• Journal of Ocean Engineering and Technology
• /
• v.14 no.2
• /
• pp.99-105
• /
• 2000

This paper describes the effect of specimen size on fatigue crack growth rate for the offshore structural high-tensile-strength steel BS4360 and machine structural steel SM45C. The purpose of the present study is to investigate the effect of stress ratio aspect ratio specimen width and specimen thickness of the fatigue crack growth behavior. Compact tension specimens with a LT orientation for BS4360 and SM45C steels were used, All testing was done at constant stress intensity factor range controlled fatigue crack growth condition. The investigation demonstrates that the fatigue crack growth rate is increased with increasing stress ratio and specimen thickness and is decreased with increasing specimen width. The fatigue crack growth rate is unaffected by aspect ratio until a/W=0.50 but is increased by increasing spect ratio from a/W=0.55.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.1
• /
• pp.60-67
• /
• 2015

In order to evaluate the bond performance of domestic larch glulam and the glass fiber reinforced plastic (GFRP) rod, the specimen with the GFRP rod bonded-in domestic larch glulam for pull-out test was produced. The test was carried out using various specimens with different gluing depth, width of glue-line and type of adhesive. The cantilever type rahmen structure specimen with bonded-in GFRP rods was produced based on the result of pull-out test, and its moment resistance performance was compared and examined with the moment resistance performance of slotted-in steel plate specimen. As a result of the pull-out test, the most excellent bond performance was found when the insertion depth of GFRP rods was 5 times larger than the diameter of GFRP rods. When the glue-line thickness was 1 mm, the bond performance improved by 17%~29% in comparison to the bond performance in the case of the glue-line thickness of 2 mm. Also, the bonded strength of the specimen used with poly-urethane adhesive was 2.9~4.0 times greater than the bonded strength of specimen used with resorcinol adhesive. The cantilever type rahmen structure specimen with bonded-in GFRP rods showed the moment resistance performance 0.82 times lower in comparison to the slotted-in steel plate specimen used with the drift pin, but the initial stiffness was similar as 0.93 times.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.9
• /
• pp.903-909
• /
• 2007

A fatigue capsule is one of the special capsules to investigate the fatigue characteristics of the nuclear materials during an irradiation test in a research reactor, HANARO. In this study, the performance test and the preliminary fatigue test results by using a cyclic load device newly developed for a fatigue capsule are described. In order to obtain the characteristics such as a realization and a controllability of the periodic wave shape and the relationship between the pressure and the load, a spring and rigid bar specimens are used. The fatigue test for the 316L stainless steel specimen with 1.8mm in diameter and 12.5mm in gage length is also performed under the same conditions as the temperature($550^{\circ}C$) of the specimen during irradiation tests. As a result of the test, the fracture of the specimen occurs at a total of 70,120 cycles(about 12 days), and the displacement in this case is 2.02 mm. It is expected that these results will be used for determining test conditions and a comparison of the in-pile fatigue test results.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.993-996
• /
• 2008

It has been reported that destruction test by core collection is the most reliable of the structural concrete strength in present building construction field. But it causes low efficiency by damage and cutting in structure due to the core collection. It also has some problems in repairing. Additionally in case of strength test with management specimen, different environment compared to the structure environment cause problems about estimation precise structure strength. Therefore, it is required to develop structure direct strength test that has test values and credibility above the ones obtained by core specimen collection strength test and seasonal specimen test to suggest a reasonable and practical management method of structural concrete.

• Journal of the Korean Society of Safety
• /
• v.25 no.6
• /
• pp.146-154
• /
• 2010

In this study the experimental results of fatigue specimen for the Strand Stay Cable Assembly of Extadosed bridges is investigated. The fatigue test and tensile experiment is conducted to 6 kinds of specimens. Test specimen OVM250-31 Strand Cable System manufactured by china OVM B-Machinery Co., Ltd, and OVM250-42 Parallel Strand Stay Cable Assembly manufactured by china OVM B-Machinery Co., Ltd, are passed for fatigue test and rupture tensile test. But Test specimen OVM250-42 Parallel Strand Stay Cable Assembly manufactured by korean A-Machinery Co., Ltd, is not passed for fatigue test conducted according to the "Recommendation for Stay Cable Design. The test result are compared to the fatigue criteria of PHI 2001 for cyclic load, and it is concluded that the current korean design code will be needed for representing the fatigue load in Hot Dip Galvanized Strand Stay Cable. It is verified that the new korean specification and quality criteria of Strand Stay Cable and exact experimental applied process will be needed.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.18 no.1
• /
• pp.153-157
• /
• 2014

Purpose: SLE (systemic lupus erythematosus) is an inflammatory autoimmune disease, characterized by various autoantibody. The detection of Anti double-stranded DNA (Anti-ds DNA) is important in the diagnostics of SLE, and include the American College of Rheumatology (ACR) diagnostic criteria for SLE. Also SLE disease activity and correlativity with the level Anti-ds DNA antibody have been reported and Anti-ds DNA antibody quantitative test is very useful for tracing before and after SLE treatment. When These Anti-ds DNA antibody test (Farr assay: $^{125}I$ labeled ds-DNA and bound Anti-ds DNA antibodies complex in serum is precipitated by ammonium sulfate and used to centrifugation, measured it) inhaled supernatant after centrifugation, a lipemic specimen does not facilitate the formation of precipitate and also occurs situation was inhaled with precipitate. To solve these problems, The Influence of the degree of lipemic specimen was evaluated. Materials and Methods: September 2012 to February 2013, We selected lipemic samples (n=81) of specimen commissioned by Anti-ds DNA antibody test. Lipemic samples were done pre-treatment (high-speed centrifugation: 14,000 rpm 5 mins) used a micro-centrifuge (Eppendorf Model 5415D). At the same time lipemic specimen and pre-treatment samples were performed Anti-ds DNA antibody test (Anti-ds DNA kit, Trinity Biotech, Ireland). Statistical analysis were analyzed Pearson's correlation coefficients and regression and paired t-test, and Difference (%). Results: Experimental group 1 (Lipemic Specimen Anti-ds DNA Ab concentration ${\leq}7IU/mL$) at y=0.368X+4.732, $R^2=0.023$, Pearson's correlation coefficient was 0.154, paired t-test (P=0.003), Difference (%) mean 65.7 and showed a statistically significant difference. Experimental group 2 (Lipemic Specimen Anti-ds DNA Ab concentration ${\geq}8IU/mL$) at y=0.983X+0.298, $R^2=0.994$, Pearson's correlation coefficient showed 0.997, paired t-test (P=0.181), Difference (%) mean -5.53 made no statistically significant difference. Conclusion: Lipemic sample of low Anti-ds DNA Ab concentration (2.5-7 IU/mL) and the result is obtained pre-treatment (high-speed centrifugation: 14,000 rpm 5 mins) were made a significant difference statistically. Anti-ds DNA is one of the primary auto-antibodies present in patients with SLE, and remain an important diagnostic test for SLE. Therefore, we recommend preprocessing (high-speed centrifugation: 14,000 rpm 5 mins) in order to exclude the influence of lipemic specimen.

• Structural Engineering and Mechanics
• /
• v.62 no.1
• /
• pp.97-106
• /
• 2017

This paper discusses an experimental programme that was carried out to study the effects of specimen size-shape and type of moulds on the compressive strength of concrete. For this purpose, cube specimens with 150 mm dimensions, cylinder specimens with $150{\times}300mm$ dimensions, and prism specimens with $150{\times}150{\times}375mm$ dimensions were prepared. The experimental programme was carried out with several concrete compositions belonging to strength classes C20/25, C25/30, C30/37, C40/50 and C60/75. Furthermore, the test results were curve-fitted using the least squares method to obtain the new parameters for the modified size effect law.

• Korean Journal of Agricultural Science
• /
• v.35 no.1
• /
• pp.19-24
• /
• 2008

A new compressive strength test specimen for linerboard and medium was developed, and tested for its agreement with conventional testing methods such as RCT and STFI. The new specimen enables compressive testing under the changing humidity and temperature. Experimental results showed that the new specimen gave equivalent compressive strengths as the other conventional methods at a constant temperature and humidity. We'll apply the methods under the cyclic humidity and temperature conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.6 s.261
• /
• pp.644-650
• /
• 2007

Mechanical property evaluation of micrometer-sized structures is necessary to help design reliable microelectromechanical systems(MEMS) devices. Most material properties are known to exhibit dependence on specimen size and such properties of microscale structures are not well characterized. This paper describes techniques developed for tensile testing of thin film used in MEMS. Epi-polycrystalline silicon is currently the most widely used material, and its tensile strength has been measured as 1.52GPa. We have developed a tensile testing machine for testing microscale specimen using electro-magnetic actuator. The field magnet and the moving coil taken from an audio-speaker were utilized as the components of the actuator. Structure of specimen was designed and manufactured for easy handling and alignment. In addition to the static tensile tests, it is described that new techniques and procedures can be adopted for high cycle fatigue test of a thin film.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.1
• /
• pp.139-145
• /
• 2000

In this experimental program specimens. designed by the test variables, such as percentage of steel fiber incorporated, were constructed and tested to evaluate the flexural performance of reinforced steel fiber concrete beams. Based on the test results reported in this study, the following conclusions are made. Comparing with the load-displacement relationship of standard specimen, specimen over 0.5% of steel fiber incorporated, could be improved significantly flexural performance, such as capacity, ductility, and crack pattern. As increasing in quantity of steel fiber incorporated(0.5%~2.0%), the flexural strength of each specimen was shown the enhancement of 13%~40% in comparision with the standard specimen BSS.