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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
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Volume & Issues
Volume 12, Issue 4 - Dec 1997
Volume 12, Issue 3 - Sep 1997
Volume 12, Issue 2 - Jun 1997
Volume 12, Issue 1 - Mar 1997
Selecting the target year
A Study on Characteristic of Probabilistic Distribution of Fatigue Fracture Toughness in SM20C steel
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 3~9
The strength of material is scattered owing to the inhomogenity of microstructure, in spite of the same material. Therefore, in order to design the mechanical structure with the reliability engineering, it is important to grasp the statistic nature of material strength. In this paper, effects of grain sizes for the statistical nature of the fatigue crack growth was discussed. And the statistical of mechanical properties was compared with statistical nature of the fatigue crack growth rate.
Sound radiation of curved beam under the action of harmonic line forces
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 10~16
The problem of sound radiation from curved beam under the action of harmonic line forces is studied. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0. The curved beam material and the elastic foundation are assumed to be lossless including a tension force(T), damping coefficient(C) and stiffness of foundation(
) will be employed. The non-dimensional sound power is derived through integration of the surface intensity distribution over the entire curved beam. The expression for sound power is integrated numerically and the results are examined as a function of wavenumber ratio(
) and stiffness factor(
A study on dual mass flywheel for a jeep vehicle with Diesel Engine
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 17~22
This paper reals with the structure and function of duel mass flywheel. Damping effects of engine rotational fluctuation are compared with those of pre-damper clutch and duel mass flywheel and driven- system behavior is estimated engine idle r.p.m. The reason of gear rattle noise is higher in summer than winter and driving longer period than initial driving is due to affection by drag torque changing. The above-contents can be used on the design of clutch system and transmission matching including engine and duel mass flywheel.
Anti-sway Control of Crane System using Time Optimal Control Method
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 23~29
In the control of crane system, the traversing time of the trolley must be reduced as much as possible and the swing must be stopped at the end point. To design the minimum time control system, Pontryagim maximum principle is applied. In order to implement the control algorithm, the dynamic equation is linearlized at an equilibrium point, so that the linear time invariant state equation can be obtained. The overall performance of the closed loop system is evaluated by means of computer simulations and practical experiments in a broad range of working conditions. The effectiveness is proved through the experimental results for the anti-sway control of the load and the position control of trolly. It is expected that the proposed system will make an important contribution to the industrial fields.
A Study on Estimation of Residual Stress in Carburized Spur Gears and Its Effect on the Stress Intensity Factor
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 30~37
This paper deals with the residual stress of carburized spur gears is calculated being on the assumption that the main cause of residual stress is the volume difference between case and core due to the martensitic transformation in cooling. A formula is proposed to estimated the residual stress from the hardness and the amount of retained austenite. The estimated residual stress is close to the stress measured by X-ray method. The estimated residual stress is applied to the analysis of the fracture mechanics of carburized spur gear teeth. The stress intensity factor due to the residual stress is demonstrated. The stress intensity factor is computed by the influence function method, and it is shown that the factor is decreased by the residual stress in Carburized gear tooth.
A Study on Corrosion Fatigue Crack Propagation Behaviors due to a Single Overload in 6063-T5 Aluminum Alloy
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 38~44
6063-T5 alloys are tested in laboratory air, water and 3% NaCl solution to investigate the effects of corrosive environment on the retardation behavior through single overload fatigue test. Also, the fatigue crack propagation and the crack closure behavior are studied. The results obtained in this experimental study are summarized as follows. 1) Behaviors of fatigue crack growth retardation are observed in water and 3% NaCl solution as they do in air. The number of delay cycles and the size of affected region by single overload decrease greatly in water and 3% NaCl compared with those in air. 2) In fractographic results, the overload marking by single overload appear remarkably in air, but indistinctly in water and 3% NaCl solution. 3) The effect of crack closure on crack propagation is most remarkable in the beginning of crack propagation. With crack propagation, the crack closure level and its effect decrease greatly.
Evaluation by modified offset method on J-R curve with negative crack growth
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 45~51
To evaluate the elastic-plastic fracture toughness by this modified offset method, the origin of J-R curve is set with drawing the blunting line on the maximum point of the negative crack growth and R curve is modified by adding the blunting factor of the experimented point on the R curve. The elastic-plastic fracture toughness
of A5083-H112 material by the modified offset method we 44kN/m on the smooth CT specimens.
A study on the characteristic and instability of the diaphram square bulge under hydraulic pressure
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 52~59
Hill's anisotropy theory and isotropy theory under the deformed profile assumed two separate cases(that is circular and ellipitical) are applied to predict the plastic deformation characteristics of bulge, the strain and polar height under instability condition, using thin square diaphragms of stainless steel, mild steel, brass, copper and aluminum. In this study it was found that the pressure-polar height curves, and the polar height-the polar radius of curvature curve, under anisotropy theory and isotropy theory, assuming a circle profile, agree well with the experimental results, and the equivalent strains of the instability condition under anisotropy theory are better good agreement with the experimental results than those of the instability condition under isotropy theory. Beside, FLCo(plane Strain Intercept) obtained by Bethlehem FLC method and standard FLC method (modified) agree well with the experimental result.
Moving Object Surveillance System based on Image Subtraction Technique
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 60~66
In this paper, a moving object surveillance system, which can extract moving object in real-time, using image subtraction method is described. This technique based on the novelty filter having the structure of neural network associative memory. Digital arithmetic and timing control parts were composed of hardwired controller to treat two-dimensional massive image information. SRAMS having 20 ns access time were used for the image buffer that has high speed write/read property. Image extraction algorithm is discussed and supported by simulation and experiments.
A Study on the Application of Asynchronous Team Theory for QVC and Security Assessment in a Power System
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 67~75
This paper presents a study on the application of Asynchronous Team(A-Team) theory for QVC(Reactive power control) and security assessment in a power system. Reactive power control problem is the one of optimally establishing voltage level given reactive power sources, which is very important problem to supply the demand without interruption and needs methods to alleviate a bus voltage limit violation more quickly. 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 and deterministic approach based on AC load flow calculations is adopted to assess it, especially voltage security. A distance measure, as a measurement for voltage security, is introduced. In order to analyze the above two problem, reactive power control and static security assessment, In an integrated fashion, a new organizational structure, called an A-team, is adopted. An A-team is well-suited to the development of computer-based, multi-agent systems for operation of large-scaled power systems. In order to verify the usefulness of the suggested scheme herein, modified IEEE 30 bus system is employed as a sample system. The results of a case study are also presented.
Prediction of Flash Points for the Flammable Ternary System
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 76~82
Flash points ire used to classify flammable liquids according to their relative flammability. Such a classification is important for the safe handling of flammable liquids which constitute the solvent mixtures. MRSM(modified response surface methodology)-1 and MRSM-2 models we suggested for the prediction of the flash points in the flammable ternary system. By means of this methodology, it is possible to predict the flash points of the flammable mixtures system using computer graphics in the triangular coordinate for the ternary system. The proposed methodology(MRSM) has been tested and compared successfully with previously reported flash points in journal for the ternary system.
A Study on the Quenching Ability of Wire Gauze in a Explosion Pipe
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 83~89
The behaviors of flame propagation and quenching ability in a pipe were investigated to make a design criteria of flame arrester. The effects of the number of wire gauzes and free area on the quenching ability were discussed. Experimental results showed that the flame velocity was important factor of the quenching ability. The flame velocity in case of closed pipe was increased about twenty times faster then that of opened. The quenching ability was increased about 10% with 3% decrease of free area and it was changed significantly by the sealing condition of the pipe end. The quenching flame velocity can be estimated by using experimental equations.
A Study on the Smoldering Zone Spread of the Heaped Saw-Dust
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 90~96
This paper was concerned with temperature aspect in the smoldering time of the accumulated each saw-dust sample of larch, oregon, aromatic trees which was formed with heaped cone-shape. The smoldering time and temperature of each sample was measured under the wind velocity of 0.10~0.15 m/s and circumstance relative humidity of 60%. As a result, the very lowest heat beginning temperature was detected in aromatic. The effective smoldering phenomena in the sample were detected when the larch saw-dust of [-20+40mesh] and the aromatic saw-dust of [-40+50mesh, -50+60mesh]. Finally the larger a particle size of saw-dust was the better a smoldering time was short. Also, it showed more increasing temperature above
in the smoldering reaction.
Adsorption and Desorption Characteristics of Fission Molybdenum on Alumina
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 97~105
Mo-99(Molybdenum) is the only source of Tc-99m(Technetium) which is most frequently used in nuclear medical diagnostics and the demand is on the increase recently. Separation and refining of Mo-99 was investigated by adsorption and desorption on alumina. At pH=0.63, adsorption isotherm of Mo was fitted by Redlich ＆ Peterson equation using the adsorption experimental data. It was found that the pore diffusion model (
) agreed well with batch adsorption experimental data. RTDs(Residence Time Distributions ) were measured and axial dispersion coefficients were obtained in the fixed bed absorber according to the changes of the flow rate using 0.05% -NaCl. From the adsorption experimental data, it was shown that the behavior of breakthroughs depended on flow rate. Mo recovery yield was increased as adsorption flow rate was increased and desorption flow rate was decreased.
Thermal Decomposition Characteristics on Sodium Azide and Metallic Oxide Mixtures
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 106~113
The thermal characteristics of two binary mixtures by sodium azide/manganese dioxide and ferric oxide, two ternary mixtures by sodium azide/silicon dioxide/manganese dioxide and ferric oxide were studied to obtain the basic data of gas-generating agents for air bags. The thermal reaction for all mixtures started at about
, but the temperature at which the reaction rate reached a maximum was different with the states of samples. According to reaction results, nitrogen, nitrogen oxide and nitrogen dioxide were detected by GC-MS and so many kinds of new chemicals from sodium azide and metal oxide mixtures by XRD. NMS is considered as most stable and reasonable mixture for this types of gas-generating agents.
Study on the Flash Point Determination of 2-Propanol-Toluene Mixtures
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 114~119
The lower flash points and upper flash points of 2-propanol and toluene mixtures were determined by air-blowing method instead of Tag-closed flash point tester. The relations between the flash points and the composition of the mixtures are as follows,
As results, the experimental data and the estimated values from the relations are considerably agreed, and we could plotted the relative diagram between flash points and the explosive range.
Structural Optimization by Global-Local Approximations Structural Reanalysis based on Substructuring
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 120~131
This paper presents an approximate reanalysis methods of structures based on substructuring for an effective optimization of large-scale structural systems. In most optimal design procedures the analysis of the structure must be repeated many times. In particular, one of the main obstacles in the optimization of structural systems are involved high computational cost and expended long time in the optimization of large-scale structures. The purpose of this paper is to evaluate efficiently the structural behavior of new designs using information from previous ones, without solving basic equations for successive modification in the optimal design. The proposed reanalysis procedure is combined Taylor series expansions which is a local approximation and reduced basis method which is a global approximation based on substructuring. This technique is to choose each of the terms of Taylor series expansions as the basis vector of reduced basis method in substructuring system which is one of the most effective analysis of large -scale structures. Several numerical examples illustrate the effectiveness of the solution process.
Strength Characteristic and Phenomenon of Heated Concrete by High Temperature
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 132~138
For many years concrete has been the major building material for most construction. It is of primary importance that fire fighters or fire investigators have a full understanding of the properties of concrete so that better control of the fire scene is achieved. This, in turn, not only help to ensure a safer fire-fighting job but also a more successful fire investigation. So far as the fire scene investigation in concerned, knowledge about the thermal behaviour of concrete can help the investigators to determine the highest temperature that a particular spot of a fire scene has ever reached thereby providing data which may be of value in reconstructing the course of the fire.
Stability and Earth Pressure Distribution of Excavated Earth Retaining Wall by Centrifugal Model Tests
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 139~146
In this study, centrifugal model tests were performed to investigate the behavior of excavated earth retaining wall with the depth of excavation and different types of wall(aluminum, steel panel). Jumunjin standard sand was used for foundation soil. The raining method was adopted to form the required relative density of the model ground. The lateral earth pressure measured from tests were compared with estimated active earth pressure by Rankine's theory. The test results have shown that the earth pressure acting on the retaining wall and the rotation displacement of the wall are influenced by the depth of excavation and the type of wall. It was found from the test results that the deformation of the wall increases with the depth of excavation.
The Stability Analysis of Submerged Excavated Slopes
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 147~154
The main purpose of this study is to investigate the failure surface in a soil mass by a excavation of the model ground. The failure mechanism of an earth structure is usually determined from field failure observations or from laboratory model tests at failure. To study the failure surface for the excavated slope, laboratory model tests were performed by changing the angle of the excavated slope and the ground condition. Results of the laboratory model tests were compared with those obtained with theoretical solutions using limit equilibrium analysis method. The results of model tests show that, there is a failure to create a straight line in the low angle of excavated surface and a create a circle as the angle increases. As the angle of excavated surface is increasing, the angle of the failure surface increases too. In the angle of the failure surface, the submerged ground is less than the dry ground at
Fault Tree Analysis and Reliability Analysis by Fuzzy Set Approach
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 155~160
The conventional fault tree and reliability analysis gives in many cases insufficient information concerning the relative frequencies of hazard events. This stems from that the basic events are not stationary and ergodic, and therefore the tolerances of the induced and top events cannot be calculated reliably based on the classical probability theory. To overcome this difficulty, the paper considers the relative frequencies of the basic events as fuzzy numbers and uses instead of probability, possible considerations for evaluating the mean values and tolerances of the top events. The possibility distribution of the basic events can be approximated based on heuristic considerations. This paper shows the use of these operators for constructing fault trees. The use of the method for numerical calculation is demonstrated on a field safety problem.
A Study on the Measurement of Back Power and the Evaluation of Compression Force at the
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 161~165
Recently, industrial accidents have been getting great damage to an enterprise management directly and indirectly, the industrial injuries of conventional type are decreasing : on the other hand, musculoskeletal injuries are trending to a rapid increase. This shows that most of carrying works have been performing in almost all production process and convey objects, machine equipment and work method. Then, they are made by unfitted design which doesn't consider physical condition of workers, so it causes them to bring about forceful motion. In this paper, it was used NIOSH standard the data of spot. The ergonomic design of machine equipment and the evaluation of biomechanical compression force at the
and back power, intend to provide the basis which can be applied, compared, and analyzed between before process improvement and after.
BEF Detection Algorithm to Improve Reliability of Three-Wire-Unigrounded Distribution Line
Wan-Ki Min ; Myeong-Ho Yoo ; Seong-Hwa Kang ;
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 166~172
The BEF on the radial distribution line refers to a class of ground faults in which the load-side power line only is grounded, with the distribution line broken into two parts, the source-side and the load-side. Because its mechanism is remarkably different from that of other earth faults, the fault current is very low, and then difficult to detect the BEF. Thus, it is necessary to analyze its properties and to find an appropriate method that can economically protect the BEF of nonautomation area in the substation. As a result of analyzing the BEF data obtained by the RTDS, EMTP simulation, and the field test data of ETSA, we believe that it is the dominant factor in distinguishing the BEF from normal conditions by a criterion value that is appropriately handled from the zero-sequence current. Thus, with this criterion value, a BEF detecting algorithm is constructed which measures the variations of the zero-sequence current and processes then properly so as to make the fault decision. To prove the accuracy of this algorithm, it is compared with the field test data of ETSA under various conditions. The results show that the proposed algorithm is accurate.
A Study on the Characterization of Intrinsic Flame Retardant and Heat Resistant Sulfur-Bridged Heterocyclic Polymers
Young-Goo Kang ; Hong Kim ; Ho-Suk Ryu ;
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 173~178
The intrinsic flame retardant and heat resistant polymers such as PQXS [poly( quinoxaline )sulfide], PIQS [poly(isoquinoline)sulfide] and PQS [poly(quinoline)sulfide] were synthesized from 2, 3-dichloroquinoxaline, 1, 3-dichloroisoquinoline and 4, 7-dichloroquinoline. They were characterized by FT-IR, UV/Vis spectroscopy, DTA and elemental analysis. The melting point above
of the polymers show higher than that of the heat resistant PPS polymer(mp.
), In the LOI test, the polymers exhibit an intrinsically high flame retardant property having the LOI values in the range of 41~42. The vertical burning test for the polymers also show an UL 94 V-0 performance.
Force Analysis of Wrist Joint to Develop Wrist Implant and Mechanical Hand Using Optimization Technique and Finite Element Method
Jung-Soo Han ;
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 178~184
Many mathematical techniques have been developed to determine the muscle forces and force distribution in biomechanical human model, because it is so important to understand internal forces resisting external loading. However, a three-dimensional mathematical model of wrist joint, which is essential to develop solid modeling and artificial wrist joint, has not been well developed. This study proposed to define three-dimensional mathematical model of distal radius and ulna of the human wrist and to develop a detailed two-dimensional finite element through comparisons to existing analytical models and experimental tests. This mathematical model were accurately recreated, allowing the internal tendon force as well as force transmission and distribution through the distal radios and ulna during dynamic loadings. The results found in this study indicate and support the findings of other investigator that cyclic loading condition results in higher compression force on distal radius and ulna and may be source of wrist disorder.
Incidents Study in Pipelines
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 185~191
Incidents Study and Assurance of Integrity in Domestic Pipelines
Journal of the Korean Society of Safety , volume 12, issue 3, 1997, Pages 192~199