Journal articles: 'Strain gauge technique'

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Gallage, Chaminda, and Chamara Jayalath. "Use of Particle Image Velocimetry (PIV) technique to measure strains in geogrids." E3S Web of Conferences 92 (2019): 12007. http://dx.doi.org/10.1051/e3sconf/20199212007.

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Geosynthetics are widely used in Geotechnical Engineering to reinforce soil/gravel in pavements, retaining wall backfills, and embankments. It is important to measure strains in geogrids in the determination of their strength parameters such as tensile strength and secant stiffness, and in evaluating their performances in geogrid-reinforced structures. Strain gauges are commonly used in measuring strains in geogrids. However, it is important to verify the strains measured by strain gauges as these strains are affected by the data logging device, gauge factors, quality of bonding between grain gauge and geogrid, and temperature. Therefore, this study was conducted to verify the performance of strain gauges attached to Geogrids and also to investigate the possibility of using PIV technique and GeoPIV-RG software to measure the local strains developed in a geogrid specimen under tensile testing in the laboratory. In the experimental program of this study, six composite geogrid specimens were tested for tensile strength (wide-width tensile tests) while measuring/calculating its tensile strain by using strain gauges attached to the specimens, Geo-PIV-RG analysis and crosshead movements of Instron apparatus. Good agreement between the strains obtained from strain gauges and geoPIV-RG analysis was observed for all the tests conducted. These results suggest that the PIV technique along with geoPIV-RG program can effectively be used to measure the local strain of geogrids in the laboratory tests. It was also able to verify that properly installed strain gauges are able to measure strain in the geogrids which are used in the field applications.

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Bicalho, AA, ADCM Valdívia, BCF Barreto, D. Tantbirojn, A. Versluis, and CJ Soares. "Incremental Filling Technique and Composite Material—Part II: Shrinkage and Shrinkage Stresses." Operative Dentistry 39, no. 2 (March 1, 2014): e83-e92. http://dx.doi.org/10.2341/12-442-l.

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SUMMARY Objectives Finite element analysis (FEA) was used to study polymerization shrinkage stress in molars restored with composites and to correlate those stresses with experimentally measured tooth deformation. Methods Three composites (Filtek LS, Aelite LS Posterior, Filtek Supreme) and three filling techniques (bulk, 2.0-mm increments, and 1.0-mm increments) for restoring a molar were simulated in a two-dimensional FEA. Polymerization shrinkage was modeled using post-gel shrinkage, which was measured using the strain gauge technique (n=10). Cuspal tooth deformation, measured at the buccal and lingual surfaces with strain gauges in a laboratory study, was used to validate the analysis. Residual shrinkage stresses were expressed in modified von Mises equivalent stresses. Linear Pearson correlations were determined between the laboratory and FEA results. Results Post-gel shrinkage values (in volume %) were: Filtek LS (0.11 ± 0.03) < Aelite LS Posterior (0.51 ± 0.02) < Filtek Supreme (0.62 ± 0.09). The 1.0-mm increment filling caused substantially higher stresses and strains in the cervical enamel region. Significant correlations were found between: elastic modulus and FEA strain, elastic modulus and FEA stress, post-gel shrinkage and FEA strain, post-gel shrinkage and FEA stress, FEA strain and cuspal deformation by strain gauge, and FEA stress and cuspal deformation by strain gauge (p<0.05). Conclusions Increasing the number of increments and high post-gel shrinkage and/or elastic modulus values caused higher stresses in the remaining tooth structure and tooth/restoration interface. Cuspal deformation measured with the strain gauge method validated the finite element analyses.

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Elmahdy, Ahmed, and Patricia Verleysen. "Challenges related to testing of composite materials at high strain rates using the split Hopkinson bar technique." EPJ Web of Conferences 183 (2018): 02021. http://dx.doi.org/10.1051/epjconf/201818302021.

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The design of sample geometries and the measurement of small strains are considered the main challenges when testing composite materials at high strain rates using the split Hopkinson bar technique. The aim of this paper is to assess two types of tensile sample geometries, namely dog-bone and straight strip, in order to study the tensile behaviour of basalt fibre reinforced composites at high strain rates using the split Hopkinson bar technique. 2D Digital image correlation technique was used to study the distribution of the strain fields within the gauge section at quasi-static and dynamic strain rates. Results showed that for the current experiments and the proposed clamping techniques, both sample geometries fulfilled the requirements of a valid split Hopkinson test, and achieved uniform strain fields within the gauge section. However, classical Hopkinson analysis tends to overestimate the actual strains in the gauge section for both geometries. It is, therefore, important to use a local deformation measurement when using these 2 geometries with the proposed clamping technique.

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Sasaki, Yasushi, Manabu Iguchi, and Mitsutaka Hino. "Measuring Strains for Hematite Phase in Sinter Ore by Electron Backscattering Diffraction Method." Key Engineering Materials 326-328 (December 2006): 237–40. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.237.

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Based on the relationship between quantified blurring degree of Kikuchi bands obtained by an electron backscattering diffraction (EBSD) technique and macroscopic strains measured by a strain gauge, the local compression strain SEBSD in sinter ore has been evaluated under various conditions. There is a good linear relationship between the SEBSD and the strains measured by a strain gauge. The local strain SEBSD evaluated by EBSD patterns can be used as an index of local strains.

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Elmahdy, Ahmed, and Patricia Verleysen. "The Use of 2D and 3D High-Speed Digital Image Correlation in Full Field Strain Measurements of Composite Materials Subjected to High Strain Rates." Proceedings 2, no. 8 (July 9, 2018): 538. http://dx.doi.org/10.3390/icem18-05439.

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The aim of this paper is to assess and compare the performance of both high speed 2D and 3D digital image correlation (DIC) configurations in the characterization of unidirectional carbon fiber reinforced epoxy composites in high strain rate tension in the transverse direction. The criteria for assessment were in terms of strain resolution and measuring the strain localization within the gauge section. Results showed the high-speed 3D DIC technique has lower strain resolution compared to the high-speed 2D DIC technique. In addition, the analysis of the full strain fields indicated that the 3D DIC technique could accurately locate and measure the concentrations of strains within the gauge section of the tested samples.

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Milgrom, Charles, David Burr, David Fyhrie, Mark Forwood, Aharon Finestone, Meir Nyska, Miki Giladi, Meir Liebergall, and Ariel Simkin. "The Effect of Shoe Gear on Human Tibial Strains Recorded During Dynamic Loading: A Pilot Study." Foot & Ankle International 17, no. 11 (November 1996): 667–71. http://dx.doi.org/10.1177/107110079601701104.

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The study was conducted to test the hypothesis that alterations in shoe gear can affect tibial strains in the human during dynamic loading. Rosette strain gauges were mounted on the medial border of the mid-diaphysis in two human subjects with a new strain gauge bonding technique using methyl methacrylate. Strain measurements were made at this site, the most frequent location for stress fractures in the Israeli Army during treadmill walking and free running while wearing various sport shoes (Rockport ProWalkers and New Balance NBX 900) and army boots (light Israeli infantry, double layered sole Israeli infantry, and Zohar infantry boots). Data were analyzed for only one of the subjects because strain gauge bonding was found to be inadequate at the time of surgical removal in the other subject. No single shoe lowered both the principal tibial compression and tensile strains, and the shear strains. The Zohar boot had the lowest principal compression strains during treadmill walking and mobile running, despite its relatively higher weight and sole durometry.

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Sayed, Sahour, Mohammed Gamil, Ahmed M. R. Fath El-Bab, and Ahmed Abd El Moneim Abd Elmoneim. "LASER Reduced Graphene on Flexible Substrate for Strain Sensing Applications: Temperature Effect on Gauge Factor." Key Engineering Materials 644 (May 2015): 115–19. http://dx.doi.org/10.4028/www.scientific.net/kem.644.115.

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New technique is developed to synthesize graphene film on flexible substrate for strain sensing applications. A flexible graphene/Poly-ethylene Terephthalate (PET) strain sensor based on graphene piezoresistivity is produced by a new simple low cost technique. Graphene oxide film on PET substrate is reduced and patterned simultaneously using 2 Watt CO2LASER beam. The synthesized graphene film is characterized by XRD, FT-IR, SEM, and Raman techniques. Commercial strain gauges are used to predict experimentally the gauge factor (GF) of the graphene film at different values of applied strain. The stability of the graphene film and its GF are studied at different operating temperatures. The fabricated sensor showed high GF of 78 with great linearity and stability up to 60 °C.

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Rosenberg, Z., M. Mayseless, and Y. Partom. "Axial Stress-Time History Measurements in Impulsively Loaded Aluminum Rods Using the Double Gauge Technique." Journal of Applied Mechanics 52, no. 4 (December 1, 1985): 977–79. http://dx.doi.org/10.1115/1.3169181.

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The purpose of this Brief Note is to present experimental stress-time histories along the centerline of impulsively loaded aluminum rods. The measurement is based on the double gauge technique in which we use both a manganin stress gauge and a constantan strain gauge at the same location in the rod. The strain gauge record enables one to eliminate the strain contribution to stress gauge resistance change and have a stress-time history. The measured stress history is compared to a calculated one using two-dimensional Lagrangian code and the agreement between them is good.

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Falk, Alexandru, Octavian Pop, Jérôme Dopeux, and Liviu Marsavina. "Assessment of Strains Produced by Thermal Expansion in Printed Circuit Boards." Materials 15, no. 11 (May 31, 2022): 3916. http://dx.doi.org/10.3390/ma15113916.

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The paper proposed an alternative optical metrology to classical methods (strain gauge measurements and numerical simulation) for strain determination on printed circuit board (PCBs) due to thermal loads. The digital image correlation (DIC) technique was employed to record the strain distribution in some particular areas of the PCB. A thermal load was applied using a heating chamber, and the measurements were performed at four different temperature steps (25 °C, 50 °C, 85 °C and 120 °C). An increase in the principal strains with temperature was observed. For validation, the principal strains on the PCB obtained with DIC were compared with the values from gauge strain measurements and numerical simulation. The conclusions highlighted that DIC represents a technique with potential for strain measurement caused by thermal deformation, with the advantages of full field measurement, less preparation of the surface and good accuracy.

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Gill, R. C., J. E. Kellow, C. Browning, and D. L. Wingate. "The use of intraluminal strain gauges for recording ambulant small bowel motility." American Journal of Physiology-Gastrointestinal and Liver Physiology 258, no. 4 (April 1, 1990): G610—G615. http://dx.doi.org/10.1152/ajpgi.1990.258.4.g610.

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Perfused-tube manometry has hitherto been the standard technique for recording intraluminal intestinal pressure in humans, but it is unsuitable for ambulant use. The aim of our study was to evaluate the ability of resistive strain gauge transducers attached to a fine catheter to detect pressure change. Simultaneous strain gauge and perfused-tube manometry was performed on six fasting subjects; in four, strain gauge activation was continuous and in two, the transducers were activated in a pulsed mode with data encoded as a pulse train with an approximate frequency of 20 Hz. Eight thousand eight hundred eighty-eight pressure waves were recorded by strain gauge, of which 96% were detected by perfused-tube manometry. There was good agreement in both phases II and III of the migrating motor complex. The amplitude of pressure waves recorded by strain gauge was slightly but significantly greater. A proportion (14-17%) of pressure waves recorded by strain gauge were bifid; this was not seen with the perfused tube. These differences are best explained by the greater sensitivity and more rapid rise time of the strain gauges. There was no loss of fidelity in the pulse-interval recording mode. A seventh subject underwent a continuous 72-h recording with the strain gauge catheter attached to a battery-operated encoder and magnetic tape cassette recorder and was freely ambulant during this period. The procedure was well tolerated and motility patterns could be clearly identified. We conclude that intraluminal strain gauge catheters are suitable for prolonged use in ambulant subjects and produce data that are closely comparable to the data acquired from perfused-tube manometry under laboratory conditions.

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Evans, Mark A., and Richard H. Groshong. "A computer program for the calcite strain-gauge technique." Journal of Structural Geology 16, no. 2 (February 1994): 277–81. http://dx.doi.org/10.1016/0191-8141(94)90110-4.

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Vuong, Quang Dao, Ji-woong Lee, Won-Ju Lee, Hyejin Choi, Kanghyun Seo, Youngmin Kim, Jin Hui Jeong, Myeong-ho Song, and Jae-ung Lee. "Establishing the True Dynamic Bending Moment of Propeller Shaft Using a Single Bridge of Strain Gauge." Applied Sciences 12, no. 18 (September 15, 2022): 9235. http://dx.doi.org/10.3390/app12189235.

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The measurement of shaft bending (whirling) moment can be performed via a telemetry system including strain gauges which can obtain the bending stress. By using a single bridge of strain gauge, it was possible to obtain only the nominal bending moment. However, in case of the propeller shaft vibration measurement, the true dynamic bending moment is needed to evaluate the effect of propeller forces on the stability of the bearings. To deal with this, typically two bridges of strain gauge at 90 degrees are needed. This research presents a novel reliability assessment method in establishing the true dynamic bending moment using only one bridge of strain gauge. This is achieved by using the actual bending stress measured by strain gauge combined with its own phase lag stress at an angle of 90 degrees. To validate this technique, the experiments were performed under the rapid turning transient states during a sea trial of a 50,000 DWT oil/chemical tanker. As a result, great fluctuations in propeller force were detected, resulting in a non-uniform oil film in the bearings. The displacement sensor was also installed and confirmed the established true dynamic bending moment.

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Rahimi, S., and I. Violatos. "Comparison Between Surface and Near-Surface Residual Stress Measurement Techniques Using a Standard Four-Point-Bend Specimen." Experimental Mechanics 62, no. 2 (October 7, 2021): 223–36. http://dx.doi.org/10.1007/s11340-021-00779-6.

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Abstract Background Determination of near-surface residual stresses is challenging for the available measurement techniques due to their limitations. These are often either beyond reach or associated with significant uncertainties. Objective This study describes a critical comparison between three methods of surface and near-surface residual stress measurements, including x-ray diffraction (XRD) and two incremental central hole-drilling techniques one based on strain-gauge rosette and the other based on electronic speckle pattern interferometry (ESPI). Methods These measurements were performed on standard four-point-bend beams of steel loaded to known nominal stresses, according to the ASTM standard. These were to evaluate the sensitivity of different techniques to the variation in the nominal stress, and their associated uncertainties. Results The XRD data showed very good correlations with the surface nominal stress, and with superb repeatability and small uncertainties. The results of the ESPI based hole-drilling technique were also in a good agreement with the XRD data and the expected nominal stress. However, those obtained by the strain gauge rosette based hole-drilling technique were not matching well with the data obtained by the other techniques nor with the nominal stress. This was found to be due to the generation of extensive compressive residual stress during surface preparation for strain gauge installation. Conclusion The ESPI method is proven to be the most suitable hole-drilling technique for measuring near-surface residual stresses within distances close to the surface that are beyond the penetration depth of x-ray and below the resolution of the strain gauge rosette based hole-drilling method.

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Litoš, P., M. Švantner, and M. Honner. "Simulation of Strain Gauge Thermal Effects During Residual Stress Hole Drilling Measurements." Journal of Strain Analysis for Engineering Design 40, no. 7 (October 1, 2005): 611–19. http://dx.doi.org/10.1243/030932405x30812.

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The hole drilling residual stress measuring method is based on drilling a small hole in a material sample and measuring the strain relieved in the hole vicinity by a special strain gauge rosette. The temperature and thermal strain induced by the drilling process can cause significant errors in the relieved strain measurement. The paper deals with computer simulation of the thermomechanical process in the sample during drilling. The first part is devoted to the evaluation of heat flux from the drilling tool to the drilled material using the sample surface temperature measured by thermography. The second part deals with determination of real strain and strain gauge thermal output (apparent strain) at the strain gauge location during and after drilling. The paper describes the computer modelling technique for solving an indirect thermal problem of drilling heat flux determination and a direct thermomechanical problem for a set of the process alternatives. Comparisons of simulated and experimentally determined temperatures and strains are presented.

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Fíla, Tomáš, Petr Zlámal, Jan Falta, Tomáš Doktor, Petr Koudelka, Daniel Kytýř, Marcel Adorna, et al. "Testing of Auxetic Materials Using Hopkinson Bar and Digital Image Correlation." EPJ Web of Conferences 183 (2018): 02045. http://dx.doi.org/10.1051/epjconf/201818302045.

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In this paper, a split Hopkinson pressure bar (SHPB) was used for impact loading of an auxetic lattice (structure with negative Poisson’s ratio) at a given strain-rate. High strength aluminum and polymethyl methacrylate bars instrumented with foil strain-gauges were used for compression of an additively manufactured missing-rib auxetic lattice. All experiments were observed using a high-speed camera with frame-rate set to approx. 135.000 fps. High-speed images were synchronized with the strain-gauge records. Dynamic equilibrium in the specimen was analyzed and optimized pulse-shaping was introduced in the selected experiments. Longitudinal and lateral in-plane displacements and strains were evaluated using digital image correlation (DIC) technique. DIC results were compared with results obtained from strain-gauges and were found to be in good agreement. Using DIC, it was possible to analyze in-plane strain distribution in the specimens and to evaluate strain dependent Poisson’s ratio of the auxetic structure.

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dos Santos, Lindemberg Ferreira, Rodrigo Nogueira de Codes, Erijanio Nonato Silva, and Rodrigo Amaral de Codes. "Study of Damage in the Medium Density Polyethylene Using Digital Image Correlation." Materials Science Forum 869 (August 2016): 356–60. http://dx.doi.org/10.4028/www.scientific.net/msf.869.356.

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The non-linear response of solids is an expression of irreversible processes that originate in microdefects, which are understood as initial material damage. This work aims to analyze the degradation of the mechanical properties of medium density polyethylene through continuum damage mechanics using Digital Image Correlation (DIC). With this technique, displacement and strain fields are obtained throughout the specimen gauge length and therefore optical gauges in any region of interest can measure the strain. Mechanical testing with successive loading and unloading were performed in order to obtain the actual magnitude of the material stiffness in certain strains. Finally, through the damage versus strain diagrams, the results showed that the damage in medium density polyethylene increases from a certain deformation.

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Brengelmann, G. L., and M. Savage. "Influence of tissue compressibility on calibration for strain-gauge plethysmography." Journal of Applied Physiology 61, no. 3 (September 1, 1986): 1210–16. http://dx.doi.org/10.1152/jappl.1986.61.3.1210.

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Strain gauges employed in plethysmography for determination of limb blood flow tend to counter the expansion of the limb during venous occlusion. Traditionally a mechanical calibration is performed in situ to compensate for tissue compressibility. Greenfield, Whitney, and Mowbray stated that, otherwise, large errors would result (Br. Med. Bull. 19: 101–109, 1963). Nonetheless, not all of the recent reports on skin blood flow in humans have been based on a calibration procedure that corrects for tissue compressibility. To evaluate the significance of this problem, we developed a new strain-gauge holder that made possible frequent, reproducible, stretching of a single-strand Whitney gauge in situ. We compared the apparent sensitivity thus obtained to electrical or bench mechanical determinations. We independently determined tissue compressibility by recording limb circumference as tension in a circumferential tube was varied. Both techniques showed that tissue compressibility is a small source of error (5%) and that compressibility decreases during occlusion. Therefore the cumbersome holder and potential artifacts associated with the traditional technique need not be tolerated. We also investigated the consequences of nonuniform tension distribution and temperature changes; practical considerations for dealing with these are discussed.

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Iliescu, Nicolae, and Costică Atanasiu. "Experimental Investigations on the Stress State in the Bearing Structure of a Special Wagon to Transport Liquid Iron." International conference KNOWLEDGE-BASED ORGANIZATION 23, no. 3 (June 27, 2017): 180–87. http://dx.doi.org/10.1515/kbo-2017-0174.

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Abstract In order to increase productivity, to reduce energy consumption and for environmental protection, a special wagon intended for the transport of liquid pig iron, in steel mills, it was designed and manufactured. This wagon consists of an especial chamotted torpedo, with a capacity of 300 tons, rested, at each end, by means of a box beam, on two buggies, with four axles each one. To evaluate the mechanical behavior of this wagon during service, its prototype was investigated experimentally in terms of the stress and strain state. Due to difficulties encountered related to the long duration of loading and unloading time of the torpedo pot with liquid cast iron and due to very large dimensions of the carriage gauge, experimental investigations were performed on the torpedo pot and box beam models, manufactured at scale. The buggy structure was investigated on a special stand, set up in the laboratory of Strength of Materials Department of the Polytechnic University of Bucharest. The torpedo pot and box beam were investigated using two combined experimental techniques (brittle coatings technique and resistive strain gauge technique). Brittle coatings technique was used to identify the principal stresses directions, which then were applied electro-resistive transducers. Using strain gauge amplifiers the principal strains were measured, and principal stresses in measurement points were calculated. The results of these studies have led to changes of constructive solutions in the case of some substructures, contributing to increase the operational safety of the wagon.

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Lim, Chhoung, Yeongseok Jeong, Suchart Limkantanyu, and Minho Kwon. "Strain Measuring of Composite Grid Using Digital Image Correlation." Advances in Materials Science and Engineering 2022 (April 14, 2022): 1–12. http://dx.doi.org/10.1155/2022/6041887.

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Digital Image Correlation (DIC) is a new advanced technique for measuring the deformation of a specimen using high-resolution images. It has been used by numerous researchers since it can measure the deformation of specimens without interference because it is contactless. Moreover, the DIC technique can be applied to any materials to which normal measuring equipment is difficult to attach such as Fiber-Reinforced Polymer (FRP) grid in this paper, undulated and small surfaces. The DIC technique is easy to set up and provides reliable results compared to conventional equipment like a strain gauge. Although it is good, its associated equipment is too expensive to be readily affordable. Hence, this paper uses an open-source DIC program called Ncorr that works in MATLAB to analyze deformations of six FRP grids from direct tensile tests by comparing their results to the results from a strain gauge. Young’s modulus—calculated from ASTM 3039, ACI 440-3R-04, and regression analysis—of each specimen will be used for comparison. The results show that the difference between Young’s modulus from DIC and strain gauge is <5% if the stress–strain graph of data from the strain gauge is perfectly linear without straying.

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Zhang, Wanfu, Jiangang Yang, Chun Li, Ren Dai, and Ailing Yang. "Theoretical and experimental research on turbo-generator shaft alignment using strain gauge method." Journal of Vibration and Control 23, no. 7 (August 9, 2016): 1183–92. http://dx.doi.org/10.1177/1077546315590908.

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Shaft alignment is a key factor for the safe and reliable operation of a turbine unit. This paper presents an approach to estimate the turbo-generator shaft alignment using strain gauge technique with two measuring sections nearby each coupling. The change of shaft bending moment is linearly proportional to the change of bearing elevation and reaction force. So the bearing load distribution can be identified from the strain values and bending moments which are measured using strain gauge. The transfer matrix method is used to calculate the detailed shaft alignment data including deflection, slopes, bearing reaction forces, influence coefficients, sag/gap values. Experiments were carried out on a test rig with 3 rotors, 2 couplings and 6 bearings. It was shown that the strain gauge identification results agree well with the results using the jack-up method. The maximum relative error of each bearing loads is almost 8.7%. The sag/gap values using the strain gauge method are close to those using the laser alignment method. The maximum relative error is less than 7.5%. Results also show that the strain gauge method is sensitive to possible disturbances in the bearing elevation. In the end, strain gauge alignment technique with two measuring sections nearby each coupling was applied on the shaft alignment estimation of a 600 MW turbine unit successfully. The bearing loads and shaft deflection were obtained accurately .

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Hiti, M. "Validation of combinatorial evaluation of strain-gauge amplifier linearity." ACTA IMEKO 9, no. 5 (December 31, 2020): 205. http://dx.doi.org/10.21014/acta_imeko.v9i5.970.

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This paper describes a validation of a combinatorial calibration technique based calibration procedure for strain-gauge amplifier calibration. The deviation between two strain-gauge amplifiers at calibration using the combinatorial technique is compared to the deviation between the same two amplifiers at calibration on a force calibration machine as a transducer-amplifier chain under unchanged conditions, serving as an amplifier linearity comparator. This enables the validation to be confirmed with a suitable expanded measurement uncertainty of 3 nV/V.

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Jönsson, J., E. Svensson, and J. T. Christensen. "Strain gauge measurement of wheel-rail interaction forces." Journal of Strain Analysis for Engineering Design 32, no. 3 (April 1, 1997): 183–91. http://dx.doi.org/10.1243/0309324971513328.

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A theoretical basis for quasi static determination of wheel—rail interaction forces using strain measures in the foot of the rail is given. Vlasov's theory for thin-walled beams is used in combination with continuous translational and rotational elastic supports based on smoothing out the stiffness of the rail sleepers. The smoothing out of the rotational elastic support has traditionally not been done. The use of this model is validated by the decay lengths of the problem and through finite element analysis. The finite element analysis is performed using discrete sleeper stiffness and Vlasov beam elements. The sensitivity of the measuring technique to parameter variations is illustrated and an example shows the simplicity of the proposed direct measuring technique.

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Drake, Daniel, Rani Sullivan, and J. Wilson. "Distributed Strain Sensing from Different Optical Fiber Configurations." Inventions 3, no. 4 (September 25, 2018): 67. http://dx.doi.org/10.3390/inventions3040067.

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Strain distributions were obtained from optical fibers arranged in three different configurations on transversely-loaded cantilevered beams. Traditional strain measurement sensors, such as strain gauges, are limited to measuring strain at discrete points on a structural member. However, distributed optical fibers can measure high spatial (<1 mm spacing) strain or temperature distributions. In this study, optical fibers in spiral, grid, and rosette configurations were bonded to aluminum cantilevered beams subjected to tip loads. Strain distributions from optical fiber sensors were measured using a swept wavelength coherent interferometric technique. The optical fiber strain measurements show good agreement with strain gauge measurements. The attributes of each sensor configuration are discussed.

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Batlogg, B., and H. Boppart. "High‐resolution pressure–volume measurements by a strain gauge technique." Review of Scientific Instruments 56, no. 3 (March 1985): 459–61. http://dx.doi.org/10.1063/1.1138322.

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Zhang, R., Z. Shao, J. Lin, and T. A. Dean. "Measurement and Analysis of Heterogeneous Strain Fields in Uniaxial Tensile Tests for Boron Steel Under Hot Stamping Conditions." Experimental Mechanics 60, no. 9 (August 31, 2020): 1289–300. http://dx.doi.org/10.1007/s11340-020-00658-6.

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Abstract Background A significant amount of uniaxial tensile tests has been carried out using Gleeble systems to investigate the viscoplastic deformation of boron steel (22MnB5) under hot stamping conditions. However, due to heat loss through the end clamps, a temperature gradient in the reduced parallel section of dog-bone shaped specimens is inevitable. Objective In the work reported in this paper, the effect of temperature gradient on measured outcomes is examined. Methods Uniaxial tensile tests on 1.5 mm thick boron steel specimens are carried out, under hot stamping conditions and strain fields are quantified using the digital image correlation (DIC) technique. The effect of gauge length on the properties of boron steel, as calculated from observed test results, is determined. Results Compared with the test at room temperature, a bell-shaped strain distribution occurs within the gauge length even before the appearance of the maximum load. Also, average strain within the gauge length, especially in the later stages, changes with gauge length within the investigated range, and thus, different engineering stress-strain curves and fracture strains are determined. In addition, normalized strain rate is significantly dependent on gauge length, which results in over 16% difference among the computed flow stresses by using a unified constitutive model. Conclusions The characterized properties of the material are dependent on gauge length and thus, a testing standard for measuring thermal-mechanical data of materials by using a Gleeble need to be defined.

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Cagáň, Jan, Jindřich Rosa, and Filip Rösler. "Comparison of Various Means of Attachment of High Temperature Strain Gauge." Applied Mechanics and Materials 732 (February 2015): 199–202. http://dx.doi.org/10.4028/www.scientific.net/amm.732.199.

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The article deals with problems of high temperature strain gauge measurements. A preliminary experimental work for purpose of mastery of this technique after a longer break has been kicked off in VZLÚ. Initially, possibilities of usage of commercial products and two means of strain gauge attachment were verified.

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Lord, Jerry D., David Penn, and P. Whitehead. "The Application of Digital Image Correlation for Measuring Residual Stress by Incremental Hole Drilling." Applied Mechanics and Materials 13-14 (July 2008): 65–73. http://dx.doi.org/10.4028/www.scientific.net/amm.13-14.65.

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The measurement of residual stress using the incremental hole drilling is well established, but the main limitations with the conventional strain gauge approach are the requirements for surface preparation, the need for accurate alignment and drilling, the restricted range of hole geometries commensurate with the specific gauge designs, and the limited range of strain data averaged over the footprint of the strain gauge grid. Recent attempts to extend the method have seen the application of full field optical techniques such as electronic speckle pattern interferometry and holographic interferometry for measuring the strain fields around the hole, but these methods are sensitive to vibration and this limits their practical use to controlled laboratory environments. There are significant potential benefits therefore of using a more robust technique based on Digital Image Correlation (DIC), and work is presented in this study on the development of the method for measuring surface displacements and strain fields generated during incremental hole drilling. Some of the practical issues associated with the technique development, including the optimization of applied patterns, the development of the optical system and integration with current hole drilling equipment are discussed, and although measurements are only presented for a single load case - the equi-biaxial stress state introduced during shot peening - the novel aspect of this work is the integration of DIC measurements with incremental drilling and an application of the Integral Method analysis to measure the variation of residual stress with depth. Validation data comparing results from conventional strain gauge data and FE models is also presented.

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Jankowski, Ludomir J., and Tomasz Nowak. "Experimental Assessment of the Glued Laminated Timber Beams in 4-Point Bending Tests and Photoelastic Coating Technique." Solid State Phenomena 240 (August 2015): 155–60. http://dx.doi.org/10.4028/www.scientific.net/ssp.240.155.

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The paper presents the results of investigation on seven glued laminated timber (GL24h class) bending beams. Bending strength and modulus of elasticity were determined. The beams were tested for four-point bending by loading them at a constant speed deflection. The strain gauge method and photoelastic coating technique were applied for strain distributions determination in selected cross-sections of the beams. Good agreement of the measurement results was obtained with both techniques. Application of the photoelastic coating technique enabled more detailed analysis of the beams failure mode, including timber defects influence on the strain distributions.

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Whan, Gabrielle, R. John Runciman, and Mark Hurtig. "Determining Effective Centroid Position in Biomechanical Testing: A Technique for Simplifying Whole Bone Analysis." Journal of Biomechanical Engineering 127, no. 5 (May 4, 2005): 736–41. http://dx.doi.org/10.1115/1.1993663.

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Background: Whole bone in vitro biomechanical compressive testing can be complicated by three factors: sample asymmetry, heterogeneous material properties, and unknown effective centroid location. Method of approach: The technique presented here facilitates the calculation of effective centroid position, modulus of elasticity and equivalent uniform strain magnitude for a cross section of bone from a simple whole bone compressive test. Simplification of section response to load is achieved through a combination of linear beam and simple planer geometry theory. The technique requires three longitudinal strain gauges be affixed around the test specimen cross section of interest, gauge position need not be determined. Sample loading is then accomplished using a simple four point loading jig. Results: Results of the technique are presented on an object with known elasticity and geometry, an aluminium tube, and seven pairs of equine third metacarpal whole bones. Conclusions: Average cross section modulus of elasticity, equivalent uniform cross section strain, and effective centroid locations were all predicted to within the range of published values. Employing the testing setup and analysis technique presented in this paper resulted in a significant savings in both implementation complexity and cost over previously available techniques.

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Juhar, G., S. Saqan, and A. M. Zihlif. "The Plastic Deformation of Fibrous Polymers via Weibull Model." Polymers and Polymer Composites 9, no. 7 (October 2001): 473–82. http://dx.doi.org/10.1177/096739110100900705.

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This work deals with the plastic deformation of polypropylene, PAN-based carbon and Kevlar fibres at different gauge lengths and uses the Weibull model. A statistical analysis for the fibre strength and breaking strain is presented to test the experimental data relating to the fibre deformation. The mechanical parameters such as fibre strength, breaking strain and Young's modulus have been studied as a function of gauge length. It was found that both strength and breaking strain increase as fibre gauge length decreases, while the Young's modulus increases with increasing gauge length and depends on both strength and breaking strain. The output of the analysis supports the concept that the Weibull model is a good technique to specify the statistical distribution for strength and breaking strain of fibres and of suitable to investigate, is the deformation behaviour of fibrous polymeric materials in general.

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Maekawa, Akira, Toru Oumaya, Michiyasu Noda, Shigeru Takahashi, and Toru Saito. "Residual Stress Distribution in Austenitic Stainless Steel Pipe Butt-Welded Joint Measured by Neutron Diffraction Technique." Materials Science Forum 652 (May 2010): 116–22. http://dx.doi.org/10.4028/www.scientific.net/msf.652.116.

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This paper describes residual stress measurements and analysis of austenitic stainless steel pipe with a butt-welded joint. The measurements were done with neutron diffraction and strain gauge techniques. The measured results had typical characteristics of butt-welded pipe regarding both the decline of stress along the axial direction and the bending distribution of axial stress along the radial direction. The measured residual stress distribution by neutron diffraction was shifted more to the tensile side than that by the finite element method simulation. However, the measured radial and axial strains, except for the hoop strain determined by neutron diffraction, coincided well with analysis strains. The hoop strain was actually equivalent strain converted by a correction method because a different lattice plane had to be used to measure hoop strain. This might be one reason why the difference occurred. Therefore, future study of the correction method would be desirable.

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Ab Ghani, Ahmad Fuad, and Jamaluddin Mahmud. "Material Characterization of Hybrid Composite: Experimental Using Strain Gauge/DIC with Finite Element Modelling Macro/Micro Scale." Key Engineering Materials 740 (June 2017): 31–40. http://dx.doi.org/10.4028/www.scientific.net/kem.740.31.

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The study presents the multi methods of determining mechanical properties and mechanical characterization under tensile loading of hybrid composite in the form of experimental technique involving measurement of strain using strain gauge and digital image correlation (DIC) technique utilizing open source platform Ncorr to compute the strain on surface of hybrid composite. The method of micro mechanical modelling using Finite Element Modelling (FEM) in the mode of representation volume element (RVE) method and macro scale FEM using commercial software Ansys have been performed to compute the modulus of elasticity in direction of uniaxial tensile loading. The four methods then compared which yields very consistent results with each other. It is observed that all four methods are reliable in determining mechanical properties of unidirectional single composite as well as hybrid composite. The experimental involved the use of ASTM D3039 standard tensile test for hybrid composite and strain are measured using strain gauges and DIC.

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Hillery, M. T., and S. Griffin. "An embedded-strain-gauge technique of stress analysis in rod drawing." Journal of Materials Processing Technology 47, no. 1-2 (December 1994): 1–12. http://dx.doi.org/10.1016/0924-0136(94)90081-7.

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Otegui, J. L., U. H. Mohaupt, and D. J. Burns. "A strain gauge technique for monitoring small fatigue cracks in welds." Engineering Fracture Mechanics 40, no. 3 (January 1991): 549–69. http://dx.doi.org/10.1016/0013-7944(91)90150-y.

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Sell, P. J. "Direct pneumatic pressure in a clamping technique during strain gauge bonding." Strain 25, no. 1 (February 1989): 21–23. http://dx.doi.org/10.1111/j.1475-1305.1989.tb00682.x.

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Smith, Tait S., Scott A. Yerby, Robert F. McLain, and Todd O. McKinley. "A Device for the Measurement of Pedicle Screw Moments by Means of Internal Strain Gauges." Journal of Biomechanical Engineering 118, no. 3 (August 1, 1996): 423–25. http://dx.doi.org/10.1115/1.2796027.

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Pedicle screws are commonly used in spinal reconstruction, and failure of pedicle screws due to bending is a significant clinical problem. To measure the moments typically placed on pedicle screws in situ we instrumented 7 mm Cotrel-Dubousset (CD) pedicle screws with internally mounted strain gauges. The screws were designed to measure flexion-extension moments at a single cross-section as dictated by strain gauge placement. It is possible to measure moments of up to 12 Nm at any location along the length of the screw by constructing transducers with varying strain gauge placements. These transducers are capable of measuring moments at points located within the vertebra including the pedicle, which is where failure usually occurs clinically. Transducer output was both linear and reproducible. These transducers are being used to investigate the load transfer characteristics between the pedicle screw and the vertebra. This technique could be applied to investigations of load sharing in reconstruction plates, lag-screws, and cross-locked intra-medullary nails.

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Gamil, Mohammed, Osamu Tabata, Koichi Nakamura, Ahmed M. R. Fath El-Bab, and Ahmed A. El-Moneim. "Investigation of a New High Sensitive Micro-Electromechanical Strain Gauge Sensor Based on Graphene Piezoresistivity." Key Engineering Materials 605 (April 2014): 207–10. http://dx.doi.org/10.4028/www.scientific.net/kem.605.207.

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A new strain gauge based on graphene piezoresistivity was fabricated by a novel low cost technique which suits mass production of micro piezoresistor sensors. The strain gauge consists of a monolayer graphene film made by chemical vapor deposition on a copper foil surface, and transferred to Si/SiO2 surface by using a polymethyl-methacrylate (PMMA) assisted transfer method. The film is shaped by laser machine to work as a conductive-piezoresistive material between two deposited electrical silver electrodes. This method of fabrication provides a high productivity due to the homogeneous distribution of the graphene monolayer all over the Si/SiO2 surface. The experimentally measured gauge factor of graphene based device is 255, which promises a new strain gauge sensor of high sensitivity.

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Rajanna, K., and S. Mohan. "Response of thin film strain gauge to tensile and compressive strains by a cantilever technique." Physica Status Solidi (a) 105, no. 2 (February 16, 1988): K181—K184. http://dx.doi.org/10.1002/pssa.2211050264.

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Wahyudi, I., T. Okuyama, Y. Sudo Hadi, H. Yamamoto, H. Watanabe, and M. Yoshida. "Relationship between Released Strain and Growth Rate in 39 Year-Old Tectona grandis Planted in Indonesia." Holzforschung 55, no. 1 (December 14, 2001): 63–66. http://dx.doi.org/10.1515/hf.2001.010.

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Summary In order to clarify the growth stress mechanism of tree species in tropical forest, peripheral and internal longitudinal released strains in 39 year-old teak (Tectona grandis) trees planted in West Java, Indonesia were investigated using the strain-gauge technique. Results showed that both of the peripheral and internal longitudinal released strains were not affected by the rate of growth of the trees. However, released strains distribution inside tree stem, from pith to periphery, were significantly affected by growth rate; slow growing trees generate steeper released strain gradients.

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Martin, Hagara, and Pástor Miroslav. "A Complex Review of the Possibilities of Residual Stress Analysis Using Moving 2D and 3D Digital Image Correlation System." Strojnícky časopis - Journal of Mechanical Engineering 71, no. 1 (September 1, 2021): 61–78. http://dx.doi.org/10.2478/scjme-2021-0006.

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Abstract Understanding the levels of residual stresses in the material is very important in predicting the service life of structural elements. One of the most widely used techniques to quantify them is the drilling method, where a small hole is milled in the structure. If the residual stresses are present, stress redistribution will occur, resulting in deformation of the hole surroundings. Nowadays, there is an effort to replace the conventionally used strain gauges, i.e. special strain gauge rosettes, with full-field optical experimental techniques. This paper deals with analysing the possibilities of measuring the relieved strains/stresses with a unique drilling/measuring device, which, unlike other non-commercial measuring systems, uses the moving digital image correlation (DIC) system. Since correlation systems do not tend to move during operation, an analysis was performed describing the effect of changing the position of the single and stereo camera correlation systems on the quality of the results of the strain/stress analysis performed in the vicinity of the milled hole. The conclusion from the analyses performed is that there is no significant accumulation of correlation errors during measurement. Therefore, the information on the magnitudes of the strains/stresses relieved obtained by the moving DIC system can be used to quantify the residual stresses with an expected error corresponding to the sensitivity of this full-field optical experimental technique.

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Rahmaan, Taamjeed, Ping Zhou, Cliff Butcher, and Michael J. Worswick. "Strain rate and thermal softening effects in shear testing of AA7075-T6 sheet." EPJ Web of Conferences 183 (2018): 02037. http://dx.doi.org/10.1051/epjconf/201818302037.

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Shear tests were performed at strain rates ranging from quasi-static (0.01 s-1) to 500 s-1 for AA7075-T6 sheet metal alloy at room temperature. A miniature sized shear specimen was used in this work to perform high strain rate shear testing. Digital image correlation (DIC) techniques were employed to measure the strains in the experiments. At maximum in-plane shear strains greater than 20%, the AA7075-T6 alloy demonstrated a reduced work hardening rate at elevated strain rates. At lower strains, the AA7075-T6 alloy showed mild positive rate sensitivity. The strain to localization (using the Zener-Holloman criterion), measured using the DIC technique, decreased with strain rate in shear loading. The strain at complete failure, however, exhibited an increase at the highest strain rate (500 s-1). The current work also focused on characterization of the thermal conditions occurring during high rate loading in shear with in situ high speed thermal imaging. Experimental results from the highest strain rate (500 s-1) tests showed a notable increase in temperature within the specimen gauge region as a result of the conversion of plastic deformation energy into heat.

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Broholm, Rikke, Niels Wiinberg, and Lene Simonsen. "Measuring systolic ankle and toe pressure using the strain gauge technique – a comparison study between mercury and indium-gallium strain gauges." Scandinavian Journal of Clinical and Laboratory Investigation 74, no. 6 (April 13, 2014): 555–59. http://dx.doi.org/10.3109/00365513.2014.903431.

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Okayama, Tsutomu. "Precision Temperature Compensation Algorithm for Semiconductor Strain Gauge Bridge by Analogue Technique." IEEJ Transactions on Electronics, Information and Systems 114, no. 1 (1994): 56–62. http://dx.doi.org/10.1541/ieejeiss1987.114.1_56.

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MacCarthy, B. L., J. M. Sharp, and N. D. Burns. "A Constrained Optimization Technique to Improve the Performance of Strain Gauge Transducers." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 200, no. 2 (March 1986): 135–41. http://dx.doi.org/10.1243/pime_proc_1986_200_105_02.

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An optimization strategy is developed to improve the performance of strain gauge transducers. For a specific transducer configuration, the method used is to select an output characteristic to be optimized and to set realistic constraints on the remaining output characteristics and on physical dimensions. Using this strategy, a non-linearly constrained optimization problem may be formulated mathematically. Numerical methods to solve problems of this type are discussed and practical details arising from their use are considered. Correctly formulated problems are solvable quickly and efficiently with routines which are generally available. The techniques introduced here are applicable to a wide range of design problems in transducers of this type and provide a significant design aid.

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Kabeya, Noriyuki, Keiichiro Imura, Kazuhiko Deguchi, and Noriaki K. Sato. "Thermal Expansion Measurements Using the Strain Gauge Technique with Kelvin Double Bridge." Journal of the Physical Society of Japan 80, Suppl.A (January 2, 2011): SA098. http://dx.doi.org/10.1143/jpsjs.80sa.sa098.

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Maksimyuk, V. À., Å. À. Sushchenko, and I. B. Fetisov. "Technique of Strain-Gauge Measurement of the Dynamic Characteristics of Percussion Music." International Applied Mechanics 56, no. 2 (March 2020): 186–91. http://dx.doi.org/10.1007/s10778-020-01012-y.

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Juneja, Mamta, Prashant Jindal, Divya Bajaj, Ishan Madhav, and Rakesh Tuli. "Methodology for Stress Measurement by Transparent Dental Aligners using Strain Gauge." World Journal of Dentistry 9, no. 1 (2018): 13–18. http://dx.doi.org/10.5005/jp-journals-10015-1499.

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ABSTRACT Aim Orthodontic tooth movement is a pressing issue nowadays. An increased esthetic demand during orthodontic treatment has resulted in several alternative treatments. However, the need to avoid conventional fixed orthodontic prosthesis has led to the usage of computer-aided scanning, imaging, and printing technology along with the emergence of transparent dental aligners. The motive of this study is to present methodology of measurement of the stress applied by transparent dental aligners on human teeth using a strain gauge-based measurement device. Materials and methods Three dimensional (3D) scanner, 3D printer, thermoforming machine, strain gauge, data acquisition device, 3Shape Ortho Analyzer software were used. Results For a full-bridge Wheatstone bridge data acquisition system (DAQ), a standard aligner can strain a constantan-based strain gauge by nearly 2.5 × 10—4. This is based on the strain gauge factor of 2, input voltage 5 V for which a change in voltage of 2.5 mV was detected. Young's modulus for constantan strain gauge is given as 17.5 MPa; hence, this produced a stress of nearly 4.38 × 10—3 MPa. Conclusion This article describes an effective and convenient methodology for orthodontic treatment design for patients with crowding problem using computer-aided design (CAD) and computer-aided manufacturing (CAM) software and, thereafter, printing different stages of maxilla and mandible using fused deposition modeling (FDM) rapid prototyping technique. A transparent aligner is fabricated using thermoforming process, and the applied stresses on manipulated teeth by aligner can be evaluated using a strain gauge-based DAQ. Clinical significance This approach is expected to understand the efficacy of the thermoformed aligners for teeth movements by calculating applied forces and stresses. How to cite this article Bajaj D, Madhav I, Juneja M, Tuli R, Jindal P. Methodology for Stress Measurement by Transparent Dental Aligners using Strain Gauge. World J Dent 2018;9(1):13-18.

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Park, Jongsung, Dong-Su Kim, Youngsam Yoon, Arunkumar Shanmugasundaram, and Dong-Weon Lee. "Crack-Based Sensor by Using the UV Curable Polyurethane-Acrylate Coated Film with V-Groove Arrays." Micromachines 14, no. 1 (December 26, 2022): 62. http://dx.doi.org/10.3390/mi14010062.

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Over the years, several bare metal and crack-based strain sensors have been proposed for various fields of science and technology. However, due to their low gauge factor, metal-based strain sensors have limited practical applications. The crack-based strain sensor, on the other hand, demonstrated excellent sensitivity and a high gauge factor. However, the crack-based strain sensor exhibited non-linear behavior at low strains, severely limiting its real-time applications. Generally, the crack-based strain sensors are fabricated by generating cracks by bending a polymer film on which a metal layer has been deposited with a constant curvature. However, the random formation of cracks produces nonlinear behavior in the crack sensors. To overcome the limitations of the current state of the art, we propose a V-groove-based metal strain sensor for human motion monitoring and Morse code generation. The V-groove crack-based strain sensor is fabricated on polyurethane acrylate (PUA) using the modified photolithography technique. During the procedure, a V-groove pattern formed on the surface of the sensor, and a uniform crack formed over the entire surface by concentrating stress along the groove. To improve the sensitivity and selectivity of the sensor, we generated the cracks in a controlled direction. The proposed strain sensor exhibited high sensitivity and excellent fidelity compared to the other reported metal strain sensors. The gauge factor of the proposed V-groove-induced crack sensor is 10-fold higher than the gauge factor of the reported metal strain sensors. In addition, the fabricated V-groove-based strain sensor exhibited rapid response and recovery times. The practical feasibility of the proposed V-groove-induced crack-based strain sensor is demonstrated through human motion monitoring and the generation of Morse code. The proposed V-groove crack sensor can detect multiple motions in a variety of human activities and is anticipated to be utilized in several applications due to its high durability and reproducibility.

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Xu, Zhao-Dong, Shu Li, and Xin Zeng. "Distributed Strain Damage Identification Technique for Long-Span Bridges Under Ambient Excitation." International Journal of Structural Stability and Dynamics 18, no. 11 (October 22, 2018): 1850133. http://dx.doi.org/10.1142/s021945541850133x.

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Distributed strain measurement, such as long-gauge fiber bragger grating (FBG) techniques, has developed rapidly in the field of structural health monitoring. However, strategies of corresponding damage identification still need to be enhanced. The damage identification technique based on distributed strain measurement is proposed identifying the structural damage under ambient excitation. Damage indices, like the distributed strain energy difference (DSED) and the relative distributed strain energy (RDSE), are derived from the power spectral density of the frequency response function of distributed strain response and further employed by detecting damages in the structure. A numerical analysis is performed on a long-span cable-stayed bridge with several assumed damage scenarios at various degrees in the girder. Damage localization capability and robustness of the proposed damage indices are discussed. In addition, damage quantification utilizing the proposed indices is conducted. The results indicate that the proposed technique can accurately identify the locations and extent of the damage under ambient vibration excitation.

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Liu, Cai Ping, and Qing Quan Duan. "Macroscopic and Mesoscopic Large Deformation Measurement Methods for Metal Materials." Advanced Materials Research 146-147 (October 2010): 1769–74. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1769.

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The stress-strain curve in the large plastic deformation process is always not available due to the strain gauge deficiencies in large deformation measurement. Considering this problem, digital marker identification technique is used to measure large deformation of Steel Q235 with images taken by with charge-coupled device. Then together with the deformation measured by traditional stain gauge at small deformation stage, the total stress and strain curve is obtained at macroscale. The mesoscopic deformation is measured by a material testing system assembled with scanning electronic microscope. The images from the initial stage to the rupture stage are captured synchronously. What’s more, using the grid method, the strain and rotation in rational mechanics is analyzed.

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Journal articles on the topic 'Strain gauge technique'

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