• Title, Summary, Keyword: tensile-shear

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Shear and tensile behaviors of headed stud connectors in double skin composite shear wall

  • Yan, Jia-Bao;Wang, Zhe;Wang, Tao;Wang, Xiao-Ting
    • Steel and Composite Structures
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    • v.26 no.6
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    • pp.759-769
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    • 2018
  • This paper studies shear and tensile behaviors of headed stud connectors in double skin composite (DSC) structure. Firstly, 11 push-out tests and 11 tensile tests were performed to investigate the ultimate shear and tensile behaviors of headed stud in DSC shear wall, respectively. The main parameters investigated in this test program were height and layout of headed stud connectors. The test results reported the representative failure modes of headed studs in DSC structures subjected to shear and tension. The shear-slip and tension-elongation behaviors of headed studs in DSC structures were also reported. Influences of different parameters on these shear-slip and tension-elongation behaviors of headed studs were discussed and analyzed. Analytical models were also developed to predict the ultimate shear and tensile resistances of headed stud connectors in DSC shear walls. The developed analytical model incorporated the influence of the dense layout of headed studs in DSC shear walls. The validations of analytical predictions against 22 test results confirmed the accuracy of developed analytical models.

Adhesion Characteristics and Anatomic Scanning of Plywood Bonded by High Density Polyethylene (고밀도 폴리에틸렌으로 접착한 합판의 접착성질과 해부학적 관찰)

  • Han, Kie-Sun;Lee, Hwa-Hyoung
    • Journal of the Korean Wood Science and Technology
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    • v.25 no.3
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    • pp.16-23
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    • 1997
  • This study was carried out to discuss feasibility of high density polyethylene(HDPE) as a new substitute for the conventional adhesives in plywood manufacture. Plywood was composed of radiata pine(Pinus radiata) and Malas(Homallium feotidium) veneers and bonded by HDPE. Adhesion characteristics and anatomical scanning has been examined through tensile-shear strength test and scanning electron microscopy(SEM). The results are as follows; 1. Optimum loading quantity was 15g/$(30.3{\times}30.3)cm^2$, and tensile-shear strength increased with the increase of loading quantity. 2. Even at the hot pressing time of 1 minute, tensile-shear strength met the value of KS(over the 7.5kgf/$cm^2$), and tensile-shear strength increased with the increase of hot pressing time. 3. Plywood composed of veneer at moisture content of 19.6% showed similar tensile-shear strength to that at air conditioned moisture content of 11.4%. 4. Under the same condition of hot pressing time, tensile-shear strength of plywood bonded by HDPE met the KS value of boil and wet test and proved the same group as phenol formaldehyde adhesive. 5. HDPE films showed mechanical adhesion through penetration into the lathe check and ray of veneer.

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Experimental Study on Shear Behavior of HPFRCC Beam (HPFRCC Beam 부재의 전단거동에 관한 실험적 연구)

  • Song, Tae-Hwa;Lee, Seong-Cheol;Shin, Kyung-Joon;Chang, Sung-Pil
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.289-292
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    • 2006
  • In this research, bending shear test of HPFRCC beams is conducted to obtain the shear strength of HPFRCC beams. Parameters are ratio of volume percentage of fibers. Also, the uniaxial tensile test of HPFRCC is conducted to obtain the tensile cracking stress of each parameters. From the uniaxial tensile test result, the shear strength of HPFRCC beams can be calculated by using the preexisting shear analysis model. Then, the shear strengths of bending shear test result and analysis result are compared.

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Shear Transfer Strength Evaluation for Ultra-High Performance Fiber Reinforced Concrete (강섬유 보강 초고성능 콘크리트의 전단 전달 모델)

  • Lee, Ji-Hyung;Hong, Sung-Gul
    • Journal of the Korean Association for Spatial Structures
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    • v.15 no.2
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    • pp.69-77
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    • 2015
  • Ultra High Performance Fiber Reinforced Concrete (UHPFRC) has a outstanding tensile hardening behaviour after a crack develops, which gives ductility to structures. Existing shear strength model for fiber reinforced concrete is entirely based on crack opening behavior(mode I) which comes from flexural-shear failure, not considering shear-slip behavior(mode II). To find out the mode I and mode II behavior on a crack in UHPFRC simultaneously, maximum shear strength of cracked UHPFRC is investigated from twenty-four push-off test results. The shear stress on a crack is derived as variable of initial crack width and fiber volume ratio. Test results show that shear slippage is proportional to crack opening, which leads to relationship between shear transfer strength and crack width. Based on the test results a hypothesis is proposed for the physical mechanics of shear transfer in UHPFRC by tensile hardening behavior in stead of aggregate interlocking in reinforced concrete. Shear transfer strength based on tensile hardening behavior in UHPFRC is suggested and this suggestion was verified by comparing direct tensile test results and push-off test results.

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.

Evaluation on the Properties of Strain Distribution of the sopt welding specimen under tensile-shear load (인장-전단하중을 받는 점 용접재의 변형률 분포 특성 평가)

  • 김덕중
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.8 no.6
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    • pp.113-118
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    • 1999
  • In order to evaluate strength of spot welded joint, at first it is importent that we should know strain distribution near nugget zone. During loading, in HAZ, compressive strain increase with Increase of load, but in nugget zone tensile strain increase. During unloading, on the other hand, even through the decreases, the strain variation is not almost appeared in nugget zone and HAZ. In nugget boundary zone, the strain range increases continuously along with load increase on outer surface, but the strain increases continunously and decreases rapidly beyond yield strength on inner surface. In this paper, strain distribution are measured in inner and outer surface with variation of thickness and load under tensile-shear load. Tensile-shear strength increased as with increase of specimen thickness. As for thickness increase rates are 25%, 50%, 100%, and 150%, tensile-shear strength in crease rates are 40%, 81%, 130% and 228%.

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Analysis of RC beam with unbonded or exposed tensile steel reinforcements and defective stirrup anchorages for shear strength

  • Wang, Xiao-Hui;Liu, Xi-La
    • Computers and Concrete
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    • v.10 no.1
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    • pp.59-78
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    • 2012
  • Although the effect of corrosion of reinforcing bar on the shear behavior of the reinforced concrete (RC) beam had been simulated by tests of the beam with unbonded, half-exposed or whole-exposed tensile steel reinforcements as well as defective stirrup anchorages, theoretical methods to accurately predict remaining capacity of this kind of RC beams, especially shear capacity, are still lacking. Considering the possible position of the critical inclined crack, the actual pattern of strains in the concrete body within the partial length and the proposed compatibility condition of deformations of the RC beam, shear strength of the RC beam with unbonded or exposed tensile steel reinforcements and/or defective stirrup anchorages is predicted. Comparison between the model's predictions with the experimental results published in the literature shows the practicability of the proposed model. Influence of the length of unbonded or exposed tensile steel reinforcements and the percentage of stirrups lacked end anchorages on the shear strength of the RC beam is discussed. It is concluded that, the shear strength of the RC beam with unbonded or exposed tensile steel reinforcements and/or defective stirrup anchorages is greatly influenced by the length of unbonded or exposed tensile steel reinforcements and the percentage of stirrups lacked end anchorages, this influence can be adverse, insignificant or even favourable, dependent on the given parameters of the corresponding normal bonded RC beam.

A STUDY OF BONDING STRENGTH AND CHANGE OF BRACKET SLOT WIDTH OF CHEMICALLY RECYCLED METAL BRACKETS (화학적(化學的)으로 재생(再生)된 금속(金屬) bracket의 접착(接着) 강도(强度)와 slot폭경(幅徑) 변화(變化)에 관(關)한 연구(硏究))

  • Ko, Young-Sam;Lee, Dong-Joo
    • The korean journal of orthodontics
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    • v.20 no.2
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    • pp.283-291
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    • 1990
  • The purpose of this study was to measure and compare tensile and shear strength for 4 types of new direct-bonding brackets and same brackets after recycling and to evaluate the change of bracket slot width after recycling. Four types of new direct-bond brackets were bonded to recently extracted human premolar teeth and the tensile and shear strength was measured by Universal Testing Machine. The brackets were recycled by chemical process and the tensile and shear test was repeated. To evaluate the change of the bracket slot width, slot width was measured by the Topcon Universal Measuring Microscope before and after recycling. Following results were obtained: 1. There was no satistically significant difference between the tensile and shear strength of recycled brackets and those of new brackets. 2. In both new and recycled brackets, the tensile and shear strength of perforated base bracket was lower than those of photoetched, foilmesh and contou-lok mesh base brackets. (P<0.01) 3. There was no statistically significant difference in bonding strengths of control group bonded only once and two times. 4. There was no statistically significant difference in the change of the bracket slow width after recycling process. 5. Of the failure, the combination type (58%) in the tensile strength and the tooth adhesive interface (65%) in the shear strength was the most common type.

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Destructive testing of adhesively bonded joints under static tensile loading

  • Ochsner, A.;Gegner, J.
    • Journal of Adhesion and Interface
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    • v.5 no.2
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    • pp.22-36
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    • 2004
  • Several in-situ testing methods of adhesively bonded joints under static short-time tensile loading are critically analyzed in terms of experimental procedure and data evaluation. Due to its rather homogeneous stress state across the glue line, the tensile-shear test with thick single-lap specimens, according to ISO 11003-2, has become the most important test process for the determination of realistic materials parameters. This basic method, which was improved in both, the experimental part by stepped adherends and easily attachable extensometers and the evaluation procedure by numeric substrate deformation correction and test simulation based on the finite element method (FEM), is therefore demonstrated by application to several kinds of adhesives and metallic adherends. Multi-axial load decreases the strength of a joint. This effect, which is illustrated by an experimental comparison, impedes the derivation of realistic mechanical characteristics from measured force-displacement curves. It is shown by numeric modeling that tensile-shear tests with thin plate substrates according to ISO 4587, which are widely used for quick industrial quality assurance, reveal an inhomogeneous stress state, especially because of relatively large adherend deformation. Complete experimental determination of the elastic properties of bonded joints requires independent measurement of at least two characteristics. As the thick-adherend tensile-shear test directly yields the shear modulus, the tensile butt-joint test according to ISO 6922 represents the most obvious complement of the test programme. Thus, validity of analytical correction formulae proposed in literature for the derivation of realistic materials characteristics is verified by numeric simulation. Moreover, the influence of the substrate deformation is examined and a FEM correction method introduced.

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Effects of Shear Span-to-depth Ratio and Tensile Longitudinal Reinforcement Ratio on Minimum Shear Reinforcement Ratio of RC Beams (전단경간비와 주인장철근비가 철근콘크리트 보의 최소전단철근비에 미치는 영향)

  • Lee Jung-Yoon;Kim Wook-Yeon;Kim Sang-Woo;Lee Bum-Sik
    • Journal of the Korea Concrete Institute
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    • v.16 no.6
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    • pp.795-803
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    • 2004
  • To prevent the shear failure that occurs abruptly with no sufficient warning, the minimum amount of shear reinforcement should be provided to reinforced concrete(RC) beams. The minimum amount of shear reinforcement of RC beams is influenced by not only compressive strength of concrete but also shear span-to-depth ratio and ratio of tensile longitudinal reinforcement. In this paper, 14 RC beams were tested in order to observe the influences of shear span-to-depth ratio, ratio of tensile longitudinal reinforcement, and compressive strength of concrete. The test results indicated that the rate of shear strength to the diagonal cracking strength of RC beams with the same amount of shear reinforcement increased as the ratio of tensile longitudinal reinforcement increased, while it decreased as the shear span-to-depth ratio increased. The observed test results were compared with the calculated results by the current ACI 318-02 Building Code and the proposed equation.