• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.260-262
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• 2007

In nuclear power plants, residual stress of dissimilar metal weld propagates cracks in the weld metal which is susceptible to stress corrosion cracking. Overlay welding is a process widely used to mitigate residual stress replacing inside tensile stress by compressing stress. The purpose of this paper is to predict the effect of weld overlay by finite element analysis.

• Journal of the Korean Data and Information Science Society
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• 제16권1호
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• pp.13-18
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• 2005

We explore the structure and usefulness of the 3-D residual plot as a basic tool for dealing with interaction in generalized linear models. If predictors have an interaction effect, the shape obtained by rotating the 3-D residual plot will show its presence. To illustrate the use of this plot as an aid to exploring the interaction, we present an example of a binomial regression model using simulated data.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.46-49
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• 1994

In order to investigate possibility of CV cable diagnosis technique, residual insulation characteristics of .long - term serviced 0.6 kV CV Cable are examined by DC leakage current residual voltage tensile strength, cross1inking density and AC & impulse breakdown. Also effect of cable structure and water tree are reported

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.60-64
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• 2008

According to previous research, welding-induced stress in steel structures can significantly affect the fatigue behaviour; it produces initial damage of weldiug part of structure locally and residual stresses reduce the fatigue strength after welding precess. In this study, through continuum damage mechanics, we can estimate the weldiug damage using the stress and strain history during welding process and the effect of welding residual stress for assessment of fatigue life. The variation of welding-induced stresses and strains need be traced precisely in advance for a reliable weldiug damage assessment. In this study, a damage and fatigue analysis techniques for steel structures with welding-induced residual stress are presented. First, We calculate the history of temperature according with welding process. And residual stress with a welding thermal history was evaluated by non-linear thermal stress analysis. Secondly, welding damage and fatigue life are estimated with kinetic damage law.

• 대한기계학회논문집
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• 제18권3호
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• pp.600-611
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• 1994

The purpose of this research is to propose a model for the prediction of residual strength. For this purpose, two-paremeter model based on Caprino's is developed and formulated by the ratio of indentation due to impact and normalized residual strength. The damage zone is considered only as an indentation. Impact tests are carried out on laminated composites by steel balls. Test material is carbon/epoxy laminate. The specimens are composed of $[{\pm}45^{\circ}/0^{\circ}/90^{\circ}]_2$ and $[\pm}45^{\circ}]_4$ stacking sequence and have $0.75^T{\times}0.26^W{\times}100^L(mm) dimension. A proposed model shows a good correlation with the experimental results And failure mechanism due to high impact velocity is discussed on CFRP laminates to examine the initiation and development of damage by fractography and ultrasonic image ststem. The effect of the unidirectional ply position on the residual strength is considered here.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.512-521
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• 1997

This paper deals with an evaluation of the residual stress due to shot peening induced in a car¬burized gear tooth and its application to the fatigue crack propagation problem. The residual stress is estimated based on the assumption that the main cause of residual stress is the volume difference between the case and core due to martensitic transformation in cooling, and the influ¬ence of both the reduction of retained austenite and the strain in the surface layer induced by shot peening are considered. The reliability of the method is examined by comparison with stresses measured by the X-ray diffraction method. The stresses intensity factors are computed by the influence function method and the reduction of the factor due to the residual stress is demonstrat¬ed and discussed based on the fracture mechanics.

• Journal of Welding and Joining
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• 제21권1호
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• pp.80-86
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• 2003

This study develops a system for effective prediction of residual stresses by the backpropagation algorithm using the neural network. To achieve this goal, a series of experiments were carried out to and measured the residual stresses using the sectional method. With the experimental results, the optional control algorithms using a neural network could be developed in order to reduce the effect of the external disturbances during GMA welding processes. Then the results obtained from this study were compared between the measured and calculated results, weld guality might be controlled by the neural network based on backpropagation algorithm.. This system can not only help to understand the interaction between the process parameters and residual stress, but also improve the quantity control for welded structures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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• pp.237-239
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• 2006

The residual flux(${\psi}_r$) in transformer's iron cores cause the distortion of short-circuit current occasionally. And some considerable distortion effect on the validation of test results. To prevent this situation, there needs some suitable control of residual flux through the pretest. This paper deals with the how to control the residual flux in pretest and the comparison between the two test results which were obtained by different test method.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.657-660
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• 2002

In this paper, a study on the residual stress of plate with longitudinal stiffeners is explained in terms of the welding sequences. In order to verify the results of numerical analysis, the hole drilling method (HDM) is performed, to measuring the residual stresses of the test plates in $CO_2$ Flux Cored Arc Welding (FCAW) under various welding conditions. The non-linear transient analysis technique for the numerical analysis in a large and complicate structure is considered. The residual stress of plate in consideration of the welding sequences and directions is evaluated by some numerical simulations and also by experiments. Comparison of numerical analysis results with experimental data shows the accuracy and validity of the proposed method.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년 추계학술발표대회 개요집
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• pp.15-17
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• 2006

Weld residual stresses can be a major concern in structural integrity assessments such as a nuclear power plant. In this paper, detailed weld residual stress analyses were presented for a typical multi-pass weld of pipe-butt weld and plate T-butt weld. The calculated residual stress distributions were compared with those of the measured data and recommended profiles in R6 and BS7910. Defect assessment which is based on the stress intensity factor(SIF) calculations was carried out for a plate T-butt weld with cracks considering the weld residual stress distributions.