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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 9, Issue 4 - Dec 1994
Volume 9, Issue 3 - Sep 1994
Volume 9, Issue 2 - Jun 1994
Volume 9, Issue 1 - Mar 1994
Selecting the target year
An Experimental Study on the Fracture Characteristics of Wire Ropes
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 3~10
This study examines fracture characteristics of wire rope of 6
37+FC 14mm B degree, Which has been widely used for the strength support for machinery, cranes and shipping. The examination Is based on the fellowing experimental conditions. Firstly, this study analyzes the effect of the strength of wlre rope. When number of broken wires is occuring at the level of 5%, 10% and 15% degree respectively in the following two cases：1) Case of broken down to each strand equally. 2) Case of broken down to one strand only. Secondly, this study analyzes the effect of corrosion on the strength of wire rope. Corrosion times are 72hours, 144hours and 216hours corrosion respectively under following conditions. 1) Case of only a corrosion without wire breaking. 2) Case of corrosion after 5% degree wire breaking to each strand equally. Some outcomes of these experiment are as follows. 1) From the of tension test, We can find that the ratio of strength reduction case of wire broke down to one strand concentrically is greater than that ratio case of broke down to each strand equally. 2) From the corrosion test, We can also find that the ratio of strength reduction case of corroded after 5% degree wire breaking to each strand equally Is greater than that ratio case of corroded without wire breaking. 3) After comparing theoretical fracture load of wires with experimental fracture load of wires, we can find the fracture load of the case of broken down to each strand equally is most similar to theoretical fracture load. 4) It is proposed that safety rules on wire rope in the Industrial safety and healthy labor of law have to change “breaking over 10% of number of wires in one strand of wire rope(excluded filler wire )”has to be replaced by“breaking over 10% of number of all wires in all strand of wire rope(excluded filler wire)”
A Study on Crack Initiation Measurement of Carburized Gear Tooth by Acoustic Emission
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 11~16
Acoustic emission technique is applied to the fatigue crack initiation in a carburized gear tooth. Acoustic emission test performed on carburized gear and three-point bending test equal to carburized gear hardness. The marked acoustic emission are detected at the early stage of crack initiation measured by a crack gauge and the final stage just before the tooth failure. The estimated acoustic emission energy rate are characteristic of the measured acoustic emission.
Effect of Chip Breaker Shape and Cutting Condition on the Chip Breaking and Surface Roughness
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 17~28
Chip breaking is important in lathe work for maintaining good surface of the products and safety of operator. The purpose of this study is to investigate the performance of chip breaking and chip shape resulted from the carbide inserts with grooved type and obstruction type chip breaker. Experiments have been performed under the following cutting conditions, (1) constant cutting speed with variable depth of cut and feed rate, (2) constant depth of cut with variable cutting speed and feed rate. Also, the flying distance of chip and it's distribution have been investigated. As a results, good performance of chip breaking can be obtained for small radius of curvature and land width of grooved type chip breaker. And the thickness of chip increase with the increase of feed rate and decrease of cutting speed, and the chip breaking becomes easier with the increase of chip thickness due to the large deformation rate. Obstraction type chip breaker shows better performance of surface roughness than the grooved type. The flying distance of the chips over 90% are less than 1 meter, and the distance decreases as the feed rate decreases.
A Study on the Creep Fracture Life of Al 7075 Alloy(II)
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 29~41
High temperature tensiles tests, steady state creep tests, internal stress tests and creep rupture tests using Al 7075 alloy were performed over the temperature range of 9
and stress range of 0.64~17.2(kgf/
) in order to investigate the creep behavior and predict creep rupture life From the apparent activation energy Qc and the applied stress exponent n measured, at the temperature range of 9
, the creep deformation seemed to be controlled by cross slip. On the other hand at the temperature of 20
the creep deformation seemed to be controlled by dislocation climb but at 47
, by diffusion creep. And the rupture life(t
) might be represented by anthermal process attributed to the difference of the applied stress dependence of Internal stress and the ratio of the Internal stress to the applied stress, the thermal activated process attributied to the temperature dependence of the internal stress. Also the ratio between stress dependence of primary creep rate and that of minimum creep rate was measured 0.46, the minimum creep rate is expected to be appromately obtained from master creep curve including the relationship primary creep rate and minumum creep rate. Finally the relationship new rupture parameter and logarithmic stress was represented with including the ratio between the dependence of primary creep rate and that of minimum creep rate, using the new rupture parameter the rupture life predition is exactly expected.d.
Slip Frequency Andative Tunning for the Compensation of Rotor Resistance Variation of Induction Motor
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 42~48
A rotor flux error-based approach for correcting the rotor time constant estimation used in the slip frequency calculator of indirect field oriented controller is presented in this paper. The controller was derived from the d-q induction machine model. Slip frequency gain is dependent on the machine parameter errors. And parameter errors result in rotor flux error. Thus, estimated rotor flux is compared to commanded rotor flux. The error between them is used for the estimation of rotor time constant. Simulation results which demonstrate the performance of this approach are presented.
Design of a DC Motor Controller for FA
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 49~57
In this paper, a speed controller using a controller is implemented and applied to a DC motor for FA ( Factory Automation ). The objective of this paper treats the analytical and experimental studies on the improvement of control circuit and control method using a SCR-LEONARD circuit for the speed control of DC motor. This system is concerned with stabilization of single input or single output systems, so the plant (SCR-LEONARD+DC motor) is simplified to the first order system. The parameters for the PID controller are obtained by the transient-response tunning method, and this control scheme has a backward-shift operator. The control algorithms (Chopper＋transient response tunning) is used to check the performance of PID Controller through Computer simulations and experiments. The good experiment results show that the direct control of the DC motor applied to industrial field such oi factory automation.
A Basic Study of Development of Electrostatic Induction Motor
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 58~68
A miniature size electrostatic induction motor has been fabricated and studied parameters Influencing dominantly to the motor speed, such as a voltage and frequency of the 3 phase ac power source supplied to the stator of fabricated motor, the surface resistivity and relative dielectric constant of the rotor surface materials and the concurrently calculated relaxation time constants. It is found that the higher resitivity and/or the higher relative dielectric constant, concurrently the longer relaxation time constant of the rotor surface materials make the motor speed get higher speed. In case of discrete coated rotor surface it is found that the motor speed was increased logarithmically as narrow as width of the discrete coated Ti. And the degree of width of discrete coated Ti to the axial direction of the rotor was 60
, the motor has got a 125% higher than that at the degree of 0
The Chemiluminescence Characteristics of the Surface Treated Low-Density Polyethylene (LDPE)
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 69~76
Low density polyethylene is widely used as an insulating material In electric power cables. It is most important to know the beginning of its aging by partial discharge and UV-ray. That Is reason which we investigate chemiluminescence of the LDPE treated by partial discharge, UV-ray and corona discharge. We find that it takes one hour on spectra of IR but 0.17 minutes on chemiluminescence in the variation of chemical by partial discharge. Also we knew that Lithium carbonate-added(1phr) LDPE offered obvious suppressing effect on aging by partial discharge through the chemiluminescence. Therefore, the chemiluminescence is a highly sensitive and effective measurement method to appreciate characteristics of the treated surface and the oxidation reaction.
A Numerical Study for the Design of Ventilation System for the gaseous Pollutants
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 77~84
A study is performed in order to design a effective ventilation equipment for the pollutants in workshop. The procedure has been used to calculate the flow in a confined rectangular space channel. A cross free stream is flowed from open space and jet stream including pollutants is injected from bottom area. Calculation results shows a wake region which exists immediarely downstream of the jet discharge and are compared with the experimental data. Calculation data are in good agreement with experimental results. A wake plays an important role on a stagnation of the pollutants. Thus ventilation equipment has to be designed without a stagnation region which give rise to concentration stratification. In this study, calculation parameters are the position and velocity of pollutants and fresh air from cross free stream. It is concluded that more measurements of local velocities, temperatures and concentrations of the pollutants.
An Experimental Study on the Safety of Temporary short pipe Scaffolding
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 85~91
In this thesis, the fracture tests and structural analysis were performed on a series of temporary scaffolding to investigate the variation of strength and the safety of temporary scaffolding. The specimens were of height 270cm and width 50cm and their span was 120cm. The joint loading and member loading were used in the tests, respectively. In these tests, the fracture mode of temporary scaffolding, relationships between the loading and the flexural strain of the specimens were observed. According to the comparison between the test results and the structural analysis results, the effects of the vertical loads and horizontal loads on temporary scaffolding and the safety of temporary scaffolding were studied.
A Study on a Method of Improvement from Domestic NATM Case
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 92~102
NATM as method of tunneling has been applied to construction of domestic subway, roads, rail way, water way etc. Accordingly we have NATM's many drafts and constructional results, but many problems and accidents have occurred under construction of tunnel using NATM for shortage of technical data, poorness of constructional improvement, systemic inconsistency etc. Especially, everyone was shocked at Gupo's train wrecking accident lately. The purpose of this thesis is presentation of means for settling technical problems, by looking into Gupo's train wrecking accident and home records that applying NATM in tunneling failed, to minimize future safety accidents we find that the general problems of home fifteen sites haying occured accidents is badly geological survey, nonconfirmation of base rock's state, formal measuring management, shortage of specialists, systemical discrepancy and that disregarding NATM's rules makes general problems. The results of this study are summarised as follows ; 1. We advise repletion of design standards to practice crosshole test for confirming connected rock base on vertical section of tunnel. 2. We advise to practice pre-boring and pre-grouting for a weak layer difficult in applying NATM. 3. We advise systemic improvements that field servicer can construct tunnel of his own free will considering base rock's state at tunnel. 4. We advise that specialist, who can make a conduct and supervise above mentioned items as well as measuring managements, should be posted at field.
An Experimental Study on the Shear Characteristics of Rock Joint by Tilting Test
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 103~111
Recently, rock slope in large scale is often accompanied with the construction of mountain roads and power plants. Rock in nature has a number of discontinuities such as bedding plane, joints, fracture zones and others. In order to improve rock slope stability, it is necessary to research shear properties of rock joint. In this paper shear properties of rock joint were studied by tilting test. Relations between properties of roughness and shear behavior of rock joint are investigated experimentally. The roughness are examined by compared with shear strength. Consequently, it becomes clear that the engineering properties and failure state modes of slope is different by JRC, and the peak friction angle is different by percent of filling.
An Experimental Study on the Absorption Properties by Rock Strength
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 112~118
Rock seems to be the ultimate excellent reaction for engineering loads, and often it Is. But the term rock includes a variety of types and conditions of material, some of which are surely not excellent and some that are potentially dangerous. Therefore, It is necessary to research absorption properties by rock strength. In this aspect the present paper deals essentially with the absorption exhibited by some Gneiss and Shale relation to its point load Index and specific gravity. In order to verify the rock strength, point load tester and two types rock specimen were used. Experimental results show that the absorption properties are highly dependent on rock strength. (suggested)
A Study on Sound Attenuation of Plant Noise by Enclosure
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 119~124
The considerations in the noise control by enclosure are the rise of temperature and sound pressure, transmission loss, absorption coefficient of the materials, the structure of the soundproof panels, an opening and coincidence frequency. But it is very difficult that we obtain the accurate data about those in design, so, the noise reduction after enclosing does not correspond with the calculation. The difference of the noise reduction between the calculation and the measurement was 8.2dBA, and we can obtain the approximate result as the following formula which correct 10dBA, safely.
A Study on the Effect of the Machine State Considering Human Skillfulness (Kalman Filtering Approach)
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 125~131
This paper proposes a dynamic recursive model with the effect analysis of machine state considering human factor(human skillfulness) In a single lot man-machine production system. This model obtained using Kalman Filtering Algorithm Is based on input state, output state, machine state. For sensitivity analysis, this model constructed is examined according to the impact of human skillfulness with computer simulation. The model studied in this paper has a great advance from the point of view a combination of three factors( human engineering, dynamic control theory, quality control ) and can also be extended in several applications.
The Characteristics of Charging Water Spray at Electrostatic Precipitator
Chung, J.H. ; S.Kanazawa ; Oh, T.kubo ; Y.Nomoto ; T.Adachi ;
Journal of the Korean Society of Safety , volume 9, issue 4, 1994, Pages 132~136
The new spray system is proposed by using a pipe with hygroscopic needle electrode In order to develop an air-cleaning ESP with high collection efficiency for submicron particles and high removal efficiency for NOx, SO
. Fundamental characteristics of charging water spray, which is not an usual wet type, are investigated experimentally. As a result, corona discharging mode and ozone generation rate are significantly affected by the operational conditions, such as the applied voltage and wet condition of the needle electrode.