• 한국산학기술학회논문지
• /
• 제19권12호
• /
• pp.918-923
• /
• 2018

항공기용 연료탱크는 평상시에는 연료저장 등의 단순한 기능을 한다. 그러나, 항공기 추락과 같은 긴급 상황에서는 연료탱크 구조건전성은 승무원의 생존과 직결되므로, 관련 성능의 보유 여부를 충돌충격시험을 통해 입증하도록 규정되어 있다. 충돌충격시험은 높은 충격하중으로 실패 위험이 높기 때문에 설계 초기 실물시험에서의 시행착오 가능성을 최소화하기 위한 노력이 진행되어 왔다. 실제 시험 전에 수행하는 수치해석도 그러한 노력의 일환이다. 하지만, 수치해석 결과가 설계에 반영되기 위해서는 수치해석의 신뢰성 확보가 필요하다. 본 연구에서는 회전익항공기 연료탱크의 충돌충격시험 수치해석의 신뢰성 확보를 위해 수치해석 결과와 시험 데이타 간의 비교를 수행하였다. 수치해석은 충돌전용 소프트웨어인 LS-DYNA을 사용하였고, 해석방법은 유체-구조연성해석 방법 중 ALE(arbitary lagrangian eulerian) 방법을 적용하였다. 시험데이터 확보를 위해 연료탱크 금속 피팅부에 변형률게이지를 설치하고 데이터 획득장비와 연동시켰다. 수치해석 결과로써 연료탱크 피팅부의 변형률과 응력을 계산하였다. 그리고, 실물 연료탱크로 수행한 충돌충격시험을 통하여 확보한 상부피팅의 변형률 측정값과 수치해석으로 계산된 변형률과의 오차를 평가함으로써 수치해석의 신뢰성을 제고하였다.

• 한국정밀공학회지
• /
• 제32권7호
• /
• pp.591-595
• /
• 2015

The roller rig tester for safety performance evaluation of wheel derailment is a test facility which can give the test load condition to the test wheel, similar to the actual dynamic condition in actual running condition. This study describes the evaluation result on the durability of the resilient wheel equipped with the ring damper and the damping material, and installed in the half part of a full scaled bogie in combination with the primary spring when it rotates under the dynamic condition. The evaluation result on durability of resilient wheel after load test of 2 million cycles shows that the safety of wheel is not affected by the applied load in visual inspection and nondestructive test, however, in the bolt used for fastening the ring damper to the wheel the loosening was found. Accordingly the use of self-locking nut and washer is recommended.

• 한국의사학회지
• /
• 제34권1호
• /
• pp.47-57
• /
• 2021

The appointment of medical officials during the Joseon Dynasty was conducted through medical testing. To date, most of the research done on these tests has focused on the testing system and its formal qualities without any study of actual test cases. This paper considers the significance of the medical examination format and contents through a test paper contained in the book "Joseonuihaksageupjilbyeongsa (朝鮮醫學史及疾病史)" by MikiSakae (三木榮). The literature confirms that the medical exam paper is the same format as "Gangji (講紙)," and that the test format called "Gangseo (講書)" is a very high-level test. Therefore, analysis of the case suggests that the format of the medical examination reflects the demand for high-quality medical learning for applicants. This consideration is meaningful because existing medical test papers are very rare.

• 한국주거학회논문집
• /
• 제15권1호
• /
• pp.175-183
• /
• 2004

The purpose of this study was to identify the actual condition of residential environment for the elderly residing in Daejeon. The data were collected through interviews and structured questionnaires. The sujects were 583 elderly people over the age of 65 in Daejeon. Sociodemographic characteristics, living characteristics, housing characteristics, neighborhood environment types, actual usage condition of neighborhood environment, relationship between sociodemographic characteristics and actual usage of neighborhood environment, actual condition of unit interior, were surveyed. The data were analyzed with frequency, percentage, χ²-test, mean using the SPSS package. The major findings were as follows. Features of unit interior which pointed generally were deterioration, soundproofing and size. Features of unit interior which need to be carefully planned were removal of height difference of entrance, removal of the thresholds, installation of emergency bell and room heating control facility. The facilities provided highly within the subject's residential environment were the eldery facility, church, hospital, bank, restaurant, beauty salon/barbershop, supermarket. and the facilities provided lowly were recreational facility, library, elderly school.

• 한국항해항만학회지
• /
• 제29권7호
• /
• pp.595-601
• /
• 2005

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.l37(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning circle test of the actual vessel. (2) Course keeping quality standard : Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard : Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds of actual vessels and examined separately the validity of all criteria of the standard.

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2005년도 추계학술대회지
• /
• pp.27-33
• /
• 2005

The IMO manoeuvrability standard was established for preventing sea accidents such as collisions and strandings due to the lack of manoeuvrability. The standard of ship manoeuvrability enforced by resolution MSC.137(76) has been applied to vessels of 100m or more in length and all chemical tankers and gas carriers regardless of the length, which were constructed on or after 1 July 1994. The IMO manoeuvrability standard is able to be divided into three kinds as followings; (1) Turning capability standard: Estimated values in design stage are to be certified by turning cir치e test q the actual vessel (2) Course keeping quality standard: Estimated values in design stage are to be certified by 10 deg. and 20 deg. zig-zag tests of the actual vessel. (3) Shortest stopping distance standard: Estimated value in design stage is to be certified by the shortest stopping distance tested by the actual vessel. In this paper, the authors verified the criteria of IMO manoeuvrability standard comparing them with the values resulted from sea trial tests of various kinds q actual vessels and examined separately the validity of all criteria of the standard.

• 한국안전학회지
• /
• 제31권1호
• /
• pp.19-24
• /
• 2016

Rubber parts are widely used in many applications such as dampers, shock absorbers, and seals used in railway and automotive industries. Much research has thus far been conducted on property estimation and life prediction of rubber parts. To predict the service life of rubber parts at room temperature, most prior work adopts the well-known Arrhenius model that needs the accelerated life test in high-temperature conditions. However, they may not reflect the actual conditions of use that rubber parts are usually used under a specific strain condition during long period of time. In this context, we propose a method for the life prediction of rubber parts in actual conditions of use. The proposed method is based on the accelerated life test using stress relaxation during which three relatively high elongation percentages (100%, 200%, and 300%) are applied to the rubber specimens. Rubber specimens were prepared in accordance with KS M 6518 standard and three stress relaxation testers were fabricated for actual experiments. Finally, a inverse power model for life prediction was derived from experimental results. The predicted life was compared with the actual test life for validation.

• Journal of Preventive Medicine and Public Health
• /
• 제38권1호
• /
• pp.16-24
• /
• 2005

Objectives : To help develop strategies to cope with the changes arising from the rapid aging process by predicting the determining factors of intention to actual use of the charged long-term care services for elderly as perceived by the middle aged who play the major role of supports. Methods : Subjects were the parents (men 177, women 507) in their 40s of the students selected from a university of Busan city. A questionnaire survey was conducted for 4 weeks in October 2003 about the knowledge for long-term care service, the intention of actual use, and the preferences about the type of service suppliers. Data analysis was performed with frequency, chi-square test, and t-test using SPSS program (ver 10.0K), along with data mining using decision tree of Enterprise Miner V8.2 by SAS. Results : About half of the subjects (53.7%) had the actual experiences of elderly supports. Intentions to use the charged services were relatively high in home visiting nursing care service (40.1%) and long-term care facilities service (40.4%), and were influenced by previous knowledge about the services. The intentions were stronger in women, those with higher education, and those with greater income levels. Actual elderly supports were mostly (80%) done by women, and the perceived burdens for the supports were bigger in women and those of lower socioeconomic level. Desired charges were about 10,000 won for the bath service, 20,000 won for the rests services per day, and about 500,000 won for the long-term care facilities service per month. From the result of decision tree analysis, the job professionalism was the most important determining factor of intention to actual use of the services with validation as $63{\sim}71%$. Health and welfare mixed type facilities were preferred, and the most important consideration was the level of professionalism. Conclusions : Intention to actual use of the charged services was largely determined by the aspects of time and cost. Polices to increase the number of service suppliers and to decrease the burdens perceived by actual supporters were strongly recommended.

• 에너지공학
• /
• 제25권3호
• /
• pp.73-82
• /
• 2016

표시가스 소비량이 70 kW 이하인 가정용 가스보일러에 대하여 여러 가지 운전조건하의 에너지 소비효율 측정에 대해 고찰하였다. 실제 운전상태와 유사한 실험조건에서 행한 에너지 효율실험 결과를 국내의 효율등급표시 실험방법 결과와 비교 분석하였다. 실험에 사용된 가정용가스보일러는 일반보일러와 콘덴싱 보일러 각 1개씩이며, 각각의 보일러에 대하여 네 가지 조건으로 실험하였다. 실험종류를 구분하면 실험실 모드와 실제 가동모드로 나누고, 각각의 모드별로 최대가스소비량 상태와 소비자판매 상태로 나누어 적용하였다. 효율실험을 위해 사용하는 장비는 KS 표준과 유럽의 EN 규격 등 가스보일러 관련 규격에서 제시하는 실험장치의 기능을 다하면서, 여러 가지 측정 인자를 지속적으로 축적, 기록 및 저장할 수 있는 장치로 하였다. 측정 대상 인자들은 유량(가스, 물), 온도(실험실, 난방공급수, 난방환수, 배기가스), 압력(가스미터 내부, 가스보일러 입구, 대기압) 등이다. 위 네 가지 모드의 실험결과 에너지소비효율은 실험실 상태(보일러의 안정화 상태로 실험 시작)로 실험할 때가 실제 소비자가 사용하는 패턴으로 실험할 때 보다 일반보일러의 경우 약 10 %, 콘덴싱 보일러의 경우 약 20% 높은 소비효율로 측정되었다. 에너지소비효율등급을 부여하는 정부 고시의 효율실험방법도 본 연구에서 실시한 것과 같이 실제상황을 가정한 효율실험방법을 도입 운영할 필요가 있다.

• 상하수도학회지
• /
• 제28권2호
• /
• pp.225-233
• /
• 2014

This paper presents a Computational Fluid Dynamics(CFD) based simulation and experimental tracer test of flow pattern and turbulent energy dissipation inside a serpentine flocculation basin with continuous operation. Research focused on the evaluation of a specific flow pattern on the hydraulic behavior on the flocculation basin. From the results of CFD simulation and actual tracer test, both results were in good accordance with each other. Also, each Morill index were calculated as 1.5 from CFD simulation and 1.7 from actual tracer test, respectively. Especially, turbulence energy was dissipated relatively higher in the vicinity of inlet to the flocculation basin than other region. The differences between the CFD simulation and actual tracer test were 1.4 min in $T_{50}$, and 1.3 min in $T_p$, respectively.