• 한국기계연구소 소보
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• s.13
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• pp.3-13
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• 1984

Fatigue failure of axle housing could cause many injuries and much financial loss. This challenges the engineer to improve design decisions involving fatigue. Endurance evaluation of axle housing is great interest to auto-mobile manufacturers for the sake of safety and reliability. Axle housing is subjected to gross vehicle weight(G.V.W)as mean load and alternating load. Theoretical design diagram involving mean and alternating stresses is used for the evaluation of axle housing fatigue endurance with the equivalent stress of fatigue critical area on the axle housing. Four point bending fatigue tests on axle housing with constant amplitude loading at approximately R=0 were performed with 50 ton servohydraulic strucural fatigue testing machine developed at KIMM. Specimens were made with the same material STKM 13B as the axle housing and tested to obtain S_N data. Five specimens of STKM 13B were tested at 253.61 MPa and weibull distribution was obtained at the same stress level. Material data and structural data were compares and fatigue stress property factor and fatigue life property factor were obtained.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.157-164
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• 2003

The pulse-echo method is one of the most widely used ultrasonic techniques for application of nondestructive evaluation. Particularly, quantitative nondestructive evaluation of defects has been considered more important to assure the reliability and the safety of structure. Frequency energy in adhesive joints is based on the ultrasonic wave analysis. The attenuation coefficient upon wave amplitude and the frequency energy that is expressed in the term of wave pressure amplitude were utilized for the primary wave experiment. By means of a control experiment, it was confirmed that the variation of the frequency energy in adhesive joints depends on transition by stress variation. In this paper, the ultrasonic characteristics were measured for single lap joint and Double Cantilever Beam specimen with different fracture modes that was subjected to stress. Consequently, the data that was obtained from the adhesive specimen was analytically compared to the fracture mechanics parameter

• Structural Monitoring and Maintenance
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• v.6 no.3
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• pp.173-190
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• 2019

Steel-confined reinforced concrete (SCRC) columns feature highly complex and invisible mechanisms that make damage evaluation and pattern recognition difficult. In the present article, the prevailing acoustic emission (AE) technique was applied to monitor and evaluate the damage process of steel-confined RC columns in a quasi-static test. AE energy-based indicators, such as index of damage and relax ratio, were proposed to trace the damage progress and quantitatively evaluate the damage state. The fuzzy C-means algorithm successfully discriminated the AE data of different patterns, validity analysis guaranteed cluster accuracy, and principal component analysis simplified the datasets. A detailed statistical investigation on typical AE features was conducted to relate the clustered AE signals to micro mechanisms and the observed damage patterns, and differences between steel-confined and unconfined RC columns were compared and illustrated.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.39-47
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• 2003

A study of the structural strength evaluation on the doubler plate, considering various load cases that were subjected to in-plane and out of plane combined load, has been performed through the systematic evaluation process. In order to estimate the proper static strength of doubler plate for various load cases, elasto-plastic large deflection analysis is introduced, including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed, based on the results. In order to compare the doubler structure with the original strength of main plate, without doubler, simple formulas for the evaluation of the equivalent flat plate thickness are derived for each load case, respectively, based on the additional series of analysis of flat plate structure. Using these derived equations, the thickness change of an equivalent flat plate is analyzed according to the variation of various design parameters of doubler platesome design guides are suggested in order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent flat plate formula and the developed buckling strength formulas are discovered, and these relations are formulated for the future development of simple strength evaluation formula of general doubler plate structure.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.2
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• pp.66-70
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• 2016

Following the 2011 Fukushima Nuclear Power Plant accident, the IAEA has issued a revised version of the Nuclear Safety Standard for beyond design basis earthquake to consider the core meltdown accident. In Korea, relevant laws and regulations were also revised to consider beyond design basis earthquake to nuclear components. In this paper, CAV, an seismic damage factor that determines the restart of nuclear power plant after operating breakdown earthquake, is proposed for extension to the beyond design basis earthquake. For pipings not satisfying the beyond design basis earthquake condition, several evaluation methods are suggested, such as strain-based evaluation methods, simple nonlinear analysis method and cumulative damage evaluation method.

• Korean Institute of Interior Design Journal
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• v.23 no.5
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• pp.112-121
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• 2014

The purpose of this study is to develop the user-oriented housing interior space sensibility evaluation tools: The user-oriented housing interior space sensibility evaluation tools shall be developed through the systematic selection process of the extracted housing interior space images, which were linked with the adjectives of sensibility evaluation selected for the housing interior space preferred by the user from the specific words of the sensibility extracted to identify the characteristics of the user's sensibility which is recently being changed. In the results of analyzing the words of sensibility for the residential space preferred by the users with 48 pairs of adjectives. The user-oriented sensibility assessment tool was built by extracting 8 sensibility factors of 'cozy', 'practical' 'cheerful', 'traditional', 'unique', 'congenial', 'sensuous', and 'gorgeous' in the exploratory factor analysis. The image scale was constructed in two-dimensions of the sense of space and the type of space for the residential interior space images. The dimension of the 'sense of space' is explained by the axis of open-closed and the dimension of 'type of space, is explained by the axis of 'natural-artificial'. Such a structural model of the residential interior design attributes were divided into 8 groups. And the 42 images representing each group were selected and the user-oriented residential interior space image tool was built by adding user's selective elements.

• The KSFM Journal of Fluid Machinery
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• v.3 no.4 s.9
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• pp.7-14
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• 2000

This paper provides integrity evaluation and root cause analysis for defects observed at volute tongue, or cutwater, of the operating centrifugal pump in power plant. The cause of the cracks are analyzed and reviewed from the viewpoint of the operation and maintenance of the pumps, and the sample obtained from the cracked volute tongue of the pump are examined. At first, in-situ hardness test and microstructure examination were performed to understand the cause of cracking at volute tongue. The evaluation of structural integrity and the possibility of the crack propagation is also evaluated. Cracks were typical intergranular cracking and propagated along with prior austenite grain boundary. At easing volute tongue, the hardness was higher than ASTM requirement and a large amount of intergranular Cr carbide was precipitated. These were due to high C content in material. P content was also higher than ASTM requirement. Therefore, Cr carbide precipitation and P segregation at grain boundary, caused by higher C and P content in material, resulted in intergranular cracking of casing volute tongue. This procedure for integrity evaluation and root cause analysis is used to guide, and support the pump designer and manufacturer's material selection and process design to avoid a costly, unplanned outage of plant.

• Journal of Korean Public Health Nursing
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• v.17 no.2
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• pp.181-191
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• 2003

Purpose: The purpose of this study was to evaluate demonstration health promotion programs offered by 18 health centers in a structural aspect of the health centers. Methods: The Evaluation Committee was organized with professors from collaboration universities and researchers of this study. Using structure evaluation frame. reports from 18 health centers were reviewed by the committee. Evaluation categories included organizational change, manpower construction, budget, and manpower training and education. Results: Only 5 health centers out of 18 have independent health promotion department. Nurses played a major role for health promotion programs. Other health personnel participated in the health promotion programs included dental hygienists, nutritionists, and exercise specialists. Related to program budgets. local government support rates were varied by the region. Various kind of manpower training was offered to health personnel for the health promotion programs including smoking control. exercise, alcohol, nutrition, and so forth. Conclusion: The study results indicated that establishment of independent health promotion department, maintenance of same manpower construction, provision of diversity manpower training were the factors that foster effective health promotion programs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.667-674
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• 1992

Recently advantages in composite and light weight material technique have led to the increased use of structural adhesives in various industries. In spite of such wide application of the adhesive joints, the evaluation method of fracture strength and design methodology of them, have not been established. In this study finite element method, theoretical and experimental analyses were investigated according to changes of lap length and adhesive for adhesive single-lap joint. As the results, the strength evaluation of adhesive joint by conventional nominal stress, was pointed out inadequate strength evaluation and design method regardless stress singularity, stress distribution and crack propagation in its adhesive layer. Also, it was examined the problems to apply fracture mechanics by means of static and fatigue test.

• Journal of the Ergonomics Society of Korea
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• v.22 no.2
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• pp.45-56
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• 2003

The purpose of this study is to develop the model including multiple causal relationship between factors to evaluate overall user satisfaction and develop an objective method to quantify the impacts and scores of each qualitative factors on overall user satisfaction using Structural Equation Model(SEM) and also test the feasibility to construct a comprehensive website evaluation model including qualitative and quantitative factors. The SEM model used 2 qualitative factors of usability and esthetic factors for the evaluation factors of user satisfaction and select 4 attributes of each factors using factor analysis. 3 shopping mall sites were evaluated to construct the SEM model, and 155 subjects participated the website evaluation using the walk-through and face-to-face survey method. Analysis results showed that the SEM model was statistically significant for all the 3 websites evaluated. Both the usability and esthetic factors showed significant effects to user satisfaction of websites and have positive correlation. The user satisfaction was more effected by the usability factor than esthetic factors, and the simplification and harmonization were the most critical attributes of the usability and esthetic factors.