• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.4
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• pp.51-57
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• 1990

There exist residual stresses and deformations in welded structures because of nonuniform temperature distribution. The thermal elasto-plastic analysis is necessary to describe the behavor of the structure during welding. In this paper, we calculated the residual stresses and deformations of the welded beam using the I-dimensional layered beam theory. In the previous 1-dimensional analyses, there were restrictions that the equilibrium conditions which were effective only on beams with infinite length were used, and the boundary conditions could not be considered adequately. But, the layered beam theory based on the incremental finite element method, can overcome these restrictions. On the other hand, in the 2-dimensional analysis, the computing time is large because of many degrees of freedom, and there was inaccuracy in the calculation of welding deformations. However, the layered beam theory can take into account the variation of properties along the depth, and can reduce the degrees of freedom considerably in comparision with the 2-dimensional analysis, and shows good agreement with the experiments.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.1
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• pp.68-76
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• 1997

The welding-induced initial imperfections such as residual stresses and initial strains in plated structures of ships and offshore structures can be effectively evaluated by the thermal elasto-plastic analysis method proposed in this paper. In the analysis of heat conduction of plate structures, both the analytical method and the numerical method are used. For the thermal elasto-plastic analysis of plates, the finite element analysis is performed, based on the initial strain method. In the plastic domain during incremental process, the 2nd order terms of stress increments and yield stress increments were considered, so that time increment could be controlled for more stable solution. To measure temperature distribution and angular distortion of plates during welding, bead-on-plate experiment are perform with various heat input and plate thickness. Measured data show good agreement with the calculated results.

• Journal of the Society of Disaster Information
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• v.11 no.4
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• pp.520-526
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• 2015

Reinforcing bar splices are inevitable in reinforced concrete structure. In these days, there are three main types of splices used in reinforced concrete construction site - lapped splice, mechanical splice and welded splice. Low cost, practicality in construction site, less time consuming and high performance make gas pressure welding become a favorable splice method. However, reinforcing bar splice experiences thermal loading history during the welding procedure. This may lead to the presence of residual stress in the vicinity of the splice which affects the fatigue life of the reinforcing bar. Therefore, residual stress analysis and tensile test of the gas pressure welded splice are carried out in order to verify the load bearing capacity of the gas pressure welded splice. The reinforcing bar used in this work is SD400, which is manufactured in accordance with KS D 3504. The results show that the residual stresses in welded splice is relatively small, thus not affecting the performance of the reinforcing bar. Moreover, the strength of the gas pressure welded splice is high enough for the development of yielding in the bar. As such, the reinforcing bar with gas pressure welded splice has enough capacity to behave as continuous bar.