• Title/Summary/Keyword: tensile set

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Tensile Behavior of Reinforced Concrete Member due to Restrained Shrinkage (구속된 건조수축이 철근콘트리트 인장거동에 미치는 영향)

  • 안태송;김진철
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.315-320
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    • 1998
  • The experimental set-up and one-dimensional analytical model have been developed to investigate the tensile behavior of reinforced concrete member due to restrained drying shrinkage. The experimental results have been compared with the analytical prediction of the maximum residual stress of steel and concrete due to restrained shrinkage. The tensile residual stress concrete by one-dimensional bilinear model shows 0.19 and 0.63 of tensile strength for 0.83% and 3.29 of steel ratio. The residual tensile stress of concrete increases as the steel ratio increases. The effect of steel fiber has not influenced the residual stress due to restrained shrinkage of concrete.

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Comparison of measurement uncertainty calculation methods on example of indirect tensile strength measurement

  • Tutmez, Bulent
    • Geomechanics and Engineering
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    • v.12 no.6
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    • pp.871-882
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    • 2017
  • Indirect measure of the tensile strength of laboratory samples is an important topic in rock engineering. One of the most important tests, the Brazilian strength test is performed to obtain the tensile strength of rock, concrete and other quasi brittle materials. Because the measurements are provided indirectly and the inspected rock materials may have heterogeneous properties, uncertainty quantification is required for a reliable test evaluation. In addition to the conventional measurement evaluation uncertainty methods recommended by the Guide to the Expression of Uncertainty in Measurement (GUM), such as Taylor's and Monte Carlo Methods, a fuzzy set-based approach is also proposed and resulting uncertainties are discussed. The results showed that when a tensile strength measurement is measured by a laboratory test, its uncertainty can also be expressed by one of the methods presented.

Tensile and fracture characterization using a simplified digital image correlation test set-up

  • Kumar, Abhishek;Vishnuvardhan, S.;Murthy, A. Ramachandra;Raghava, G.
    • Structural Engineering and Mechanics
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    • v.69 no.4
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    • pp.467-477
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    • 2019
  • Digital image correlation (DIC) is now a popular and extensively used full-field metrology technique. In general, DIC is performed by using a turnkey solution offered by various manufacturers of DIC. In this paper, a simple and economical set-up for DIC is proposed which uses easily accessible digital single-lens reflex (DSLR) camera rather than industrial couple-charged device (CCD) cameras. The paper gives a description of aspects of carrying a DIC experiment which includes experimental set-up, specimen preparation, image acquisition and analysis. The details provided here will be helpful to carry DIC experiments without specialized DIC testing rig. To validate the responses obtained from proposed DIC set-up, tension and fatigue tests on specimens made of IS 2062 Gr. E300 steel are determined. Tensile parameters for a flat specimen and stress intensity factor for an eccentrically-loaded single edge notch tension specimen are evaluated from results of DIC experiment. Results obtained from proposed DIC experiments are compared with those obtained from conventional methods and are found to be in close agreement. It is also noted that the high resolution of DSLR allows the use of proposed approach for fracture characterization which could not be carried out with a typical turnkey DIC solution employing a camera of 2MP resolution.

An Experimental Study of Tension Properties on New Developed Up-Set Coupler (Up-Set Coupler 이음철근의 인장특성에 대한 실험적 연구)

  • Sim, Jong-Sung;Park, Cheol-Woo;Kang, Tae-Sung;Kim, Tae-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.5
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    • pp.109-115
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    • 2008
  • As structures are getting super-rise and large-sized, introducing the construction methods such as prefabrication of bar-meshes and complex method are being actively discussed to pursue the high quality of reinforced concrete, the simplification of field works, and the reduction of duration, as well as the study on how to connect reinforcing rods, which occurs while applying the same methods, is in progress Also, the pressure welded joint is a kind of method that heats the ends of reinforced bars locally and joint them, and after the pressure welding, the vulnerable part in the reinforced bar occur. Thus, in the construction field, the throughout quality control is necessary because of the delayed duration and the lowered construct ability. In this study, of the traditional lap splice method and the mechanical splice one, the screw coupler, we tried to look into through experiments the prefabrication method of bar-meshes, a typical joint method usually used for the joint parts for PSC structures applying the reinforced bar with its big diameter, and a newly-developed up-set coupler method. And we also examined the characteristic of tensile.

Rotation of Orthotropy Axes under Plane Stress (평면응력하에서의 직교이방성 대칭축의 회전)

  • 인정제;김권희
    • Transactions of Materials Processing
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    • v.3 no.3
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    • pp.320-334
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    • 1994
  • A set of full size cold rolled steel sheets has been prestrained in the direction of rolling by uniform tensile elongation of 3% and 6%. Then mid-sized tensile specimens were cut from each of the full size sheets at 30, 45, 60 and 90 degrees to the rolling direction. The mid-sized tensile specimens were then prestrained again by uniform tensile elongation by 1%, 2%, 5%, 10% and 15%. finally, miniature tensile specimens were prepared from each of the mid-sized specimens at every 10 degrees to the specimen axis. From the tensile tests on miniature specimens material's hardening behavior under non-proportional loading has been investigated. There are a number of new observations which has not been known to the authors before current work. One of them is continuous reservation of orthoropic symmetry during tensile elongation of mid-sized specimens. Another is continuous rotations of orthotropy axes. Existing theories seem to fail to explain this observations. A new model is proposed in relation to the rotation of orthotropy axes.

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Effects of Tool Plunge Position on Mechanical Properties of Friction-stir-weleded Region in A6061-T6/AZ31 Dissimilar Metals (A6061-T6/AZ31 이종금속 마찰교반접합부의 기계적 특성에 미치는 툴 삽입 위치의 영향)

  • Lee, Kwang-Jin;Kim, Sang-Hyuk
    • Journal of Welding and Joining
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    • v.30 no.5
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    • pp.22-26
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    • 2012
  • Butt-joints of A6061-T6 and AZ31 plates were successfully manufactured by using a friction stir welding method. Off-set free joints and off-set joints were fabricated to investigate the effect of the tool plunge position on the mechanical properties of the joints. Hardness test, tensile test and charpy impact test was performed to evaluate the mechanical properties of the joints. Off-set condition resulted in increase of mechanical properties of the joints. The variation of the hardness distribution in the SZ was also stabilized in the off-set condition. Tensile strength of the off-set joint was about 85% against to that of the AZ31 base metal. Impact absorption energy by Charpy-Impact-Test of the off-set joint also increased by almost 2 times against to that of the AZ31 base metal.

Measurement of Tensile Properties Dependent on the Small-Scaled Specimen Dimension for Evaluation of In-Service Materials Properties (사용재 물성 평가를 위한 미소 시험편 크기에 따른 인장 특성 평가)

  • Huh, Yong-Hak;Kim, Dong-Iei;Kim, Dong-Jin;Lee, Hae-Moo;Park, Jong-Seo
    • Journal of the Korean Society of Safety
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    • v.23 no.5
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    • pp.30-34
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    • 2008
  • To evaluate the mechanical properties of in-service materials, tensile properties measurement using small-scaled specimen has been carried out. Tensile testing specimens with various dimensions, including standard and sub-size specimen specified in ASTM and ISO and small-scaled specimen, were prepared. Tensile strain in small-scaled specimen was measured using micro-ESPI system set up in this study. This system was used in the specimen with the parallel length of 2 mm and in subsequently measuring the strain under tensile loading. From each type of tensile specimen, stress-strain curves were determined. The dimension effect of the tensile properties was investigated comparing the tensile results obtained from standard specimens and small-scaled specimens. It was shown that the tensile strength for the small-scaled specimen is lower by 15% than those for the standard specimen.

Study on a Prediction Model of the Tensile Strain Related to the Fatigue Cracking Performance of Asphalt Concrete Pavements Through Design of Experiments and Harmony Search Algorithm (실험계획법 및 하모니 검색 알고리즘을 이용한 아스팔트 포장체의 피로균열 공용성 관련 인장변형률 추정모델 연구)

  • Lee, Chang-Joon;Kim, Do-Wan;Mun, Sung-Ho;Yoo, Pyeong-Jun
    • International Journal of Highway Engineering
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    • v.14 no.2
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    • pp.11-17
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    • 2012
  • This research describes how to predict a model of the tensile strain related to the fatigue cracking performance of several asphalt concrete structures through design of experiments(e.g., Response Surface Methodology) and harmony search(HS) algorithm. The axisymmetric analysis program of finite element method, which is the KICTPAVE, was used to determine the strain level at the interface layer between asphalt layer and lean concrete layer. Once the training database set of various strain levels was constructed under the several condition of layer stiffnesses and thicknesses in the asphalt concrete structures, the data set was trained through the HS algorithm in order to determine the regression coefficients defined based on a response surface methodology. Furthermore, the testing set, which was not used for the training procedure of HS algorithm, was also constructed in order to evaluate whether the regression coefficients of a prediction model can be appropriately applied for other cases in asphalt concrete structures.

Dynamic tensile behavior of SIFRCCs at high strain rates

  • Kim, Seungwon;Park, Cheolwoo;Kim, Dong Joo
    • Computers and Concrete
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    • v.26 no.3
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    • pp.275-283
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    • 2020
  • Reinforced concrete (RC) does not provide sufficient resistance against impacts and blast loads, and the brittle structure of RC fails to protect against fractures due to the lack of shock absorption. Investigations on improving its resistance against explosion and impact have been actively conducted on high-performance fiber-reinforced cementitious composites (HPFRCCs), such as fiber-reinforced concrete and ultra-high-performance concrete. For these HPFRCCs, however, tensile strength and toughness are still significantly lower compared to compressive strength due to their limited fiber volume fraction. Therefore, in this study, the tensile behavior of slurry-infiltrated fiber-reinforced cementitious composites (SIFRCCs), which can accommodate a large number of steel fibers, was analyzed under static and dynamic loading to improve the shortcomings of RC and to enhance its explosion and impact resistance. The fiber volume fractions of SIFRCCs were set to 4%, 5%, and 6%, and three strain rate levels (maximum strain rate: 250 s-1) were applied. As a result, the tensile strength exceeded 15 MPa under static load, and the dynamic tensile strength reached a maximum of 40 MPa. In addition, tensile characteristics, such as tensile strength, deformation capacity, and energy absorption capacity, were improved as the fiber volume fraction and strain rate increased.

Quality Evaluation of Resistance Spot Welding using Acoustic Emission (음향방출을 이용한 저항 점용접의 용접 품질평가)

  • Jo Dae-Hee;Rhee Zhang-Kyu;Park Sung-Oan;Cho Jin-Ho;Kim Bong-Gag;Woo Chang-Ki
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.4
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    • pp.98-104
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    • 2006
  • In this paper, for the purpose of investigation the acoustic emission(AE) behaviors during resistance spot welding process and tension test of spec steels. As the results present the resistance spot welding method that can get suitable welding qualities or structural integrity estimating method. The resistance spot welding process consists of several stages: set-down of the electrodes; squeeze; current flow; forging; hold time; and lift-off. Various types of AE signals are produced during each of these stages. For tensile-shear test and cross tensile test in resistance spot welded specimens, fracture pa 야 ems are produced: tear fracture; shear fracture; and plug fracture. Tensile-shear specimens strength appeared higher than cross tensile specimens one. In case of tensile-shear specimen happened tear fracture that crack happens in most lower plate. Also, in case of cross tensile specimens, upper plate and lower plate are detached perfect fracture was exposed increases a little as acting force is lower than ordinary welding condition. Therefore, the structure which is combined by resistance spot welding confirmed that welding design must attain so that shear stress may can interact mainly.