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Lee, Sang-rae;Kim, Jae-hwan;Kim, Jae-hoon
- Journal of the Korean Society of Propulsion Engineers
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- v.23 no.2
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- pp.111-117
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- 2019
An experimental study on the welding part of a heat transfer plate that constitutes the lightweight and high efficiency recuperator is presented in this paper. In particular, to find out the service life of the welded part, fatigue characteristics were determined through experiments. Experiments were carried out on two materials (STS347, AL20-25 + nb), which are selected as the material of the recuperator; further, the specimens were manufactured through the methods used for actual fabrication and the standards recommended by ASTM. To evaluate the mechanical properties of the specimens at room and high temperature, MTS-810 was used in a high-temperature furnace. The tensile test was carried out at room and high temperatures for each specimen. The fatigue test was carried out by setting the load ratio corresponding to 50%, 40%, 30%, 20%, and 10% of the tensile strength at the stress ratio of 0.1. Finally, the fatigue life characteristics obtained by the experiment were compared with the stresses owing to the load generated in the operating conditions of the recuperator, and the lifetime of the welds was evaluated to prepare for the operation time required by the UAV.
https://doi.org/10.6108/KSPE.2019.23.2.111 인용 PDF KSCI

Park, Chi-Yong;Lee, Kyoung-Soo;Kim, Maan-Won;Song, Ki-Oh
- Transactions of the Korean Society of Mechanical Engineers A
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- v.34 no.9
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- pp.1311-1316
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- 2010
In this study, straight slot welding was carried out using a 316L stainless steel test block, and numerical simulation of the slot weld process was performed using finite element analysis. Data on the residual stress were obtained at equally spaced points on the top surface of the test block along directions parallel and perpendicular to the welding direction. After electrolytic polishing of the top surface of the block, the residual stress was measured by the X-ray diffraction method. The calculated weld residual stresses were compared with the measured data, and they were in good agreement with the data. The weld residual stress distribution inside the plate was determined from the results of finite element analysis, and the characteristics of the distribution were discussed in detail in this paper.
https://doi.org/10.3795/KSME-A.2010.34.9.1311 인용 PDF KSCI

Lee, Young Hak;Seo, Sang Hoon;Kim, Min Sook;Kim, Hee Cheul;Lee, Sung Min
- Journal of Korean Society of Steel Construction
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- v.20 no.5
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- pp.601-608
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- 2008
Joints of single-layer latticed domes show various flexural behaviors according to their shapes and connecting methods. Ball joints are relatively easy to apply and build while their rigidities are relatively small and have disadvantage in long span. Welded joints have many advantages in rigidity, internal force and long span. However few experimental studies have been performed. In this paper, improved welded joint for the single layer latticed domes was proposed through both analytical and experimental analyses. Length of inserted plates, thickness of inserted plates and hole of sub steel pipes were selected as parameters for experimental comparisons and defining the effects of the selected variables.
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