• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.3
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• pp.217-222
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• 2006

Recently, LG chemical corporation developed new material called HYPERIER, which has an excellent barrier characteristic. It has many layers which are made of nano-composite within LDPE(Low-Density Poly Ethylene). In order to guarantee the quality of the final product from the production line, a certain test equipment is required to investigate the existence of layers inside the HYPERIER. In this work, ultrasonic sensor based test equipment for investigating the existence of inner layers is proposed. However, it is a tedious job for human operators to check the existence by just looking at the resounding waveform from ultrasonic sensor. Therefore, to enhance the performance of the ultrasonic test equipment, wavelet and PCA(Principle Componet Analysis) schemes are introduced into neural network scheme which is used for classification. To verify the feasibility of the proposed scheme, some experiments are executed.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.91-98
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• 2009

A reliable tensile test technique for PDP's barrier rib materials was introduced. A tensile specimen was prepared by punching out of green sheet, curing the specimen in a high temperature furnace, attaching sand paper tabs on each grip ends, and then attaching two strain gages for the strain monitoring and specimen alignment. Preliminary tensile tests were successfully done with the specimens made from ZnO-based lead-free green sheet. The specimens cured at 3 different maximum curing temperatures were tested to demonstrate the applicability of the test method. The Young's modulus was 88 ${\pm}$ 4 GPa regardless of the maximum curing temperature. The ultimate tensile strength was decreased with increasing the temperature. The tensile test method proposed in this study was proven to be reliable, useful and easy to estimate the bulk mechanical properties of barrier rib materials.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.496-499
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• 2008

The noise reducing devices installed on the noise barrier have been developed in many shapes and ways to reduce noise around road traffic areas. In this study, test and estimation method for the noise reducing device witch installed on the top of a noise barrier was suggested. For this, the authors have considered sound power flow around the device and sound pressure levels for the far field area. To estimate the area effect behind the barrier, area average of noise pressure level difference divided by two area, upper and bellow the sight-line. Comparing the attenuation difference of these areas, the tendency of noise reduction effect was studied according to type of noise reducing devices. Compared with noise shielding efficiency of the devices that using equivalent height of a simple barrier calculated by the SoundPlan, the commercial environment noise simulation software.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.13-21
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• 2017

PURPOSES : In this research, an SB3-level roadside barrier for a highway transition zone that meets the newly established guide Installation and Management Guide for Roadside Safety Appurtenance is developed. Its performance is evaluated by a numerical simulation and real-scale vehicle impact test. METHODS : The commercial explicit dynamic software LS-DYNA is utilized for impact simulation. An FE model of a passenger vehicle developed and released by the National Crash Analysis Center (NCAC) at George Washington University and a heavy goods vehicle (HGV) model developed by the TC226/CM-E Work Group are utilized for impact simulation. The original vehicle models were modified to reflect the conditions of test vehicles. The impact positions of the passenger vehicle and truck to the transition guardrail were set as 1/2 and 3/4 of the transition region, respectively, according to the guide. RESULTS : Based on the numerical simulation results of the existing transition barrier, a new structural system with improved performance was suggested. According to the result of a numerical simulation of the suggested structural system, two sets of transition barriers were manufactured and installed for real-scale vehicle impact tests. The tests were performed at a test field for roadside safety hardware of the Korea Highway Corporation Research Institute. CONCLUSIONS : The results of both the real-vehicle impact tests and numerical simulations of the developed transition barrier satisfied the performance criteria, and the results of numerical simulation showed good correlation with the test results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.11a
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• pp.245-249
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• 2008

The purpose of this study is to test performances of 14 types of root barrier materials by applying testing plants and soils suitable for weather and natural features of Korea. For testing plants, Plioblastus pygmaed Mitford A. and Pyracantha angustifolia have been selected. For testing soil, mixture of pearlite and peat moss in 3:1 ratio(volume). Testing container has been fabricated with duplicated structure having inner and outer containers. And the outer container has 2 hinges on its side wall to allow opening and closing. Wet rock wool with 50mm in thickness has been inserted between inner and outer containers to allow root to penetrate through root barrier material and continue to grow. We planted 12 Plioblastus pygmaed Mitford A. and 4 Pyracantha angustifolia per one testing container. Three testing samples have been made for 1 type of root barrier material, which become a total 42 specimens. Planted testing samples have been installed within the greenhouse, which will be observed regularly for 2 years from now on. We started test from July 11, 2008 and had performed intermediate observations every month for initial 3 months. From the 3rd intermediate observation on Sept. 18, we confirmed that 6 types of root barrier materials have penetrated roots. Even though two types of them(EDPM Sheet, Polyethylene Sheet) have been generally used as root barrier materials for roof planting system, all of three testing samples have a lot of penetrated roots. This result proves that it is not reasonable to introduce testing methods of root barrier from Europe or Japan.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.650-658
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• 1998

The pressure level and the insertion loss at the receiving point behind finite length noise barriers are measured in an anechoic room by scale model test. The measured sound pressure level which are conducted under the several experimental conditions such as the length of the noise barrier, the distance between the noise barrier and the receiving point, the number of noise barriers, and the existence of the reflective building behind receiving point) and the insertion loss of a noise barrier having simple shape are well agreed with theoretical calculation which is based on Lam's model.

• Geomechanics and Engineering
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• v.35 no.1
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• pp.13-27
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• 2023

The model production for large-scale (lateral length ≥ 2.0 m) capillary barrier (CB) model tests is time and cost-intensive. To address these limitations, the framework of a small-scale CB (SSCB) model test under the lateral no-flow condition has been established. In this study, to validate the experimental methodology of the SSCB model test, a series of seepage analyses on the SSCB model test and engineered slopes in the same and additional test conditions was performed. First, the seepage behavior and diversion length (L_D) of the CB system were investigated under three rainfall conditions. In the seepage analysis for the engineered slopes with different slope angles and sand layer thicknesses, the L_D increased with the increase in the slope angle and sand layer thickness, although the increase rate of the L_D with the sand layer thickness exhibited an upper limit. The L_D values from the seepage analysis agreed well with the results estimated from the laboratory SSCB mode test. Therefore, it can be concluded that the experimental methodology of the SSCB model test is one of the promising alternatives to efficiently evaluate the water-shielding performance of the CB system for an engineered slope.

• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.123-129
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• 2008

The purpose of this study is to test performances of 14 types of root barrier materials by applying testing plant: and soils suitable for weather and natural features of Korea. For testing Plants, Plioblastus pygmaed Mitford A and Pyracantha angustifolia have been selected. For testing soil, mixture of pearlite and peat moss in 3:1 ratio Testing container has been fabricated with duplicated structure having inner and outer containers. And the outer container has 2 hinges on its side wall to allow opening and closing. Wet rock wool with 50mm in thickness has been inserted between inner and outer containers to allow root to penetrate through root barrier material and continue to grow. We planted 12 Plioblastus pygmaed Mitford A. and 4 Pyracantha angustifolia per one testing container. Three testing samples have been made for 1 type of root barrier material, which become a total 42 specimens. Planted testing samples have been installed within the greenhouse, which will be observed regularly for 2 years from now on. We started test from July 11, 2008 and had performed intermediate observations every month for initial 3 months. From the 3rd intermediate observation on Sept. 18, we confirmed that 6 types of roe barrier materials have penetrated roots. Even though two types of them have been generally used as root barrier materials for roof planting system, all of three testing samples have a lot of penetrated roots. This result proves that it is not reasonable to introduce testing methods of root barrier from Europe. USA or Japan.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.3
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• pp.168-174
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• 2020

Recently, the size of Liquified Natural Gas (LNG) carriers has been increasing, in turn increasing the load generated during operation. To handle this load, the thickness of LNG Cargo Containment Systems (CCSs) should be increased. Despite increasing the thickness of LNG CCSs, a secondary barrier is still used in conventional thickness. Therefore, the mechanical performance of the existing secondary barrier should be verified. In this study, tensile test of the secondary barrier was performed to evaluate mechanical properties under several low- and cryogenic-temperature conditions considering LNG environment, and in each fiber direction considering that the secondary barrier is composed of anisotropic composite materials depending on the glass fibers. Additionally, the coefficient of thermal expansion was measured by considering the degradation of the mechanical properties of the secondary barrier caused by the generated thermal stress during periodical unloading. As a result, the mechanical performance of secondary barrier in the Machine Direction (MD) was generally found to be superior than that in the Transverse Direction (TD) owing to the warp interlock structure of the glass fibers.

• Journal of KSNVE
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• v.9 no.6
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• pp.1106-1115
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• 1999

This paper sums up the study of the soundproof facilities (noise barriers) to be placed on the test track section within the Seoul-Pusan H.S.T. project. The objective of this study is to determine optimum design of soundproof including height, length, location, sound absorbing materials for test track(chonan-taejon). This paper shows the model to design the shape and materials of noise barrier for high speed trains(TGV, ICE, ect). The design of soundproof facilities is to be conducted by MITHRA for the prediction of noise impact of the TGV and for optimising noise barriers in order to reduce the noise generated by high speed trains. A number of computer simulations are carried out in order to determine the specification of noise barrier on test track.