• Title/Summary/Keyword: edge failure

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Numerical investigations on anchor channels under quasi-static and high rate loadings - Case of concrete edge breakout failure

  • Kusum Saini;Akanshu Sharma;Vasant A. Matsagar
    • Computers and Concrete
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    • v.32 no.5
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    • pp.499-511
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    • 2023
  • Anchor channels are commonly used for façade, tunnel, and structural connections. These connections encounter various types of loadings during their service life, including high rate or impact loading. For anchor channels that are placed close and parallel to an edge and loaded in shear perpendicular to and towards the edge, the failure is often governed by concrete edge breakout. This study investigates the transverse shear behavior of the anchor channels under quasi-static and high rate loadings using a numerical approach (3D finite element analysis) utilizing a rate-sensitive microplane model for concrete as constitutive law. Following the validation of the numerical model against a test performed under quasi-static loading, the rate-sensitive static, and rate-sensitive dynamic analyses are performed for various displacement loading rates varying from moderately high to impact. The increment in resistance due to the high loading rate is evaluated using the dynamic increase factor (DIF). Furthermore, it is shown that the failure mode of the anchor channel changes from global concrete edge failure to local concrete crushing due to the activation of structural inertia at high displacement loading rates. The research outcomes could be valuable for application in various types of connection systems where a high rate of loading is expected.

Effect of Specimen Geometries on the Pin Bearing Strength of Unidirectional CFRP Composites (일방향 CFRP 복합재료의 핀 베어링강도에 관한 시험편 치수의 영향)

  • Jeon, Jin-Tak;Kim, Jae-Dong;Koh, Sung-Wi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.4
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    • pp.346-351
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    • 1997
  • The pin bearing strength is one of the most important design parameters for mechanical joints composed of fiber reinforced composites. Thus the effect of the edge distance and the width of specimen on the pin-bearing strength of unidirectional CFRP composites were experimentally investigated in this paper. As results, the failure modes and the pin bearing strength of mechanical joints turned out to depend on the edge distance and also the width of specimen. The failure of specimen with low ratio of width to hole diameter was caused by the net tension from the hole boundary, on the other hand, the failure of specimen with low ratio of edge distance to hole diameter was caused by the shear-out. The bearing strength in case of the failure by shear-out was quite lower than that in case of failure by net tension.

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A Parameter Study on the Shear Failure Behavior of Post-installed Set Anchor for Light Load (저하중용 후설치 세트앵커의 전단파괴거동에 관한 매개변수 연구)

  • Um, Chan-Hee;Yoo, Seung-Woon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.3
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    • pp.55-63
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    • 2015
  • Post-installed concrete set anchors are installed after the concrete hardened. These anchors increasing usage in development of construction equipment and flexible construction. The anchor loaded in shearing exhibits various failure modes such as steel failure, concrete failure, concrete pryout, depending on the shear strength of steel, the strength of concrete, edge distance and anchor interval, etc,. In this study, the objective is to investigate the effects of the variations like anchor embedment depth, edge distance and concrete strength on experimental and finite element analysis of shear failure behavior of post-installed concrete set anchor for light load embedded in concrete. The results of embedment depth experiments show that concrete strength has much affection on the shallow embedment depth. Concrete strength has no much affection with anchor interval and edge distance parameter and both experimental results occurred same failure mode. By comparing the experimental results that occurred steel failure mode show that as strong as concrete strength are the displacement results are small.

An Experimental Study on the Shear Failure Behavior of Post-installed Set Anchor for Concrete (콘크리트용 후설치 세트앵커의 전단파괴거동에 관한 실험적 연구)

  • Um, Chan-Hee;Yoo, Seung-Woon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.2
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    • pp.367-375
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    • 2014
  • Recently the use of concrete post-installed set anchors has been increasing because this constructing method is flexible and easy to attach or fix structural members when we repair, reinforce, or remodel a concrete structures. Depending on the shear strength of steel, the strength of concrete, edge distance and anchor interval, etc, the anchor loaded in shearing exhibits various failure modes such as steel failure, concrete failure, concrete pryout. In this study, the objective is to investigate the effects of the variations like anchor embedment depth, anchor interval, edge distance and concrete strength on the shear failure behavior of post-installed concrete set anchor embedded in concrete. The results of embedment depth experiments show that concrete strength has much effection on the shallow embedment depth. Steel failure occur to all results of the anchor interval experiments, but concrete is failed when edge distance experiments that less than the embedment depth. Through the comparision of the same parameters experiments results show that as strong as concrete strength are the displacement results are small.

Valvular Failure due to the Laceration of Tissue Valve (조직판막 열상에 의한 판기능부전 -1예 보고-)

  • 정종수
    • Journal of Chest Surgery
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    • v.21 no.5
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    • pp.893-898
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    • 1988
  • A number of centers have recorded a significant incidence of primary tissue valve failure with the Ionescu-Shiley pericardial valve. Clinically, Endothelialization and host tissue ingrowth on the cloth and the leaflets at the edge of the frame greatly reduced the amounts of abrasion and the incidence of tissue failure. In most cases severe regurgitation was caused by leaflet tears adjacent to the edge of the cloth-covered stent. We report a case of spontaneous disruption of one cusp on the Ionescu-Shiley pericardial xenograft in mitral position at 6years and its successful management.

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Analysis of Contact Tractions influenced by Edge Machining (모서리가공에 따른 접촉응력 해석)

  • Kim, Hyung-Kyu;Kang, Heung-Seok;Yoon, Kyung-Ho;Song, Kee-Nam
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.389-395
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    • 2001
  • To restrain contact failure, present study investigates the influence of edge machining of an indenter (punch). As for the edge machining, rounding, chamfering, and chamfering and rounding are considered. Contact mechanics is consulted to examine the traction profile and the size of the contact region which are directly influenced by the end profile of the indenter. The effect of rounding size (i.e., radius) in the case of the chamfering and rounding edge-indenter is studied. Shear traction is also evaluated within the regime of partial slip. Size of slip region and its expansion rate due to the increase of shear force are considered to investigate the shape effect of the indenter on contact failure.

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Shear Strength of Single Anchors in Uncracked and Unreinforced Concrete (비균열·무근콘크리트의 단일앵커 전단내력 평가)

  • Kim, Sung-Yong;Kim, Kyu-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.4
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    • pp.171-181
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    • 2003
  • This study concerns the prediction of shear capacity, as governed by concrete breakout failure, concrete pryout failure and steel failure, of single anchors located close to free edge and located far from a free edge and installed in uncracked, unreinforced concrete. For this purpose, the methods to evaluate the shear capacity of the single anchors in concrete are summarized and the experimental data are compared with capacities by the two present methods: the method of ACI 349-90 and concrete capacity design (CCD) method.

A Study On The Propagation Failure Modes of Ion Implanted Magnetic Bubble Computer Memory Devices (이온주입식 자기버블 전산기 기억소자에서의 자기버블 전파실패에 관한 연구)

  • Jo, Soon-Chul
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.339-342
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    • 1988
  • Typical magnetic bubble propagation failure modes of ion implanted magnetic bubble computer memory devices were observed and their failure mechanisms were analize. The skidding failure mode is due to the pushing of a strong repulsive charged wall. If this pushing is stronger than the edge affinity of the bubble in the cusp, the bubble moves out of the cusp when it is supposed to stay there. The stripeout failure modes across the adjacent track or along the track can be explained by considering the relative strength of the charged wall and the edge affinity encountered by both ends of the stripe. The skipping of the first cusp of a track is believed to be due to the whipping motion of the charged wall. The bubble moves directly to the second cusp via the long charged wall pointing to the second cusp skipping the first cusp.

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Bolted connectors with mechanical coupler embedded in concrete: Shear resistance under static load

  • Milicevic, Ivan;Milosavljevic, Branko;Pavlovic, Marko;Spremic, Milan
    • Steel and Composite Structures
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    • v.36 no.3
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    • pp.321-337
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    • 2020
  • Contemporary design and construction of steel-concrete composite structures employs the use of prefabricated concrete elements and demountable shear connectors in order to reduce the construction time and costs and enable dismantling of elements for their potential reuse at the end of life of buildings. Bolted shear connector with mechanical coupler is presented in this paper. The connector is assembled from mechanical coupler and rebar anchor, embedded in concrete, and steel bolt, used for connecting steel to concrete members. The behaviour and ultimate resistance of bolted connector with mechanical coupler in wide and narrow members were analysed based on push-out tests and FE analyses conducted in Abaqus software, with focus on concrete edge breakout and bolt shear failure modes. The effect of concrete strength, concrete edge distance and diameter and strength of bolts on failure modes and shear resistance was analysed. It was demonstrated that premature failure by breakout of concrete edge occurs when connectors are located 100 mm or closer from the edge in low-strength and normal-strength reinforced concrete. Furthermore, the paper presents a relatively simple model for hand calculation of concrete edge breakout resistance when bolted connectors with mechanical coupler are used. The model is based on the modification of prediction model used for cast-in and post-installed anchors loaded parallel to the edge, by implementing equivalent influence length of connector with variable diameter. Good agreement with test and FE results was obtained, thus confirming the validity of the proposed method.

Application of FEM on first ply failure of composite hypar shells with various edge conditions

  • Ghosh, Arghya;Chakravorty, Dipankar
    • Steel and Composite Structures
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    • v.32 no.4
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    • pp.423-441
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    • 2019
  • This study aims to accurately predict the first ply failure loads of laminated composite hypar shell roofs with different boundary conditions. The geometrically nonlinear finite element method (FEM) is used to analyse different symmetric and anti-symmetric, cross and angle ply shells. The first ply failure loads are obtained through different well-established failure criteria including Puck's criterion along with the serviceability criterion of deflection. The close agreement of the published and present results for different validation problems proves the correctness of the finite element model used in the present study. The effects of edge conditions on first ply failure behavior are discussed critically from practical engineering point of view. Factor of safety values and failure zones are also reported to suggest design and non-destructive monitoring guidelines to practicing engineers. Apart from these, the present study indicates the rank wise relative performances of different shell options. The study establishes that the angle ply laminates in general perform better than the cross ply ones. Among the stacking sequences considered here, three layered symmetric angle ply laminates offer the highest first ply failure load. The probable failure zones on the different shell surfaces, identified in this paper, are the areas where non-destructive health monitoring may be restricted to. The contributions made through this paper are expected to serve as important design aids to engineers engaged in composite hypar shell design and construction.