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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Safety
Journal Basic Information
Journal DOI :
The Korean Society Safety
Editor in Chief :
Volume & Issues
Volume 11, Issue 4 - Dec 1996
Volume 11, Issue 3 - Sep 1996
Volume 11, Issue 2 - Jun 1996
Volume 11, Issue 1 - Mar 1996
Selecting the target year
Evaluation of Fatigue Strain Intensity Factor on Fatigue Crack Propagation Rate (da/dN)
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 3~8
Fatigue fracture is the cyclic fracture phenomena at a very small local area near a crack tip. Therefore, the detailed quantitative experimental analysis about local cyclic strain distribution near a crack tip is prerequisite In order to make an effective parameter able to account for fatigue fracture problems. However, there are few reports on detailed quantitative experimental analysis of a local cyclic strain distribution near a crack tip, because of experimental difficulties. In this study, the distribution of local fatigue strains near a fatigue crack tip was in detail studied using by fine dot grid strain measurement method. From these results, a single parameter, which characterizes local fatigue strain field, was proposed. In addition, this parameter was applied to evaluate the fatigue crack propagation rate.
An Extension Behavior of an Interface Kinked Crack by CED
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 9~15
The characteristics on the extension of the CED(Crack energy density) concept to the interface kinked crack problems in a dissimilar material are examined. Each mode contributions of CED are found by symmetric and antisymmetric components and domain independent integrals. Finite element calculation is carried out to simulate the Interface kinked crack growth on bimaterial. The focus is the establishment of fracture criterion with CED and finding the orientation of crack extension. From the results, a prediction about the extension behavior of an interface kinked crack can be done. And we show that CED can be a parameter to indicate fracture criterion at an Interface kinked crack.
Study on the Path Independency of
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 16~24
In this study we simulate the fatigue test of a compact tension specimen and obtain the displacements, stresses and strains by using the finite element method. And we examine the path independency of
J integral values and compare it with
J integral values calculated from load-load line displacement curve. From the results of this study, we can find that
J integral show the path Independency for saturated materials. We can also find that the path independency of
J Is not satisfied when different material Is assumed near the crack tip, but the difference in
J is small. And
J integral values calculated from load-load line displacement is very analogous with those from integration path but always have lower values than those from integration paths. In the case of crack closing, we found that
J integral values from load-load line displacement should be calculated with the load Increment values based on the crack opening point. The unsaturated material is also simulated and its
J shows different values according to the path, but the difference is small.
Evaluation of Fracture Damage Analysis System Using Image Processing
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 25~32
This paper describes an experimental study of growing ductile crack-tip behaviors by means of computer image processing technique and finite element method. Here, the displacement field near a crack-tip is first measured by the computer image processing technique. Combined with the finite element technique, strain and stress fields are evaluated from the measured displacement. Then, crack-tip parameters such as J-integral are evaluated using the obtained displacement, strain and stress fields. The present technique Is applied to a growing crack problem of tensile CT specimen made of 304 stainless steel. The ductile crack growth behaviors accompanied by unloading are discussed in detail through the comparison between the experimental and the theoretical results.
A study on heat transfer during solidification of phase change material on a finned vertical cooling tube
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 33~41
Experiments were performed to study solidification of phase change material on a finned vertical tube when either conduction In the solid or natural convection in a liquid controls the heat transfer. The liquid was housed in a cylindrical containment vessel whose surface was maintained at a uniform, time-invariment temperature during a data run, and the solidification occurred at a finned and unfinned vertical tube positioned along the axis of the vassel. The phase change material(PCM) employed in this experiment is 99 percent pure n-Octacosan paraffin(
). For conduction-controlled and convection-controlled solidification, the enhancement of the solidified mass rate due to finning is great when the solidified layer is thin and decreases as the layer grows thicker. It is studied that the latent energy(
) is the largest contributor to the total extracted energy(
) and the total extracted energy rate at a finned vertical tube is greater than that at a unfinned vertical tube.
Study on the Diagnosis System of Taper Roller Bearing used on the Lower Bearing of V.A.W.T.
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 42~51
Taper roller bearing is used on rotating shaft where radial and thrust loads are attended. To avoid the sudden failure and maintain the good condition of rotating machinery it is necessary to monitor the condition of bearing and diagnose the defect of bearing. In this study the diagnosis program of taper roller bearing which is used on the lower bearing of V.A.W.T. (Vertical Axis Wind Turbine) is developed. By plenty of test the database is constructed and by Gaussian distribution obtained from database the defect probability of bearing is calculated.
A New Method for Assessing Dynamic Reliability for the Mid-loop Operation
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 52~59
This paper presents a new approach for assessing the dynamic reliability in a complex system such as a nuclear power plant. The method is applied to a dynamic analysis of the potential accident sequences which may occur during mid-loop operation. Mid-loop operation is defined as an operation to make RCS water level below the top of the flow area of the hot legs at the junction with the reactor vessel for repairs and maintenance of steam generators and reactor coolant pumps for a specific time. The Idea behind this approach consists of both the use of the concept of the performance achievement/requirement correlation and of a dynamic event tree generation method. The assessment of the system reliability depends on the determination of both the required performance distribution and the achieved performance distribution. The quantified correlation between requirement and achievement represents a comparison between two competing variables. It is demonstrated that this method is easily applicable and flexible in that it can be applied to any kind of dynamic reliability problem.
The Effect of
Affect to Thermally Stimulated Current of Insulating Silicone Rubbers
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 60~66
In order to look into the internal structure and electrical properties of insulating Silicone rubbers added reinforcing fillers ; Silica(0-140 phr ), and to examine the behavior of charged particles, and the properties of thermally stimulated current (TSC) are investigated, respectively. From the TSC which are formed by applying the electric field of 2~5 ㎸/mm to specimen at temperature range from -150 to
, the results arp as following. In the case of non-filled specimen, four peaks of
and u are obtained at the temperature of
, respectively and the case of filled specimen, three peaks of
are observed at the temperature of of
, respectively. The origins of these peaks are that, the
peak seems to the result from the contribution of side chain methyl radical, and the
peak from the depolarization of space charge polarization owing to added imputity during during manufacturing specimens, and the
peak from the orientation of
dipole, and the
near the temperature of
from carboxyl acid that is formed by the thermal oxidation of high temperature.
Effects of the Maghemite for Explosive accident Prevention to Liquefied Petroleum Gas
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 67~78
Gas sensing element,
was synthesized by dehydration, reduction, and oxidation of
-FeOOH, which was synthesized with
and NaOH. They were produced as a bulk-type, a thick film-type. Then, their responses and mechanisms of response to the gas of liquefied-petroleum were studied. The qualities of gas sensing elements are decided by the structure and the relative surface area. In the process of
synthesis, the effects of reaction conditions as the equivalent ratio, on the structure and the relative surface area of gas sensing element were observed. The changes of the structure were measured with XRD, SEM, TG-DTA and BET. The resistance changes of the synthesized gas sensor in the air were measured. The response ratio were also measured for the changes of working temperature and gas concentration. As a result of analysis with XRD, it was confirmed that the the best conditions for the synthesis of
were equivalent ratio 0.65. The thick film-type element of
responded more quickly than the bulk-type did. The structure and the relative surface area of the
were confirmed as the important factors deciding gas response charcteristics.
Analysis of spray sodium fire phenomena in the containment vessel
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 79~88
A hypothetical accident in the containment vessel of liquid metal reactor could cause a pressure, temperature rise, and a strong aerosol release. The computer codes relating to the modelization of these accident make it necessary to use various input parameter, among which is the dynamic shape factor of aerosols produced. Combustion experiments of sodium spray fire carried out in a closed vessel, which was vertical cylinder made of 1.2m in diameter and 1.8m hight with a volume of 1.7
. The results of theoretical analysis presented here was compared to data obtained from experiments. The experimental results were summarized as follows. 1) The aerodynamic diameter and geometric diameter of aerosols are decreasing with increasing of injection pressure and injection temperature of sodium 2) The dynamic shape factor of aerosol is proportional to the aerodynamic diameter for a given particle. 3) The correspondence between the aerodynamic diameter and geometric diameter can be as
. 4) Peak pressure rose with increase in pressure and temperature of injection sodium, being more sensitive to the injection pressure than the injection temperature.
Prediction of Service Life of a Respirator Cartridge by the Occupational Environment -Simulation of Breakthrough Curve for Respirator Cartridge and Sampling Tube-
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 89~95
To predict the service life of an organic vapor respirator cartridge, the breakthrough curve of respirator was simulated using a fixed-bed adsorption model and compared with that of sampling tube. And the effects of bed porosity, length to diameter ratio and flow rate of the sampling tube were studied. The life time of respirator cartridge was increased with the decrease of particle size and bed porosity. And the breakthrough time of sampling tube was affected by the flow rate, however not by the length to diameter ratio. The 10% breakthrough time of the sampling tube was corresponded with that of cartridge.
Elutriation and Production of Fines in a Fluidized Bed Coal Combustor
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 96~101
The effects of coal type and mixing fraction of coal on attrition and elutriation were studied in a 15. 5cm diameter fluidized bed coal combustor. The domestic low-grade anthracite coal with heating value 2010kcal/kg and the imported bituminous coal from Australia with heating value of 6520kcal/kg were used as coal sample. It was found from the experimental that the elutriation rate inclosed with an increseing anthracite mixing fraction. The size of elutriated particle had a very wide distribution was found in this experiment. The mean size of elutriated particle increased with decreaseing anthracite mixing fraction.
A Study on Air Pollution Measurement Model in Inchon City
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 102~108
Urban air pollution has been gradually increasing by the increase of population and vehicles recently. There are shown larger effects of air pollution in Incheon city which has more than 2 million people and has heavy holding amounts ratio of transportation vehicles as compared with other cities. However, it is very difficult to predict the air quality condition of their moving pollutants. Therefore, in this study air pollution measuring model was designed to estimate the air pollution level by line sources(transprtation vehicles ) of air pollutants and to detect the
emission amounts in ordinary times, and it became clear that it is functionally operative.
Variation of Seepage Line through Embankments by Permeability of Layer
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 109~115
The movement of water through a river embankment and its influenced upon the stability of the slope of the embankment are described. The stability of the embankment is depended upon the location of seepage line. As the seepage flow occurs in the embankment, the slope of the embankment loses its stability. Of particular interest is the stability following a rapid change of water level. The variation of seepage line in the embankment model by a fluctuation of water level is discussed. The experimental models were construction with slopes of 1 : 1.5, 1 : 2.0, 1 : 2.5 and the flow velocity was turned from 60cm/sec~90cm/sec. Based on the experimental study, the following conclusions are drawn. 1) When water level is raised, the seepage line of downstream slope Is raised rapidly as flow velocity increases. 2) For the case of permeable layer, the seepage line raised rapidly as compare with impermeable layer when water lever is raised.
Influence of Elastic Constraints at Free End on Stability of Timoshenko Cantilever Beam Subjected to a Follower Force
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 116~121
On the stability of Timoshenko cantilever beam subjected to a follower force, the influence of the characteristics of elastic constraints at the free end Is studied. The equations of motion and boundary conditions of this nonconservative elastic system are estabilished by using the Hamilton's principle. Upon evaluation of the stability of this system, the effect of shear deformation and rotatory inertia is considered in calculation. Using cowper's formulae Timoshenko's shear coefficient K'are determined. From this imvestigation it is found that the constrain parameter have an appreciable stabilizing effect in this nonconservative system. Moreover, it is obvious that the small values of K'decrease the flutter load of this system.
A Study on the Safety Management of Streamflows by the Kalman Filtering Theory
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 122~127
The purpose of this study has been studied and investigated to prediction algorithms of the Kalman Filtering theory which are based on the state-vector description, including system identification, model structure determination, parameter estimation. And the prediction algorithms applied of rainfall-runoff process, has been worked out. The analysis of runoff process and runoff prediction algorithms of the river-basin established, for the verification of prediction algorithms by the Kalman Filtering theory, the observed historical data of the hourly rainfall and streamflows were used for the algorithms. In consisted of the above, Kalman Filtering rainfall-runoff model applied and analysised to Wi-Stream basin in Nak-dong River(Basin area :
A Study on HPMA System for Establishment of Voluntary Safety Management
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 128~135
The aim of this study is that HPMA(Hazard Potentials in My Areas) System is to present for establishment of the voluntary safety management on industrial region. HPMA System Itself means that manager, supuryisor and worker on process-line find out the hazardous and/or unsafe potentials from their work places and make the plan of improvement by means of mutual communication with top manager and the department of safety staff, eventually put in the practice. In case that it takes the longer time to improve hazard potentials and is impossible improvement by existing technique, appropriate check-list will be used by the worker himself on the identified production line. Form this system, therefore, it makes them to get more and more sensitivity to the hazards. In this study, we present the voluntary safety management system which is controlable systematically and in the final analysis the direction of safety management by computerization of HPMA System which is activated in their work places.
A Study Investigation on the Grinding Safety of Bench Grinder
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 136~142
In this paper the safety problems of bench grinder have been reported. The safety status of bench grinders in 169 companies in Kyungbuk province was investigated. It was found that the two most important safety problems are the improper installations of workrests and the use of side (instead of front) of the grinding wheels.
Opto-Digital fingerprint identification system for security verification
Seung Hyun Lee ; Sang-Yi Yi ; Hyung Ji Kim ;
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 143~149
We propose an Opto-Digital hybrid fingerprint Identification system based on the binary phase extraction joint transform correlator(BPEJTC) for validation and security yerification. It is shown that since the BPEJTC provides higher peak-to-sidelobe ratio than that of the conventional JTC and does not cause correlation peaks due to intra-class association, this system is well-adaptive to the multiple object environments. Experimental results show that this system has a good performance in the presence of multiple images and the variations of the same person.
A-team Based Approach for Reactive Power/Voltage Control Considering Steady State Security Assessment
Kim, Doo-Hyun ;
Journal of the Korean Society of Safety , volume 11, issue 2, 1996, Pages 150~159
In this paper, an A-team(Asynchronous Team ) based approach for Reactive power and volage control considering static security assessment in a power system with infrastructural deficiencies is proposed. Reactive power and voltage control problem is the one of optimally establishing voltage level given several constraints such as reactive generation, voltage magnitude, line flow, and other switchable reactive power sources. It can be formulated as a mixed-integer linear programming(MILP) problem without deteriorating of solution accuracy to a certain extent. The security assessment is to estimate the relative robustness of the system in Its present state through the evaluation of data provided by security monitoring. Deterministic approach based on AC load flow calculations is adopted to assess the system security, especially voltage security. A security metric, as a standard of measurement for power system security, producting a set of discrete values rather than binary values, is employed. In order to analyze the above two problems, reactive power/voltage control problem and static security assessment problem, in an integrated fashion for real-time operations, a new organizational structure, called an A-team, is adopted. An A-team is an organization for agents which ale all autonomeus, work in parallel and communicate asynchronously, which is well-suited to the development of computer-based, multi-agent systems for operations. This A-team based approach, although it is still in the beginning stage, also has potential for handling other difficult power system problems.