• Journal of Ocean Engineering and Technology
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• v.8 no.2
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• pp.38-46
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• 1994

The method of JSME S001-83 and ASTM E813-87 have been adapted for evaluation of the elastic-plastic fracture toughness J sub(IC) of SB41 steel. This SB41 steel have the characteristics of low-stength CT specimens. The test results obtained have been considered and compared on the basis of resulted data from two kinds of methods(JSME S001-83, ASTM E813-87) and two kinds of specimen configurations(smooth, side-grooved). On the basis of results from consideration and comparison, the difficulties for its application were presented in case when the standard ASTM E813-87 method was employed for the measurement of J sub(IC) in SB41 steel. A modified method was applied for measuring J sub(IC) in SB41 steel that it used the blunting line real-measured by experiment instead of the standard blunting line theoretically determined, and the result from that procedure was analyzed and the usefulness of that method was examined and considered.

• Tribology and Lubricants
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• v.34 no.6
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• pp.300-306
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• 2018

In this study, the performance of foil thrust bearings was investigated by performing bearing take-off and load capacity tests, using an in-house designed and manufactured vertical bearing test rig. The mean take-off rotational speed and maximum load capacity of the bearing specimen were ~18,000 rpm and ~80 kPa, respectively. The vertical bearing test rig was observed to yield higher coefficients of friction and frictional torques than a horizontal bearing test rig under identical test conditions. This was a result of its structural characteristics, in that the bearing specimen is placed atop the thrust runner, which keeps it from being separated from the runner after the bearing take-off. In addition, bearing take-off was observed at a higher runner rotational speed as this structure keeps air from flowing between the top foil and runner surfaces, which requires a higher runner speed. The parallel alignment between the bearing specimen and runner surfaces can be maintained within a certain range more easily in a vertical test rig than in a horizontal test rig. Because of these advantages, Korean Industrial Standard, KS B 2060, recommends a vertical bearing test rig as the standard test device for foil thrust bearings.

• Corrosion Science and Technology
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• v.8 no.5
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• pp.193-196
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• 2009

For the estimation of uncertainty in potentiodynamic polarization resistance measurement, the type A uncertainty was measured using type 316 stainless steel in an acidified NaCl solution. Sensitivity coefficients were determined for measurand such as scan rate of potential, temperature of solution, concentration of NaCl, concentration of HCl, surface roughness of specimen and flow rate of purging gas. Sensitivity coefficients were large for the measurand such as the scan rate of potential, temperature of solution and roughness of specimen. However, the sensitivity coefficients were not the major factors influencing the combined standard uncertainty of polarization resistance due to the low values of uncertainty in measurements of the measurands. A major influencing factor was the concentration of NaCl. The value of type A uncertainty was 1.1 times the value of type B uncertainty, and the combined standard uncertainty was 10.5 % of the average value of polarization resistance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.97-100
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• 2004

In-place curing box for specimens is used to cure the compressive strength specimens for control in place concrete. The box if composed of insulating chamber maintaining 20$\pm$3$^{\circ}C$ of temperature, in this paper, strength and temperature history of specimens cured at in plate curing box are investigated to verify field applicability. According to test results, air temperature at measured time shows large temperature variation and below zero, whereas, inside temperature of in place curing box maintains within 20$\pm$3$^{\circ}C$ due to temperature control function. For curing condition. temperature of specimens cured at outside shows large temperature deviation. specimens lured at in-place curing box is not affected by outer temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.379-382
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• 2002

Among the CMM calibration techniques, the calibration with standard specimen is most accurate way to acquire the required precision. When there is no standard specimen, the calibration of CMM with itself is possible. This calibration method is called "self-calibration". In this paper, we developed self-calibration algorithm for CMM XY plane. It is possible to calculate the in-plane error and out-of-plane error of CMM with 3 different measurement of same artifact. Experimental result shows that the non-orthogonality error is dominant in in-plane error and the self-calibration result and laser interferometer measured result have almost same value.ame value.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.174-177
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• 2006

To restore an earthquake damaged community as quickly as possible, well-prepared reconstruction strategy is most essential. This paper reports experimental data on the seismic capacity of diagonal reinforced HPFRCC coupling beams with the Japanese Standard for Seismic Evaluation of Existing RC Buildings. Precast Based on the experimental results, HPFRCC specimen have more residual seismic capacity than RC specimen, but much study is necessary to improve the accuracy of the damage evaluation.

• Transactions of Materials Processing
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• v.19 no.8
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• pp.494-501
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• 2010

The main objective of this study is to examine the sensitivity of calibration curves of FEA of ring compression test to frictional shear factor. Ring compression test has been investigated by measuring dimensional changes at different positions of ring specimen and they include the changes in internal diameter at the middle and top section of the specimen, outer diameter at the middle and top section, surface expansion at the top surface, respectively. Initial ring geometries employed in analysis maintain a fixed ratio of 6 : 3 : 2, i.e. outer diameter : inner diameter : thickness of the ring specimen, which is generally known as 'standard' specimen. A rigid plastic material for different work-hardening characteristics has been modeled for simulations using rigid-plastic finite element code. Analyses have been performed within a definite range of friction as well as over whole range of friction to show different sensitivities to the interfacial friction for different ranges of friction. The results of investigation in this study have been summarized in terms of a dimensionless gradient. It has been known from the results that the dimensional changes at different positions of ring specimen show different linearity and sensitivity to the frictional condition on the contact surface.

• Steel and Composite Structures
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• v.15 no.6
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• pp.659-677
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• 2013

This paper introduces new specimens of Steel-Carbon Fibre Reinforced Polymer composite developed in accordance with standard test method and definition for mechanical testing of steel (ASTM-A370). The main purpose of this research is to study the behaviour of steel-CFRP composite specimen under uniaxial tension to use it in beams in lieu of traditional steel bar reinforcement. Eighteen specimens were prepared and divided into six groups, depending upon the number of the layers of CFRP. Uniaxial tensile tests were conducted to determine yield strength and ultimate strength of specimens. Test results showed that the stress-strain curve of the composite specimen was bilinear prior to the fracture of CFRP laminate. The tested composite specimens displayed a large difference in strength with remarkable ductility. The ultimate load for Steel-Carbon Fibre Reinforced Polymer composite specimens was found using the model proposed by Wu et al. (2010) and nonlinear FE analysis. The ultimate loads obtained from FE analysis are found to be in good agreement with experimental ones. However, ultimate loads obtained applying Wu model are significantly different from experimental/FE ones. This suggested modification of Wu model. Modified Wu's model which gives a better estimate for the ultimate load of Steel-Carbon Fibre Reinforced Polymer (SCFRP) composite specimen is presented in this paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.4
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• pp.352-361
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• 2004

One important element of the Leak-Before-Break analysis of nuclear piping is how to determine relevant fracture toughness (or the J-resistance curve) for nonlinear fracture mechanics analysis. The practice to use fracture toughness from a standard C(T) specimen is known to often give conservative estimates of toughness. To improve the accuracy, this paper proposes a new method to determine fracture toughness using a nonstandard testing specimen, curved wide-plate in tension. To show validity of the proposed curved wide-plate test, the J-resistance curve from the full-scale pipe test is compared with that from the curved wide-plate test and that from the C(T) specimen. It is shown that the J-resistance curve form the curved wide-plate tension test is similar to, but that from the C(T) specimen is lower than, the J-resistance curve from the full-scale pipe test. Further validation is performed by investigating crack-tip constraint conditions via detailed 3-D FE analyses, which shows that the crack-tip constraint condition in the curved wide-plate tension specimen is indeed similar to that in the full-scale pipe under bending.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.3
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• pp.43-53
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• 2019

It is well-known fact that the stone-mastic asphalt (SMA) mixture has shown superior rut resistance, compared with the dense-graded asphalt (DGA) mixture in highway pavements. However, the SMA is measured to be inferior to DGA mixes when tested by well-known high-temperature test methods, such as the wheel tracking (WT), asphalt pavement analyzer, the Marshall Stability and Kim Test. Therefore, this study examined the reasons why it was measured to be inferior, and devised a potential procedure by which the superiority of SMA could be measured at $60^{\circ}C$. The strength against deformation ($S_D$), which was known to show very high correlation with WT results for DGA mixes, was measured by the Kim Test on the specimen confined in the compacted mold. In standard Kim Test, which used the specimen without confinement, the DGA was measured to show higher $S_D$ than the SMA. But by confining specimen, it was found that the $S_D$ of SMA was measured to be higher than that of DGA. Therefore, the confined static test protocol devised in this study was found to be feasible for evaluating rut resistance of SMA mix.