• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.154-160
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• 2004

Hydraulic breaker of excavator has been used for the destruction and disassembling of buildings, crashing road pavement, breaking rocks at quaky and etc. The performance of breakers is evaluated their own destructive force and the number of impact by input hydraulic flow rate and pressure on the operating conditions. Because hydraulic breakers generate high impact energy, the accurate measurement of the impact force has been facing a technical challenge. In this study, the hydraulic pressure transducer system was developed based on the characteristics of pressure variation in closed vessel fur testing the impact energy. The hydraulic pressure transducer system is consisted with a hydraulic cylinder, main base, pressure & temperature sensors, LVDT, data acquisition system and etc. The developed hydraulic pressure transducer system was applied to measure the impact energy for hydraulic breaker. The measured impact force was 438.8 kgf.m within the designed impact force bounds. The developed hydraulic pressure transducer system as a simple tester could be applied to measure the impact force and the number of impact.

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.31-36
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• 2002

In this paper, we developed a working adaptation evaluation system using finger force measurement which interact between material and biological system. The system consists of a finger force transducer, a signal conditioner, an A/D converter, a computer, and a software system for data processing. The finger force transducer is made by a load cell and a special mechanism. The data processing software controls the A/D converter, data monitoring, and data analysis for group classification. The developed system were tested by 4 different materials in left hand and the finger forte transducer in the other hand's thumb and index finger with 16 persons. As the results of experiments, the developed system could measure the finger force quantitatively and classify the measured values into four groups.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.47-52
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• 2008

The force transducer in the acceleration plant due to dynamic fracture is calibrated by dynamically using the stress pulses from a longitudinal bar. The bar is supported by two strings attached to the ceiling. The bar velocities before and after impact are measured and a full bridge at bar and transducer is formed by the four strain gauges. A transient recorder is used to store the stress pulse signals of force transducer and bar. For the first test series, three point bend test specimens can be chosen by means of test rig design and the inspection as sample experiment in this presented paper is sufficient for proving with the numerical simulation of the specimen model.

• Journal of KSNVE
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• v.1 no.2
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• pp.115-120
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• 1991

The impact hammer is extensively used in experimental modal analysis as a means to provide force over a broad range of frequencies. The hammer mass and the impact head are often changed to achieve a desired impact time duration with its corresponding input frequency spectrum, these mass changes affect the performance and sensitivity of the force transducer employed to measure the impact force. Both a mathematical model describing the effects of impact head and hammer mass on the performance of the force transducer and experimental verification of this model are presented here.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.3
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• pp.477-484
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• 1997

This paper describes the build-up force measuring system of 9.9 MN capacity which consists of nine force transducers of each having 1.1 MN capacity. We have specially designed a force transducer for a build-up force measuring system to reduce the uncertainty of a build-up system and to accomodate the new test procedure for a build-up system. It reveals that the relative uncertainty of the force measuring system is less than 1.5*10$^{-4}$ in the ran9e of 1-4.5 MN irrespective of loading direction. The force measuring system may be used to calibrate a 10 MN force standard machine to be used as a large force standard in Korea.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2194-2205
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• 1995

In order to reduce the systematic error of a build-up system, we have proposed a new test procedure in which all force transducers in a build-up system are rotated by 90.deg. with a base platen fixed on a force standard machine. The setting positions of force transducers on the output of a build-up system were investigated using an orthogonal array. The effects of the parallelism of a build-up system and of the bending moment sensitivity of a force transducer were considered. The experimental results show that the setting position of the base platen hardly affects the output of the build-up system, but the setting positions of force transducers affects it strongly. It reveals that the new test procedure reduces effectively the systematic error of a build-up system.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.1
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• pp.33-43
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• 2007

Using the more common conventional chordwise aerodynamic approach, flapping a flat plate wing with zero degree chordwise pitch angle of attack and no relative wind should not produce lift. However, in hover, with no forward relative velocity and zero degree chordwise pitch angle of attack, flapping flat plate wings does in fact produce lift. In the experiments peformed for this paper, the flapping motion is considered pure(downstroke and upstroke) with no flapping stroke plane inclination angle. No changes in chordwise pitch angle are made. The total force is measured using a force transducer and the net aerodynamic force is determined from this measured total force by subtracting the experimentally determined inertial contribution. These experiments were repeated at various flapping frequencies and for various wing planform sizes for flat plate wings. The trends in the aerodynamic lift variation found using a force transducer have nearly identical shape for various flapping frequencies and wing planform sizes.

• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.257-268
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• 1990

A system has been developed for monitoring the effect of neuromuscular blocking frugs and the neuromuscular function during anesthesia and surgery. This system is composed of software and hardware, the latter are nerve stimulator, force transducer, interface board(preamplifier, filter, peripheral input/output) and personal computer (apple ll) , the former are programmed in ASSEMBLY and BASIC language. The nerve stimulator which is controlled by personal computer is capable of delivering single shocks at o.)Hz, train of four at 2Hz and tetanic stimulation at 30, 100, 200Hz. The response, adduction of the thumb, is sensed by the force transducer. The output of the force transducer Is amplified, filtered, converted digital signal and then processed by the per- sonal computer. The personal computer quantia4es twitch and traln of four tesponse and calculates the 74 ratio (Ta/Tl )between the first and fourth response of train of four. This ratio is used to estimate the level of the neuromuscular block. This system has reaserch potential for determining the effect of newer neuromuscular blocking drugs for comparlsion with presently used drugs of alternatively, for delerminig the effects of blocking drugs in altered physilogical states.

• Journal of electromagnetic engineering and science
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• v.8 no.1
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• pp.6-11
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• 2008

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.

• Journal of Sensor Science and Technology
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• v.15 no.4
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• pp.251-256
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• 2006

This paper describes the flexible force sensor using fiber Bragg grating (FBG) and silicone rubber for the tactile sensation to detect the distributed normal force. The newly designed FBG flexible force has simple structure and can be easily multiplexed with simple wiring compared with the other electric mechanical sensors. We designed the flexible silicone rubber transducer and found the optimum embedding position of FBG in the transducer using the finite element analysis. This flexible force sensor has good performance and is immunity to the electromagnetic field compared with any other kinds of small force sensors for tactile sensation.