• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.385-390
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• 2000

The alignment of the prosthetics is very important in an amputee's gait. In the present study. a static prosthesis-alignment device was developed. It consisted of a force plate with four load cells, a laser beam controlled by a step motor, and a control part programmed by PCBASIC. Using the static prosthesis-alignment device, we measured the distance between the load line and various joints of 24 normal volunteers in three standing postures. such as neutral, forward leaning, and backward leaning. Only neutral postures were evaluated on four trans-tibial amputees. The load line for the normal person's neutral position located anterior to the ankle, the knee, and the greater trochanter, but posterior to the shoulder joint. Forward and backward leaning of the normal person resulted in a significant anterior and posterior movements of the load line, respectively. The load line for the amputated side of the trans-tibial amputee also located anterior to the ankle, the extremity prostheses, providing a good relative locations of the load line with respect to various joints.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.538-544
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• 2009

A vibration excitation system was designed and built of forced vibration experiments for using stepping motor and load cell. The identified flutter derivatives of the thin-plate acrylic model were very close to the analytical results of the idealized plate presented by Theodorsen. Five types of sectional models were tested in the wind tunnel using the proposed forced vibration method. To investigate the frequency, amplitude and angle of attack effects on flutter derivatives.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.77-85
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• 2014

The helical pile has become popular with some constructional advantages because relatively compact equipment is needed for installing helical piles. However, field loading tests for estimating the bearing capacity of helical piles have drawbacks that the required dead load should be as much as the operation load, and reaction piles or anchors are required. In this paper, the bi-directional load test without necessity of reaction piles and loading frames was applied to the helical pile, and the load-settlement curves of the helical piles were measured. The bi-directional load test was performed in two separate stages with the aid of a special hydraulic cylinder whose diameter is equal to that of the pile shaft. In the first stage, the hydraulic cylinder is assembled immediately above the bottom helix plate, and the end bearing capacity of the helical pile is measured. In the second stage, the hydraulic cylinder is assembled above the top helix plate, and the skin friction of the helical pile is measured. The pile loading-test program was carried out for the two different helical piles with the shaft diameter of 89 mm and 114 mm, respectively. However, the configuration of helix plates is identical with three helix plates of 450-, 350-, 200- mm diameter. Results of the bi-directional load test were verified by the conventional static pile loading test. As a result, the bearing capacity estimated by the bi-directional load test is in good agreement with the result of the conventional pile loading test.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.1
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• pp.83-92
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• 2011

Evidence on the effect of $O_2$ reduction or current passage on the microstructure and morphology of the LSM and Ni-YSZ electrodes in solid oxide fuel cells. The microstructures of the electrodes were characterized as plate-like agglomerates. Current of $0.1\;A/cm^2$, $0.2\;A/cm^2$, $0.3\;A/cm^2$, at $800^{\circ}C$ were passed for 3 h. Then, we observed the cell structure and measured the cell performance before and after the experiment. There are changed with the load condition. The TPB of the cell increased when the cell structure changed. In particular, the decrease in activation loss is apparent as load increased. As a result, cell performance improved, and we confirmed that a optimal load condition existed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.73-78
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• 2000

This paper describes the effect of span-to-depth ratio, which describes aspect of cell formed with top diaphragm steel plate, on capacity in composite steel-concrete structure of sandwich system. The span-to-depth ratio \ulcorner load-carrying mechanism and load-distribution capacity of structure. Therefore, stress levels of members and load-resis\ulcorner of system vary according to span-depth ratio. In this study, numerical nonlinear analysis was performed to various ratio for two types(MA, MB) composite structure of sandwich system to analyze the influence of span-to-depth ratio or, behavior. The difference of load-carrying mechanism and stress of members results from analysis results, then bas\ulcorner differences, the effects of span-to-depth ratio on shear capacity, flexural capacity and load-resistance capacity were analyze effects on failure mode and ductility were briefly. As a results of this study, as span-to-depth ratio increases, \ulcorner bottom steel plate and concrete lower. This implies an increase in effective flexural and shear capacity. Therefore lo\ulcorner capacity of structure improves as span-to-depth ratio increases, Especially, the effect is greate in shear than flexural span-to-depth ratio increases, this difference between flexural and shear capacity may change failure mode and ductility. span-to-depth ratio increases capacity increases more than flexural capacity, we should expect that structural behavior mode gradually change from shear to flexural and ductility of structure gradually improves.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.34-40
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• 2015

A stack in the proton exchange membrane fuel cell (PEMFC) consists of bipolar plates, a membrane electrode assembly, a gas diffusion layer, a collector and end plates. High current density is usually obtainable partially from uniform temperature distribution in the fuel cell. A size optimization method considering the thermal expansion effect of stacked plates was developed on the basis of finite element analyses. The thermal stresses in end, bipolar, and cooling plates were calculated based on temperature distribution obtained from thermal analyses. Finally, the optimization method was applied and optimum thicknesses of the three plates were calculated considering both fastening bolt tension and thermal expansion of each unit cell (72 cells, 5kW). The optimum design considering both thermal and mechanical loads increases the thickness of an end plate by 0.64-0.83% the case considering only mechanical load. The effect can be enlarged if the number of stack increases as in an automotive application to 200-300 stacks.

• Steel and Composite Structures
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• v.39 no.3
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• pp.275-290
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• 2021

The main purpose of this research work is to investigate the critical buckling load of functionally graded (FG) porous plates with graphene platelets (GPLs) reinforcement using generalized differential quadrature (GDQ) method at thermal condition. It is supposed that the GPL nanofillers and the porosity coefficient vary continuously along the plate thickness direction. Generally, the thermal distribution is considered to be nonlinear and the temperature changing continuously through the thickness of the nanocomposite plates according to the power-law distribution. To model closed cell FG porous material reinforced with GPLs, Halpin-Tsai micromechanical modeling in conjunction with Gaussian-Random field scheme are used, through which mechanical properties of the structures can be extracted. Based on the third order shear deformation theory (TSDT) and the Hamilton's principle, the equations of motion are established and solved for various boundary conditions (B.Cs). The fast rate of convergence and accuracy of the method are investigated through the different solved examples and validity of the present study is evaluated by comparing its numerical results with those available in the literature. A special attention is drawn to the role of GPLs weight fraction, GPLs patterns through the thickness, porosity coefficient and distribution of porosity on critical buckling load. Results reveal that the importance of thermal condition on of the critical load of FGP-GPL reinforced nanocomposite plates.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.357-361
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• 2012

Anemometer is a meteorological instrument that measures wind direction and wind speed in real time, and is mounted to the cranes that are used at ports, shipbuilding yards, off-shore structure, or construction sites that are influenced by wind, and it is used in conjunction with the safety system. Load cell-type anemometer measures the wind direction through the ratio of load between 4 positions by mounting the thin plate to 4 load cells, and measures wind velocity through the summation of loads. In this study, we compared and analyzed the results in the theoretic approach, analytic approach and experimental approach to derive the correlation between load ratio and wind direction. Wind direction was selected as the design variable, and selected 9 wind direction conditions from $0^{\circ}{\sim}90^{\circ}$ with $11.25^{\circ}$ space for analysis, and 10 wind direction conditions with $10^{\circ}$ space for experiment.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.4
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• pp.304-312
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• 2002

In this study, the performance of the $5Nm^3/hr$ compact type steam reformer which was developed for application of fuel cell or hydrogen station was evaluated in terms of gas process efficiency. For these purposes, reforming efficiency and total efficiency with system load change were analyzed. The reforming efficiency was calculated from the total molar flow of hydrogen output over total fuel flow input to the reformer and the burner on the higher heating value(HHV). In the case of the total efficiency, recovered heat at the heat recovery exchanger was considered. From the results, it was known that system performance was stable, because methane conversion showed the a slight decline which is about 2% though increasing system load to full. Reforming efficiency was increased from 20% to 58%, respectively as increasing system load from 10% to 90%. It was found that total efficiency was higher then reforming efficiency because of terms of heat recovered. As a results, it was known that total efficiency was increased form 75% to 83% at the 10% and 90% system load, respectively. From these results, it is concluded that compact steam reformer which is composed of stacking plate-type reactors is suitable to on-site hydrogen generator or to fuel cell application because of quick start within 1 hr and good performance.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.1072-1076
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• 2001

A biomechanical study was conducted in this study to investigate if in-line skating wrist guards can effectively reduce the impact forces so as to protect the wrist from fracture. The forearm specimens with and without wrist guards were dropped using a specially designed sled to simulate the impact on the wrist while falling. A force plate was used to measure the total impact force on the dropping weight whereas a load cell was attached to the proximal end of the specimen and used to quantify the impact transmitted through the wrist joint. From the non-destructive tests, mean peak force measured from a force plate showed no difference between the guarded and unguarded groups whereas mean impulse of the guarded group was significantly greater than that of the unguarded group (p<0.01). Comparing the peak force and impulse measured from the load cell, the peak force of the guarded group was significantly less than that of the unguarded group (p<0.001), while the impulse values were similar. When the specimens were dropped from a higher position (2.5ft ve. 1ft), all unguarded specimens had severe wrist fractures whereas fracture was found in three out of 5 guarded specimens. Comparison of mean peak forces and impulses showed as significant difference between the guarded and unguarded groups only in the mean impulse measured from the force plate. These results suggest that the wrist guard may protect the wrist by attenuating the peak force transmitted to radius and ulnar although it may not be effective when the wrist is subjected to an impact sufficiently large to cause fractures.