• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.1949-1957
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• 2000

All the loads in the real world act dynamically on structures. Since dynamic loads are extremely difficult to handle in analysis and design, static loads are utilized with dynamic factors. The dyna mic factors are generally determined based on experiences. Therefore, the static loads can cause problems in precise analysis and design. An analytical method based on modal analysis has been proposed for the transformation of dynamic loads into equivalent static load sets. Equivalent static load sets are calculated to generate an identical displacement field in a structure with that from dynamic loads at a certain time. The process is derived and evaluated mathematically. The method is verified through numerical tests. Various characteristics are identified to match the dynamic and the static behaviors. For example, the opposite direction of a dynamic load should be considered due to the vibration response. A dynamic bad is transformed to multiple equivalent static loads according to the number of the critical times. The places of the equivalent static load can be different from those of the dynamic load. An optimization method is defined to use the equivalent static loads. The developed optimization process has the same effect as the dynamic optimization which uses the dynamic loads directly. Standard examples are solved and the results are discussed

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.2
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• pp.107-114
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• 2004

NPS pollutant loads from sandy clayey and clayey loam runoff plots were measured. Runoff plots were 2$\times$10 m in size and 8~10% in slope and paddy area was 4,620 $m^2$. Soybean, corn, tobacco and control (natural weed) were cultured. Precipitation during the growing season of June to October, 2002 was 869.5 mm. Runoff and water quality were measured more than 10 times during the measurements depending on the growing stage. Pollutants loads were estimated by using respective concentration and runoff volume. Runoff occurred when daily rainfall exceeded about 30 mm. The largest runoff was observed from the paddy but pollutant loads were larger from upland crops than those from paddy. SS loads from paddy and upland were 1.4 ton/ha/yr and 3.1~4.3 ton/ha/yr, respectively. COD loads 30 kg/ha/yr and 66~90 kg/ha/yr, T-N loads 13 kg/ha/yr and 14~23 kg/ha/yr, T-P loads 1 kg/ha/yr와 4 kg/ha/yr, nitrate nitrogen loads 1 kg/ha/yr and 4~8 kg/ha/yr, and phosphate phosphorus loads 0 kg/ha/yr and 4~6 kg/ha/yr, respectively. It was concluded that NPS pollutant loads from upland crop culture have greater impact on the quality of the receiving water body than those from paddy culture.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.1-8
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• 2005

Civil aviation regulation such as FAR and loads analysis procedure based on this was explained, and loads analysis procedure and results for Smart UAV was presented for application case. For loads analysis, applicable regulations and loads conditions should be prepared in advance, and modeling for aerodynamics, weight, and structure should be performed. Panel method is usually adopted for aircraft loads analysis to obtain aerodynamic loads. In this study, ARGON which is multidisciplinary fixed wing aircraft design software co-developed by KARI and TsAGI was used for loads analysis. ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis of 4-seater canard airplane was performed with ARGON and that results were presented.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.534-539
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• 2005

The purpose of this study is the introduction of pollutant loads's estimation into Saemangeum watershed area with M.E.'s guidebook for TMDL and GIS tool. To estimate reliable pollutants loads, it is necessary to think about characteristic of removal, discharge and runoff as time series. In this study, it was calculated for generation loads which be came from pollutant source, discharge loads which be reduced in the treatment facilities and delivery loads which be considered the self purification parameter and delivery distance. To assess the delivery distance handily, it was particularly estimated using Arc-GIS. It was met with good results that delivery loads of BOD, T-N and T-P was reflected to seasonal precipitation. Lastly to verify the estimated pollutant loads, HSPF developed by USEPA was applied to it. It was showed a relativity of observed to simulated data for flow, Temperature, DO, BOD, $NO_3^--N$ TN and TP. Consequantly, this delivery loads can make full use of model input data for prediction of pollutant loads.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.76-84
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• 2005

For flight loads analysis of Smart UAV, applicable regulations and loads conditions should be prepared in advance, and modeling for aerodynamics, weight, and structure should be performed. Panel method is usually adopted for aircraft loads analysis to obtain aerodynamic loads. In this study, ARGON which is a multidisciplinary fixed wing aircraft design software co-developed by KARI and TsAGI was used for loads analysis. ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis of Smart UAV which is a FAR 23 category airplane was performed with ARGON and the results were presented.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.159-166
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• 2000

Structures with a long span have a higher possibility of experiencing excessive vibration induced by human activities such as walking, running, jumping and dancing. These excessive vibration give occupants annoyance. The general method for the vibration analysis of structures subjected to walking loads is to apply a series of nodal loads with assigned time delays at the nodes. But this method has a limit in representing the walking loads. In this study, the equivalent nodal loads are introduced for an effective analysis of floor vibration induced by walking loads. And, walking loads with difference walking rate are measured and applied to the analytical model for numerical analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.267-274
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• 2003

The objective of this study is to estimate the frequency characteristics of group walking loads based on the information of measured responses. At first, dynamic properties such as natural frequencies and modes are obtained from input/output relation for building structures by heel drop test. Second, a method to estimate group walking loads by the transfer functions from measured responses to group walking loads is proposed. The method turned out to estimate the group walking loads accurately. Higher modes could be important in estimating the amplitude of group walking loads with the information of single walking load.

• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.2
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• pp.87-92
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• 1986

The differential equation, which can determine the dynamic critical loads for low parabcoic arches, is derived in this study. The dynamic critical loads of the parabolic arches subjected to a concentrated step load are nummerically analyzed for the changes of load positions. In cases of arches with different end conditions (both hinged, fixed hinged, both fixed), the effect of end conditions and that of the rises are investigated in detail. The summary of the results are the following: 1)The snapthrough does not occur when the rise of arch is very low, and the bifurcation appears clearly as the rise of arch increases. 2)The regions in which the dynamic critical loads are not defined for the both ends fixed are broader than that for the both ends hinged. 3)For all case, the load positions of minimum dynamic critical loads exsit at the near position from the end hinged. Thus, the results obtained in present study show that the magnitude of dynamic critical loads, the load positions of minimum dynamic critical loads and the regions in which the dynamic critical loads are not defined depend on end conditions of arches.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.513-518
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• 2004

KARI(Korea Aerospace Research Institute) has developed smart unmaned aerial vehicle(UAV) since 2002. Smart UAV has tilt rotor configuration which can take off and land vertically. For designing and developing smart UAV, it is necessary to obtain design loads. ARGON which use the panel method is multidisciplinary aircraft design program developed and modified by KARI and TsAGI. Panel method is very useful to obtain aerodynamic loads, so it have been used widely for aircraft loads analysis. For flight loads analysis, we have to prepare regulations and load conditions, and then design aerodynamic panel model, mass model and structure model. In this paper, we introduce the flight loads analysis procedure briefly, and show the smart UAV loads analysis procedure and result using ARGON.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.45-52
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• 2009

In this paper, a guideline for designing breakwater in wave loads and in seismic loads is proposed. A simple model structure in breaking wave zone is examined using Morison equation in consideration with the effect of an impact load, for evaluation of the wave loads. As the impact load effect is not significant, pressure distributions according to Goda are applied for evaluation of wave loads on breakwater. Structural behavior of breakwater in wave loads can be obtained using the Goda method, as well. For seismic analysis, Ofunato and Hachinohe models, as well as an artificial seismic acceleration loads model, are adopted. Soil-structure interaction analysis is carried out to find the seismic load effect. It is found that, in certain cases, structural deformation in wave loads is in the same level as deformation that in seismic loads. Thus, it is our recommendation that these two loads are considered at the same level in breakwater design.