• 대한기계학회논문집A
• /
• 제33권10호
• /
• pp.1099-1107
• /
• 2009

Numerical simulation and experimental study to evaluate the critical speed of the railway bogie according to the tread inclination of wheel profile were conducted using 1/5 scale model. It has been shown that the results of the critical speed analysis for the scale bogie model is very close to the test results using scale bogie model and the critical speed is decreased in proportion to the increase of equivalent conicity of wheel profile. Results of this study show that the scale model could be applied to research area relating to vehicle stability as an alternative to overcome the experimental problems caused by full scale test on the roller rig.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.313-318
• /
• 2004

필 댐이나 제방의 침투에 의한 파괴현상을 원심모형실험으로 모사하는 경우, 지금까지는 물을 이용해 파괴시키는 원심모형실험이 실시되고 있었다. 그리고 점성유체를 사용한 원심모형실험도 실시되고 있지만, 상사법칙의 검증이 이루어지지 않은 상태에서의 실험결과에는 의문이 남아있다. 본 연구에서는, 물의 n배 점성용액을 사용해 상사법칙을 성립시켜 Modeling of Models의 방법에 따라 검증하였다.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권1호
• /
• pp.225-229
• /
• 2016

Background: It is important to validate scales related to cancer screening beliefs in order to better understand perceptions. The aim of this study was to test the psychometric properties of the colorectal cancer screening belief scale based on Health Belief Model (HBM) constructs. Materials and Methods: Data were collected from 600 persons referred to outpatient laboratory units in Iran through a convenience sampling procedure. In this cross-sectional study, exploratory and confirmatory factor analyses were used to examine construct validity of scale. Results: Through exploratory factor analysis, 52 items of the scale converged to five constructs of HBM with 4 items omission. Construct validity was determined by confirmatory factor analysis through which correlated model was supported. Cronbach's alpha coefficient for the whole scale was obtained as 0.78, which indicates reliability of the scale. Conclusions: The study findings showed that this scale is a valid and reliable instrument that can be used for measuring HBM constructs about colorectal cancer screening with the fecal occult blood test.

• 대한조선학회논문집
• /
• 제53권3호
• /
• pp.171-179
• /
• 2016

In order to study correlation of the propeller cavitation performance between a full-scale ship and a model ship for the MR Tanker, the full-scale ship and the model tests were conducted. The full-scale ship test is composed of cavitation observation, pressure fluctuation and noise measurements, which are conducted using 2 observation windows and 8 pressure transducers installed inside the full-scale ship above the propeller. The model test in the Large Cavitation Tunnel(LCT) was conducted at the same conditions as that of the full-scale ship and its results are compared with those of the full-scale ship. Through the model-ship correlation analysis, it is considered that the experimental technique for the MR Tanker class ship was verified in LCT.

• Journal of Ship and Ocean Technology
• /
• 제5권4호
• /
• pp.44-50
• /
• 2001

Large container carriers are suffering from lack of knowledge on reliable correlation allowances between model tests and full-scale trials, especially at fully loaded condition, Careful full-scale sea trial with a full loading of containers both in holds and on decks was carried out to clarify it. Model test results were analyzed by different methods but with the same measuring data to figure out appropriated correlations factors for each analysis methods, Even if it is no doubt that model test technique is one of the most reliable tool to predict full scale powering performance, its assumptions and simplifications which have been applied on the course of data manipulation and analysis need a feedback from sea trial data for a fine tuning, so called correlation factor. It can be stated that the best correlation allowances at fully loaded condition for both 2-dimensional and 3-dimensional analysis methods are fecund through the careful sea trial results and relevant study on the large size container carriers.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 춘계 학술발표회
• /
• pp.1094-1103
• /
• 2010

The safety of pile foundation is getting declined when the pile foundation acting on lateral load is exposed by dredging. So appropriate reinforcement is needed for stability secure. Thus, in this study, the stability variation and reinforcement range caused by dredging is estimated on the basis of down scale test. The scale effect is determined by real scale numerical analysis. the behavior of pile by dredging stages is estimated by load control type. The credibility is verified through the comparison between down scale model test and numerical analysis.

• Advances in concrete construction
• /
• 제1권4호
• /
• pp.289-304
• /
• 2013

A reliable concrete constitutive material model is critical for an accurate numerical analysis simulation of reinforced concrete structures under extreme dynamic loadings including impact or blast. However, the formulation of concrete material model is challenging and entails numerous input parameters that must be obtained through experimentation. This paper presents a damage scale analytical model to characterize concrete material for its pre- and post-peak behavior. To formulate the damage scale model, statistical regression and finite element analysis models were developed leveraging twenty existing experimental data sets on concrete compressive strength. Subsequently, the proposed damage scale analytical model was implemented in the finite element analysis simulation of a reinforced concrete pier subjected to vehicle impact loading and the response were compared to available field test data to validate its accuracy. Field test and FEA results were in good agreement. The proposed analytical model was able to reliably predict the concrete behavior including its post-peak softening in the descending branch of the stress-strain curve. The proposed model also resulted in drastic reduction of number of input parameters required for LS-DYNA concrete material models.

• 화약ㆍ발파
• /
• 제22권4호
• /
• pp.1-6
• /
• 2004

본 연구에서는 발파해체에 대한 축소모형실험의 폭원에 대한 차원과 축소율을 산정하고, 이로부터 축소모형실험의 적정 길이의 축소율을 고찰하였다. 그 결과 길이 축소비를 1/4로 할 때 축원의 축소율은 1/256로 모형실험과 실제 구조물에서 사용한 화약량의 비로 구한 축소율과 유사한 값을 보였다. 길이 축소율은 1/4 이상으로 하는 것이 바람직하다고 판단된다

• 대한조선학회논문집
• /
• 제58권6호
• /
• pp.415-423
• /
• 2021

There have been many experimental studies on the manoeuvrability of KRISO Container Ship (KCS). However, the scale ratio of the model ship and the test procedure for each institute are slightly different, so direct comparison for the data is technically difficult to perform. This paper presents the manoeuvrability of the ship with different scale ratios: 1/65.8, 1/42.0, and 1/31.6 in model scale. KRISO conducted Free Running Model Tests (FRMT): 35° turning circle tests and 20/20(10/10) zigzag manoeuvring tests. The test results indicated that advance and tactical diameter in turning circle tests were similar, and overshoot angles in two zigzag manoeuvring tests increased as the model ship size increased. In addition, a basic concept for the FRMT method with an auxiliary X-thrust device was proposed so that the scale effect could be considered in model ship tests.

• 대한기계학회논문집B
• /
• 제25권5호
• /
• pp.634-644
• /
• 2001

The test facility of a 1/60-scale model for train-tunnel systems has been recently developed to investigate the effects of tunnel portal shapes, hood shapes and air-shafts for reducing the micro-pressure waves radiating towards the surroundings from the tunnel exit. The present test rig has been advanced from a 1/70-scale facility at NLR in Netherlands. The NLR test rig has the two-wise guidance system that needs two ears attached on the external surface of a model train nose. Therefore, their train models have irregular nose shapes. The main characteristics of the present facility are that the train model is guided by only one wire from the compressed air launcher to the absorber parts of test facility and the wire guidance hole is located at the axial center of a train model. In the present test rig, after a train model is launched, the air jet from the launcher does not enter the tunnel model. Experimental results were compared with numerical predictions to prove the performance of the test facility.