The Fluidic Load Cell

1974 ◽  
Vol 96 (3) ◽  
pp. 358-360
Author(s):  
Tadeusz M. Drzewiecki
Keyword(s):  
Strain Gage ◽  
Dynamic Range ◽  
Compressive Load ◽  
Load Cell ◽  
Force Measurements ◽  
Output Pressure ◽  
Through Flow ◽  
Load Cells ◽  
Amplifier Gain ◽  
Fluidic Resistance

A possible fluidic load cell design consists of three parts: a structural member that deforms linearly with load, a fluidic strain gage having fluidic resistance that changes with deformation, and a three-stage laminar proportional amplifier-gain block that amplifies the change in strain gage through-flow to useful levels. This Technical Brief presents design relations for the first two parts of such a system. Two compressive load cells were built, incorporating different fabrication techniques and deformation-sensing methods. The loading range of these cells is about 0 to 20 kN (0 to 2 tons) with a dynamic range greater than 100 and a typical full-scale output pressure of 30 pascals (4 × 10−3 psi). Possible applications for fluidic load cells include force measurements in highly incendiary or radiative environments and/or when other fluid control circuitry is used.

LTCC Post Load Cell

2006 ◽  
Vol 3 (4) ◽  
pp. 169-176
Author(s):  
Mário R. Gongora-Rubio ◽  
M. Roberti ◽  
Z M. da Rocha ◽  
L Fraigi
Keyword(s):  
Low Temperature ◽  
Thick Film ◽  
Strain Gage ◽  
Mechanical Load ◽  
Cell Structure ◽  
Compressive Load ◽  
Compressive Force ◽  
Load Cell ◽  
Strain Level ◽  
Load Force

This paper presents the development of a force post compressive load cell, fabricated using Low Temperature Cofired Ceramics (LTCC) technology. It was implemented as an LTCC mechanical load cell structure with a z-axis thick film strain gage using two different approaches. Fabrication methods and materials are explored in this work and fabricated devices are presented. This paper will also present the results of initial electromechanical sensitivity to load force and temperature tests. Compressive force behavior is consistent, in a strain level up to 1.500 micro-strain.

Experimental and Theoretical Rotordynamic Characteristics of a Hybrid Journal Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 132-141 ◽  
Author(s):  
J. T. Sawicki ◽  
R. J. Capaldi ◽  
M. L. Adams
Keyword(s):  
Journal Bearing ◽  
Operating Conditions ◽  
Dynamic Force ◽  
Test Results ◽  
Force Measurements ◽  
Lubrication Equation ◽  
Load Cells ◽  
Theoretical Predictions ◽  
Stiffness And Damping

This paper describes an experimental and theoretical investigation of a four-pocket, oil-fed, orifice-compensated hydrostatic bearing including the hybrid effects of journal rotation. The test apparatus incorporates a double-spool-shaft spindle which permits independent control over the journal spin speed and the frequency of an adjustable-magnitude circular orbit, for both forward and backward whirling. This configuration yields data that enables determination of the full linear anisotropic rotordynamic model. The dynamic force measurements were made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. Theoretical predictions are made for the same configuration and operating conditions as the test matrix using a finite-difference solver of Reynolds lubrication equation. The computational results agree well with test results, theoretical predictions of stiffness and damping coefficients are typically within thirty percent of the experimental results.

Improvements in Data Acquisition for Propulsion Shaft Alignment

2015 ◽  
Author(s):  
W. David Joiner ◽  
Charles J. Cook
Keyword(s):  
Data Acquisition ◽  
Strain Gage ◽  
Strain Gages ◽  
Construction Process ◽  
Crucial Step ◽  
Ship Construction ◽  
Shaft Line ◽  
Load Cells ◽  
Shaft Alignment

Propulsion shaft alignment is a necessary and crucial step in the ship construction process, with manning and schedule constraints requiring accurate results as efficiently as possible. There are two methods for measuring the bearing loading along the shaft line: strain gages and load cells. The legacy method for using strain gages required a lot of man power and the legacy method for using load cells was dependent on the quality of machinist made available. Strain gages are the transducers of choice for measurement; however the data acquisition, especially for ships with long shafting systems, can require many strain gage positions and personnel to conduct tests. Load cells are used to validate the accuracy of the strain gage method and to calculate the shaft runout at each bearing location.

scholarly journals Open Source Digitally Replicable Lab-Grade Scales

2020 ◽  
Author(s):  
Benjamin R. Hubbard ◽  
Joshua M. Pearce
Keyword(s):  
Open Source ◽  
Low Cost ◽  
Cost Savings ◽  
Load Cell ◽  
Significant Cost ◽  
Load Cells ◽  
The Cost ◽  
Cell Data ◽  
Precision Balance ◽  
Multiple Load

This study provides designs for a low-cost, easily replicable open source lab-grade digital scale that can be used as a precision balance. The design is such that it can be manufactured for use in most labs throughout the world with open source RepRap-class material extrusion-based 3-D printers for the mechanical components and readily available open source electronics including the Arduino Nano. Several versions of the design were fabricated and tested for precision and accuracy for a range of load cells. The results showed the open source scale was found to be repeatable within 0.1g with multiple load cells, with even better precision (0.01g) depending on load cell range and style. The scale tracks linearly with proprietary lab-grade scales, meeting the performance specified in the load cell data sheets, indicating that it is accurate across the range of the load cell installed. The smallest loadcell tested(100g) offers precision on the order of a commercial digital mass balance. The scale can be produced at significant cost savings compared to scales of comparable range and precision when serial capability is present. The cost savings increase significantly as the range of the scale increases and are particularly well-suited for resource-constrained medical and scientific facilities.

A Load Cell System in Foot Pressure Analysis

1982 ◽  
Vol 11 (3) ◽  
pp. 121-122 ◽  
Author(s):  
W V James ◽  
J F Orr ◽  
T Huddleston
Keyword(s):  
Low Cost ◽  
Cell System ◽  
Load Cell ◽  
Foot Pressure ◽  
Cost System ◽  
Pressure Sensitive ◽  
Low Profile ◽  
Load Cells ◽  
Pressure Analysis

A method of displaying discrete areas of pressure beneath the foot has been produced. The device employs a pressure sensitive elastomer which gives quantitative readings of the pressure developed. The 512 load cells are enclosed in a low profile platform only one inch in depth which provides a low-cost system that can be employed in clinical situations.

scholarly journals Contact-free unconstraint respiratory measurements with load cells under the bed in awake healthy volunteers: breath-by-breath comparison with pneumotachography

2019 ◽  
Vol 126 (5) ◽  
pp. 1432-1441 ◽  
Author(s):  
Shiroh Isono ◽  
Natsuko Nozaki-Taguchi ◽  
Makoto Hasegawa ◽  
Shinichiro Kato ◽  
Shinsuke Todoroki ◽  
...  
Keyword(s):  
Respiratory Rate ◽  
Human Subjects ◽  
Load Cell ◽  
The Body ◽  
Phase Changes ◽  
Body Postures ◽  
Load Cells ◽  
Centroid Shift ◽  
Lower Load ◽  
Contact Free

Rate of respiration is a fundamental vital sign. Accuracy and precision of respiratory rate measurements with contact-free load cell sensors under the bed legs were assessed by breath-by-breath comparison with the pneumotachography technique during two different dynamic breathing tasks in 16 awake human adults resting on the bed. The subject voluntarily increased and decreased the respiratory rate between 4 and 16 breaths/min ( n = 8) and 10 and 40 breaths/min ( n = 8) at every 2 breaths in 6 different lying postures such as supine, left lateral, right lateral, and 30, 45, and 60° sitting postures. Reciprocal phase changes of the upper and lower load cell signals accorded with the respiratory phases indicating respiratory-related shifts of the centroid along the long axis of the bed. Bland-Altman analyses revealed 0.66 and 1.59 breaths/min standard deviation differences between the techniques (limits of agreement: −1.22 to 1.36 and −2.96 to 3.30) and 0.07 and 0.17 breaths/min fixed bias differences (accuracy) (confidence interval: 0.04 to 0.10 and 0.12 to 0.22) for the mean respiratory rates of 10.5 ± 3.7 and 24.6 ± 8.9 breaths/min, respectively, regardless of the body postures on the bed. Proportional underestimation by this technique was evident for respiratory rates >40 breaths/min. Sample breath increase up to 10 breaths improved the precision from 1.59 to 0.26 breaths/min. Abnormally faster and slower respirations were accurately detected. We conclude that contact-free unconstraint respiratory rate measurements with load cells under the bed legs are accurate and may serve as a new clinical and investigational tool. NEW & NOTEWORTHY Four load cells placed under the bed legs successfully captured a centroid shift during respiration in human subjects lying on a bed. Breath-by-breath comparison of the breaths covering a wide respiratory rate range by pneumotachography confirmed reliability of the contact-free unconstraint respiratory rate measurements by small standard deviations and biases regardless of body postures. Abnormally faster and slower respirations were accurately detected. This technique should be an asset as a new clinical and investigational tool.

Cord Force Measurements in Radial Tires

1972 ◽  
Vol 94 (2) ◽  
pp. 678-682 ◽  
Author(s):  
J. D. Walter
Keyword(s):  
Strain Gage ◽  
Simple Formula ◽  
Rubber Matrix ◽  
Force Measurements ◽  
Inflation Pressure ◽  
Force Transducers ◽  
In Series ◽  
Straight Ahead ◽  
Automobile Tires

Miniature force transducers in the form of strain gage instrumented tension links are used to measure the loads developed in the rayon cords in both the stabilizer and body plies of automobile tires of radial construction. These transducers are placed in series with the cord and are embedded in the rubber matrix of the tire during building. Cord forces are obtained at various wheel loads and inflation pressures for straight ahead rolling and cornering of the tires in operation. It is shown that a relatively simple formula can be used to theoretically predict the cord tension developed in the sidewall region due to inflation pressure.

Development of a Force Sensing Instrument Assisted Soft Tissue Mobilization Device

2016 ◽  
Author(s):  
Ahmed M. Alotaibi ◽  
Sohel Anwar ◽  
M. Terry Loghmani ◽  
Stanley Chien
Keyword(s):  
Soft Tissue ◽  
Load Cell ◽  
Force Measurements ◽  
Clinical Practices ◽  
Stroke Frequency ◽  
Graston Technique ◽  
Overall Design ◽  
Force Components ◽  
Soft Tissue Mobilization ◽  
Force Data

Instrument assisted soft tissue mobilization (IASTM) is a form of massage using rigid manufactured or cast devices. The delivered force, which is a critical parameter in massage during IASTM, has not been measured or standardized for most clinical practices. In addition to the force, the angle of treatment and frequency play an important role during IASTM. As a result, there is a strong need to characterize the delivered force to a patient, angle of treatment, and stroke frequency. This paper proposes a novel mechatronic design for a specific instrument from Graston Technique® (Model GT-3), which is a frequently used tool to clinically deliver localize pressure to the soft tissue. The design uses a 3D load cell, which can measure all three force components force simultaneously. The overall design is implemented with an IMUduino microcontroller chip which can also measure tool orientation angles and provide computed stroke frequency. The prototype of the mechatronic IASTM tool was validated for force measurements using an electronic plate scale that provided the baseline force values to compare with the applied force magnitudes measured by the device. The load cell measurements and the scale readings were found to be in agreement within the expected degree of accuracy. The stroke frequency was computed using the force data and determining the peaks during force application. The orientation angles were obtained from the built-in sensors in the microchip.

THE POTENTIAL OF DIGITAL SEISMIC RECORDINGS FOR MULTICHANNEL PROCESSING

Geophysics ◽  
1970 ◽  
Vol 35 (3) ◽  
pp. 461-470 ◽  
Author(s):  
J. P. Lindsey
Keyword(s):  
Dynamic Range ◽  
Single Channel ◽  
Recording Equipment ◽  
Field Equipment ◽  
Reflection Data ◽  
Field Recording ◽  
Amplifier Gain ◽  
Multichannel Processing ◽  
New Processing ◽  
Processing Techniques

The availability of seismic digital field recording equipment has made possible new processing techniques which achieve significant reflection data enhancement. Typical of the processes that are now used routinely are deconvolution, autocorrelation and crosscorrelation, Fourier transformation, and spectral alteration. A recording fidelity that reduces errors to 1 part in 10,000 has provided the motive for developing and using these techniques. An additional capability of digital field equipment is the recording of amplifier gain information to a precision of 0.1 percent. This appears to provide a motive for developing multichannel processes which expand further our processing capabilities beyond the essentially single channel ones now in use. The present study evaluates the multichannel processing potential afforded by present day seismic digital field recording systems. The evaluation is based on measurement and computation of the effects of channel performance deviations. Each component of the field recording system (geophone, cable, amplifier, filters, sampling skew) separately, and the system as a whole, are evaluated in this context. Results of the study indicate that whereas any given channel possesses a dynamic range of 80 db, channel‐to‐channel variations establish a dynamic range of only 15 db. The 15 db range sets a serious limit on the performance of multichannel processes and points up the need for additional improvements in field hardware capabilities.

On the force fluctuations acting on a circular cylinder in crossflow from subcritical up to transcritical Reynolds numbers

1983 ◽  
Vol 133 ◽  
pp. 265-285 ◽  
Author(s):  
Günter Schewe
Keyword(s):  
Reynolds Number ◽  
Critical Reynolds Number ◽  
Dynamic Range ◽  
Reynolds Numbers ◽  
Band Spectrum ◽  
Transitional Region ◽  
Force Measurements ◽  
Unsteady Forces ◽  
Number Range ◽  
Critical Reynolds Numbers

Force measurements were conducted in a pressurized wind tunnel from subcritical up to transcritical Reynolds numbers 2.3 × 104[les ]Re[les ] 7.1 × 106without changing the experimental arrangement. The steady and unsteady forces were measured by means of a piezobalance, which features a high natural frequency, low interferences and a large dynamic range. In the critical Reynolds-number range, two discontinuous transitions were observed, which can be interpreted as bifurcations at two critical Reynolds numbers. In both cases, these transitions are accompanied by critical fluctuations, symmetry breaking (the occurrence of a steady lift) and hysteresis. In addition, both transitions were coupled with a drop of theCDvalue and a jump of the Strouhal number. Similar phenomena were observed in the upper transitional region between the super- and the transcritical Reynolds-number ranges. The transcritical range begins at aboutRe≈ 5 × 106, where a narrow-band spectrum is formed withSr(Re= 7.1 × 106) = 0.29.

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