• Geomechanics and Engineering
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• 제9권3호
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• pp.345-360
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• 2015

Wave equation analysis programs (WEAP) such as GRLWEAP and TNOWave were primarily developed for pre-driving analysis. They can also be used for post-driving measurement applications with some refinements. In the case of pre-driving analysis, the programs are used for the purpose of selecting the right equipment for a given ground condition and controlling stresses during pile driving processes. Recently, the program is increasingly used for the post-driving measurement application, where an assessment based on a variety of input parameters such as hammer, driving system and dynamic behaviour of soil is carried out. The process of this type of analysis is quite simple and it is performed by matching accurately known parameters, such as from CAPWAP analysis, to the parameters used in GRLWEAP analysis. The parameters that are refined in the typical analysis are pile stresses, hammer energy, capacity, damping and quakes. Matching of these known quantities by adjusting hammer, cushion and soil parameters in the wave equation program results in blow counts or sets and stresses for other hammer energies and capacities and cushion configuration. The result of this analysis is output on a Bearing Graph that establishes a relationship between ultimate capacity and net set per blow. A further application of this refinement method can be applied to the assessment of dynamic formulae, which are extensively used in pile capacity calculation during pile driving process. In this paper, WEAP analysis is carried out to establish the relationship between the ultimate capacities and sets using the various parameters and using this relationship to recalibrate the dynamic formula. The results of this analysis presented show that some of the shortcoming of the dynamic formula can be overcome and the results can be improved by the introduction of a correction factor.

• Geomechanics and Engineering
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• 제5권4호
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• pp.363-377
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• 2013

Any structure constructed on the earth is supported by the underlying soil. Foundation is an interfacing element between superstructure and the underlying soil that transmits the loads supported by the foundation including its self weight. Foundation design requires evaluation of safe bearing capacity along with both immediate and long term settlements. Weak and compressible soils are subjected to problems related to bearing capacity and settlement. The conventional method of design of footing requires sufficient safety against failure and the settlement must be kept within the allowable limit. These requirements are dependent on the bearing capacity of soil. Thus, the estimation of load carrying capacity of footing is the most important step in the design of foundation. A number of theoretical approaches, in-situ tests and laboratory model tests are available to find out the bearing capacity of footings. The reliability of any theory can be demonstrated by comparing it with the experimental results. Results from laboratory model tests on square footings resting on sand are presented in this paper. The variation of bearing capacity of sand below a model plate footing of square shape with variation in size, depth and the effect of permissible settlement are evaluated. A steel tank of size $900mm{\times}1200mm{\times}1000mm$ is used for conducting model tests. Bearing capacity factor $N_{\gamma}$ is evaluated and is compared with Terzaghi, Meyerhof, Hansen and Vesic's $N_{\gamma}$ values. From the experimental investigations it is found that, as the depth of sand cushion below the footing ($D_{sc}$) increases, ultimate bearing capacity and settlement values show an increasing trend up to a certain depth of sand cushion.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.118-128
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• 1998

Finite element analyses are carried out to provide results usable in the design of airbag module that consists of inflater, cushion, cover, mounting plate, etc. In the first phase, a deployment process of airbag module is analyzed to evaluate the pressure waveform of developed airbag and deployment characteristics, and is compared with the test results. Interaction between head form and inflated airbag module is investigated in the second phase. In the last stage, sled test with rigid dummy, airbag midule, driving system and car interior part are simulated to investigate the influence of airbag design factor on the behavior of dummy with seat belt. The procedures can be provided as a guideline for airbag module design and improvement of airbag module performance.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.131-137
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• 2003

Proper door effort, required force to open or close a vehicle door, is an essential door design factor for the safety of passengers and pedestrians. Section shape of the door checker arm is the most influential design parameter for achieving a door effort design target. In this research. an analysis procedure to predict door effort using a simplified plane strain finite element model wes investigated for two passenger cars, for which mechanism of checker systems were: different. The variation of checker arm force to be required during moving on arm in opening and closing direction was estimated through analysis, and the result was transformed to the door effort with respect to door opening angle by considering door characteristics. Also, the self·closing force due to door weight was theoretically calculated and added to the door effort from checker arm force. Finally the estimated results of door effort were compared with test results.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.110-120
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• 1997

One of the most important factor for the comfort of the passenger vehicles is the minimization of the compressible transmissibility during the running vehicles. Seat foam materials of I2 series(index 95 and the contents of isocyanate TDI was changed in percentages 75, 70, 65, 60, 50, 40) and DI series(density 50kg/$\textrm{m}^3$, index was changed 100, 95, 90) showed the significant differences in their transmissibility depended upon their chemical constitution such as index and contents of isocyanate TDI. The minimum trasmissibility of seat foam materials of I2 series was found from the materials with the contents of 65% isocyanate TDI and the index 95 at the frequency 4.79~5.31Hz. Also the minimum transmissibility of seat foam materials of DI series was found from the materials with the index 90 and the density of 50kg/$\textrm{m}^3$ at the frequency of 4.79~5.31Hz.

• 설비공학논문집
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• 제15권1호
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• pp.40-49
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• 2003

This study has been conducted to identify and quantify the emissions of Volatile Organic Compounds (VOCs) from a new carpet. The carpet sample consists of polypropylene cushion and latex backing. The VOCs have been sampled on sorbent tubes and analyzed by thermal desorption unit and GC/MSD. For over 240 hours, concentration of VOCs has been measured in a small chamber made of stainless steel. With the measured data, emission factor and mass balance have been considered. The experiments have been conducted in accordance with ASTM D5116-97. The carpet has emitted a variety of VOCs, but in this study, 7 VOCs compounds have been considered： chlorobenzene, ethylbenzene, styrene, isopropylbenzene, bromobenzene, 2-chlorotoluene, and 1,2,3-trimethylbenzene. The results show that the concentrations of VOCs and the emission factors have exponentially decayed from relatively high level to low level with time. The gradients of the concentration of VOCs and emission factors are different for various components. It is found that styrene, 2-chlorotoluene are emitted more than others with higher concentrations.

• 한국의류학회지
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• 제21권7호
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• pp.1124-1138
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• 1997

This study intended to investigate the concept of Clothing Involvement and Brand and to provide useful basic data for building on affective brand strategy. The purpose of this study is as follows: first, It is to measure the result of Brand Extension attitudes and Brand Extension items by clothing involvement (high involvement/low involvement). Second, It is to classify the factors of Clothing Involvement which suggested in theoretical research and to clarify correlation between clothing involvement factor and brand evaluation, brand extension attitudes. Third, It is to investigate the affect that clothing involvement, demographic variable and brand type on Brand Extension Evaluation. Subjects of this study were the adult women in Seoul, who were extracted by sampling randomly during the fall of 1995. Questionnaire was used as major method of gathering data. They were analyzed by the SAS method such as Frequency, Anova, Duncan, Correlation, multiple regression, Factor analysis. Main result of this study were as follows : 1. In brand extension attitude evaluation by high-involve group and low-involve group, quality, reputation and buying intension of brand extension attitudes showed significant difference. B brand extension attitudes and items of high-involve group was high compare to low-involve stoup. High-involve group evaluated watch, underwear, shoes and stocking of extension items highly, and there is no involvement difference of perfume, parasol, cushion. 2. In order to classify the dimension of Clothing Involvement, it was carried out factor analysis. 1 found that Clothing Involvement was composed of 4 factors, namely, interest - fashion.perceived risk symbolism. Correlation between clothing involvement and brand extension attitude was as followed; Interest factor of clothing involvement was correlated the existing brand attitude. Brand preference of the existing brand attitude was related the image of brand extension attitude, interest of advertising was the quality and the reputation-image was the buying intension. 3. For evaluation of a factor influenced on Brand Extension, it was produced multiple -regression test. Demographic variables and brand types had some influence of Clothing Involvement and Clothing Involvement had on brand extension. 27% of interest, 26% of symbolism was explained by brand types and 15% of fashion, 6% of perceived risk was explained by brand types, demographic variables. And, 10% of brand extension was explained by interest, fashion and symbolism.

• 한국콘텐츠학회논문지
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• 제22권7호
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• pp.676-683
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• 2022

전산화단층촬영 유도하 폐 병소의 생검(CT guided lung biopsy)시 환자의 움직임을 최소화 하는 것은 시술에 있어 중요한 요소이다. 이에 움직임을 최소화 하고자 진공 고정기구(vacuum cushion)를 사용하여 그 효용성을 평가하였다. 연구대상은 자세 고정 및 호흡 조절이 잘 협조된 환자 40세 이상, 총 116명을 대상으로 하였다. 자세 측정은 폐 병소 생검 병변의 각 위치에 따라, 바로누운자세, 엎드린자세, 사방향자세, 측와위자세로 측정 하였다. 측정 위치는 해부학적 자세 기준으로 전방향, 후방향, 우측, 좌측에서 측정하였다. 엎드린자세에서 posterior의 미사용의 평균과 사용의 평균차는 1.7905이며 t=2.913(p<0.01)로 미사용/사용의 평균 차이는 통계적으로 유의미하다. 오른쪽방향의 미사용 평균과 사용 평균의 차는 2.4105로 나타났으며 t=3.684(p<0.01)로 왼쪽방향의 평균 차이 또한 유의미했다. 오른쪽방향의 미사용 평균과 사용 평균 차는 2.3263이며 t=3.791(p<0.01)로 미사용과 사용의 평균 차이는 통계적으로 유의미하다. 통계 분석 결과 고정기구를 사용하여 폐 병소의 생검을 시술 한 경우가 모든 자세에서 움직임이 적었다. CT유도하 폐 병소의 생검의 시술시 고정기구를 활용하여 보다 정확한 생검시술과 환자의 자세 움직임을 최소화 할 수 있음에 대한 연구를 진행하였다는 데에 의의가 있다고 사료된다.

• 한국화재소방학회논문지
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• 제27권4호
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• pp.41-46
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• 2013

본 연구는 가구류를 구성하는 주요 재료의 열적조건에 따른 반응특성과 화염전파해석에 필요한 열해리 물성을 제공하기 위해 열중량분석을 수행하였다. 실험대상 시편은 가구류에 널리 적용되는 MDF 판재와 코팅재, 합성피혁과 쿠션재 등이며 가열율 $10^{\circ}C/min$, 최대 온도 $600^{\circ}C$까지 실험을 수행하였다. 실험결과 MDF 소재의 경우 $324^{\circ}C$에서 피크 반응을 나타냈었으며 MDF 코팅재의 경우 초기 피크반응온도가 $270{\sim}280^{\circ}C$로 감소하였다. 합성피혁과 폼 소재의 경우 재료를 구성하는 폴리머의 종류에 따라 기준온도와 기준 반응율이 차이를 보였으나 기준온도는 $270^{\circ}C$와 $420^{\circ}C$ 정도로 비교적 유사한 경향을 나타냈다. Lyon 등이 제시한 방법에 의해 반응상수와 활성화 에너지를 산정하기 위해 시편의 기준 온도와 기준 반응율을 제시하였으며 이러한 기초 물성연구를 통해 화염전파특성을 이해함과 동시에 화재해석의 신뢰성을 향상시키는데 기여하고자 한다.

• 한국포장학회지
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• 제27권2호
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• pp.109-114
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• 2021

The characteristics of vibrational stress (shock and vibration) during transport and the possibility of damage to the packaged pears by functional PLA tray were investigated. And this study was conducted to analyze how environmental conditions by simulated transport environment affect quality factors such as weight loss (%) and soluble solid content (SSC, %), and firmness (bioyield strength, kPa) of packaged pears by PLA tray and Expanded PET foam pad (Group 1), EPE cushion cup pad and net (Group 2) for exporting. Pears with or without vibration stress were stored for 30 days at low temperatures (5 ± 0.8℃, 80 ± 5% relative humidity). There was the statistically significant difference (p ≤ 0.05) between pears with and without vibration stress for weight loss, soluble solid content, and firmness (bioyield strength) after 30 days storage. Vibration stress accelerated pear quality deterioration during storage, resulting in increased weight loss, soluble solids content, and reduced hardness. The firmness (bioyield strength) and weight changes of pears with PLA trays were smaller than those of conventional packaging box systems. It was determined that the firmness of agricultural products was a quality factor closely related to the storage period and that PLA could be applied.