• Title, Summary, Keyword: Specimen

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A Study on the Fatigue Characteristics of Spot Weld Specimen use in Vehicle Body as the Applied Load Pattern (하중작용방식에 따른 차체용 점용접체의 피로특성에 관한 연구)

  • 송삼홍;배준수;장성재
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.668-671
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    • 1995
  • In this study, the fatigue charateristics of weld specimen was studied experimentally by using the various specimen types. The specimen type were tensile shesr(TS) specimen, cross tension(CT) specimen, and T typr (TT) specimen. Tensile test and fatigue test were carried out and microstucture was investigated. Finite element method was used to investigate stress distribution near nugget edge. Finally fracture mechanics approach was tried to the various specimen types.

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An Experimental Study on the Characteristics of Fiber-Reinforced Concrete Beam Without Shear Reinforcement (전단보강근이 없는 섬유보강 철근콘크리트 보의 특성에 관한 실험적 연구)

  • Kim, Jeong-Sup;Go, Song-Kyoon;Choi, Jin-Seok
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.3
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    • pp.83-90
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    • 2003
  • This study examines the material characteristics of fibers and their influences on reinforced concrete through the tests of reinforced concrete by the types of fibers including non-reinforced, steel, polypropylene and cellulose fibers and the test of compressive strength and reinforced concrete beam without shear reinforcement and consequently it obtains the following conclusions. As a result of conducting compressive strength by the types of specimens, fiber reinforced specimen with the highest compressive strength value at 28 days of age was cellulose fiber reinforced specimen as 280.4kgf/$\textrm{cm}^2$ and steel fiber specimen had the highest compressive strength of 250.7kgf/$\textrm{cm}^2$ at 180 days of age. In case of non-reinforced specimen, its compressive strength was 277.4kgf/$\textrm{cm}^2$ at 28 days of age and 273.1kgf/$\textrm{cm}^2$ at 180 days of age. Comparing the compressive strength of non-reinforced specimen to that fiber reinforced specimen showed that the compressive strength of fiber reinforced specimen was lower in the passage of age and the results of this experiment showed no effects of fiber reinforcement. As a result of testing reinforced concrete beam without shear reinforcement, ductility factors of specimens were 4.67 for non-reinforced specimen, 8.18 for steel fiber reinforced specimen, 6.20 for polypropylene fiber reinforced specimen and 5.49 for cellulose reinforced specimen, and it is found that steel fiber reinforced specimen was highest. When non-reinforced specimen and steel fiber reinforced specimen were compared, steel fiber reinforced specimen had higher ductility factor of about 75.2% than that of non-reinforced specimen.

Effect of Specimen Thickness to Corrosion Fatigue Crack Propagation Behavior of Structure Rolled Steel (일반구조용 압연강재의 부식피로균열전파거동에 미치는 시험편 두께의 영향)

  • 조약래
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.3
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    • pp.286-294
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    • 1992
  • In this paper, the corrosion fatigue crack propagation behavior of structure rolled steel (SWS 41C) was investigated by changing the thickness, and this experiment was done by the three point bending corrosion fatigue tester. The main results obtained are as follows: 1) As the thickness of specimen becomes thicker, the corrosion sensitivity to initial stage crack becomes some sensitive, and that the fatigue life becomes more sensitive. 2) The crack growth rate to initial stage crack (da/dN) was retarded as the thickness of specimen becomes thicker. But after initial stage crack, as the thickness of specimen is more thicker, da/dN is more rapid. 3) As the corrosion fatigue crack length grows, the accelerative factor of thick specimen (t=12mm) is more higher than that of thin specimen (t=6mm). 4) As the corrosion fatigue crack length grows, the corroson potential of both thick specimen and thin specimen becomes more less noble potential, however thick specimen (t=12mm) tends to more less noble potential than that of thin specimen(t=6mm).

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Design of a Laboratory Specimen for Simulation of Weld Residual Stress (용접 잔류음력 모사를 위한 시편 설계)

  • Kim, Jin-Weon;Park, Jong-Sun;Lee, Kyoung-Soo
    • Journal of the Korean Society of Safety
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    • v.24 no.1
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    • pp.7-13
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    • 2009
  • The objective of this study is to design a laboratory specimen for simulating residual stress of circumferential butt welding between pipes. Specimen type and method to generate residual stress were proposed based on the review of prior studies and parametric finite element analysis. To prove the proposed specimen type and loading method, the residual stress was generated using the designed specimen by applying proposed method and was measured. The measured residual stress using X-ray diffraction reasonably agreed with the results of finite element analysis considered in the specimen design. Comparison of residual strains measured at several locations on the specimen and given by finite element simulation also showed good agreement. Therefore, it is indicated that the designed specimen in this study can reasonably simulate the axial residual stress of a circumferential butt welding of pipe.

Design of Specimen for Weld Residual Stress Simulation (용접 잔류응력 모사를 위한 시편 설계)

  • Kim, Jin-Weon;Park, Jong-Sun;Lee, Kyung-Soo
    • Proceedings of the KSME Conference
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    • pp.67-72
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    • 2008
  • The objective of this study is to design a laboratory specimen for simulating residual stress of circumferential butt welding of pipe. Specimen type and method for residual stress generation were proposed based on the review of prior studies and parametric finite element simulation. To prove the proposed specimen type and loading method, the residual stress was generated using the designed specimen by applying proposed method and was measured. The measured residual stress using X-ray diffraction reasonably agreed with the results of finite element simulation considered in the specimen design. Comparison of residual strains measured at several locations of specimen and given by finite element simulation also showed good agreement. Therefore, it is indicated that the designed specimen can reasonably simulate the residual stress of circumferential butt welding of pipe.

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Extended Compliance Solution of ESET Specimen for Thermal fatigue Crack Growth Test (열피로 균열성장시험을 위한 ESET 시편의 확장된 컴플라이언스 해)

  • Lee, Ho-Jin;Kim, Maan-Won;Lee, Bong-Sang
    • Journal of the Korean Society of Safety
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    • v.20 no.1
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    • pp.62-67
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    • 2005
  • An eccentrically-loaded single edge crack tension specimen (ESET) is similar to a compact tension(CT) specimen loaded in tension-tension. The standard ESET specimen exhibits advantages over other types of cracked specimen, such as n, single-edge crack, and middle-crack tension specimen. The details of ESET specimen configuration, test procedure, and calculations are described in ASTM E647 standard. However, a difficulty in attaching COD gage to the knife-edge on the front foe of the specimen can be found when the size of ESET specimen is small for rapid cooling and heating in thermal fatigue testing. The finite element analysis is performed for the ESET specimen with projected knife-edge on the front foe and a crack-length-compliance equation is suggested for the new specimen configuration. Calibration test are conducted with 347 stainless steel to compare the measured crack length with the calculated crack length from the suggested compliance expression. The test results showed good agreements with those of analysis.

Small-size Specimen's Effectiveness That is Used to Mortar Layer of Slab (Heavy-weight Floor Impact Sound) (슬래브 상부 몰탈층에 사용된 작은시편의 유효성 검토(중량충격음을 중심으로))

  • Chung, Jin-Yun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.2
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    • pp.184-191
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    • 2009
  • This study examined small-size specimen's effectiveness that is used to evaluate floor impact sound performance. Floor impact sound level of small-size specimen is higher than full-size. This is due to excessive impact power of Bang machine. Impact hammer that has small impact power relatively can solve this problem. But, according to the size of specimen, mode shape and frequency that influence to structural borne sound is changed. Slab mode of full-size specimen was changed to frequency design of resilient materials. But in case of small-size specimen, there is no change of vibration mode by resilient materials change, Vibration mode of small-size specimen is the same. Therefore, it is not proper that use small-size specimen in floor impact sound estimation.

Focused Ion Beam-Based Specimen Preparation for Atom Probe Tomography

  • Lee, Ji Yeong;Ahn, Jae-Pyoung
    • Applied Microscopy
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    • v.46 no.1
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    • pp.14-19
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    • 2016
  • Currently, focused ion beams (FIB) are widely used for specimen preparation in atom probe tomography (APT), which is a three-dimensional and atomic-scale compositional analysis tool. Specimen preparation, in which a specific region of interest is identified and a sharp needle shape created, is the first step towards successful APT analysis. The FIB technique is a powerful tool for site-specific specimen preparation because it provides a lift-out technique and a controllable manipulation function. In this paper, we demonstrate a general procedure containing the crucial points of FIB-based specimen preparation. We introduce aluminum holders with moveable pin and an axial rotation manipulator for specimen handling, which are useful for flipping and rotating the specimen to present the backside and the perpendicular direction. We also describe specimen preparation methods for nanowires and nanopowders, using a pick-up method and an embedding method by epoxy resin, respectively.

The Magnetic Properties of Electrical Steel for Rotating Machine according to the Specimen

  • Choi, Yun-Yong;Chin, Jun-Woo;Hong, Jung-Pyo
    • Journal of Magnetics
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    • v.21 no.2
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    • pp.209-214
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    • 2016
  • This paper analyzes the magnetic property according to the machined shape of steel material with non-oriented silicon steel (50PN470/50A470), that is most commonly used in the design of electrical equipment. Toward this end, specimens were produced and divided into Bar-Specimen (Epstein Frame Tester) and Ring-Specimen (Toroidal Ring Tester). The characteristics of the electrical Silicon steel were measured using the instruments solely dedicated to measuring each specimen. The core loss of the Bar-Specimen, which is commonly used, was found to be less than that of the Ring-Specimen. This is a very important design factor in achieving the objectives of improving the product efficiency and predicting the performance of electrical equipment. It serves as a critical point of view in order to reduce the error between design value and product value. A comparative analysis was conducted regarding various characteristics (Hysteresis, B-H characteristic, Iron loss, Minor loop, Coercive force, Residual magnetic flux density, etc.) of the electrical silicon steel considered in the design of the electrical equipment according to the specimen.

Study on Bearing Response of Single Lap Riveted Joint (Single Lap Riveted Joint의 베어링 거동 연구)

  • Heo Kwang-Su;Yoon Sung-Ho;Jeong Jong-Cheol;Lee Sang-Jin;Kim Jung-Seok
    • Proceedings of the KSR Conference
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    • pp.326-331
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    • 2005
  • In this study, bearing response in single lap riveted joint is investigated by menas of single lap shear specimens with different types of adherend and fastener. Single lap shear specimen consists of adherend of SUS403 and carbon fabric/epoxy composite. Rivet of Avdel 2691 with 9.6mm diameter is used. Two types of fastener in single lap riveted joint are considered. One is a single lap shear specimen with single fastener, and the other is a single lap shear specimen with double fasteners. Especially, in case of single lap shear specimen with single fastener, the width of the specimen is varied as 2D, 3D, 4D, 6D at a fixed edge distance of 3D. Also the edge distance of the specimen is varied as 1.0D, 1.5D, 2.0D, 2.5D, 3.0D at a fixed width of 4D. In case of single lap shear specimen with double fasteners, two types of specimen are considered. One is a specimen with the width of 6D and edge distance of 3D. The other is a specimen with the width of 4D and edge distance of 2D. Here D designates the hole diameter for riveted joint.

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