• Journal of Welding and Joining
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• v.23 no.1
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• pp.35-40
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• 2005

In this paper, static and fatigue load tests for the specimens, components and carbody were carried out to investigate the strength of welded joints in aluminum rolling stock. Tensile test results showed that the static strength of welded joint for the heat-treated alloy is reduced significantly and fatigue strength data are scattered by the welding imperfections. Component and whole carbody fatigue test results showed agreements with the design fatigue strength standards for specimens of the same joint detail. Test results revealed that full penetration welding and strict management of welding procedure are crucial for securing the strength of welded joint in aluminum carbody.

• Computers and Concrete
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• v.11 no.6
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• pp.587-602
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• 2013

In the current study, a method for concrete compressive strength prediction (based on cement strength class), incorporated in a software package developed by the authors for the estimation of concrete service life under harmful environments, is presented and validated. Prediction of concrete compressive strength, prior to real experimentation, can be a very useful tool for a first mix screening. Given the fact that lower limitations in strength have been set in standards, to attain a minimum of service life, a strength approach is a necessity. Furthermore, considering the number of theoretical attempts on strength predictions so far, it can be seen that although they lack widespread accepted validity, certain empirical expressions are still widely used. The method elaborated in this study, it offers a simple and accurate, compressive strength estimation, in very good agreement with experimental results. A modified version of the Feret's formula is used, since it contains only one adjustable parameter, predicted by knowing the cement strength class. The approach presented in this study can be applied on any cement type, including active additions (fly ash, silica fume) and age.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.338-344
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• 2016

The study is actively being performed to increase fuel injection pressure of common rail system among countermeasures to meet the emission regulation strengthen of the Diesel engine. The common rail fuel injection tube in such ultra high pressure common rail system has the weakest structural characteristics against vibration that is generated by fuel injection pressure and pulsation during engine operation and driving. Thus the extreme durability is required for common rail fuel injection tube, and the drawing process is being magnified as the most important technical fact for strength of seamless pipe that is the raw material of common rail tube. In this respect, we analyzed the characteristic of dimension and stress variation of the ultra high pressure common rail fuel injection tube by variation of Die and Plug angle in drawing process. Based on the analysis, we tried to obtain the raw material strength of common rail fuel injection tube for applying to the ultra high pressure common rail system. As a result, Plug angle is more important than entry angle of Die and we could obtain the target dimension and strength of the ultra high pressure common rail fuel injection tube through optimization of Plug angle.

• Journal of East-West Nursing Research
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• v.9 no.1
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• pp.15-24
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• 2004

The purpose of this research was to compare the effects of Danjeon Breathing exercise and walking exercise on physical fitness of middle-aged women. The Danjeon breathing exercise group(20) took health management counseling and performed an eighty-minute Danjeon breathing exercise three times a week for 12 weeks while the walking exercise group(25) took health management counseling and performed a walking exercise seven hours per week for 12 weeks. The control group(20) received only health management counseling. $VO_2max$, back strength, flexibility, balance, power and agility were measured using the Health Management System developed by the Korea Physical Science Institution. The collected data were analyzed by using the SPSS PC program and $x^2$, ANOVA, repeated measures of ANOVA and LSD. The result of this study are as follows: 1. There were significant differences on back strength, flexibility, agility and power among Danjeon breathing exercise group, walking exercise group and control group. The degree of back strength, flexibility and power of the Danjeon breathing exercise group was higher than that of the walking exercise group and the control group. The degree of agility of the walking exercise group was lower than that of the control group. 2. There were no significant differences on $VO_2max$ and balance among Danjeon breathing exercise group, walking exercise group and control group. In conclusion, Danjeon breathing exercise improves back strength, flexibility and power than walking exercise and walking exercise improves agility than Danjeon breathing exercise.

• Construction Engineering and Management
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• v.12 no.1
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• pp.33-35
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• 2011

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.29-36
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• 2021

The allowable strength based on experiments and the design allowable strength calculated using the design criteria were compared, which suggested a ratio between the allowable strengths for the reused vertical members of the system scaffolding and system support. By investigating a total of 421 certification reports for reused vertical members, the experimental allowable strengths were collected. Using design criteria such as the road bridge design and KDS 14 30 10, the design allowable strengths were calculated for various slenderness ratios. For the system scaffolding, the average ratio between the experimental and design allowable strengths was calculated to be 0.880 by assuming a normal distribution for all specimens. However, by analyzing the strength ratio according to the slenderness ratio, the lowest average strength ratio was found to be at least 0.844. Therefore, it is reasonable to assume that the allowable strength of the reused vertical members was 80-84% of the design allowable strength. In addition, assuming the allowable strength to be 85% of the design allowable strength is a possible method for reused vertical members of system supports.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.4
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• pp.111-126
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• 2002

This paper presents an interactive decision procedure to aggregate each group member's preferences when each group member articulates his or her preference information incompletely. An index, an indicative for the preference strength between alternatives, is derived to aid each decision maker to articulate preference information about alternatives. We develop a mathematical programming model that can establish dominance relations when the preference information about values of alternatives, attribute weights, and group member's importance weights are provided incompletely. Also, the preference relation between alternatives is to be considered in the model. Based on the preference strength measure and mathematical model, we develop an interactive group decision support procedure.

• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.21-32
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• 1992

The only property of the random stresses to affect the life length are their damage amount and are independent of the especial realization in stress case. This paper shows the result is discussed that the randomness of the life length is caused by the randomness of the strength rather than by the randomness of the stress when the load is a random function and the strength is random as well. This special model is well-suited model for comparative calculations since it connects fatigue life for random stresses to fatigue life for periodically curve loads, which is usually measured in experiments.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.04a
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• pp.80-85
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• 2006

HSS (high strength steel) is widely applied to reduce the weight but improve the strength in automobiles. This research has been peformed to secure a methodology to accurately predict the springback of HSS for successful tool and process designs in sheet stamping operations. We first peformed U-draw bending test to evaluate the springback characteristic. We then evaluated forming and springback processes using the 1-row model of the finite element method. Based on the peformance measure and parameters selected, extensive analyses of the factor effects on the springback have been made using experimental design concepts. We specifically selected Taguchi's orthogonal array, $L_{18}(2^1{\times}3^7)$, and the optimal level combination of the factors have been drawn from the analysis.

• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.623-631
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• 2008

In this study, with the objects of 173 institutions of university and research institutions, investigation was carried out through visit investigation and questionnaire investigation. Frequency and strength of occurrences was acquired mainly through universities and research institutions which have reported occurrences of accidents to the Ministry of Education, Science, and Technology. Quantitative danger evaluation was conducted through frequency and strength of occurrences. Case study was carried out by selecting bio science laboratory of university and as the result of this study, degree of danger among the inspection objects of bio science laboratories, laboratory work place was evaluated as the most dangerous with the scores of 155.00 and as the result of average danger level, compression gas cylinder was evaluated as the most dangerous with the scores of 6.4000.