• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1382-1390
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• 1995

Electronic Speckle Pattern Interferometry (ESPI) with a CW laser, a video system and an image processor was utilized to measure the in-plane displacement. Unlike traditional strain gauges or Moire method. ESPI method measure the in-plane displacement on real time with out any surface preparation on surface attachment. The specimen has a crack of 10*0.1 mm in the middle of plate and strain gauge was also attached on that surface to compare with ESPI method. This study reveled the ESPI method to measure the displacement and distribution of strain in the specimen. It was shown in tensile tests that the measurement by ESPI method was comparable with strain gauge.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.716-721
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• 2001

The present study describes the experimental method to measure the strain of tire. In this study. the strain distributions of tire with air pressure and vertical load were measured at the bead filler edge region and on the carcass cord using strain gauges and the results were compared with indoor bead durability test results. The strain amplitude of carcass cord near the rim check line of tire is one of the main factors that affects bead durability characteristic.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.724-730
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• 2010

A load cell is a converter that generates voltage signals when a certain force is effected in a given direction. An essential measurement device for electronic scales that indicate weight by numbers. These load cells are being applied in various areas such as daily life, distribution, laboratory and industrial. Recently the study to manufacture load cells in a more simple method while increasing performance is being persisted. In this study based on the comparison of load cells manufactured through single surface processing using strain gauges. Those manufactured through dual surface processing using strain gauges. Ultimately persist a more simple method of load cell manufacturing while increasing its performance. The elements that were compared were linearity, hysteresis, creep and eccentricity which are short tenn performance factors. The conclusion was that single surface processing showed almost identical data as that of dual surface processing, and the load cell error rate(0.005%) also excess regulation. The manufacturing time was shortened while mass-production was possible. Which indicates a development in the weighing industry.

• Geomechanics and Engineering
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• v.28 no.1
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• pp.25-33
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• 2022

The energy transferred on drill rods by dynamic impact mainly determines the penetration depth for in-situ tests. In this study, the dynamic response and transferred energy of drill rods are determined from the frequency of the stress waves. AW-type drill rods of lengths 1 to 3 m are prepared, and strain gauges and an accelerometer are installed at the head and tip of the connected rods. The drill rods are hung on strings, allowing free vibration, and then impacted by a pendulum hammer with fixed potential energy. Increasing the rod length L increases the wave roundtrip time (2L/c, where c is the wave velocity), and hence the transferred energy at the rod head. At the rod tip, the first velocity peak is higher than the first force peak because a large and tensile stress wave is reflected, and the transferred energy converges to zero. The resonant frequency increases with rod length in the waveforms measured by the strain gauges, and fluctuates in the waveforms measured by the accelerometer. In addition, the dynamic response and transferred energy are perturbed when the cutoff frequency is lower than 2 kHz. This study implies that the resonant frequency should be considered for the interpretation of transferred energy on drill rods.

• Journal of Drive and Control
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• v.20 no.2
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• pp.24-30
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• 2023

This study aimed to analyze the fatigue of forklifts in industrial settings by assessing their stress levels during operation. Strain gauges were affixed to the dynamic components of the forklifts to gather real-time data and enhance the reliability of the analysis. Although monitoring structural loads in harsh testing environments can be challenging, the affixed strain gauges on the dynamic components can provide more precise results and improve the interpretation of data. By creating testing modes that simulate forklift usage environments and performing experiments with selected cargo and driving modes, a comparison of the damage severity of forklift parts under different driving conditions was done. These results can be utilized to forecast the lifespan of forklift parts under extreme driving conditions and assist in the design and optimization of new parts in the future.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.454-461
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• 2003

This study addressed a procedure to carry out an experimental study on a behavior of simple and continuous concrete beams. For this purpose, sample concrete beams were fabricated and sensors for the measurement of strains and deflections were attached both on the surface of the beams and inside them. Two types of sensors were used to measure strains associated with loading: electric resistance strain sensors and fiber optic sensors. Displacement gauges were also attached on the bottoms of beams to investigate the behavior of beams more rationally. The behavior of the beams was then evaluated throughout the results measured from different sensors while they were subject to steady loading up to failure. From results of this study, it was found that concurrent use of sensors and displacement gauges is helpful in investigating the behavior of concrete beams more effectively. Especially, combined-type strain sensors specifically fabricated in this experiment were found not to be affected by the occurrence of cracks so significantly and to be very effective in monitoring strains of concrete structure. It was also observed that beams show nonlinear force-displacement relationship and reinforcing bars take charge of resisting the external force once cracks occur in concrete beams.

• Advances in concrete construction
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• v.11 no.5
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• pp.375-386
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• 2021

In this paper, a study of stability and health of a newly-built railway tunnel is presented. The field test was implemented to monitor the secondary lining due to the significant cracking behaviors influenced the stability and health of the tunnel structure. Surface strain gauges were installed for monitoring the status of crack openings, and the monitoring outputs demonstrated that the cracks were still in the developing stage. Additionally, adjacent tunnel and poor condition of surrounding rock were identified as the causes of the lining cracking by systematically characterizing the crack spatial distribution, tunnel site and surrounding rock conditions. Reconstruction of partial lining and reconstruction of the whole secondary lining were designed as the maintenance projects for different cracking regions based on the construction feasibility. For assessing the health conditions of the reinforced lining, embedded strain gauges were set up to continuously measure the strain and the internal force of the reconstructed structures. For the partially reconstructed lining, the outputs show the maximum tensile elongation is 0.018 mm during 227 days, which means the structure has no obvious deformation after maintenance. The one-year monitoring of full-section was implemented in the other two completely reconstructed cross-sections by embedded strain gauge. The outputs show the reconstructed secondary lining has undertaken the pressure of surrounding rock with the time passing. According to the calculated compressive and tensile safety factors, the completely reconstructed lining has been in reliable and safe condition during the past year after reinforcement. It can conclude that the aforementioned maintenance projects can effectively ensure the stability and health of this tunnel.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.52.3-52
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• 2002

Natural frequencies and mode shapes are two important modal data which specify the system. If the real system and FE model don't have the same local physical parameters, there will be a difference between modal data from real system and FE model. Because there is little difference in displacement mode shapes measured by an accelerometer, displacement modal update based on mode shapes including measurement errors may not be successful. In this research, strain mode shapes are used as modal data because the strain mode shapes measured by strain gauges are more sensitive than the displacement mode shapes with respect to the change of the parameters concerned in FE stiffness matrix...

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.717-723
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• 2007

Statement of problem. Unreasonable distal cantilevered implant-supported prosthesis can mask functional problems of reconstruction temporarily, but it can cause serious strain and stress around its supported implant and surrounding alveolar bone. Purpose. The purpose of this study was to evaluate strain of implants supporting distal cantilevered fixed prosthesis with two different cantilevered length under distal cantilevered static load. Material and methods. A partially edentulous mandibular test model was fabricated with auto-polymerizing resin (POLYUROCK; Metalor technologies, Stuttgart, Swiss) and artificial denture teeth (Endura; Shofu inc., Kyoto, Japan). Two implants-supported 5-unit screw-retained cantilevered fixed prosthesis was made using standard methods with Type III gold alloy (Harmony C&B55; Ivoclar-vivadent, Liechtenstein, Germany) for superstructure and reinforced hard resin (Tescera; Ivoclar-vivadent, Liechtenstein, Germany) for occlusal material. Two strain gauges (KFG-1-120-C1-11L1M2R; KYOWA electronic instruments, Tokyo, Japan) were then attached to the mesial and the distal surface of each standard abutment with adhesive (M-bond 200; Tokuyama, Tokyo, Japan). Total four strain gauges were attached to test model and connected to dynamic signal conditioning strain amplifier (CTA1000; Curiotech inc., Paju, Korea). The stepped $20{\sim}100$ N in 25 N increments, cantilevered static load 8mm apart (Group I) or 16mm apart (Group II), were applied using digital push-pull gauge (Push-Pull Scale & Digital Force Gauge, Axis inc., Seoul, Korea). Each step was performed ten times and every strain signal was monitored and recorded. Results. In case of Group I, the strain values were surveyed by $80.7{\sim}353.8{\mu}m$ in Ch1, $7.5{\sim}47.9{\mu}m/m$ in Ch2, $45.7{\sim}278.6{\mu}m/m$ in Ch3 and $-212.2{\sim}718.7{\mu}m/m$ in Ch4 depending on increasing cantilevered static load. On the other hand, the strain values of Group II were surveyed by $149.9{\sim}612.8{\mu}m/m$ in Ch1, $26.0{\sim}168.5{\mu}m/m$ in Ch2, $114.3{\sim}632.3{\mu}m/m$ in Ch3, and $-323.2{\sim}-894.7{\mu}m/m$ in Ch4. Conclusion. A comparative statistical analysis using paired sample t-test about Group I Vs Group II under distal cantilevered load shows that there are statistical significant differences for all 4 channels (P<0.05).

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.5-11
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• 2007

Internal stress variation in the face slab concrete induced by reservoir water pressure may affect on the stability of the dam so that the reclamation type of strain gauge is applied for measuring internal stress variation. In this study, internal as well as external stress variation of dam was measured by using strain gauge that was reclaimed to the ${\circ}{\circ}$ dam. In the result, it was confirmed that other measurements by relevant gauges need to be supplemented as the use of strain gauge only is insufficient to evaluate the stability analysis and global behavior of the dam.