• Korean Journal of Computational Design and Engineering
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• v.22 no.2
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• pp.101-109
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• 2017

In order to reduce the number of casualties by improving the survivability of the combat vehicle, the vulnerability analysis of the combat vehicle is needed. However, the actual test for the vulnerability analysis requires large experimental space and expensive equipment costs long time and large expense. It is needed to develop a new method that can replace the actual test. In the paper, we suggested a new approach to analyzing the vulnerability using the M&S method instead of the actual test. To analyze the vulnerability, the shot line analysis is performed to find out which part is penetrated by the bullet. The component of the parts is simplified to "Single-Target", "Double-Target", "Air gapped-Target" and can be performed the penetration analysis using the ANSYS Explicit Dynamics. The penetration depth and the residual velocity of the bullet are calculated by analyzing penetration of each part of the combat vehicle. The penetration data calculated the penetration analysis can be used to define the damage level of the combat vehicle. The purpose of this paper is to collect penetration data for various targets and bullets. And "7.62mmAP" is used as the bullet, "7075-T6" is used as a target.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.157-164
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• 2002

Based on the results of prototype air-shaft construction, penetration capacity of RBM(Raise Boring Machine) was analyzed and compared with TBM(Tunnel Boring Machine) performance in this study. Utilization, down time, net penetration rate and advance rate were evaluated and compared. By conducting the laboratory tests for rock properties with the analysis of penetration capacity, relation of penetration capacity and geotechnical parameters was studied. The results showed that much more higher value of utilization, however lower value of net penetration rate for RBM was obtained compared to those of TBM. In addition, as the strength of rock penetrated increased, higher value of net penetration rate was obtained contrarily to the results of TBM performance. Finally, new relationship between total hardness and net penetration rate for weak and weathered rock was derived from these results.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.225-228
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• 2004

In order to estimate the chloride ion penetration, the model, which considers diffusion and sorption, is proposed on the basis of Finite Element Method (FEM). The FEM program provides the estimation of chloride concentration according to cyclic humidity and sorption. After the humidity diffusion analysis is carried out, the chloride ion diffusion and sorption analysis are conducted on the basis of the preestimated humidity data in each element. Each element has different analysis variables at different ages and locations. At early ages and constant outer humidity, the difference between inner and outer relative humidity causes the chloride ion penetration by sorption. As the humidity diffusion reduces the difference with age, the effect of sorption on the chloride ion penetration decreases. By the way, the cyclic humidity increases the effect of sorption on the chloride ion penetration at early ages, and the quantity of chloride ion around steel at later ages. Therefore, the in-situ analysis of chloride ion penetration for marine concrete structures must be performed considering the cyclic humidity condition and the long term sorption.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.85-98
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• 2001

Cone penetration was analyzed by arbitrary Lagangian-Eulerian(ALE) method. In order to simulate full penetration, steady state analyses were performed using ABAQUS/Explicit, which models upward flow of soil layers. In the analysis of homogeneous layer it was found that the paths and the strain of soil particles were consistent with the result of the strain path method and that the ultimate resistance were reasonably evaluated. The cone penetration through different soil layers was also analyzed and that showed the transfer of cone resistance. The steady state ALE analysis could perform full penetration through the layered soils.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.133-140
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• 2019

In this paper, the penetration process of Shaped charge jet(SCJ) was simulated through finite element analysis to obtain physical quantities such as jet incidence velocity, penetration rate, and penetration increment. As a result of applying these physical quantities to the hydrodynamic theory, it was confirmed that the penetration efficiency of the jet with a high incident velocity is higher than that of the following slow jet. This efficiency decreased sharply when the jet was slower than the hydrodynamic limit(HL). On the other hand, the comparison of penetration increment and jet consumption over time showed that the length extension effect should be considered for SCJ's theoretical penetration analysis.

• Journal of Ocean Engineering and Technology
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• v.34 no.3
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• pp.202-207
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• 2020

A track-type underwater construction robot (URI-R) was developed by the Korea Institute of Ocean Science & Technology. Because URI-R uses tracks to move on the seabed, insufficient ground strength may hinder its movement. For smooth operation of URI-R on the seabed, it is important to determine the geotechnical properties of the seabed. To determine these properties, standard penetration test (SPT), cone penetration test (CPT), and sampling are used on land. However, these tests cannot be applied on the seabed due to a high cost owing to the vessel, crane, sampler, and analysis time. To overcome these problems, a free fall cone penetration tester (FFCPT) is being developed. The FFCPT is a device that acquires the geotechnical properties during impact/penetration/finish phases by free fall in water. Depth information is crucial during soil data acquisition. As the FFCPT cannot measure the penetration depth directly, it is estimated indirectly using acceleration. The estimated penetration depth was verified by results of real tests conducted on land.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.259-260
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• 2012

As RC structures in the marine environment rapidly increase, the interest and the importance of Chloride Penetration durable design have been growing. However, there is hardly any domestic Chloride Penetration durability of RC structures designed analysis programs. Currently, Chloride Penetration durable design method is studied and launched actively as a program in the United States, Europe, Japan and etc., but it is limited to Chloride Penetration durability of RC structures excluded from maintenance construction. Also, the level of dependence on the foreign technology is high; the foreign program is imported and used when needed. The main objective is to compare and to evaluate with the durability assessment program and several conditions when considering the design of Chloride Penetration durability through the programs developed abroad.

• Journal of Biosystems Engineering
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• v.25 no.4
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• pp.287-292
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• 2000

The herbicide penetration on weed leaves was spatially analyzed by using chlorophyll fluorescent emission and machine vision technique. Velvetleaf and metribuzin were used as experimental materials in the study. The herbicide spray images were obtained by a combinaton of a fluorescent dye and a UV lighting system. The herbicide penetration was analyzed by means of detecting chlorophyll fluorescent emission under blue-green lighting. According to the experiment results, the number and the size of spray droplets decreased with coverage increasing. The herbicide penetrated mainly along leaf veins and the time for complete penetration over the whole leaf was approximately 100 minutes after herbicide spraying. When the coverage of herbicide droplets on the surface of leaves increased, the speed of herbicide penetration also increased. This study suggested a way of characerizing herbicide spatial penetration and distribution in leaves.

• Computers and Concrete
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• v.22 no.2
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• pp.239-248
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• 2018

TBM penetration rate is a function of intact rock properties, rock mass conditions and TBM operational parameters. Machine rate of penetrationcan be predicted by knowledge of the ground conditions and its effects on machine performance. The variation of TBM operational parameters such as penetration rate and thrust plays an important role in its performance. This study presents the results of the analysis on the TBM penetration rates in schistose rock types present along the alignment of Golab tunnel based on the analysis of a TBM performance database established for every stroke through different schistose rock types. The results of the analysis are compared to the results of some empirical and theoretical predictive models such as NTH and QTBM. Additional analysis was performed to find the optimum thrust and revolution per minute values for different schistose rock types.

• Geomechanics and Engineering
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• v.29 no.3
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• pp.259-267
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• 2022

The rheological and penetration characteristics of sodium alginate and xanthan gum aqueous solutions were analyzed for the development of biopolymer-based injection materials. The results of viscosity measurements for the rheological characteristics analysis show that all aqueous biopolymer solutions exhibit a tendency for shear-thinning, i.e., the apparent viscosity decreases as the shear rate increases. In addition, a regression analysis using several models (Power-law, Casson, Sisko, and Cross) was applied to the shear-thinning fluid analysis results, the highest accuracy was determined by applying the power-law model. The micromodel experiment for the penetration characteristics analysis determined that all biopolymer aqueous solutions show higher pore saturation than water, and that pore saturation tends to increase as the flow rate and concentration increases. When comparing the rheological and penetration characteristics of the biopolymer aqueous solution used in this study, the xanthan gum aqueous solution showed a fully developed shear-thinning tendency, unlike the sodium alginate aqueous solution. This tendency is considered to have the advantage of enhancement injectability and pore saturation.