• Advances in aircraft and spacecraft science
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• v.4 no.6
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• pp.613-637
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• 2017

The development systems for the Structural Health Monitoring has attracted considerable interest from several engineering fields during the last decades and more specifically in the aerospace one. In fact, the introduction of those systems could allow the transition of the maintenance strategy from a scheduled basis to a condition-based approach providing cost benefits for the companies. The research presented in this paper consists of a definition and next comparison of four methods applied to numerical measurements for the extraction of damage features. The first method is based on the determination of the Structural Intensity field at the on-resonance condition in order to acquire information about the dissipation of vibrational energy throughout the structure. The Damage Quantification Indicator and the Average Integrated Global Amplitude Criterion methods need the evaluation of the Frequency Response Function for a healthy plate and a damaged one. The main difference between these two parameters is their mathematical definition and therefore the accuracy of the scalar values provided as output. The fourth and last method is based on the Mode-shape Curvature, a FRF-based technique which requires the application of particular finite-difference schemes for the derivation of the curvature of the plate. All the methods have been assessed for several damage conditions (the shape, the extension and the intensity of the damage) on two test plates: an isotropic (steel) plate and a 4-plies composite plate.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.1-6
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• 1999

SpeROD, the optical design program. is developed far specular reflectors of fluorescent luminaries. SpeROD can save much tirre when to design specular reflectors. SpeROD calculates conditions 2-dimensionally. The conditions for designing reflectors considered in this program are the intensity distribution, reflector type, and Tangent Spiral Design method. Using SpeROD, uniform intensity distribution type and bat-wing type reflectors are simulated in this paper, and alrrnn(T8) diarreter fluorescent lamp and lmnm width reflector are used for the setting. The sarre setting was simulated in FIElD, the intensity distribution prediction program. and the' result represented the intensity distribution and the efficacy simulated in SpeROD were satisfactory.actory.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.986-990
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• 2009

Using artificial rainfall simulator, the soil loss, which is deemed as most cause of muddy water problem among Non-point source(NPS) pollutant, was studied by the analysis of direct runoff flow, groundwater runoff, and groundwater storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared boxes which are 5%, 10%, and 20% sloped respectively. Also the direct runoff volume from straw covered surface boxes were much lower than bared surface boxes. It's deemed as that the infiltration capacity of straw covered surface boxes were increased, because the surface sealing by fine material of soil surface didn't occurred due to the straw covering. Under the same rainfall intensity and slope condition, 2.4 ${\sim}$ 8.2 times of sediment yield were occurred from bared surface boxes more than straw covered surface boxes. The volume of infiltrated were increased due to straw cover, the direct runoff flow were decreased with decreasing of tractive force in surface. To understand of relationship the rate of direct runoff flow, groundwater runoff, and groundwater storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, expect between the rate of groundwater storage and rainfall intensity.

• Journal of the Korean Society of Combustion
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• v.11 no.4
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• pp.27-35
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• 2006

The impacts of equivalence ratio on flow structure and flame dynamic in a model gas turbine combustor are investigated using large eddy simulation(LES). Dynamic k-equation model and G-equation flamelet model are employed as LES subgrid model for flow and combustion, respectively. As a result of mean flow field for each equivalence ratio, the increase of equivalence ratio brings about the decrease of swirl intensity through the modification of thermal effect and viscosity, although the same swirl intensity is imposed at inlet. The changes of vortical structure and turbulent intensity etc. near flame surface are occurred consequently. That is, the decrease of equivalence ratio can leads to the increase of heat release fluctuation by the more increased turbulent intensity and fluctuation of recirculation flow. In addition, the effect of inner vortex generated from vortex breakdown on the heat release fluctuation is increased gradually with the decrease of equivalence ratio. Finally, it can be identified that the variations of vortical structure play an important role in combustion instability, even though the small change of equivalence ratio is occurred.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.525-528
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• 2002

The objective of this study is to investigate characteristics of flow by the Rod shape and the choice of the turbulent intensity enhancement section. The Rod was setup vertically to the way of a nozzle exit flow and nozzle diameter is 17mm. Rod height is 5mm and its shapes are square, triangle, and circle. Characteristics of fluid such as velocity vector distribution, kinetic energy, turbulent intensity, and etc. were visualized, observed, and considered at 3 kinds of Re No. such as 2000, 3000, and 4000. The characteristics of flow field were investigated in each case of the distance rate from the nozzle exit to impinging plate(H/B=8, 10). The temperature of water is $20^{\circ}E$ and the measurement region divided by 3 sections(I, II, III). The nozzle diameter is 17mm. As the experimental result by PIV measurement, scale of the vector profile showed a tendency to an unbalance parabola distribution as increasing of the Re No. When the impinging plates such as square, triangle, and circle shape are installed respectively in front of the flow accelerated, rod shape of the highest velocity vector is circle shape and rod shape of the highest turbulent Intensity is square shape.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.36-42
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• 1997

This paper purposes the measurement method of vibration intensity in building structure which is a method of measuring the intensity and the flow of vibration energy. We derived basic theory and measuring theory for a simple beam, and comparison of the experimental results with calculated results. As a result, according to the calculated value from acceleration distribution and the measurement result from the method of vibration intensity under the condition except near field of measurement zone. The measured results, show that this method is useful for measuring the vibration energy flow in building structure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.91-98
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• 1980

Three kinds of shading materials, styrol-foam board, pine board and polytex, were examined and compared with ordinary shading, and the effects of light intensity and the temperature under the shadings on the photosynthesis and the root growth of the Korean ginseng were studied to improve the shading on the ginseng field. The amounts of photosynthesis of the ginseng leaves at 2$0^{\circ}C$ were significantly larger than those at 3$0^{\circ}C$ in the same light intensity. At 2$0^{\circ}C$, the maximum photosynthesis occured at 35, 000 lux, but at 3$0^{\circ}C$, the amount of photosynthesis was rapidly reduced by higher light intensity over 26, 200 lux. The best root growth occurred under the polytex shading and the styrol-foam board shading was also effective for ginseng growth. Under the ordinary shading, the root growth of ginseng planted on rear line was very poor but under the styrol-foam or the polytex shading, the root growth showed little difference between the ginsengs planted on rear line and front line.

• Journal of Korean Medical classics
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• v.21 no.2
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• pp.49-57
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• 2008

Objective : To overcome the limit which is unaware of the herbal effects intensity of Traditional study based on "Yakdaeron(藥對論)", classification methods based on the curative effects, we aimed to express the herbal formula's effects numerically, compare one herbal formula with other herbal formulas and calculate the herbal effects and the herbal effects intensity by using conception, weight of the herbal effects. Method : We calculated the herbal effects through the proportion of each herbal quantity to whole quantity of the herbal formula and weight of the herbal effects through frequency and quantity in use on specific herbal effects field and the other herbal effects fields. We applied the weight of the herbal effects to calculating the herbal effects through the proportion of each herbal quantity to whole quantity of the herbal formula. Results : We expressed the herbal formula's effects numerically. By giving weight to the herbal effects, we found that 3-4 major effects among 4-5 major effects are ranked in 5th.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1659-1670
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• 2001

It has been reported that cracks at mechanical fastener holes usually nucleate as elliptical corner cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. The weight function method is an efficient technique to calculate the stress intensity factors fur elliptical cracks using uncracked stress field. In this study the weight function method for three dimensional mixed-mode problem applied to elliptical comer cracks Is modified for elliptical arc through cracks and the stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by the weight function method. This study consists of two parts and in part I , the weight function method for elliptical arc through cracks is developed and verified.

• Journal of Welding and Joining
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• v.3 no.2
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• pp.52-63
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• 1985

Fillet welded joints, specially in ship structure, are well known the critical part where stress concentrate or crack initiates and grows. This paper is concerned with the study of the behavior of fatigue crack growth t the root and toe of load carrying cruciform fillet welded joints under three points bending by the determination of stress intensity factor from the J-Integral, using the Finite Element Method. The stress intensity factor was investigated in accordance to the variation of the weld size (H/Tp). weld penetration (a/W) and plate thickness (2a'/Tp). As mixed mode is occurred on account of shearing force under the three points bending, Stern's reciprocal theory is applied to confirm which mode is the major one. The main results may be summarized as follows 1) The calculation formula of the stress intensity factor at the both of root and toe of the joint was obtained to estimate the stress intensity factor in the arbitrary case. 2) The change of stress field around crack tip gives much influence on each other at the roof and toe as H/Tp decreases. 3) Mode I is a major mode under the three points bending.