Semiconductor Strain Gauges Research Articles

Direct tensile behavior of a transversely isotropic rock

Abstract The tensile behavior of a transversely isotropic rock is investigated by a series of direct tensile tests on cylindrical argillite specimens. To study the deformability of argillite under tension, two components of an electrically resistant type of strain gage with a parallel arrangement, or a semiconductor strain gage, are adopted for measuring the small transverse strain observed on specimens during testing. The curves of axial stress vs axial strain and vs average volumetric strain are presented for argillite specimens with differently inclined angles of foliation. Experimental results indicate that the stress-strain behavior depends on the foliation inclination of specimens with respect to the loading direction. The five elastic constants of argillite are calculated by measuring two cylindrical specimens in the manner recommended by Wei and Hudson. Based on theoretical analysis results, the range of the foliation inclination of the specimens tested is investigated for feasibility obtaining the five elastic moduli. A dipping angle of the foliations (θ) of 30–60° with respect to the plane normal to the loading direction is recommended. The final failure modes of the specimens are investigated in detail. A sawtoothed failure plane occurs for the specimens with a high inclination of foliation with respect to the plane perpendicular to the loading direction. On the other hand, a smooth plane occurs along the foliation for specimens with low inclination of foliation with respect to the plane normal to the loading direction. A conceptual failure criterion of tensile strength is proposed for specimens with a high inclination of foliation.

Direct tensile behavior of a transversely isotropic rock

The tensile behavior of a transversely isotropic rock is investigated by a series of direct tensile tests on cylindrical argillite specimens. To study the deformability of argillite under tension, two components of an electrically resistant type of strain gage with a parallel arrangement, or a semiconductor strain gage, are adopted for measuring the small transverse strain observed on specimens during testing. The curves of axial stress vs axial strain and vs average volumetric strain are presented for argillite specimens with differently inclined angles of foliation. Experimental results indicate that the stress-strain behavior depends on the foliation inclination of specimens with respect to the loading direction. The five elastic constants of argillite are calculated by measuring two cylindrical specimens in the manner recommended by Wei and Hudson. Based on theoretical analysis results, the range of the foliation inclination of the specimens tested is investigated for feasibility obtaining the five elastic moduli. A dipping angle of the foliations (θ) of 30–60° with respect to the plane normal to the loading direction is recommended. The final failure modes of the specimens are investigated in detail. A sawtoothed failure plane occurs for the specimens with a high inclination of foliation with respect to the plane perpendicular to the loading direction. On the other hand, a smooth plane occurs along the foliation for specimens with low inclination of foliation with respect to the plane normal to the loading direction. A conceptual failure criterion of tensile strength is proposed for specimens with a high inclination of foliation.

単一応力波によるエネルギ反射率の測定

In order to study the propagation characteristics of stress pulses in various structures, the reflection wave reflected from a fillet part is measured. The part is made of same material as the structure. A semiconductor strain gauge is used for the detection of stress waves. The reflection coefficient is obtained as the summation of the transfer function. The reflection coefficient is calculated by changing the duration of stress pulse and the curvature of fillet. As the result, it becomes clear that the reflection coefficient can be obtained from strain energy without using Discrete Fourier Transform if a single pulse is used.

Effect of applied stresses on magnetostriction of low carbon steel

We have measured the magnetostriction of low carbon steel specimens while applying magnetic fields, being both parallel and perpendicular to the uniaxial applied stress. An individual domain of a polycrystalline steel is elongated in its magnetization direction, which coincides with one of the crystallographic axes, 〈100〉. The magnetization appears as a result of the domain wall movement induced by the applied magnetic field. The rotation of the domain magnetization participates, when the field becomes larger. As the magnetic field is increased, the magnetostriction in the magnetization direction first increases and then shows a maximum when the rotation of the domain magnetization starts to occur. Since the stress affects the domain structure through magnetoelastic interaction, the maximum magnetostriction shows the stress dependence. The magnetoelastic interaction tends to increase the volume of the domains being either parallel to the tensile stress or perpendicular to the compressive stress. The amount of the domain wall movement, equivalently the maximum magnetostriction, is thus larger for the magnetization which is either perpendicular to the tensile stress or parallel to the compressive stress. In the experiment, the maxima of magnetostriction, up to 17 × 10 −6, were measured with sufficient accuracy using semiconductor strain gauges attached to the specimens. The results support the above physical prediction. We found that the stress dependence of the maxima is almost insensitive to the relation between the rolling direction and the loading direction, which ensures that the magnetostriction method is suitable for the residual stress measurement.

Condensation pressure during amalgam placement in patients.

The purpose of this study was to investigate the condensation pressure during amalgam placement in patients. Forty-four practitioners were asked to fill two class 2 cavities in the lower jaw on their patients in their own practice with the aid of a force-measuring plugger. This device, with semiconductor strain gauges, allowed the dentist to have an identical tactile feedback as with any other plugger. Three different amalgams, with different shapes of alloy particles, were tested. The results showed a maximum condensation pressure of 8.9+/-2.4 MPa and 5.5+/-1.8 MPa with a small and a large amalgam plugger, respectively. Average condensation pressures were 3.7+/-1.3 MPa for the small and 2.2+/-0.9 MPa for the large instrument. The total working time required to fill a cavity was on average 131 s; the amalgam was effectively condensed for 44 s. No significant differences between amalgams with different shapes of alloy particles, no influence of time of day, and no difference between female and male dentists were found. This study showed that the condensation pressure is lower than often recommended, and that it is not statistically different from the values obtained in a previous laboratory study.

What is the desirable stimulus to induce the rectoanal inhibitory reflex?

This study was designed to find other methods to induce rectoanal inhibitory reflex. Twenty healthy children were studied manometrically using three different types of stimuli, air, balloon, and water. Reflex occurred with all three kinds of stimuli; however, the free-air method was more sensitive and convenient than the common inflating balloon method. The lowest feeling amount and lowest amount in the free-air method are significantly lower than those in the balloon method (P < 0.05). The highest amount in the free-air method is significantly lower than those in the balloon method (P < 0.02). The highest drop and sustain time in both the free-air and balloon methods are not significant. The internal and sphincter has the function to respond to air (flatus). The semiconductor strain gauge catheter is better than the air-filled or water-filled balloon and water-infused catheter for the study of rectal physiology.

Diamond-like carbon overcoat for magnetic thin film recording disks

Diamond-like carbon (DLC), which shows excellent hardness and a low friction coefficient, has recently been used as the overcoat for magnetic thin film recording disks. The performance of the thin (about 20 nm) DLC film is highly dependent on its microstructure, surface morphology, and chemical composition, and thus depends on its fabrication process. The DLC overcoat is fabricated by d.c. magnetron sputtering of a graphite target in a gas mixture of argon and hydrogen. The hydrogen content, the gas flow and pressure, and sputtering power are found to be the key process parameters that affect the properties and characteristics of the DLC film. The chemical structure and composition are characterized using Raman spectroscopy and Rutherford forward scattering spectrometry. The film hardness, electrical resistance, optical reflectance, and plasma etch rate are also measured, and their relation to film structure and hydrogen content discussed. The final wear and stiction test on the DLC film was carried out using disk drives equipped with semiconductor strain gauges and customer designed computer-controlled hardware/software. The test results are interpreted in terms of film hardness, structure and electrical resistance.

New high gauge-factor thick-film transducer based on a capacitor configuration

Abstract A highly sensitive thick-film sensor developed by using a novel thick-film resistor composition, coupled with design and layout techniques, is reported. The thick film paste is based on the combination of oxides of bismuth, indium and ruthenium. By varying the layout and composition of the thick-film sensors, high gauge-factor values usually attributed to silicon semiconductor strain gauges have been achieved. Various strain gauge parameters have been analysed including linearity, hysteresis and temperature effects. Gauge factor values between 75 to 85 in both resistive and capacitive gauge applications have been observed.

Historical note: Warren P. Mason (1900-1986) physicist, engineer, inventor, author, teacher

This paper is based on an invited talk in the Warren P. Mason Memorial Session at the 117th meeting of the Acoustical Society of America, Syracuse, NY, May 22-26, 1989. Warren Perry Mason, a Charter Member, Fellow, President, and Gold Medalist of the Acoustical Society of America, consistently applied his understanding of fundamentals to explain physical processes and create practical devices. As a physicist, he led us to a better understanding of fundamental effects in liquids and solids. He made the first measurement of shear elasticity in liquids and helped establish the type of motion that polymer chains can make. In solids, he contributed to quantitative understandings of phonon drag on charge carriers in semiconductors, fatigue of metals, and damping of acoustic waves in metals, insulators, semiconductors, alloys, and rocks. As an engineer and inventor, he led advances in mufflers and noise control, electromechanical filters for carrier frequency telephony, piezoelectric crystals and ceramics for electromechanical transducers, and semiconductor strain gauges. With about 200 patents, he is the most prolific inventor in the history of Bell Labs. As an author and teacher, he wrote more than 200 papers and four reference books that teach fundamental concepts, give complete tensorial descriptions of numerous physical interactions in crystals, describe research results, and guide the reader to the related literature. In this paper, we show some early pictures of Mason and his family, transmit some stories, and give an example of a communication device in which Mason would surely have been interested, namely an acoustically tuned optical filter.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Magnetostrictions of electrical iron sheets under controlled magnetization

The magnetostriction of electrical iron sheets was measured under several controlled magnetizing conditions. Samples were a washer type and a strip type of non-oriented electrical iron sheets. The magnetic induced voltage was controlled by using a microcomputer system to be required waveforms; sine, rectangle and rectangle with steps. The magnetostriction was measured using base-less semiconductor strain gauges applied on the samples. Signals of the magnetostriction under the rectangular or rectangular-with-steps excitation had many higher harmonic components that included the shape resonance of samples. A resonance pattern was complicated for the washer-type sample because of the existence of many resonance modes, while it was relatively simple for the strip. These resonant components are not due to the essential magnetostriction and were removed by signal processing. The original signal thus obtained gradually changed for the pause time, for which the magnetic induction keeps its maximum value. This suggests the existence of internal magnetization change for the pause time, which is considered to be one of causes of the increase in magnetic losses per cycle with the pause time.

Sputter-induced random micro texturing on NiP plated aluminium and alternate substrates

Random micro texturing can be developed on both NiP/Al and alternate substrate disks by sputtering nonwetting and seed layers. The nonwetting layer was first sputtered on the substrate, then the seed layer, chrome underlayer, CoCrPtTa magnetic layer and carbon overcoat were sequentially deposited on top of the nonwetting layer. The seed layer melting point, film thickness, substrate surface energy, and temperature were found to be key parameters affecting the properties and characteristics of sputter-induced micro texturing (SIMT). The surface topography and roughness of micro texturing were characterized using SEM, Atomic Force Microscope (AFM), and glide height avalanche tests. Tribology tests were conducted using 1 RPM stiction test and a CSS test on disk drives equipped with semiconductor strain gauges. By carefully controlling process parameters, the number of texturing summits at the desired threshold level can be increased significantly without changing the surface roughness as measured by optical interferometry. Consequently, disk stiction can be greatly improved without deteriorating glide performance.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

アナログ手法による半導体ひずみゲージブリッジの高精度温度補償法

アナログ手法による半導体ひずみゲージブリッジの高精度温度補償法

Internal stress wave measurements in solids subjected to lithotripter pulses

Semiconductor strain gauges were used to measure the internal strain along the axes of spherical and disk plaster specimens when subjected to lithotripter shock pulses. The pulses were produced by one of two lithotripters. The first source generates spherically diverging shock waves of peak pressure approximately 1 MPa at the surface of the specimen. For this source, the incident and first reflected pressure (P) waves in both sphere and disk specimens were identified. In addition, waves reflected by the disk circumference were found to contribute significantly to the strain fields along the disk axis. Experimental results compared favorably to a ray theory analysis of a spherically diverging shock wave striking either concretion. For the sphere, pressure contours for the incident P wave and caustic lines were determined theoretically for an incident spherical shock wave. These caustic lines indicate the location of the highest stresses within the sphere and therefore the areas where damage may occur. Results were also presented for a second source that uses an ellipsoidal reflector to generate a 30-MPa focused shock wave, more closely approximating the wave fields of a clinical extracorporeal lithotripter.

Magnetostrictive Materials

Smart materials combine sensors, intelligence, and actuators to allow a material to respond to its environment. Magnetostrictive materials can be used as both the sensors and actuators in such materials. High-power magnetostrictive actuators can deliver forces greater than 50 MPa with strains of up to 0.6%, while other magnetostrictive sensor materials can provide hundreds of times the sensitivity of semiconductor strain gages. Magnetoelastic materials also have adaptable elastic moduli which may be varied by external magnetic fields.Magnetostriction is the change in any dimension of a magnetic material caused by a change in its magnetic state. In this article we concentrate on ferromagnetic materials exhibiting Joule magnetostriction, which is a change in linear dimension parallel to an applied magnetic field (see Figure 1), and the reciprocal effect in which the material changes its magnetic state under the influence of applied stress.The phenomenon of magnetostriction has been known for well over a century, since Joule discovered in 1847 the change in length of an iron rod when magnetized. The modern era of magnetostrictive materials began in 1963 with the measurement of nearly 1% magnetostrictive strains at low temperatures in the basal planes of Dy and Tb. A search for magnetostrictive materials with high magnetostriction at room temperature led to the alloying of rare earths with transition metals, culminating in the discovery in 1971 of giant room-temperature magnetostriction in the Laves phase compound TbFe2.

衝撃貫入試験法の開発と試験結果

Impact penetration test is important to observe the behaviour of rock undergoing very rapid loading which can not be realized by a testing machine. A force-penetration relationship is considered to be closely related to performance of percussive rock fragmentation process.A lot of experimental studies have been carried out and it was found that the slope of force-penetration curve in impact penetration test is steeper than that in static penetration test. However, qualitatively much difference exists from author to author.A system of impact penetration test developed in this study comprises a hammer and a cylindrical bar with a bit at one end. Stress wave is measured by a pair of semi-conductor strain gauges, and penetration is calculated by the measured stress wave.Nine rocks were tested and force-penetration curves in impact and static tests were obtained together with uniaxial compressive strength, indirect tensile strength, Young's modulus, Poison's ratio, rebound hardness by Schmidt hammer and Shore hardness. Good correlation was found between force-penetration curves in impact and static tests, and slope by impact test, Kd can be expressed by slope in static test, Ks as Kd=1.2KsThe difference between Kd and Ks is not so much as expected, just 20%.

Length-tension recording system for strabismus surgery

To meet the need for both scientific information and a clinical means for measurement of the mechanical parameters of the most difficult individual strabismus cases we present a technique for directly measuring and plotting the length-tension characteristics of the tissues supporting the eye. Semiconductor strain gauges mounted on the shanks of a custom machined eye forceps and an ultrasonic method of making continuous duction measurements of the eye have proved feasible. When the forceps are interfaced with a dedicated microcomputer, the system provides a permanent, quantitative, length-tension record displayed in real-time. The instrumented length-tension forceps system has provided a noninvasive means for quickly and simply assessing the mechanical underlying determinants of strabismus pathology in the office, the laboratory or in the operating room, and can aid in the planning and immediate intraoperative alteration of strabismus surgery. Under operator coordination, measurements can be made which precisely define the mechanical load which the eye muscles must move. The resulting objectively determined tissue stiffness asymmetries and muscle restrictions limiting ocular motion indicate the purely mechanical contributions to a patient's strabismus. Measurements of active force indicate the magnitudes and patterns of innervation over the entire range of gaze. By comparison of these active force and passive stiffness records, nerve signal imbalances may be quantitatively distinguished from mechanical imbalances in strabismus. It is the detailed interaction of these nonlinear muscle forces and mechanical elements which determines the position of each eye in strabismus and therefore the proper surgical treatment. A brief description of actual use and a few examples of clinical results are included from over 200 human records.

Data processing of tactile information for three-axis tactile sensor.

In order to improve the intelligence of a robot with a sense of touch, we have developed a tactile sensor array which can detect the distribution of the three components of a force vector. The tactile sensor consists of a 6×15 matrix of 3×3 mm sensing sites; each site is made of two single-crystal silicon rings on which semiconductor strain gauges are formed by means of a semiconductor processing technique. In this paper, we have introduced formulas to calculate applied force/moment, a center of distributed pressure, and some parameters of slip and hardness, and then carried out sensing tests in order to validate those formulas. Experimental results show that applied force/moment and the center of distributed pressure can be detected with practical accuracy. Slipping, rolling and rotating states can be distinguished by combinations of the slip parameters. Moreover, mechanical properties can be sensed by means of combinations of the hardness parameters. A lump in a soft object can be recognized using an adequate threshold method.

AXLE INSTRUMENTATION FOR TRACTIVE PERFORMANCE PARAMETER MEASUREMENT

ABSTRACT Strains spanning the range expected in tractor axles were measured in a rotating shaft in the laboratory. Strain measurements were made with semiconductor strain gages at arbitrary angles of shaft rotation. The measured strains were resolved into orthogonal force components corresponding to the net traction and dynamic load, as well as the total applied load and its direction. The strain gage selection, excitation and signal amplification, and tests of the transducer accuracy and sensitivity are discussed.

A new principle for a short-duration six component balance

The presented principle of a sting balance applying semiconductor strain gauges bears a number of advantages in comparison with classical strain gauge balances. Simultaneous, highly time resolved measurement of all six aerodynamic force components is possible. The manufacturing is comparatively easy, a milling machine is sufficient to achieve reasonable accuracy. The balance needs only little space, which makes it suitable for small and especially for short models. The disadvantages of semiconductor strain gauges like zero drift and temperature effects do not play a significant role during the test time of five milliseconds. However, they have to be taken into account during the long lasting calibration process. The attachment of the model to the cross is critical with regard to preloadings and hysteresis. Therefore a connecting part is used between balance and model, which should not be removed once the balance is calibrated. The model should be attached to the balance so that the centre of mass is located at the origin of the coordinate system shown in Fig. 2. Then, the moment of inertia with respect to the balance fixed coordinate system is minimal, whereas the natural frequencies of the rotating degrees of freedom are maximized. If the flow over a model is studied the coordinate system only has to be rotated to obtain the aerodynamic forces. Furthermore, gauging and wiring of the strain gauges is uncomplicated, all locations of the gauges are easy to reach. As the construction is compact and of high stiffness it may withstand high loads. The existing balance has a design load of 1,000 N. Strain gauges with a gauge factor of k=130 were used. With an amplification factor of 10,000 even forces below 1 N can be observed, using an appropriate amplifier (e.g. “2311 Signal Conditioning Amplifier”, Vishay Measurements Group). The accuracy of the measurement mainly depends on the efforts invested in the calibration and data processing. With a suitable algorithm as proposed by Schnabl (1987), an accuracy in the order of one percent should be possible. So far the balance has not been applied for measurements on a model, but a number of tests is being made to investigate the natural frequencies and short time response. The results of these tests will lead to the final geometry of the balance and its attachment to the model. It is hoped to have the next prototype manufactured, gauged and calibrated by the end of this year. First results of the investigation of a model with the balance might be presented in 1990.

Warren P. Mason (1900–1986), physicist, engineer, inventor, author, teacher

Warren Perry Mason, a Charter Member, Fellow, President, and Gold Medalist of the Acoustical Society of America, consistently applied his understanding of fundamentals to explain physical processes and create practical devices. As a physicist, he led us to a better understanding of fundamental effects in liquids and solids. He made the first measurement of shear elasticity in liquids and helped establish the type of motion that polymer chains can make. In solids, he contributed to quantitative understandings of phonon drag on charge carriers in semiconductors, fatigue of metals, and damping of acoustic waves in metals, insulators, semiconductors, alloys, and rocks. As an engineer and inventor, he led advances in mufflers and noise control, electromechanical filters for carrier‐frequency telephony, piezoelectric crystals and ceramics for electromechanical transducers, and semiconductor strain gauges. With about 200 patents, he is the most prolific inventor in the history of Bell Labs. As an author and teacher, he wrote over 200 papers and 4 reference books that teach fundamental concepts, give complete tensorial descriptions of numerous physical interactions in crystals, describe research results, and guide the reader to the related literature. This talk will sample Mason's contributions to physical acoustics and will give an example of a communications device made at Bellcore, in which Mason would surely have been interested, namely an acoustically tuned optical filter [B. L. Heffner et al., Electron. Lett. 24, 1562–1563 (1988)].