• Polymer(Korea)
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• v.38 no.6
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• pp.820-826
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• 2014

The objective of this study is to find the relationship between the tensile strength of the polymer film and the bond strength and tensile strength of the polymer-modified mortar using styrene (St) and butyl acrylate (BA), and porosity. In the test results, the bond strength and tensile strength of the polymer-modified mortar increased with increases in the tensile strength of polymer film and the fine pore volume.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.1-10
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• 1982

Degree of grain shattering which is of varietal character is an important determinant for the magnitude of field loss of grains during harvest and threshing. Seven Indica \times Japonica progeny varieties and four Japonica varieties were subjected to measurements of tensile strength of grains, degree of grain shattering when panicles were dropped at 1.5m above concrete floor, and moisture content of grains (wet basis) during a period 35 to 63 days after heading. In addition, two varieties were tested for the relation of tensile strength of grains to the magnitude of field loss of grains in actual binder harvest. The 11 varieties differed conspicuously in tensile strength of grains and the degree of grain shattering: the weakest average tensile strength of grains of a variety was about 90g and the strongest about 250g with varying standard deviation of 30 to 60g. Three Indica \times Japonica varieties and one Japonica variety shattered I to 30% of the grains under the falling test. The threshold tensile strength of grains allowing grain shattering was estimated to be 180g on average for a sampling unit of 10 panicles, but only the grains having tensile strength weaker than 98g within the samples shattered. A decrease in average tensile strength by 10g below the threshold value corresponded to an increase of 3 to 5% in grain shattering. Most varieties did not change appreciably the tensile strength of grains and degree of grain shattering with delay in time of harvest and showed a negative correlation between the tensile strength and the moisture content of grains. The average tensile strength of grains was negatively correlated linearly with field loss in binder harvest. The average tensile strength for zero field loss in binder harvest was estimated to be 174g and a decrease in the average tensile strength by 10g corresponded to an increase of 40kg per hectare in field loss of grains. Instead of the average tensile strength of grains, the percentage of grains having tensile strength weaker than 100g is recommended as a criterion for the estimation of field loss of grains during harvesting operations as well as a basis of variety classification for grain shattering, since the standard deviation of tensile strength of grains varies much with variety and time of harvest, and individual grains having tensile strength stronger than 98 did not shatter practically.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.655-664
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• 2007

The inherent characteristic of concrete tensile cracks, directional nonlocal crack damage, causes so-called rotating tensile crack damage and softening of compressive strength. In the present study, a plasticity model was developed to describe the behavior of reinforced concrete planar members In tension-compression. To describe the effect of directional nonlocal crack damage, the concept of microplane model was combined with the plasticity model. Unlike existing models, in the proposed model, softening of compressive strength as well as the tensile crack damage were defined by the directional nonlocal crack damage. Once a tensile cracking occurs, the microplanes of concrete are affected by the nonlocal crack damage. In the microplanes, microscopic tension and compression failure surfaces are calculated. By integrating the microscopic failure surfaces, the macroscopic failure surface is calculated. The proposed model was implemented to finite element analysis, and it was verified by comparisons with the results of existing shear panel tests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.670-677
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• 2016

Laboratory and meta-analyses were done for 9% NI Steel for use in a liquefied natural gas carrier. The meta-analysis is based on a previous study. The laboratory analysis examines the effects of a single pass and multiple passes on the tensile strength through an impulse-response test. The tensile strength increased from pass one to pass three and decreased from pass four to pass ten. The pass and multi-pass welding had a positive effect on the tensile strength. Lastly, the welding and tensile time had a positive effect on the tensile strength.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.459-465
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• 2016

In this paper, it was performed the fatigue test to examine the effect of cyclic loading for the simple T-joint. Axial force of bolt by clamping and the change of the force by applied load were measured in the joint. And the bolt force, the failure mode and the fatigue strength under cyclic loading were investigated. The parameters of the tension joint were set to be the flange thickness and the diameter of bolt to a different stiffness of the joint in response to the combination. From the fatigue test, failure mode of tensile joints under cyclic loading could be evaluated using a static ultimate load of the specific failure mode in EC3. The fatigue strength of the tension joints was considerably higher than the fatigue strength of the EC3(36) that does not consider a lever action. However, the additional axial force by lever action occurs to an increase in the axial force of the bolt it requires a careful evaluation of the fatigue strength.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.7
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• pp.769-776
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• 2012

The damage analysis method in this paper needs a material property and failure criteria. The material properties and the failure criteria could be easily obtained from the results of notched bar tensile tests carried out on other materials studied previously. However, for the cast stainless steel (CF8M) material in this paper, because of the variance in the results from notched bar tensile tests under the same conditions, the material property and the failure criteria could be obtained differently, depending on the analyzer. Therefore, a proper procedure that can confirm the material property and failure criteria are needed. In this work, the averaged material property was obtained from the notched bar with a 16-mm notch radius, and three failure criteria for CF8M material by finite element analysis were obtained. Applying the material property and the failure criteria, FE damage analysis for the J-R fracture toughness test was conducted. For validation, the simulated results were compared with the experimental results.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.785-796
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• 2008

Longitudinal elongation develops in reinforced concrete beams that exhibit flexural yielding during cyclic loading. The longitudinal elongation can decrease the shear strength and deformation capacity of the beams. In the present study, nonlinear truss model analysis was performed to study the elongation mechanism of reinforced concrete beams. The results showed that residual tensile plastic strain of the longitudinal reinforcing bar in the plastic hinge is the primary factor causing the member elongation, and that the shear-force transfer mechanism of diagonal concrete struts has a substantial effect on the magnitude of the elongation. Based on the analysis results, a simplified method for evaluating member elongation was developed. The proposed method was applied to test specimens with various design parameters and loading conditions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.223-230
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• 2004

It is growing the application of the removal ground anchor with tension force for earth retaining constructions in the downtown. Nowadays, we can find the compression dispersion anchor on many site. But, it is occur some probelems in behabior of anchors because of impossible to tense p.c strand uniformly with existing equipment due to different length of p.c strand. So we tried to tense each p.c strand uniformly with auto back equipment in-situ test. This study compared and analyzed apply to elastic theory in-situ test results of an existing equipment with those of auto back equipment. As a result of the test, It has been proved that differences of tension force in the existing equipment increases with increasing the number of p.c strand. This can cause an ultimate failure of the concentrated p.c strand and a shear failure of ground. So it has been proved that auto back equipment is necessary.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.49-56
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• 2015

Ultra-High Strength Concrete(UHPC) has ultra-high material performance including high strength and high flowability. On the other hand it is less ductile than high ductile fiber reinforced cementitious composite. This study investigated the effect of combination of steel fiber and micro fiber on the tensile behavior of UHPC. Four types of UHPC containing combination of steel fiber, polyethylene(PE), polyvinyl alcohol(PVA), and basalt fiber were designed. And then uniaxial tension tests were performed to evaluate the tensile behavior of UHPC according to combination of fibers. And density was measured to evaluate whether micro fiber induces unintentional high pore or not. From the test results, it was exhibited that PE fiber with high strength is effective to improve the tensile behavior of UHPC and basalt fiber is effective to increase the cracking and tensile strength of UHPC. Furthermore, it was also verified that micro fiber does not make high pore.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.367-374
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• 2019

Drying shrinkage in the hardened cement is known to change in volume by decreasing the moisture content in the hardened body, and it is known that the higher the W / C and the higher the content of the paste, the larger the drying shrinkage. In the case of ECC, more drying shrinkage occurs compared to concrete, since it does not contain coarse aggregate. Since ECC is an important material for tensile performance, the effect of restrained tensile stress on mechanical tensile behavior should be considered. The purpose of this study is to analyze the effect of stress caused by restraint on the tensile behavior of ECC. The mechanical properties of the specimens were tested by uniaxial tension tests with different restraints. As a result, the difference of tensile behavior according to restraint stress was observed and the cause was analyzed.