• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.5
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• pp.20-27
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• 1998

According as the member of the automobile body structure have been thinned their thickness and have become high strength, each part of the body structure has been put more severe stress condition. And, because fatigue strength of the spot welded lap joint is influenced by its geometrical and mechanical factors, welding condition and etc., there needs a quantitative and systematic evaluation method for them. In this study, by considering nugget edge of the spot weld part of the IB-type spot welded lap joint under tension-shear load to the ligament crack. fatigue strength of various IB-type spot welded lap joints was estimated with the stress intensity factor(S.I.F.) KIII which is fracture mechanical parameter. We could find that fatigue strength evaluation of the IB-type spot welded lap joints by KIII is more effective than the maximum principal stress ($\sigma$1max) at edge of the spot weld obtained from FEM analysis.

• Journal of Welding and Joining
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• v.11 no.4
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• pp.112-124
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• 1993

It has been reported that fatigue damage sometimes occurred at the stress concentrated and dynamic loaded structural members of bulk carrier. In this paper, studies on fatigue strength of hull structures are reviewed, and the program for evaluating fatigue strength is developed. And the fatigue crack initiation and propagation on the end part of cargo hold frame of bulk carrier were calculated by FEM stress analysis and the fatigue strength evaluation program. These method can be applied not only to the crack initiation life but also to crack propagation life for the hull structural members at the hull design stage and be effective as the guideline to prevent the crack initiation or to estimate the fatigue strength for repairing of the fatigue damaged structures of real ships.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.201-202
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• 2012

Recently, High-Strength steel reinforcement has been studied throughout the internal and external. One of the advantages using High-Strength steel reinforcement in construction is the economic effect due to the decreasing of its quantity. Also, another good effect is the increases of workability by reason of reducing the congestion. But, realistically it is not used in nuclear power plant construction site because of the restriction of design standard. The purpose of this report secures the reliability and changes the code through the performance evaluation test of the wall using the high-strength steel reinforcement in nuclear power plant.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.130-135
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• 1995

We can consider that the study on early evaluation of strength of concrete is useful to raise safety of building and utility of quality control of concrete is useful to raise safety of building and utility of quality control of concrete. In this paper, was proposed to method early to predict strength of concrete with key parameters, such as Water/Cement(W/C) ratio and Sand / Aggregate(S/A) ratio. Through a series of experiment, the obtained results are summarized as follow. $\circled1$ The ratio of resistance was decteased as the increase of W/C ratio. $\circled2$ The maximum value for the ratio of resistance and compressive strength was presented in the case of 40% S/A ratio. $\circled3$ The relationship. of the ratio of resistance and compressive strength on 28days according to the change of W/C and S/A ratio is to be: $F_{28}=-0.00104R^2 + 2.263R - 935.5$ (W/C Ratio) $F_{28} = 0.007R^2 - 10.693R - 4269.1$ (S/A Ratio)

• Journal of Ocean Engineering and Technology
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• v.8 no.1
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• pp.96-104
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• 1994

The use of advanced composite materials has grown in recent years in aerospace and other structures. Out of various kinds of repairing methods the one selecteh for this study is an idealized case which simulates a situation where a damaged laminate has been repaired by drilling a hole and therefter plugging the hole with reinforcement. Two typesof reinforcement are investigated ;adhesively bonged plug reinforcement or snug-fit unbonded plug in the hole. For each case of reinforcement, four different sizes of hole diameter and three types of reinforcing material(steel, aluminum, plexiglass) are employed for investigation. The experiment are mainloy forced on the evaluation of ultimate strength of laminate with reinforced hole in comparison to its counterpart with the open hole.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.337-343
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• 2002

This study deals with evaluation of bending fatigue strength in shaving gears. The saying gears were manufactured by processes that are currently used in most gears manufacturing companies. The test gears are bobbed, then the tooth surface are treated by a combination of shaving, carburizing and shot peening. The constant stress amplitude fatigue test is performed by using an electro-hydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. In this study, the effect of shaving process and shot peening was investigated and evaluated quantitatively on the fatigue strength. The enhancement of fatigue strength due to shaving process and shot peening is clarified.

• 한국기계연구소 소보
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• s.15
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• pp.75-87
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• 1985

A review was performed on fatigue life prediction and strength evaluation of shot peened parts. Fatigue strength of machine parts can be improved by shot peening due to compressive residual stresses on such parts. Compressive residual stress cannot be uniquely define by peening intensity. Several measuring methods of residual stress and the principle of hole drilling method are presented. Exploratory measurement of residual stress was performed on the shot peened SM35C plate with the hole drilling method. Fatigue life and failure location of shot peened parts under bending load can be predicted by a damage parameter which is incorporated with material properties, residual stress, and applied stress conditions. Some method are presented to predict the fatigue strength of shot peened parts at any given life. Shot peening gives its full benefit to the notched machine parts of high strength steels.

• Geomechanics and Engineering
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• v.12 no.6
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• pp.871-882
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• 2017

Indirect measure of the tensile strength of laboratory samples is an important topic in rock engineering. One of the most important tests, the Brazilian strength test is performed to obtain the tensile strength of rock, concrete and other quasi brittle materials. Because the measurements are provided indirectly and the inspected rock materials may have heterogeneous properties, uncertainty quantification is required for a reliable test evaluation. In addition to the conventional measurement evaluation uncertainty methods recommended by the Guide to the Expression of Uncertainty in Measurement (GUM), such as Taylor's and Monte Carlo Methods, a fuzzy set-based approach is also proposed and resulting uncertainties are discussed. The results showed that when a tensile strength measurement is measured by a laboratory test, its uncertainty can also be expressed by one of the methods presented.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.155-161
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• 2007

A bogie frame is typical safty part of railway vehicle. Main performance of a bogie frame is to support a car body and passenger weight and transfer traction and braking force. This paper is to evaluate the static strength and fatigue strength for the end trailer bogie with UIC 615-4 code. Therefore stress analysis of the end trailer bogie frame has been performed for various loading condition according to the UIC 615-4 code and haigh diagram is used for evaluation of fatigue strength. By the results of these analysis, static and fatigue strength of the end trailer bogie is satisfied with a applied criterion.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.162-169
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• 2001

Tubular joints are usually reinforced using thicker can section or ring stiffeners to increase the load carrying capacity. In this paper, a numerical study has been performed for evaluation of axial strength for X-joints with internal ring stiffener, The finite element analysis software was used for nonlinear strength analysis. According to variation of ring geometries, the effect of ring stiffener for X-joints are investigated. Internal ring stiffener is found to be efficient improving ultimate strength of tubular joints. Relations of thickness of ring and axial strength are observed considering geometric parameters of ring stiffeners.