• Transactions of the Korean Society of Mechanical Engineers
• /
• v.3 no.3
• /
• pp.98-103
• /
• 1979

The fatigue limit of an ion-nitrided steel was investigated experimentally and analytically. It is found that fatigue limit can singificantly be increased by ion-nitriding, and that the case depth is the most important parameter which determines the fatigue limit. The data indicate that fatigue limit increases with the case depth as well as the surface hardness of the nitrided steel. The fracrographs of the fracture surfaces taken by a scanning electron microscope show that the fisch-eye is located at the subsurface of failed specimens. Assuming that crack propagates from the subsurface inclusions, an analytical model is proposed to predict the fatigue limit. Taking into account the stress distrbution of a nitrided specimen, fatigue limit is predicted as a function of the case depth. The proposed semiemprical formula agrees satisfactorily with the experimental data obtained from rotating beam fatigue testing.

• Journal of Food Hygiene and Safety
• /
• v.12 no.2
• /
• pp.160-174
• /
• 1997

Progress in commercialization of the irradiation process, greater international trade in irradiated food, differing regulations relating to use of the technology in many countries, and consumer demand for clear labeling of irradiated food highlighted the need for tests that could be applied to the food itself. Scientists have had to focus on identifying and isolating the minute changes caused in the component food molecules by the process. A number of investigators have reviewed the changes occurring in food after irradiation, detecting and measuring the effects of irradiation. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture organised a coordinated program on analytical detection methods in irradiation treatment of food (ADMIT) which promoted cooperation in this area and sponsored collaborative testing of some of the most promising methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1042-1048
• /
• 2007

This work analytically investigated the radiated noise of a helical gear-housing system due to the excitation of helical gears. The helical gears were modeled as a 12-degree of freedom mass-spring-damper system; the shaft was modeled as a rod, a beam, and a torsional shaft; and the gear housing was modeled as a clamped circular plate with viscous damping. The modeling of this system used transfer matrices for helical gears, shafts, and bearings. Damping for both the bearings and the plate were obtained by modal testing. For the evaluation of noise, sound pressure from the plate due to the force and the moment in both radial and tangential directions was analytically derived by the Rayleigh integral. The analytical derivation and parameters from the experiment were applied to an analysis of noise for the two sets of helical gears with differing gear ratios. The analysis showed that the moment excitation in both helical gears contributed more to the noise of the plate than axial force excitation.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.273-278
• /
• 1993

Conventional measurement methods for non-destructive testing(NDT) in nuclear power plants other industrial plants have been performed as the methods of contact with objects to be inspect, but those methods have been taken relatively much time to be inspected. Holographic interferometry which is a non-contact optical measurement method using a coherent light can overcome these demerit, and also has an advantage that the quantitative measurement of small deformation for large areas can be accomplished at a time with high precision. In this paper the comparisons of the experimental results from holographic interferometry with those form the finite element method(FEM) and the analytical solutions of elastic equation are discussed.

• Communications for Statistical Applications and Methods
• /
• v.23 no.5
• /
• pp.363-383
• /
• 2016

The Weibull family of lifetime distributions play a fundamental role in reliability engineering and life testing problems. This paper investigates the potential usefulness of transmuted new generalized Weibull (TNGW) distribution for modeling lifetime data. This distribution is an important competitive model that contains twenty-three lifetime distributions as special cases. We can obtain the TNGW distribution using the quadratic rank transmutation map (QRTM) technique. We derive the analytical shapes of the density and hazard functions for graphical illustrations. In addition, we explore some mathematical properties of the TNGW model including expressions for the quantile function, moments, entropies, mean deviation, Bonferroni and Lorenz curves and the moments of order statistics. The method of maximum likelihood is used to estimate the model parameters. Finally the applicability of the TNGW model is presented using nicotine in cigarettes data for illustration.

• Journal of Korea Technology Innovation Society
• /
• v.6 no.1
• /
• pp.20-40
• /
• 2003

Many studies have regarded an information infrastructure as one of the crucial factors for national or regional innovation in the information society, but few studies have empirically tested the role and the effects of it. Also, the information society have been studied to what extent, but information space structure and the reorganization for the resource of the material and the labour have not been considered. Therefore, this study is examining the relation between the linkage structure and the information change in the manufacturing sector. And for the empirical analyses, regional labour data for 16 Metropolitan Areas(Si) and Provinces(Do) in 1991-1996 are used. An analytical model and hypotheses are proposed for empirical testing. The main finding is that if inter-regional wages condition is identical, inter-regional labour flow has positive correlations with regional information level.

• Proceedings of the Safety Management and Science Conference
• /
• 2006.04a
• /
• pp.1-8
• /
• 2006

By the effect of globalism and information the workplace environment is complicated and diversified little by little. The job stress due to the life style, the idea and culture, and the automated facility system etc. is to a tendency which compared to increase more. It will not be able to prevent a industrial accident basically because the oriental and western life style is different. Therefore this paper presents the Korean life change unit model through statistical testing in order to minimize industrial accident with the proposed life change unit factors on the workers living In the middle area. Finally, the analytical result of this paper can be easily used in order to minimize the industrial accidents by the job stress with the worker and the occupational safety & health manager in real fields.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.846-851
• /
• 1995

A motor-integrated high-speed spindle system with .psi. 65*25, 000rpm is modeled for analytical and experimental studies related to the dynamic characteristics. And the systematic and rational identification processes for evaluating the material properties of spindle and built-in motor is introduced. The impulse excitation method is applied for the experimental model testing, and the dynamic characteristics of test model is theoretically analysed by using the finite element method based on Timoshenko theory. Especially, the experimental and theoetical results reveal that the test model under the required operational conditions has no critical problem for dynamic characteristics.

• Structural Engineering and Mechanics
• /
• v.36 no.2
• /
• pp.165-179
• /
• 2010

Maximum deflection in a beam is a design criteria and occurs generally at or close to the mid-span. Neural networks have been developed for the continuous composite beams to predict the inelastic mid-span deflections (typically for 20 years, considering cracking, and time effects, i.e., creep and shrinkage, in concrete) from the elastic moments and elastic mid-span deflections (neglecting instantaneous cracking and time effects). The training and testing data for the neural networks is generated using a hybrid analytical-numerical procedure of analysis. The neural networks have been validated for four example beams and the errors are shown to be small. This methodology, of using networks enables a rapid estimation of inelastic mid-span deflections and requires a computational effort almost equal to that required for the simple elastic analysis. The neural networks can be extended for the composite building frames that would result in huge saving in computational time.

• Coupled systems mechanics
• /
• v.7 no.3
• /
• pp.281-295
• /
• 2018

This study aims to investigate the capacity of different models to reproduce the nonlinear behavior of reinforced concrete framed structures. To accomplish this goal, a combined experimental and analytical research program was carried out on a large scaled reinforced concrete frame. Analyses were performed by SAP2000 and compared to experimental and VecTor2 results. Models made in SAP2000 differ in the simulation of the plasticity and the type of the frame elements used to discretize the frame structure. The results obtained allow a better understanding of the characteristics of all numerical models, helping the users to choose the best approach to perform nonlinear analysis.