• Journal of Biosystems Engineering
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• v.28 no.6
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• pp.485-490
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• 2003

Flexural rigidity(EI) and deflection characteristics of rice stalks were studied to investigate the mechanical interaction between a rice stalk and a combine reel in harvesting. Deflection of a rice stalk caused by reel operation is so large that conventional equation of small deflection fer elastic beam cannot be applied to the study of deflection characteristics. Therefore, an equation of large deflection for elastic beam was introduced in this study. Feasibility of this equation was examined by comparing theoretical calculation with the measured results for piano wire, and by the relationship between deflection and load acting on a rice stalk which was presumed by this equation. Results showed that the large deflection equation could predict the measurement data quite well. From this research, the following results were obtained. 1. Flexural rigidity(EI) calculated from the equation of large deflection was 4.0${\times}$l0$^4$N$.$$\textrm{mm}^2$(diameter 1.4mm, deflection 300mm) while the actual EI value of a piano wire(diameter 1.4mm) was 3.9${\times}$10$^4$N$.$$\textrm{mm}^2$. 2. The relationship between deflection and load acting on a rice stalk could be presumed by the large deflection equation. Flexural rigidity values of tested rice stalks calculated from the equation of large deflection were 1.6∼2.4${\times}$ l0$^4$N$.$$\textrm{mm}^2$(Hwa sung), 2.7∼3.5${\times}$ l0$^4$N$.$$\textrm{mm}^2$(Il pum) and 1.7∼2.4${\times}$ l0$^4$N$.$$\textrm{mm}^2$(Damakum)

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.5
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• pp.389-404
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• 2017

The main purpose of this presented investigation is to build up the BHMS based on GNSS. This proposed monitoring system can conduct the deflection and dynamic characteristics analysis by using only GNSS positioning solution. The general bridge monitoring system being operated recently is composed of a combination of various sensors that are able to conduct deflection monitoring and dynamic characteristics monitoring analysis at the same time. However, GNSS based BHMS has the unique procedure in terms of data analysis. In the other words, GNSS positioning solution is firstly applied to deflection monitoring analysis then, this deflection analysis can be sequentially reflected in the dynamic characteristics. Unfortunately, the adjustment result of GNSS positioning solution estimated through various options and conditions and the process of monitoring analysis has not been fulfilled systematically. This means that different results or analysis value are presented according to the methodology and officers. Most of researches have been focusing on deflection monitoring analysis and some investigation regarding to dynamic characteristics is recently introduced. Moreover, it is not still reported the systematic investigation with regards to proper filtering and analysis methodology. This study was carried out based on a large amount of data, from this, various variables not reported yet are actively considered. Therefore, specific software for both monitoring analysis have been developed.

• Journal of the Korean Institute of Navigation
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• v.12 no.2
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• pp.33-42
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• 1988

As a basic study for enhancing the sensitivity of the follow-up system of the marine gyrocompass, the geometric characteristics of the deflection sensor were investigated and the theoretical model of it was formulated. The output signal voltage of the deflection sensor was esamined by changing the attitude of gyrosphere against follow-up container. The characteristics of the output are found to be indentical with those of the distance difference versus the relative azimuthal deflection of the gyrosphere against the follow up container. On the base of the theoretical model, some useful points for the design of the deflection sensor are suggested as following : 1. When the difference between semidiamter of gyrophere and that of the follow-up container decreases, the sensitivity of deflection sensor increases. 2. If the semidiameter difference of two spheres is constant, the sensitivity of deflection sensor is proportional to the magnitude of the semidiamter of each sphere. 3. The farther the gyrosphere is deviated from the center of follow-up container, the higher the sensitivity of deflection sensor is. 4. It is recommendable that the value of the datum deflection of the electrodes on the gyrosphere should be within the range between $4^{\circ}$ and $16^{\circ}$deviated from north-south line.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.775-776
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• 2011

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.54-62
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• 2021

This study has investigated the 3-D deflection characteristics of a flexible plate levitated by non-contact grippers using SPIV method. The measuring instrument consisted of a flexible plate located under four non-contact grippers and two cameras at the bottom of a transparent acrylic plate. Measurements were made on two materials (PVC and PC) for the plate with 50×50 cm2 area and 1 mm thickness. The deflection characteristics and flatness vary depending on the plate material, the gripper position and the air flow supplied to the gripper. For the material of PVC, the overall defection is convex. As the gripper position goes outward from the plate center, the upmost bending point also moves to the outside of the plate with the flatness increasing. However, the air flow rate does not affect the deflection pattern except for the small increase of flatness. For the material of PC, the shape of deflection changes from convex to concave as the gripper position goes out. The flatness is the highest at the point of transition from convex to concave, but the air flowrate has little effect on the flatness.

• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.387-395
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• 1998

In general, the laminated rubber bearing (LRB), a composite structure laminated with the elastic rubber and steel plates, has a complex hysteretic nonlinear characteristics in relationships between the restoring force and shear deflection. The representative nonlinear characteristics of LRB include the change of hysteresis loop with cyclic shear deflections and the hardening effects at large shear deflection regions. Changes of the hysteresis loop of LRB with cyclic shear deflections affect the horizontal stiffness and the damping characteristics. The hardening behavior of LRB in large shear deflection region results in an increased horizontal stiffness and therefore, has a great impacton the seismic responses. In this paper, the seismic response analysis is carried out using the modified hysteretic bi-linear model of LRB, which takes into account the hysteresis loop change and the hardening behavior with cyclic shear deflection. The results on seismic responses are compared with those obtained using the widely used hysteretic hi-linear model. The new model is found to reveal the greater amount of peak acceleration response.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.820-823
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• 2000

The characteristics of wire deflection, surface roughness and roundness were observed on changing discharge time for electrical discharge machining(EDM) of tungsten carbide in various conditions of thickness. The wire deflection was decreased as increasing discharge time and wire tension, the gap of deflection was decreased after thickness 60mm and discharge time of 6$\mu\textrm{s}$ due to the changing from fundamental mode to vibration mode. The deflection is the smallest at the water specific resistivity of 7.5 kΩ ㆍcm. The deflection is found to be decreased as increasing dwell time, and the result is due to the vibration of the pressure and the amount of the dielectric. The component of copper(Cu) and zinc(Zn), which is the main material of wire electrode, was observed for rough wire-cutting EDM of STD-11. This phenomena is found to be decreased as the number of EDM is increased. But it will be improved by changing the material and the shape of wire. The roundness of middle is found to be worse than that of upper and it is increased as the thickness of material is increased.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.97-103
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• 2002

Vibration isolation technology using an air spring and laminated rubber bearing is widely used because it has excellent vibration isolation characteristics. In the part of that, we usually make use of the self-damped air suing. It is occupied two chambers, restrictor, diaphragm and load plate. Two chambers contain compressed air and the volume of chambers and the area of load plate give a definition of stiffness and load. The restrictor and the volume ratio of two chambers give a definition of damping ratio. The conventional model of restrictor is made of one orifice and it causes turbulent flow in the orifice at the region of large deflection. The stillness of air suing is larger and the damping is lower in the region of large deflection. In the multi-orifice case, the stiffness is similar to air spring with one orifice but damping ratio is larger than conventional air spring. And damping ratio is smaller than conventional air suing in small deflection region. Deflection is small in the region of high frequency so small damping is better than large damping. As a result, we can reduce the storage stiffness of air suing in the wide region of deflection and increase the damping ratio in the region of large deflection. After this, we will try to and the relation of Reynolds Number and Flow Resistance then we are going to make another restrictor for air spring to improve damping ratio and stiffness.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.287-294
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• 2000

Calculation of the flexural rigidity value (EI) is indispensable for prescription of deflection characteristics of crop stalks in harvesting□Conventionally□EI has been determined by either average EI of the whole stalk or average EI of each stems divided into node through the calculation method of cantilever with homogeneous section□However□deflection characteristics of crop stalks caused by mechanical operation such as combine harvester were not exactly presumed by these conventional EI through the experiment by authors. Further, actual EI of a stalk changes in company with a change of moisture contents as time passes during the experiment. Finally, efficient calculation method for determining EI is needed in order to improve these problems. In this study, mechanical model based on actual structure of the crop stalk with variety sectional area was proposed. This mechanical model is calculated by the theory of cantilever with continuous stages. Therefore, improvement of both calculating accuracy on EI and efficiency of measuring system was tried. At first, this calculation method was applied to piano wire of which EI was recognized in advance. As a result, EI calculated from this new method coincided approximately with piano wire's EI. Next, applying to crop stalks as same as piano wire, relationship between loads acting on crop stalks and deflection values calculated by EI using this new calculation method was exactly presumed in comparison with conventional method. Further, measuring time of deflection test was greatly reduced. Finally, new calculation method of EI will be available for estimating mechanical characteristics of so many kinds of crop stalks in harvesting operation. Further, in this study, new deflection test using image-processing apparatus by computer will be introduced.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.4
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• pp.323-330
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• 1982

The vibration characteristics of continuous span periodically supported beams with moving loads are determined theoretically and experimentally. Moving loads are assumed to travel at constant acceleration with constant magnitude. Analyses by using the Fourier Transform technique are developed to determine the dynamic performance of moving load interacting with multiple and continuous beam. Equation of motion for the moving load is non-dimensionalized. Non-dimensional deflection proflies of continuous beam are presented in detail for the single concentrated moving load with constant acceleration. Experimental moving load and continuous beam models are developed. The maximum deflections at each midpoints 5,7 and 9 span beam are measured and their non-dimensional maximum deflections are presented. The non-dimensional maximum deflection of continuous beam is compared with measured maximum deflection of 9 span beam and found to agree reasonably well. The deflection of continuous beam due to moving load with acceleration is strongly influenced in the resonance region.