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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 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
Appropriate Choice of Window Function for Noise Reduction
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 3~8
This paper shows a performance estimation of windowing a single tone with added Gaussian noise and uniform noise. Signal-to-noise ratio can be determined by the ratio of the output noisy signal variance to the input noisy signal variance of a window. Standard deviation of noise is reduced by windowing Signal-to-noise ratio of the noisy signal is reduced by the windowing operation. Thus, performance of window function can be determined by this filtering operation that improved the signal-to-noise ratio.
A Study on the Hand drum form of Wire-Cut Electric Discharge Machining
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 9~14
From the experimental study of wire-cut Electric Discharge Machining for alloyed steel and tungsten carbide, the characteristics such as hand drum form has been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, their thickness become thinner, wire tension become larger and number of cutting is done so many times. When wire-cut 60mm thickness tungsten carbide in normal condition, Hand drum form becomes larger due to the low conductivity inducing cobalt composite rising by electrolysis.
A Study on the Fatigue Crack Propagation Behavior by the Variation of Heat Treatment Temperature and Thickness in ATOS 55 Steel
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 15~20
This study is to investigate the behavior of fatigue crack growth with ATOS 55 steel which can be applied to the commercial car Dump Frame. It is to obtain the material coefficients after tensile and fatigue crack growth test with the variation of thickness or heat treatment. Also, that is proved the Pari's law by experiment. The summarized results are as follows ; 1) Increasing thickness, tensile and yield strength measured highly regardless to heat treatment and measured lowly as variation of heat treatment temperature. 2) Specimen of thickness 8.0㎜ measured the faster of crack growth rate than another thickness according to the results of experiment. It was the different of stress conditions in crack tip. 3) It was found that the experimental constant m was range of 2∼5 to the relationship between fatigue crack growth rate and stress intensity factor range. Also, it was to prove the Paris's law by the experiment.
Risk Monitor Development for On-Line Maintenance
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 21~26
Korea Atomic Energy Research Institute (KAERI) developed a risk monitor called Risk Monster which supports for plant operators and maintenance schedulers to monitor plant risk and to avoid high peak risk by rearranging maintenance work schedule. Risk Monster can update the plant risk continuously according to the change of system/component configuration since Risk Monster reevaluates the plant risk based on the Probabilistic Safety Assessment (PSA) results. A brief description of Risk Monster is provided. The PSA model of UCN 3, 4 nuclear power plant was converted by KAERI to Risk Monster model. Using this Risk Monster model, a feasibility study of the on-line maintenance of an Essential Service Water (ESW) pump was performed. On-line maintenance of one ESW pump has been shown to be acceptably safe, and has economic benefits. In addition, it is not a violation of technical specification to continue plant operation with an out-of-service ESW pump.
A Study on the Crack Growth Behavior of a Inclined Crack in a Non-Uniform Thickness Material
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 27~38
The effect of geometry factors on the combined mode stress intensity factor behaviors of a slant crack in a non-uniform thickness material was analysed by 2-dimensional theoretical analysis. The analysis is based on the Laurent's series expansions of complex potentials where the complex coefficients of the series are determined from the compatibility and the equilibrium conditions of the thickness interface and the stress free conditions of the crack surface. In numerical calculations the perturbation technique is employed. The expressions for the crack tip stress intensity factor are given in the form of power series of dimensionless crack length
, and the function of crack slant angle
and thickness ratio
. The results of numerical calculations for each problems are represented as the correction factors F(
). The results clearly show the following characteristics : The correction factors of the combined mode stress intensity factors for a non-uniform thickness material can be defined in the form of F(
). The stress intensity factor values for a given crack length are decreased with increase of thickness ratio
A Study on Automatic Technology for a industrial Industrial Involute Gears Design
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 39~46
This study describes a computer aided design system on involute gear for power transmition. Input data for gear design are pressure angle
, transmitted power, gear volume, gear ratio, addendum ratio of rack, dedendum ratio of rack, edge radius of rack, allowable contact stress and allowable bending stress etc. Bending strength contact strength and scoring are considered as the design constraints. Method of optimization developed this study. The developed gear design system can design the optimized gear that minimize the number of pinion teeth with face tooth.
Vibration Control of a Semi-Active Engine Mount Using an ER Fluid
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 47~56
This paper presents the vibration control of an engine mount featuring an ER(electro-rheological) fluid. The Bingham properties of the ER fluid to be employed to the ER engine mount are experimentally obtained through Coeutte type viscometer. The ER engine mount is devised ant its governing equation is derived. After evaluating the performance of the ER engine mount on the basis of the mathematical model, the novel type of the ER engine mount is then designed and manufactured. The electric field-dependent transmissibility of the ER engine mount is evaluated by changing the particle concentration and the electrode gap size. To investigate the control performance of the ER engine mount, neuro-control algorithm is adopted. It is shown that the proposed ER engine mount has prominent capabilities of controlling the damping force by tuning the electric fields and excellent vibration isolation performance.
A Study on Mechanical Strength in AI7075/CFRP Hybrid Composite
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 57~62
The combined structure of hybrid composite made through the bonding process of materials of different properties greatly defines its mechanical characteristics, as the results of the experiments on materials of different properties show much dissimilarity. When carbon/epoxy materials are applied to hybrid composite, the carbon materials helps to improve the mechanical properties of the hybrid composite, and the epoxy reduces its fracture strain and impact resistance. Carbon fiber which is now in general commercialization is classified as high modulus or high strength system, and its manufacturing methods are various. The study of the materials having combined structure is focused on the numerical analysis of the layers of bonding surface in materials with difference modulus. The hybrid composite made through the multilayered bonding of reinforced aluminium sheets with aramid fiber now faces the marketing phase, and especially its excellent fatigue resistance and mechanical properties promote active researches on the similar products of hybrid composite. This study aims to investigate the effects of CFRP volume ratio and fiber's orientation over the properties of mechanical strength and fatigue life of the hybrid composite, AI7075/CFRP. To carry out this study, static tensile and fatigue tests were given to some of the panels which, made through the co-cure processing in an autoclave, have different CFRP volume ratio and carbon fiber orientations.
Filter Design Method for an Inverter System
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 63~69
This paper presents a design method for a filter application in a parts-of FA(Factory Automation). Normal equations for ripple voltage and current are derived in terms of dimensionless quantities, and these equations can be used directly to evaluate the values of LC-filter components, taking into consideration the effect of the ripple components on the rms value of the PWM-generated ripple components. Using describing function technique, design equations of the filter are derived. The data needed for the filter evaluation are the amplitude of current ripple and the frequency of square pulses delivered by the HE(Harmonic Elimination) inverter algorithm. Experimental results show that the design of the filter can be based on the method proposed and that the filter can provide a significant reduction of ripple components.
A Study on the Formation of Smoke Layer and the Zone modelling in Compartment Fire
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 70~78
The objective of this research is to study on the upper and lower layer temperature, interface height and pressure in case of carpet, chair, trashcan and wardrobe fires in a residential room by performing the theoretical and experimental studies. The theoretical results of the upper and lower layer temperature, the interface height and the pressure were qualitatively well coincided with the experimental results. The uniformly distributed fire in case of carpet showed that the ignition and the initial growth period were relatively short while the fully developed period was considerably long. The concentrated fires such as the wardrobe showed that the ignitions and the initial growth periods were relatively long. The interface heights were around 1m as the steady state. However, at the time of the maximum temperature, the interface height was lowered to 0.5m from the floor. The pressure variation in the fire room ranged between 0.1mmAq and 0.4mmAq, and the temperature reached the highest while the pressure was maximum.
Silica Coating on Polymethylmethacrylate by Sol-Gel Process
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 79~85
In order to improve the surface characteristics of polymethylmethacrylate(PMMA), oxide thin film coatings were applied using the sol-gel dip-coating technique. The
, tetra-ethyl-ortho-silicate(TEOS) was used as a starting material for
coating. The hardness of the alkoxy-derived oxide-coated PMMA was increased from 190 MPa for non-coated PMMA with increasing film thickness. By optimizing the heating conditions and the hydrolysis conditions, a maximum apparent hardness obtained In the present study was achieved 310 MPa using the withdrawal velocity of 5cm/min and heat treatment at
for 5 hours, which is about 1.6 times larger than that of uncoated PMMA.
A Study on the Risk Assessment in LPG Transportation by Tank Lorry
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 86~92
Demand of LPG and LNG will increase continuously due to high calories, clearness, and convenience for usage. These gases are used widely for power plants, industrial plants, and domestic fuel. But accidents related with gas are increasing in proportion to increment of gas usage. Especially LPG has high ignitability due to weak dispersion to air and accumulation at low place because LPG is heavier than air. There are many hazards during transportation as well as production, storage, and usage of LPG. Commonly, tank lorry is used for inland transportation of LPG. If tank lorry were to raise leakage incidents and then LPG released during transporting, the accidents cause serious effects on the environment as well as human damage of surrounding area. In this study, therefore, hazards which cause LPG of tank lorry to leak during transportation were identified and risk of LPG transportation was assessed quantitatively. Also, the result of this study might be a useful measure for predicting damage and preparing safe transportation strategies of LPG tank lorry
A Study of Improvement on Collaboration Treatment Method of Electroplating Wastewater
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 93~101
A modified procedure for electroplating wastewater treatment using formaldehyde and hydrogen peroxide can destroy free cyanide. The representative diagram which is quite sensitive on reaction temperature is showed for this kinds of treatment. Principally free cyanide and some kinds of cyanide complex should be treated first, and then toxic heavy metals can be removed because cyanide component will be inhibited to remove other pollutants, if it is not destroyed perfectly. Formaldehyde and hydrogen peroxide are added in controlled amounts to cyanide treatment tank. Reasonable amounts of these chemicals are (HCHO/CN)=0.9 and (
)=1.1 in molar ratios, it is also variable on reaction temperature. Of course, actual treatment processes depending on plating material and chemical are good applicable, also to systematize operation manual for treating electroplating wastewater process, further works are desirable.
The Influence of Ground Stability with Blasting Vibration
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 102~107
Ground vibrations are an integral part of the process of rock blasting. The sudden acceleration of the rock by the detonation gas pressure acting on the drillhole walls induces dynamic stresses in the surrounding rock mass. This sets up a wave motion in the ground much like the motion in a bowl of jelly when disturbed by the action of a spoon. The wave motion spreads concentrically from the blasting site, particularly along the ground surface, and is therefore attenuated, since its fixed energy is spread over a greater and greater mass of material as it moves away from its origin. Some theoretical aspects of the generation and propagation of vibrations produced in rock blasting are analyzed; although it must be indicated that this is just a mere approximation to the problem, as the actual phenomena are much more complex owing to the interaction of different types of waves and their modifying mechanics.
Influence of Suction Force of Plate Anchor Embedded in Kaolinite
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 108~113
Plate anchors are primarily used in the foundation construction of earth-supported and earth-retaining structures. In order to estimate uplift capacity as well as suction force of clay, model tests were peformed with respect to various embedment depths and two different moisture contents in the prepared saturated kaolinite. Further, suction effects on the ultimate uplift capacity, at the various embedment depths of anchor, were also taken into account. Test results show that ultimate uplift capacity including suction force increases from 4.2kg at H/D=1 upto 11.6kg at H/D=5 in K1 and from 2.3kg at H/D=1 upto 7.3kg at H/D=5 in K2 respectively. The ratio of
decreases along with the increases in the embedment ratio. In general, mud suction force under the ultimate uplift capacity in kaolinite decreases or becomes constant along with the increase of the embedment ratio.
Pullout Characteristics of Multi Helical Anchors in Clay
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 114~121
Helical anchors are foundation structure that designed to resist uplift loads are installed by applying in load to shaft while rotating it into the ground. These can be a cost effective means of proving tension anchorage for foundation where soil conditions permit their installation because of ease of installation. At present time, tapered helical anchors are commonly used to carry uplift loads. The uplift capacity includes the following factors : the height of overburden above the top helix, the resistant along a cylinder, the weight of the soil in the cylinder and suction force. In order to make clear behavior characteristics of helical anchors with pullout, model tests were conducted with respect to various embedment depth, space of helix, shape of helix. Based on the experimental study, the following conclusions are drawn. 1) The uplift capacity of multi helical anchors increase with embedment ratio of anchors The increase is smooth after critical uplift capacity. 2) Critical breakout factors and critical embedment ratio of multi helical anchor exist 7∼8, 4∼6 respectively. 3) Variation of uplift capacity with helix spaces show down after S/D=5. 4) Critical breakout factors of helical anchor in the laboratory test are similar to Das's theory.
A Study on the Analysis of Causes for Fatal Accident in Construction Works
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 122~133
Various types of fatal accidents are increasing in Korean construction work site. Simply repeated and conventional accidents as well as new types of potential hazards which are caused by large-scaled work, complexity and negligence of temporary structures in construction are increasing, so that analysis of fundamental causes are necessary to control the construction accidents. In this study 739 fatal accidents are informally classified by the types of work and work process. The classified items which are based on ANSI Z 16.2, are modified adapted to the construction fields and are given code numbers and are analyzed by the data-base program. The exact causes of various types of accidents are analyzed by the accident types, agencies and hazardous conditions and through the Cross-tabulation method in order to find out the cause between relevant accidents.
The Analysis of the Slope Stability in Embankment(I)
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 134~142
The stability of an embankment Impounding a water reservoir is highly depend upon the location of seepage line with the embankment. To evaluate the accurate safety factor of an embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid change (drawdown) of reservoir level Seepage forces in embankments are easily determined if frictional forces are expressed in relation to hydraulic gradient Ⅰ. If a piezometer is inserted into a body of embankment, the level to which free water rises is a measure of the energy at that point. From model test result, it is possible to calculate safety factors of earth embankment. To assure the validity of this research, tests were conducted with numerical experimental models. And the experiment models were constructed with slopes of 1:1.0, 1:1.5, 1:2.0, 1:2.5. Analysis of experimental results, seepage force was analyzed according to downstream time, internal friction angle and cohesion, respectively.
Safety and Reliability Assessment for Nuclear Power Plants
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 143~152
Probabilistic Safety Assessment(PSA) is an engineering analysis of the possible contributors to the risk from a nuclear power plant. It consist of three phases named as Level 1, 2 and 3. Level 1 PSA mainly focused in this paper is the phase of system analysis which includes the development of accident scenarios and the frequency estimation of each scenario. It covers also the system reliability analysis, component data analysis, and human reliability analysis. PSA have become a standard tool in safety evaluation of nuclear power plants. The main benefit of PSA is to provide insights into plant design, performance and environmental impacts, including the identification of dominant risk contributors and the comparison of options for reducing risk.
Investigation of Cumulative Trauma Disorders in Manual Tasks - Case Study at Osram Sylvania, Inc. -
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 153~160
The purpose of this paper is to present design recommendations intended to reduce the risk of cumulative trauma disorders(CTD) at the Osram Slvania, Inc. The CTD risk index score is a method which quantifies the risk factors to CTD incidence, namely extreme postures, high force elements, frequent damaging hand motions, and other miscellaneous factors. The risk index score quantified the jobs as a single composite value by weighting the scores for each risk factor. Jobs were prioritized for capital outlays in workstation redesign, and the factors of highest risk within each job could be identified. Three jobs which presented the greatest risk of CTD incidence were redesigned ergonomically.
A Quantitative Analysis on Human Errors in Shifting Hazardous Materials of Semiconductor Plants
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 161~168
Most plants producing semiconductors use a lot of chemicals, hazardous materials, and explosive gases. Though those materials are hazardous too much, some works still have to be done manually by human workers. However, according to a historical survey, more than half industrial accidents of those plants resulted from human errors or malfunctions. Thus, this research aimed 1) to diagnose shifting hazardous materials of semiconductor plants, 2) to estimate failure probability of human workers through human reliability analysis, and 3) to find out the tasks on which educational emphasis should be put. Through personal interview and visiting working spots, shifting tasks were analyzed, and modelled into a 24-step work, and after that, THERP and ETA was applied. During the shifting work, estimated human failure probability under the assumption of independency, 2.3004E-05, underestimated that probability 8. l008E-05 which could be calculated under the assumption of dependency. And this analysis showed that gas leakage from an old cylinder occupies 78.27% in the case of independent failures whereas gas leakage from a new cylinder occupies 75.06% in the case of dependent failures. So it was concluded that dependency assumption may gloss real situations. In addition, confirming gauge of regulators and closing valves turned out to be the most important tasks than purge tasks.
An analysis of the Child Head Impact Injury with Finite Element Model
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 169~179
The dynamic response of the human brain to direct impact was studied by three-dimensional finite element modeling. The model includes a layered shell closely representing the cranial bones with the interior contents occupied by an incompressible continuum to simulate the brain. Falx and tentorium modeled with 4 node membrane element were also incorporated. The computed pressure-time histories at 4 locations within the brain element compared quite favorably with previously published experimental data from cadaver experiments. Therefore, the purpose of this study was to determine the effects of the impact direction on the dynamic response of the brain in children. A parametric study was subsequently conducted to identify the model response when the age and impact site were varied.
A Study on the rapid calculating of reliability for Fault Tree
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 180~190
A new method in the fault tree analysis (FTA) for the reliability calculation is suggested. Two steps are necessary in traditional method in evaluation of the occurrence probability of top event in fault tree (FT). The first step is to find the minimal outsets, and the second one is to substitute the result into the poincare equation. In order to reduce the enormous computing time of this method, lots of rapid algorithms have been developed. Almost of all achievements were, however, based on the partial structural properties of FT. In this paper, the FT is transformed to a non-linear graph G which has the same minimal outsets of original n, and then the reliability is calculated using the domination theory. In this new method, the required number of equation terms are at most
(n is node number of graph G), while
-1 (m is the number of minimal cutsets) calculation terms are required in the poincare equation in traditional method. Since m>>n in general. our new method reduces the calculation time significantly.
A Study on the Noise Produced by Unsteady Exhaust Efflux of Engine
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 191~200
This paper discusses prediction of the sound pressure level produced by simple engine exhaust systems(plain pipe, plain expansion chamber pipe, plain expansion chamber with internally extended inlet and outlet pipe, perforated pipe enclosed in a plain expansion chamber) and a computer program has been developed which predicts the sound pressure level and the frequency spectrum. The program utilizes unsteady flow gas dynamic theory and acoustic theory to predict the pressure-time history in the exhaust system and the mass flow rate-time history at the open end of the system and the sound pressure levels(1/3 Octave band levels) and the frequency spectrum in semi-anechoic room. The predictions are compared with measured levels and show a high degree of correlation.
Human Factors Design Review of CFMS for Improving the Safety of Nuclear Power Plant
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 201~208
In order to improve the safety of nuclear power plant, we performed a human factors review for the CFMS(Critical Function Monitoring system) design of nuclear power plant. Three works were performed in this study. In first work, we developed human factors engineering program plan(HFEPP) and human factors engineering verification and validation plan (HFE-V & V plan) to effectively perform CFMS design and review. In second work, we identified human engineering discrepancies(HEDs) for CFMS design through human factors design review and proposed those resolutions. In the third work, we developed the evaluation and management methodology for identified KEDs. Methodology developed in this study can be used in other complex system as well as in CFMS design review.
An Approach to Ergonomics Evaluation of Grip Strength - Case by the Manual Lifting -
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 209~213
Manual lifting techniques are commonly defined in terms of the postures adopted at the start of the lift. Quantitative definition is problematic, however, because the absolute joint angles adopted to lift an object are influenced by task parameters, such as the initial height of the load. The main objective of this study is to investigate the grip strength of the both hands at the initial lifting points. The survey is conducted by measuring the compression force, anthropometric data and grip strength at the lifting postures for the subjects(n=50) who is assigned to their job as usual. The experiment is peformed at the four lifting postures which involving the combination of two horizontal factors(H1 : 35 cm, H2 : 55 cm) and two vertical factors(V1 : 20~80 cm, V2 : 47~102 cm). The analysis result of lifting posture indicated that each H1-V1, H2-V1 combinations are about 60
and each H1-V2, H2-V2 combinations are about
. There are significant differences on grip strength between
stooped posture. The results of this study can be provided a method defining lifting postures at the minimum grip strength. Also, it is eliminated a hazard of the injuries which are cumulative trauma disorders(CTDs) and back pain, increased a productivity and improved a welfare of workers.
Optimum Monitoring Parameters for the Safety of Mechanical Seals
Soon-Jae Lim ; Man-Yong Choi ;
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 214~219
The mechanical seals, which are installed in rotating machines like pump and compressor, are generally used as sealing devices in the many fields of industries. The failure of mechanical seals such as leakage, crack, breakage, fast and severe wear, excessive torque, and squeaking results in big problems. To identify abnormal phenomena on mechanical seals and to propose the proper monitoring parameter for the failure of mechanical seals, sliding wear experiments were conducted. Acoustic emission, torque, and temperature were measured during experiments. Optical microstructure was observed for the wear processing after every 10 minute sliding at rotation speed of 1750 rpm and scanning electron microscopy was also observed. Except for the initial part of every experiment, the variation of acoustic emission was well coincided with torque variation during the experiments. This study concludes that acoustic emission and torque are proper monitoring parameters for the failure of mechanical seals. The intensity of acoustic emission signals is measured in root mean square voltage. Temperature of sealing face will be used as a parallel parameter for increasing the reliability of monitoring system.
Buckling Analysis of Arches Using DQM
Ji-Won Han ; Ki-Jun Kang ;
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 220~229
The differential quadrature method (DQM) is applied to computation of the eigenvalues of the equations governing in plane and out-of-plane buckling. In-plane buckling and twist-buckling under uniformly distributed radial loads are investigated by this method. Critical loads are calculated for various end conditions and opening angles. Results are compared with existing exact solutions where available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used. New results are given for two sets of boundary conditions not previously considered for this problem clamped-clamped and clamped simply supported ends.
Fracture Characteristics of Polypropylene Fiber Reinforced Concrete
Shin-Won Paik ;
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 230~240
An experimental research investigation of the fracture properties of polypropylene fiber reinforced concrete is reported. Fibers used in this experiment were two types, monofilament and fibrillated polypropylene fibers. Fiber length was 19 mm, and volume fractions were 0, 1, 2, and 3%. Also, as initial notch depths influence the fracture properties of fiber reinforced concrete, the notch depth ratios by specimen height were 0.15, 0.30 and 0.45. The main objective of this experimental program is to obtain the load-deflection and the load-CMOD curves, to investigate the fracture properties of the polypropylene fiber reinforced concretes. Therefore, the flexural specimen testings on the four-point bending were conducted. Then, the load-load point displacement and the load-crack mouth opening displacement curves were measured. The effects of different volume fractions of the monofilament and the fibrillated polypropylene fiber reinforced concrete on the compressive strength, flexural strength and toughness, stress intensity factor, and fracture energy were investigated through the experimental results.
Development Procedure of Generic Component Reliability Data Base in PSA and Its Application
M.J. Hwang ; K.Y. Kim ; T.J. Lim ; W.D. Jung ; T.W. Kim ;
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 241~248
This paper presents the development procedure and application of the generic component reliability data base considering the dependency among dependent generic compendia in NPPs (Nuclear Power Plants) PSA (Probabilistic Safety Assessment) under construction or without operating history. We use MPRDP (Multi-Purpose Reliability Data Processor) code developed in KAERI (Korea Atomic Energy Research Institute) based on a PEB (Parametric Empirical Bayesian) procedure to estimate the reliability. The employed model in this study accounts for the relative credibility as well as the dependency among generic estimates. Numerical examples and the part of summarized reliability data table are provided as the application.
Hydrogen Storage Material as an Dream Energy Resources
Journal of the Korean Society of Safety , volume 12, issue 4, 1997, Pages 249~256