• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.48-53
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• 1997

Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar laserm, a video system and an image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment wpecimen was loaded in parallel with a loadcell. The specimen was the cold rolled sdteel sheet of 2mm thickness, which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.5
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• pp.661-669
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• 2010

The effects of laser peening on metallic materials have been investigated with water-penetrable frequency-doubled Nd:YAG laser. Laser pulses of 200 mJ energy and 8 ns duration focused on samples underwater with 0.8 mm spot diameter. X-ray study showed that compressive residual stress was imparted on SKD61 from the surface to nearly 2 mm depth. Stress corrosion cracking (SCC) was prohibited for sensitized SUS304 even in a severely corrosive environment fatigue lives of SUS316L and SM490A welded samples were prolonged significantly in the high-cycle regime. Since 1999, laser peening has been applied to prevent SCC in operating nuclear power plants in Japan.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.156-164
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• 1999

The body structure of a bus is generally assembled by using various spot welded box sectional members. The shape of window pillar joint is ordinarily built up by T-type member. It has been shown that T-type member has problems like high stress concentrations, low fatigue strength and low structural rigidity. In this study, to solve these problems a new approach to optimize the design of the bus window pillar joint was tried by FEM analysis and experiments. To describe the shape of the gusset connecting the vertical and horizontal members of the T-type window pillar joint B-spline curve was adopted and this curve was optimized . It was found that the new model developed could effectively improve fatigue durability an structural rigidity.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.3
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• pp.162-168
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• 2006

Speckle interferometry with phase-shifting method has been applied to measurement of micro-scale displacement through optical signal processing. Four-step phase-shifting method by PZT is used to measure out-of-plane displacement in spot-welded cantilever and results of optical experiments are comparable to those of FEM. Phase-shifting method using Fourier transform by PZT is applied to measurement of in-plane displacement on rectangular steel plate with a circular hole. The results of optical experiment agree well with theoretical calculation. New phase-shifting method in speckle interferometry has been implemented with a quarter wave plate. In-plane displacement of specimen is measured by the new phase-shifting method. Results of optical experiment show that the quarter wave plate can be used for phase-shifting method that is cheap and easy to use in speckle interferometry.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.655-663
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• 2006

Large-scale model tests of welded tubular K-joints were carried out to observe the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The fatigue crack behaviors for various loading conditions were measured and investigated around the critical joint sections. The experimental results have been verified with numerical approaches and also compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The hot spot strss method was applied in the study. The SCF factor for tubular K-joint was also obtained.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.255-257
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• 2004

This report presents S-N testing results of the butt and T-joint weldment which are produced by single sided welding with cenramic backing material. The specimen is designed in accordance with JISZ 3103 aid the test is peformed by the JSME S002. The nominal and hot spot stress based design S-N curves derived from fatigue tests are compared with the BS design curve. For butt and T-joint, it can be known that the double-sided butt welding process could be replaced by the single sided butt welding.

• Journal of Ocean Engineering and Technology
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• v.19 no.3
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• pp.54-58
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• 2005

Large-scale model tests of welded tubular K-joints were carried out to observe the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The fatigue crack behaviors for various loading conditions were measured and investigated around the critical joint sections. The experimental results have been verified with numerical approaches and were also compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The hot-spot stress method was applied in the study. The SCF factor for tubular K-joint was also obtaine.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.217-222
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• 2006

Large-scale model tests of welded tubular K-joints were carried out to observe the fatigue behavior of API 2W Gr.60 steel produced by POSCO. The fatigue crack behaviors for various loading conditions were measured and investigated around the critical joint sections. The experimental results have been verified with numerical approaches and also compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The hot spot stress method was applied in the study. The SCF factor for tubular K-joint was also obtained.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.52-57
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• 1997

Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar. laser, a video system and an image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or Moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment specimen was loaded in parallel with a loadcell. The specimen was the cold rolled steel sheet of 2mm thickness, which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.147-155
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• 2000

To reduce the noise from wood cutting saw at the saw mill(lumber mill) or a construction area, some multi-layer sandwich saw blades which a aluminum or copper plate was inserted between the two steel plates were developed and were tested of the wood cutting noise level at various test places. From the research, it was found that the multi-layer saw blade with copper or aluminum plate between steel plates and spot welded 60 points could reduce the wood cutting sound level about 8.3 dB(97.031 dB - 88.743 dB) at indoor test and 3.8 dB(84.805 - 81.638 dB) at field test.