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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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
A Study on the Penetration Fracture Strength of Fragile Plates subjected to High Speed Impact
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 3~9
In this study, comparison of theoretical solutions with experimental results is examined through fracture conditions for the case of float glasses subjected static loading. The range of fracture generation limits and critical penetration energies are solved according to the impactor mass under the high velocity, and analytical method of fracture strength and penetration strength are presented. Also, fracture patterns are investigated according to impact velocities. The results obtained from this study are as follows ; 1) Radial cracks are generated from the loading point regardless of plate thickness in the case of the plate subjected to the static loading. In the case of high-speed impact, dimensions of ring cracks become to smaller and length of radial cracks becomes shorter with the rapidity of impact velocity. 2) Kinetic change volume of collision after/before is constant regardless of velocities over the range of critical penetration velocity. 3) Although the same impact energy is working, the critical penetration energy is increased with the shorter of impactor mass. 4) Although the same impact energy is working, the penetration fracture of lighter Impactor mass is generated more than that of heavier impactor mass, and the impulse of lighter impacter mass appear more than that of heavier impactor mass. Therefore, the penetration fracture in the case of greater impulse is generated earlier regardless of the of the dimensions of Impact loading.
A Fracture Mechanics Study on the Fatigue Crack Propagation of the Pressure Vessel Pad Weldment
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 10~15
In studying the fatigue strength of fillet welded the section of pressure vessel pad, this study was to evaluate the effect of weld toe notch and to compare the results of numerical analysis with the results of fatigue experiments of fillet welded A5l6 grade 60 steel specimens. The fatigue life for the Bead welded specimen was about 1.4 times as much it as the 1Pad welded specimen. Also, The fatigue life for the 2Pad welded specimen was about 1.5 times as much it as the 1Pad welded specimen. In
curve, the fatigue crack growth rate for the 1Pad welded specimen appeared higher than that of the 2Pad welded specimen in the same initial region of
, had a similar Inclination In the stabled region.
A Study on the optimal structure of 6 D.O.F F/T Sensor using the condition number
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 16~23
In controlling manipulators interacting with the external environment, an important role is played by the Force/Torque(F/T) sensors. Recently, a number of structures for F/T sensors have been proposed, and some criteria for their evaluation have been introduced. This paper presents a systematic analysis of F/T sensor at the design stage. A model of the F/T sensors, based on Stewart Platform structure, is developed on the basis of static and kinematic equation. The condition number defined by the kinematic velocity and force analysis of F/T sensor is used as a performance Index. Thus, 4 optimal structure factors of 6 D.O. F. F/T sensor are determined by using the condition number.
A study on the velocity distribution measurement for the fine water mist spray by using LSP method
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 24~28
The speckle photography technique is one of the novelest velocity measurement methods. This study examines the possibility that this technique will become practically applicable. In this study, LSP is applied to the fine water mist spray. Moreover, a He-Ne gas laser is employed as the light source in order to enhance the validity of this technique. It becomes clear that this technique using a He-Ne gas laser can obtain a whole instantaneous two-dimensional velocity distribution and also apply to test the performance of fine water spray.
A Study on Comparison of UT with RT for the Detection of Defects in Weldzone
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 29~33
In this study, specimens were prepared which have some defects on the buttweld joint of mild steel. In order to detect the defects of specimens, the following tests were put to : AUT and RT. When the results of the three tests were compared, the conclusion could be brought to as follows. 1) AUT outstrips RT in the abillity to detect plane defects like slags or cracks, but RT excels AUT in the ability to detect spheroidal defects like blowholes. 2) RT detects neither taper cracks nor very closed cracks, whereas AUT detects both of them. 3) AUT can detect at once plane defects like cracks and spheroidal defects like blowholes.
A Study on Effective Enclosing Method for Noise Reduction of Press Machine
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 34~41
The purpose of this study is to obtain an effective enclosing method for noise reduction of press machine operating in a manufacturing company located in Taegu region. Noise level of the machine is about 95～120 ㏈ which is higher than legal standards by industrial safety and health law. In this study, two experiments were conducted to achieve the above purpose. In the first experiment in which the effects of three independent variables-type and depth of sound-absorbing materials, and depth of air space-on noise level was investigated, it was found that depth of sound-absorbing materials and air space was significant at
= -0.01. In the second experiment studying relationship between depth of sound-absorbing materials and air space and noise level, it was shown that noise level lowered as depth of sound-absorbing materials and air space became thick. Based on these results, two alternatives of enclosing method adequate for the selected company's noise characteristics were suggested.
A Study on the Accuracy Improvement of Fatigue Strength Data
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 42~48
Since the fatigue phenomenon is characterized as a probability feature and test data cannot be easily collected number its small sample data are uncertain. Therefore, statistical evaluation methods should necessarily be introduced into data evaluation. With such a basic concept in mind, this study attempted to apply conventional statistical processing methods to the fatigue data and thereby present a new evaluation method in consideration of the fact that the fatigue test is usually performed within a limited number. That is a package evaluation method was adopted which co-realtes parameters between different levels of capacity in E-N or S-N level. So far fatigue limits have been found by means of stiarcase method. But it was also disclosed that this new method has its own disadvantage because limited frequencies are not duely considered.
Analysis Techniques of Corona Discharges in Air with Needle-Plane Electrode System
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 49~53
Corona discharges in air insulated electric power systems cause power loss, produce interfering electromagnetic radiation, and can indicate incipient failure. An understanding of corona discharges in air gap is clearly Important. The Wavelet transformation is an extended method of fourier transformation. The fourier method is a powerful tool for signal analysis, but it can't include information for time. However the wavelet transformation analysis can include on the information of time and frequencies at the same time. In this paper we apply the wavelet transformation to the corona signals in needle-plane air gap for the purpose of analysis of developing aspects of corona discharges. We analyzed the developing aspects of corona discharges, namely, corona discharge current, repetition rates, width of Pulse distribution region, pulseless region and frequencies distribution of corona discharge pulses.
An Establishment of Expert System for Fault Diagnoses of the Cooling System In the Xylene Oxidation Reaction Process
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 54~63
We establish an expert system for the xylene oxidation reaction process of chemical plants using HAZOP(Hazard and Operability Studies). Our research focus Is only reduced to the cooling system of the total chemical plant due to lack of information. This expert system shows the priority of reasons for the system failure using confidence factor.
A Study on the Detonation Characteristics of
in Shock Tube
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 64~71
Detonation phenomena of
were invesgated using the various shock tube. To study the detonation characteristics according to the composition of
-air mixtures, the composition were varied from 5 to 90% and 5 to 50% of acetylene each other. A spiral ring was installed in the shock tube to study the effect of obstacles in DDT phenomena. Detonation velocities were measured using the photodiode, and the DDT phenomena was visualized using the high speed schlieren photograph. From the experimental result, it was found that the detonation velocity was most high near the 1. 8times the stoichiometric ratio of acetylene. And from the visualization of DDT phenomena, it was found that the detonation wave was strengthened throuth the pile up of small compression wave of burned gas. And the obstacles in shock tube accelerate the detonation reaction by turblent effect of flammable gas mixture.
Prediction of Service Life of a Respirator Cartridge by the Occupational Environment(II)
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 72~78
The breakthrough curves of a sampling tube were studied to predict the service life of a respirator cartridge for organic vapors. The fixed bed adsorption model was applied to respirator cartridge and it's variables were calculated from tile experiment of sampling tube. By the experiment and simulation, it was possible to predict the service life of a respirator cartridge, however, not adequate at low
concentration less than 700ppm and at high air humidify. The breakthrough curves of sampling tube were irregular compare to that of respirator cartridge due to .packing density.
Decomposition of Hazardous Gaseous Substances by Discharge Plasma
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 79~83
In this study, in attempt to develop a new application technique of discharge plasma, we employed a kind of discharging method called SPCP ( short for Surface discharge induced Plasma Chemical Process). Applications of SPCP have been widely used for years. Compact ozonizers to deodorize household equipments like refrigerators we a part of such applications. We took advantages of the compactness and durability of the SPCP electrode to set up an experimental apparatus for decompositing vapor of aromatic hydrocarbons such as toluene, benzene and xylenes, which are major substances given off In painting or washing processes and aggravate working conditions. Results obtained from this study are summarized as follows. 1) Aromatic hydrocarbon vapors of up to 2,000ppm were almost thoroughly decomposed at the flow rate of 4ℓ/min or lower under the discharge with electric power of 400 Watts. 2) In dry air, as the decomposition progresses, tar-like substance deposits on the discharging areas, which deteriorated the decomposition rate in the end. This substance, however, was almost thoroughly removed by keeping discharge in dry air containing no solvent vapor.
The Study on the Detoxification of Aflatoxin
in Cancer Compound
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 84~89
The Oxidation of aflatoxin
) with ozone in chloroform solvent gave the stable ozonide into ozonization of the double bond in the terminal furan ring, and this reaction have been carried out for 3hr at -78. 5
. The chloroform solvent was removed in a stream of nitrogen and the residue was separated by elution chromatography(EC). The structure of this compound have been identified by using MS,
and I. R spectroscopy, respectively. This compound was formed the normal stable AFG
-ozonide into spontaneous rearrangement after unstable ozonide according to sigmatropic rearrange ment dependent upon cyclo addition by ozone.
A Study on the Performance of the Newly Developed De-inking Machine
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 90~96
This paper examines the De-inking characteristics of mechanical methods using the newly developed De-inking machine along with experiments to enhance the manufacture of recycled kraft pulp with the addition of newspaper. This study concluded that : First, the De-Inking ratio was affected by shear stress and friction resistance operating In the stainless steel net. Second, the brightness improvement ratio was raised by 6.2% under the following conditions : 120rpm rotor speed, 2.18% concentration, using two treatment cycles. Third, it was shown that the tearing strength was improved by about 10 to 20% , and the tensile strength remained the same when recycled kraft pulp was added with 20% wasted paper. In sum, by these experiments we have proven that the performance of the newly developed De-inking machine can be improved.
A Thermal Decomposition Characteristics of Propellants for Safety Bag
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 97~106
Some of accidents are based on unstable chemical substances. These chemicals are easily decomposed or Ignited by heats or mechanical shocks like sodium azide. Sodium azide is commonly used as propellant for inflating automotive safety bags and the other chemical manufacturing purposes. The investigation of thermal hazard potential of sodium azide is very important because unexpected traffic accident can be occureed. The experiments were carried out by DSC, TG an ARC in air, oxygen, argon and nitrogen atmosphere. The decomposition temperatures were about
by DSC and
by ARC, this is very significant result for treatment of chemical. The heats of decomposition were about 81 kcal/mol in ai. and 10 kcal/mol in other atmosphere.
A Study on the Safety Improvement of the High Temperature Ceramic Heat Recovery System
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 107~114
A study to Improve the safety of the ceramic heat exchanger In the high temperature heat recovery system was performed in terms of air flow passes. The numerical and finite element analyses on the heat transfer and thermal stresses in the ceramic core related with air passes were carried out. The results showed that the stresses in the ceramic core induced by the thermal expansion are large enough to cause failure of the brittle ceramic core. The imployment of triple-pass air flow for the same ceramic core could increase the efficiency and effectively release approximately 20% of the maximum thermal stressess, thus improving the safety of the ceramic heat exchanger. The use of triple-pass, however, is limited by the amount of air flow due to the increase of pressure drop.
An Analysis of Stress Intensity Factor for Presented Crack in L.N.G. Piping
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 115~121
This paper describes an analysis of the stress intensity factor (SIF) of the presented cracks in LNG piping. The stress analysis used the Finite Element Method. The stress Intensity factor calculated Raju & Newmann equation and ASME Section XI method. The cracks in the flanges are found to be influenced by temperature, but the cracks of the piping are found not to be influenced by temperature. If the cracks shape in the flanges and the cracks shape of the piping are same each other, the cracks in the flange will be dangerous more than the cracks of the piping.
A Study on the Safety of Highway Bridges by the Primary Capacity of Load
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 122~126
In this thesis, the field test results of fifty-one highway bridges were analyzed in order to Investigate the primary capacity of load of highway bridges. From this study, it was known that primary capacity of load are decreased with the serviced years, and those are small in T-beam bridges rather than I-beam bridges. And the average primary capacity of load of highway bridges is seemd about 15. 5ton in T-beam bridges and in I-beam bridges about 19.7ton.
On Change of Manual Dexterity with Aging
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 127~134
Recently, in Korea the birthrate is declining and the average life span has been increasing. Thus, compared to the previous periods nowadays, older people are required to work. Even elderly people are rejoining the workforce. Korean companies set the retirement age between 55 and 60 years of age, however, accidents occur frequently. Thus, it becomes necessary to evaluate the ability of the elderly person. Since the required function of the worker varies from job to job the evaluation of the capability must also be conducted according to the desired functions. One of the methods used in this study is the continuous control knob to evaluate the tracking control ability to investigate the relationship of manual dexterity and age. The result of the study Indicates that the manual dexterity decreases with age. However, there are differences among individuals. The individuals lifestyle affected the manual dexterity of that individual. As a result, a company may use the manual dexterity as an measure to evaluate the elderly persons work ability.
Prediction of the Noise Levels for a Newly-founded Petrochemical Plant
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 135~142
Prolonged in-plant personnel exposure to high noise levels results in permant hearing damage. There are no way to correct this hearing damage by treatment or use of hearing aids. Therefore, every employer is responsible for providing a workplace free of such hazards as excessive noise. This study was carried out to evalute and predict a given noise environment based on specific limit as the noise guarantee for a newly-founded petrochemical plant. The maximum total sound level should not exceed 85dBA in the work area, except where the area is defined as a restricted area and 70dBA at the plant boundary. Prediction of the noise levels within the plant area for a newly-founded petrochemical plant was achieved by dividing all plant area into 20m
20m regular grid spaces and noise level inside the area or unit that in-plant personel exposure to high noise levels was estimated computed into 5m
5m regular grid spaces. The noise level at the grid point that was propagated from each of the noise sources(equipments) computed using the methematical formula was defined as follows :
=sound pressure level at distance
from the source
=sound pressure level at distance
from the source As a result, the equipments exceeded noise limit or irritaring noise levels were identified on the specific grid coordinates. As for equipments in the area that show high noise levels, appropriate counter-measures for noise control (by barriers, enclosure, silencers, or the change of equipments, for example) should be reviewed. Methods for identifying sources of noise applied in this study should be the model for prediction of the noise levels for any newly-founded plant.
Fracture and Hygrothermal Effects in Composite Materials
Kook-Chan Ahn ; Nam-Kyung Kim ;
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 143~150
This is an explicit-Implicit, finite element analysis for linear as well as nonlinear hygrothermal stress problems. Additional features, such as moisture diffusion equation, crack element and virtual crack extension(VCE ) method for evaluating J-integral are implemented in this program. The Linear Elastic Fracture Mechanics(LEFM) Theory is employed to estimate the crack driving force under the transient condition for and existing crack. Pores in materials are assumed to be saturated with moisture in the liquid form at the room temperature, which may vaporize as the temperature increases. The vaporization effects on the crack driving force are also studied. The Ideal gas equation is employed to estimate the thermodynamic pressure due to vaporization at each time step after solving basic nodal values. A set of field equations governing the time dependent response of porous media are derived from balance laws based on the mixture theory Darcy's law Is assumed for the fluid flow through the porous media. Perzyna's viscoplastic model incorporating the Von-Mises yield criterion are implemented. The Green-Naghdi stress rate is used for the invariant of stress tensor under superposed rigid body motion. Isotropic elements are used for the spatial discretization and an iterative scheme based on the full newton-Raphson method is used for solving the nonlinear governing equations.
The Theoritical Analysis of the Slope Stability subjected to Seepage Force
Gi-Bong Choi ;
Journal of the Korean Society of Safety , volume 11, issue 4, 1996, Pages 151~155
The main purpose of this study was to develop a useful method for analysing slope stability by seepage force. The stability of an embankment impounding a water reservoir is highly depend upon the location of seepage line with the embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid rise change of reservoir level. Seepage forces in embankments are easily determined if frictional forces are expressed in relation to hydraulic gradient i. Seepage forces can combine with soil weights to improve stability or worsen it, depending on the direction in which the forces act ;n relation to the geometric cross section.