HVDC) systems. A non-linear controller for VR-BFCL has been developed to insert a variable optimum resistance during the inception of system disturbances in order to limit the fault current. The non-linear controller takes the amount of DC link voltage deviation as its input and provides variable duty to generate a variable effective resistance during faults. The VSC-HVDC system’s real and reactive power controllers have been developed based on a current control loop where direct axis and quadrature axis currents are used to control the active and reactive power, respectively. The efficacy of the proposed non-linear control-based VR-BFCL solution has been proved with balanced as well as unbalanced faults. The results confirm that the oscillations in active power and DC link voltage have been significantly reduced by limiting the fault current through the insertion of an optimum effective resistance with the proposed control technique. The real time digital simulator (RTDS) has been used to implement the proposed approach. The performance of the proposed non-linear control based VR-BFCL is compared with that of traditional fixed duty control.

Performance-based seismic design of bridges: a global perspective and critical review of past, present and future directions

The concept of performance-based design (PBD) originated several decades ago and has been evolving since. PBD in its current form aims at achieving one or more predicted performance levels after pre-defined hazards. This paper reviews the fundamentals, evolutions and the current practices of PBD for bridges. The review starts with damage states proposed by researchers, design criteria used in different jurisdictions, along with loss estimate methodologies. The code review covers the United States, Canada, New Zealand, China, Japan and Europe. A case study is performed to compare the various design codes. Among the reviewed codes, the Canadian Code (CSA S6-14) has the most stringent criteria. Apart from reviewing current practices, challenges are also discussed. Most design codes quantify the damage of columns but are not clear on the damage states of other components (e.g. foundations, joints). Bridge damage states are not directly related to residual vertical load capacity after earthquakes, which pose difficulty in predicting traffic interruptions. To address this issue, this study suggests a vertical load capacity factor, which needs to be further investigated in future research. At the end of the review, damage avoidance designs are briefly discussed, which are expected to further improve seismic resistance of bridges.

A study on behavior of steel joints that combine high-strength bolts and fillet welds

In recent years, considerable attention has been paid to the research and development of high-strength steel plates, with particular emphasis on the enhancement of the seismic resistance of buildings and bridges. Many efforts have also been undertaken to improve the properties of high-strength bolts and weld materials. However, there are still different opinions on steel joints that combine high-strength bolts and fillet welds. Therefore, it is necessary to verify the design specifications and guidelines, especially for newly developed 1,400-MPa high-strength bolts, 570-MPa steel plates, and weld materials. This paper presents the results of literature reviews and experimental investigations. Test parameters include bolt strengths, weld orientations, and their combinations. The results show that advances in steel materials have increased the plastic deformation capacities of steel welds. That allows combination joints to gain their maximum strength before the welds have fracture failures. When in combination with longitudinal welds, high-strength bolts slip, come in contact with cover plates, and develop greater bearing strength before the joints reach their maximum strength. However, in the case of combinations with transverse welds, changes in crack angles cause the welds to provide additional strength. The combination joints can therefore develop strength greater than estimated by adding the strength of bolted joints in proportion to those of welded joints. Consequently, using the slip resistance as the available strength of high-strength bolts is recommended. That ensures a margin of safety in the strength design of combination joints.