• Proceedings of the KWS Conference
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• 2006.10a
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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.

• Geomechanics and Engineering
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• v.7 no.6
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• pp.633-647
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• 2014

Biopolymers, polymers produced by living organisms, are used in various fields (e.g., medical, food, cosmetic, medicine) due to their beneficial properties. Recently, biopolymers have been used for control of soil erosion, stabilization of aggregate, and to enhance drilling. However, the inter-particle behavior of such polymers on soil behavior are poorly understood. In this study, an artificial biopolymer (${\beta}$-1,3/1,6-glucan) was used as an engineered soil additive for Korean residual soil (i.e., hwangtoh). The geotechnical behavior of the Korean residual soil, after treatment with ${\beta}$-1,3/1,6-glucan, were measured through a series of laboratory approaches and then analyzed. As the biopolymer content in soil increased, so did its compactibility, Atterberg limits, plasticity index, swelling index, and shear modulus. However, the treatment had no effect on the compressional stiffness of the residual soil, and the polymer induced bio-clogging of the soil's pore spaces while resulting in a decrease in hydraulic conductivity.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.6
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• pp.494-502
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• 1999

This paper represents an electrostatic micro plate resonator which consists of a rigid plate suspended with four bridges and a counter electrode. The bridges of the resonator are designed corrugated so that the residual stress are released. The FEM simulation results confirmed that the deflection characteristic of the corrugated bridge is hardly affected by the initial residual tensile stress. One resonator with the corrugated bridges and the other with the flat bridges were fabricated by the boron diffusion process and the anisotropic etch process. The vertical deflection of the fabricated electrostatic resonator was measured with a laser vibrometer, and the data were compared with the calculation results. The deflection of the resonator with the flat bridges is smaller than the deflection of that with the corrugated ones because of the residual stress. The residual stress release effect was confirmed by the fact that the measured deflection of the resonator with the corrugated bridges in close to the calculated deflection of the resonator with the flat ones with the initial stress neglected.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.334-339
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• 2003

The welding residual stress has on important effect on welding deformation, fatigue fracture, buckling strength, brittle fracture, etc. For the purpose of relaxation of welding residual stress, post welding heat treatment is widely used. In this paper, residual stresses were calculated by two dimensional thermal elasto-plastic analysis using finite element method. Heat transfer analysis are performed by transient analysis. Also structure analysis are carried out by of thermal-mechanical coupled analysis. Numerical analysis are used by ANSYS 5.7.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.76-82
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• 2000

It is well known that during the oxygen cutting process residual thermal stresses are produced in weldment. The local non-uniform heating and subsequent cooling which takes place during any welding process causes complex thermal strains and stresses to finally lead to residual stresses exceed to the yield stress. High tensile stresses combined with applied structural load in the region near the welded joint can given rise to distortion brittle fracture change of the fatigue strength and stress corrosion cracking. The appropriate treatment of the welded component which reduces the peak of he welding residual stresses is believed to lower risk of the fracture during the service of the structure. In this study the impact loading in oxygen cutting frame was applied to reduce the residual stress. After applying the impact loading redistribution of resid-ual stress was measured by cutting method and the effect of fatigue was tested.

• Steel and Composite Structures
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• v.29 no.2
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• pp.161-173
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• 2018

Point bending is often used for cambering and curving structural steel girders. An analytical solution, applicable in the elasto-plastic range only, that relates applied loads to the desired curve was recently developed for inducing horizontal curves using four-point bending. This solution does not account for initial residual stresses and geometric imperfections built-in hot-rolled sections. This paper presents results from a full-scale test on a hot-rolled steel section curved using four-point bending. In parallel, a numerical analysis, accounting for both initial geometric imperfections and initial residual stresses, was carried out. The models were validated against the experimental results and a good agreement for lateral offset and for strain in the elasto-plastic and post-plastic ranges was achieved. The results show that the effect of initial residual stresses on deformation and strain is minimal. Finally, residual stresses due to cold bending calculated from the numerical analysis were assessed and a revised stress value for the service load design of the curved girder is proposed.

• Journal of the Korean Society for Heat Treatment
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• v.5 no.3
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• pp.157-164
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• 1992

Barkhausen noise (BN) is created by the abrupt changes in the magnetization of materials under applied AC magnetizing field. These changes are known to be sensitive to residual and applied stresses. In this study, BN theory was reviewed and it was examined how BN intensity was affected by simultaneous stress, hardness and microstructural changes. Also, magnetoelastic effect was used to evaluate residual stresses through carrying out the cantilever beam test. An increase in BN intensity was observed when applied and residual stress changes from compression into tension. Microstructural softening by tempering also increased the amount of BN. Therefore, the quantitative evaluation of residual stress and microstructural changes will be possible, provided BN method is more studied about various materials through comparing with different stress measuring techniques.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.110-114
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• 2008

Determination of weld-induced residual stress has been an important issue in nuclear power industry because several failures were reported in dissimilar metal weld parts due to primary water stress corrosion cracking. In this context, a couple of remarkable round robin analyses were conducted to quantify the welding simulation variables and to establish optimized numerical analysis process. The purpose of the present research is to introduce welding simulation results for a safety and relief nozzle, which has a dissimilar metal weld part as well as a similar metal weld part. First, finite element analyses are carried out to calculate residual stresses at the inside of nozzle considering only dissimilar metal welding. Subsequently, residual stresses taking into account both the dissimilar and similar metal welding are computed. The similar metal weld effect is evaluated by compa

• Journal of Welding and Joining
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• v.17 no.4
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• pp.76-84
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• 1999

The residual stress generated when the steel plates were produced, did not influence on the out-of-plane deformation and residual stress generated by welding. When the initial deflection shape was a concave(Type I), the out-of-plane deformation became the same shape as that of the initial deflection and its magnitude became small. When the initial deflection made a winding in the welding direction(Type III), the out-of-plane deformation became large in the plate width. The initial deflection shape did not influence on residual stress and plastic strain produced by welding.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.157-164
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• 2000

It is known that residual aligning torque of tires causes vehicle pull. There is, however, only a little literature available which shows how the residual aligning torque of tires causes vehicle pull. In this paper, a vehicle model in two degrees of freedom was adopted for the analysis of a vehicle under the straight-ahead motion. The analysis with this vehicle model clearly shows the effect of residual aligning torque of tires on vehicle pull. In order to show the validity of the analysis, a vehicle commercially available was selected. This vehicle was modeled in 137 degrees of freedom system with multibody dynamics software. Vehicle pull simulation results show that vehicle model drifts in lateral direction due to the residual aligning torque of tires. Vehicle test results with the car were also included.