• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.15 no.2
• /
• pp.31-39
• /
• 2019

Cracked component analysis is needed for structural integrity analysis under seismic loading. Under large amplitude cyclic loading conditions, the change in material properties can be complex, depending on the magnitude of plastic strain. Therefore the cracked component analysis under cyclic loading should consider appropriate cyclic hardening model. This study introduces a procedure for determining an appropriate cyclic hardening model for cracked component analysis. The test material was nuclear-grade TP316 stainless steel. The material cyclic hardening was simulated using the Chaboche combined hardening model. The kinematic hardening model was determined from standard tensile test to cover the high and wide strain range. The isotropic hardening model was determined by simulating C(T) test under cyclic loading using ABAQUS debonding analysis. The suitability of the material hardening model was verified by comparing load-displacement curves of cyclic C(T) tests under different load ratios.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.23 no.4
• /
• pp.231-238
• /
• 2019

A conventional lumped-mass stick model is based on the tributary area method to determine the masses lumped at each node and used in earthquake engineering due to its simplicity in the modeling of structures. However the natural frequencies of the conventional model are normally not identical to those of the actual structure. To solve this problem, recently an updated lumped-mass stick model is developed to provide the natural frequencies identical to actual structure. The present study is to investigate the seismic response accuracy of the updated lumped-mass stick model, comparing with the response results of the shaking table test. For the test, a small size four-story steel frame structure is prepared and tested on shaking table applying five earthquake ground motions. From the comparison with shaking table test results, the updated model shows an average error of 3.65% in the peak displacement response and 9.68% in the peak acceleration response. On the other hand, the conventional model shows an average error of 5.15% and 27.41% for each response.

• The KIPS Transactions:PartD
• /
• v.11D no.4
• /
• pp.885-892
• /
• 2004

Weibull distribution Iincluding Rayleigh and Exponential distribution is a typical model to estimate the effort distribution which is committed to the software testing phase. This model does not represent standpoint that many efforts are committed actually at the test beginning point. Moreover, it does not properly represent the various distribution form of actual test effort. To solve these problems, this paper proposes the Sigmoid model. The sigmoid function to be applicable in neural network transformed into the function which properly represents the test effort of software in the model. The model was verified to the six test effort data which were got from actual software projects which have various distribution form and verified the suitability. The Sigmoid model nay be selected by the alternative of Weibull model to estimate software test effort because it is superior than the Weibull model.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.1C
• /
• pp.1-10
• /
• 2011

This paper simulates the piping effect, found levees with large difference in coefficient of permeability within the foundation such as the Gim-po Levee, via centrifuge model test which is a model test. We have also conducted a numerical analysis under the same conditions as the centrifuge model test to compare its results. First, we decided to use the centrifuge model based on the Gim-po Levee, and the tests were executed on a model levee with pore water pressure transducers. We have found that most of the water flows through the permeable layer and causes the piping effect. Via video camera footage, we have found that the piping effect occurred at the toe of the model levee. The characteristic of pressure head distribution, obtained from the pore water pressure transducers, also proves the occurrence of the piping effect. The numerical analysis results also showed the same results as the centrifuge model test. We have simulated the piping effect via centrifuge model test and believe that the centrifuge model test is viable for various tests, predictions and evaluation of the levee problems.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.9
• /
• pp.205-213
• /
• 2003

This study describes the mathematical equation of drawdown test model and introduces the experimental test apparatus and procedure to estimate the desorption rate ratio of a filter. The characteristics of a hydraulic filtration system of drawdown test were demonstrated by numerical simulation for various properties of filters and operation conditions. Experiments for three kinds of fuel filters were conducted according to the proposed test method. And the test results of desorption rate ratio were compared with those values anticipated in precedent multipass filtration tests. Experimental results revealed the validation of drawdown test method proposed in this study. Domestic fuel filter yielded high desorption rate ratio comparing with other foreign products, which means that the Beta ratio decreases a lot during the test. The results also showed that filtration system model could be developed including desorption rate ratio to estimate the variable Beta ratio in service life.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.14 no.2
• /
• pp.9-16
• /
• 2006

FAA AC120-40B Level D flight dynamics model for T-50 Full Mission Trainer was successfully developed. Since AC120-40B Level D requires the quantitative validation tests for simulation model compared with flight test data, T-50 flight test data for each validation test item was gathered, and also automatic test environments which include AFT (Automatic Fidelity Tester) and STA (Simulation Test Analyzer) were developed. The final test results after the iterative test-tuning processes were all within the tolerances specified in AC120-40B Level D. Qualification Test Guide, QTG contains the detail test processes and results.

• Journal of Industrial Technology
• /
• v.25 no.A
• /
• pp.3-14
• /
• 2005

In order to accurately analyze the detailed hydraulic characteristics of the curved channel in the downstream of dam with the hydraulic structures such as bridge piers, RMA2 model which is one of two-dimensional models is applied to ChunCheon dam downstream curved channel. A series of hydraulic model tests are carried out for comparison studies. HEC-RAS model is also applied to the same site. There are no errors when velocities and water levels resulted from HEC-RAS model RMA2 model are compared with those of hydraulic model test on the straight channel. But, it is found that results of RMA2 model have a better agreement with those of hydraulic model test than those of HEC-RAS model on the curved channel with bridge piers. Additionally, RMA2 model can be predicted the eddy phenomena around bridge piers of the curved channel.

• Environmental Mutagens and Carcinogens
• /
• v.17 no.2
• /
• pp.92-96
• /
• 1997

The micronucleus test using peripheral blood reticulocytes (RETs) was evaluated in ICR mice treated with N-methyI-N-nitrosourea (MNU) and benzo(a)pyrene [B(a)P] as model clastogens. The frequency of micronucleated reticulocytes (MNRETs) in both positive compounds was similar to other results which were reported previously. On the other hand, an anticlastogenic effect of the natural antioxidant, $\beta$-carotene and one of taroholds, galangin as model anticlastogens were investigated using simultaneous treatment. Mice were treated with a model clastogen alone, or with a model clastogen and a model anficlastogen simultaneously. Both $\beta$-carotene and galangin showed anticlastogenic effects against MNU- or B(a)P-induced micronuclei in mice. However, galangin has stronger activity than $\beta$-carotene. Results from our experiment suggest that the in vivo supravital staining micronucleus test using peripheral blood is useful in the evaluation of clastogenic and anticlastogenic effects.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2001.10a
• /
• pp.86-90
• /
• 2001

Demand of good seakeeping perfomace is increasing for sea going vessels such as cruisers, naval ships and container ships. Especillay roll motion is one of major concerns in evaluation of seakeeping performance due to its large resonace motion. Since large roll resonance motion is mainly arised from inherent small damping. use of additional mechnism to provide roll damping can significantly reduce roll motion. In this paper, a reliable performace evaluation method of fin stabilizer, which is very useful for stabilizing roll motion of mid and high speed vessls, is described. Model test and time domain simulation methods are adopted for performance evaluation in which real operating situation of fin stabilizer can be exactly modelled. Model test and simulation results show good correlations between model test and simulation results.

• Proceedings of the KSME Conference
• /
• 2000.04b
• /
• pp.611-618
• /
• 2000

The test facility of the 1/60-scale models for the train-tunnel interactions was recently developed to investigate the effects of entry portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating to the surroundings of the tunnel exits by KRRI in Korea. The launching system of train model was chosen as air-gun type. In present test rig, after train model is launched, the blast wave by the driver did not enter to inside of the tunnel model. The train model is guided on the one-wire system from air-gun driver to the brake parts of test facility end. Some cases of the experiments were compared with numerical simulations to prove the test facility.