• Tunnel and Underground Space
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• v.23 no.5
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• pp.362-371
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• 2013

We conducted hollow cylinder tensile strength tests and Brazilian tests in Seokmo granite to measure tensile strength necessary for estimating the magnitude of the maximum horizontal principal stress in hydraulic fracturing stress measurements. Two different pressurization rates were used in hollow cylinder tests. Tensile strengths were determined to be higher at higher pressurization rate, which suggests that tensile strength should be measurement at the same rate used in actual in situ hydraulic fracturing tests. Considering the effect of pressurization rate and specimen size on tensile strength, the hollow cylinder tests and Brazilian tests yield similar results each other. This demonstrates that Brazilian tests can be utilized to produce representative tensile strengths for interpretation of hydraulic fracturing test results.

• Tunnel and Underground Space
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• v.13 no.3
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• pp.180-186
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• 2003

The fracture processes under dynamic loading in tension were simulated using a proposed numerical approach and analyzed to determine dynamic tensile strength. The dynamic tensile strength and the scatter of the strength data decreased with increasing uniformity coefficients. The differences of static and dynamic tensile strength were due to the stress concentrations and redistribution mechanisms in the rock specimen. Although there were different mechanisms for the static and dynamic fracture processes, the static and dynamic tensile strengths were close to the mean microscopic tensile strength at high values of the uniformity coefficient. This paper shows that the rock inhomogeneity has an effect on dynamic tensile strength and is a factor that contributes to the different specimen strengths under dynamic and static loading conditions.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.419-428
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• 2020

This study was intended to academically redefine the art of seal engraving of the Joseon Dynasty through seal analysis related to Kim Jeong-hui and to widely promote its excellence. Previous studies on seals were examined, and comparative studies were conducted focusing on the seals engraved by Kim Jeong-hui and the related seals. The importance of the real seal study, not the stamp, was confirmed. If there was a byeongwan on the side of the seal, it was possible to understand that Kim Jeong-hui directly carved the seal. Also, it was possible to confirm the stone quality of the seal, the method of writing, the method of layout, and the method of holding graver. The imitation seal engraved with a tool rather than hand made it easy to grasp the uncertain production intent. All were analyzed by actual tensile, so it was a possible study result. The results of this study will serve as an indicator to judge the authenticity of the seal when evaluating an ancient painting in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4A
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• pp.303-309
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• 2011

Laminated rubber bearing is the most commonly used device for seismic base isolation of bridge structures. It is important to know performance and behavior characteristics of the laminated rubber bearings. The main evaluation factors of the rubber bearing are classified as compressive, shear and tensile behavior characteristics. The reference data of compressive and shear characteristics are rich, but the reference data of tensile characteristics is scarce. In this study, tensile test results of the rubber bearing with variation of shape factor and shear deformation are investigated for mechanical property. When tensile deformation in normal condition is increasing, tensile cycle behavior curve becomes non-linear and tensile breaking point is 300%. On the other hand, tensile breaking point is shear deformation condition is about 40%. Furthermore, when shape factor is lower, tensile breaking point is decrease. This results mean that tensile breaking point is decreased in triaxial tensile deformation because of cracks caused by internal void of the rubber bearings. This experimental data can be used as the reference data of tensile characteristics for designing seismic isolation of structures.

• Journal of the Korean Geotechnical Society
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• v.31 no.3
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• pp.5-16
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• 2015

The characteristics of tensile strength of fiber-reinforced grouting (cement paste) injected into rocks or soils were studied. A tensile strength of such materials utilized in civil engineering has been commonly tested by an indirect splitting tensile test (Brazilian test). In this study, a direct tensile testing method was developed with built-in cylinder inside a cylindrical specimen with 15 cm in diameter and 30 cm in height. The testing specimen was prepared with 0%, 0.5%, or 1% (by weight) of a PVA or steel fiber reinforced mortar. A specimen with 5 cm in diameter and 10 cm in height was also prepared and tested for the splitting tensile test. Each specimen was air cured for 7 days or 28 days before testing. The tensile strength of built-in cylinder test showed 96%-290% higher than that of splitting tensile test. The 3D finite element analyses on these tensile tests showed that the tensile strength from built-in cylinder test had was 3 times higher than that of splitting tensile test. It is similar to experimental result. As an amount of fiber increased from 0% to 1%, its tensile strength increased by 119%-190% or 23%-131% for 7 days or 28 days-cured specimens, respectively. As a curing period increased from 7 days to 28 days, its strength decreased. Most specimens reinforced with PVA fiber showed tensile strength 14%-38% higher than that of steel fiber reinforced specimens.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.133-141
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• 2002

Isotropic rock and anisotropic rock have different tensile strength which has the greatest influence on rock failure. In this study, elastic modulus of anisotropic rock is obtained through uniaxial compression test, and tensile strength and tension failure behavior are analyzed through indirect tensile strength test. Stress concentration factor of a specimen at the center is obtained from anisotropic elastic modulus and strain by indirect tensile strength test. Theoretical solutions for tensile strength of isotropic and anisotropic rock are compared. Stress concentration factor of anisotropic rock is either higher or lower than isotropic rock depending on the inclination angle of bedding plane. The use of stress concentration factor of isotropic rock resulted in overestimation or underestimation of tensile strength.

• Journal of Sericultural and Entomological Science
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• v.14 no.2
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• pp.105-112
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• 1972

The effects of the stretching speed and the swelling degree of cocoon filaments on load-elongation curve were tested by tensilon with special attachments. The values of breaking strength, elongation at break and initial tensile strength obtained from load elongation curves are summarized as follows; 1. The breaking strength of the swollen cocoon filament appeared to increase at the high stretching speed, while elongation at break decreased. 2. Load-elongation curve became crinkled at the low speed of stretching. It suggests that both slip and break of the macrofibrils may occur in swelling of cocoon bave. 3. Breaking strength appeared to considerably decrease and elongation at break not to increase in swelling test at 9$0^{\circ}C$ for 60 min. 4. The initial tensile strength was influenced by the stretching speed and swelling degree of cocoon filaments.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.433-436
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• 2008

In order to estimate the mechanical properties of ultra high performance concrete, the most important is to evaluate its tensile behavior. The tensile behavior of concrete is generally characterized by the elastic behaviour before cracking and tensile stress-crack width relationship after cracking. We carried out the direct tensile and flexural tensile test and compared the tensile behaviors obtained by the direct tensile test and by inverse analysis of the flexural tensile test results. We compared the obtained tensile behavior with that of JSCE recommendations for ultra high performance concrete as well. we could see that the tensile stress-crack width relationship obtained from the flexural tensile test results using inverse analysis had good agreement with directly obtained tensile behaviour with direct tensile test and showed similar tensile softening behaviour introduced in JSCE recommendations for ultra high performance concrete.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1505-1516
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• 2014

In this study, a cylinder embedded within cemented soils was used to cause directly tensile failure of cemented soils. An existing dumbbell type direct tensile test and a split tensile test that is most general indirect tensile test were also carried out to verify the developed built-in cylinder tensile test. Testing specimens with two different sand/cement ratios (1:1 and 3:1) and two curing periods (7 and 28 days) were prepared and tested. Total 10 specimens were prepared for each case and their average value was evaluated. Unconfined compression tests were also carried out and the ratio of compressive strength and tensile strength was evaluated. The tensile strength determined by built-in cylinder tensile test was slightly higher than that by dumbbell type direct tensile test. The dumbbell type test has often failed in joint part of specimen and showed some difficulty to prepare a specimen. Among three tensile testing methods, the standard deviation of tensile strength by split tensile test was highest. It was shown that the split tensile test is applicable to concrete or rock with elastic failure but not for cemented soils having lower strength.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.715-724
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• 2011

A turn buckle inserted between tension members that sustain the structural loads in a suspension structure system is a device that is capable of adjusting the tensile force. The tension member is an important element of a tension structure, but no simple and economical method of measuring a tensile force applied to members has been proposed yet. Thus, a turn buckle for measuring the tensile force in a tension member was developed in this study. The turn buckles of the measurement limit loads of 100kN, 200kN, and 300kN were tested through a theoretical analysis and a finite element analysis. There was no significant difference in the results of the theoretical analysis, FEA, and the test. In addition, the ultimate strength of the turn buckle using FEA showed that a new turn buckle is sufficiently safe to use even when there is a five-times overload in the measurement limit load.