• 한국산학기술학회논문지
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• 제17권12호
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• pp.670-677
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• 2016

본 연구는 LNG 저장 탱크 운반선 9% NI Steel에 대한 실험분석과 메타분석 연구이다. 본 연구는 LNG 저장 탱크 운반선 9% NI Steel에 대한 선행연구에 기초해서 메타분석을 수행한 후에, 9% Ni Steel의 패스(pass)와 다층용접(multi pass)이 인장강도(tensile strength)에 미치는 영향을 분석하기 위하여 충격반응검정(impulse-response test)을 통한 실험분석을 수행하였다. 본 연구의 실험분석 결과 다음과 같은 연구결과를 얻었다, 첫째, 9% Ni Steel의 다층용접(multi pass welding)에 대한 인장강도(tensile strength)를 시험한 결과 패스 1부터 패스 3까지 인장강도가 증가하였으나, 패스 3 이후부터 다층용접의 인장강도는 감소하는 것으로 보인다. 둘째, 다층용접(Multi pass welding)이 인장강도(tensile strength)에 미치는 영향을 분석한 결과, 패스(pass), 다층용접(multi pass)이 인장강도(tensile strength) 에 유의한 정(+)의 영향을 미치는 것으로 보인다. 용접시간(welding time)이 인장강도(tensile strength)에 미치는 영향을 분석한 결과, 용접시간(welding time), 인장강도시간(tensile time)이 인장강도(tensile strength) 에 유의한 정(+)의 영향을 미치는 것으로 보인다.

• 동력기계공학회지
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• 제14권4호
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• pp.56-62
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• 2010

This paper is concerned with the stochastic nature of elevated temperature tensile strength and creep rupture time in 18Cr-8Ni stainless steels. The Weibull statistical analysis using the NRIM data sheet has been performed to investigate the effects of variability of the elevated temperature tensile strength and creep rupture time on the testing temperature. From those investigations, the distributions of temperature tensile strength and creep rupture time were well followed in 2-parameter Weibull. The shape parameter and scale parameter for the Weibull distribution of tensile strength were decreased with increasing the testing temperature. For the creep rupture time, generally, the shape parameter were decreased with increasing the testing temperature.

• Journal of Welding and Joining
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• 제27권5호
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• pp.81-87
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• 2009

Recently, extruded aluminium-alloy panels have been used in the car bodies for the purpose of the light-weight of railway vehicles and FSW(Friction Stir Welding), which is superior to the arc weldings, has been applied in the railway vehicles. This paper presents the optimum design of the FSW process on A6005 extruded alloy for railway vehicles to improve its mechanical properties. Rotational speed, welding speed and tilting angle of the tool tip were chosen as design parameters. Three objective functions were determined; maximizing the tensile strength, minimizing the hardness and maximizing the difference between the normalized tensile strength and hardness. The tensile tests and the hardness tests for fifteen FSW experiments were carried out according to the central composite design table. Recursive model functions on three characteristic values, such as the tensile strength, the hardness difference(${\Delta}Hv$) and the difference of normalized tensile strength and ${\Delta}Hv$, were estimated according to the classical response surface analysis methodology. The reliability of each recursive function was verified by F-test using the analysis of variance table. Sensitivity analysis on each characteristic value was done. Finally, the optimum values of three design parameters were found using Sequential Quadratic Programming algorithm.

• Steel and Composite Structures
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• 제21권6호
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• pp.1327-1345
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• 2016

$Al_2O_3$/SiC particulate reinforced (Metal Matrix Composites) MMCs which were produced by using stir casting process, bending strength and hardening behaviour were obtained using an analysis of variance (ANOVA) technique that uses full factorial design. Factor variables and their ranges were: particle size $2-60{\mu}m$; the stirring speed 450 rpm, 500 rpm and the stirring temperature $620^{\circ}C$, $650^{\circ}C$. An empirical equation was derived from test results to describe the relationship between the test parameters. This model for the tensile strength of the hybrid composite materials with $R^2$ adj = 80% for the bending strength $R^2$ adj = 89% were generated from the data. The regression coefficients of this model quantify the tensile strength and bending strengths of the effects of each of the factors. The interactions of all three factors do not present significant percentage contributions on the tensile strength and bending strengths of hybrid composite materials. Analysis of the residuals versus was predicted the tensile strength and bending strengths show a normalized distribution and thereby confirms the suitability of this model. Particle size was found to have the strongest influence on the tensile strength and bending strength.

• 수산해양기술연구
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• 제29권2호
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• pp.117-123
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• 1993

In order to analysis the tensile properties of the high-tech fibers for fishing gear materials. tensile strength was tested on raw materials, single yarns and netting twines(plied yarns)made of nylon, kevlar 29 and techmilon respectively. The results obtained are as follows: 1. The tensile stress and tenacity of unknotted single yarns in dry and wet conditions were 3 to 3.5 times greater in the high-tech fibers than in nylon. But the elongation of the high-tech fibers was about 15% of that in nylon. 2. The tensile strength of knotted single yarns in dry and wet conditions was arranged in order of as follows : techmilon. kelver 29, and nylon. The ratio of knot strength to tensile strength, knot efficiency, was the highest in nylon. 3. The tensile strength of unknotted netting twines in dry and wet conditions was 2.3 to 2.5 times greater in the high-tech fibers than in nylon. 4. The tensile strength of knotted netting twines in dry and wet conditions was arranged in order of as follows : techmilon, kevlar 29, nylon. The knot efficiency was the highest in nylon.

• 비파괴검사학회지
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• 제29권3호
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• pp.219-223
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• 2009

This paper prescribed the structural integrity of the API 5L X65 pipeline subjected to tensile pre-strain. The effects of pre-strain on the mechanical properties of API 5L X65 pipe were substantially investigated through a variety of the experimental procedures. Axial tensile pre-strain of 1.5, 5 and 10% was applied to plate-type tensile specimens cut from the pipe body prior to mechanical testing. Tensile test revealed that yield strength and tensile strength were increased with increasing tensile pre-strain. The increasing rate of the yield strength owing to the pre-strain is greater than that of the tensile strength. However, the pre-strain up to 5% had a little effect on the decreasing of the fracture toughness. The structural integrity of the API 5L X65 pipeline subjected to large plastic deformation was evaluated through the fitness-for service code.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.603-610
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• 2003

The influence of Poisson's ratio on the tensile strength of brittle materials is neglected in many studies. When brittle materials are loaded in compression or impact, substantial tensile stresses are induced within the materials. These tensile stresses are responsible for splitting failure of the materials. In this paper, the state of stress in a spherical particle due to two diametrically opposed forces is analyzed theoretically. A simple equation for the state of stress at the center of the particle is obtained. An analysis of the distribution of stresses along the z-axis due to distributed pressures and concentrated forces, and on diametrically horizontal plane due to concentrated forces, shows that it is reasonable to propose the tensile stress at the center of the particle at the point of failure as a tensile strength of the particle. Moreover, the tensile strength is a function of the Poisson's ratio of the material. As the state of stress along the z-axis in an irregular specimen tends to be similar to that in a spherical particle compressed diametrically with the same force, this tensile strength has some validity for irregular particles as well. Therefore, it can be proposed as the tensile strength for brittle materials generally. The effect of Poisson's ratio on the tensile strength is discussed.

• Computers and Concrete
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• 제7권2호
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• pp.169-190
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• 2010

The focus of this research effort was characterization of the flexural and tensile properties of a specific ultra-high-strength, fiber-reinforced concrete material. The material exhibited a mean unconfined compressive strength of approximately 140 MPa and was reinforced with short, randomly distributed alkali resistant glass fibers. As a part of the study, coupled experimental, analytical and numerical investigations were performed. Flexural and direct tension tests were first conducted to experimentally characterize material behavior. Following experimentation, a micromechanically-based analytical model was utilized to calculate the material's tensile failure response, which was compared to the experimental results. Lastly, to investigate the relationship between the tensile failure and flexural response, a numerical analysis of the flexural experiments was performed utilizing the experimentally developed tensile failure function. Results of the experimental, analytical and numerical investigations are presented herein.

• 한국강구조학회 논문집
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• 제14권1호
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• pp.121-130
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• 2002

This paper presents the tensile behavior of a Concrete-Filled Square Steel Tubular (CFT) column to H-beam welded connections. These connections were externally reinforced with T-shaped stiffeners at the junction of CFT column and beam. The tensile loading tests of eighteen tee-joint connections and finite element analysis using ANSYS were carried out. The main parameters of tests are as follows: 1) the thickness of Square Steel Tubular Column : 6 mm, 9 mm, 2) the strength ratios of tensile strength of horizontal stiffeners to tensile strength of beam flange : 70 %, 100 %, 150 %, 3) the strength ratios of shear strength of vertical stiffeners to tensile strength of beam flange : 80 %, 115 %, 160 %. The results of the tests demonstrate that overall behavior and failure modes of all the specimens are governed mainly by the horizontal stiffeners rather than the vertical stiffeners, and the vertical stiffener played only a role in transferring load introduced from beam to column.

• 대한건축학회논문집:구조계
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• 제35권3호
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• pp.27-33
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• 2019

The purpose of this study is to provide and evaluate the tensile properties of masonry element such as tensile strength, strain, modulus of elasticity and stress-strain relationship through the direct tension test with varies of mortar strength. From the experiment, the tension fracture was observed along the interfaces between the brick and the mortar. Tension properties of masonry element was significantly affected by compressive strength of mortar, $f_m$, indicating that higher tensile strength and modulus of elasticity of masonry element were obtained with increase of $f_m$. The strain of a masonry element was inversely proportional to $f_m$ due to the lower ductility of a higher mortar strength. A tensile stress-strain relationship of masonry element was generalized based on the numerical analysis and the regression analysis using test data. The proposed model shows fairly good agreement with the test measurements.