• Title, Summary, Keyword: quasi-static test

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A Study on Residual Strength of Carbon/Epoxy Face Sheet and Honeycomb Core Sandwich Composite Structure after Quasi Static Indentation Damage (탄소섬유/에폭시 면재, 알루미늄 허니컴 코어 샌드위치 복합재 구조의 압입 손상에 의한 잔류강도 연구)

  • Kong, Chang-Duk;Park, Hyun-Bum;Lee, Seoung-Hyun
    • Composites Research
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    • v.22 no.2
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    • pp.24-29
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    • 2009
  • This study aims to investigate the residual strength of sandwich composites with Al honeycomb core and carbon fiber face sheets after the quasi-static indentation damage by the experimental investigation. The 3-point bending test and the edge-wise compressive strength test were used to find the mechanical properties, and the quasi-static point load was applied to introduce the simulated damage on the specimen. The damaged specimens were finally assessed by the 3-point bending test and the compressive strength test. The investigation results revealed the residual strength of the damaged specimens due to the quasi-static indentation. The both test results showed that the residual strength of the damaged specimen was decreased according to increases of the damaged depth.

Quasi-Static Test for Seismic Performance of Circular R.C. Bridge Piers Before and After Retrofitting (유리섬유 보강 원형 철근콘크리트 교각의 내진성능에 관한 준정적 실험연구)

  • 정영수;이강균;한기훈;이대형
    • Journal of the Korea Concrete Institute
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    • v.11 no.5
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    • pp.107-118
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    • 1999
  • 10 RC bridge piers have been made on a 1/3.4 scale model, and six piers of them were retrofitted with glassfiber. The have been tested in the quasi-static cyclic load so as to investigate their seismic enhancement before and after retrofitting with glassfibers. The objective of this experimental study is to investigate how to strength the ductility of reinforced concrete bridge piers which have been nonseismically designed and constructed in Korea before 1992. Important test parameters are axial load, load pattern, retrofit type. Glassfiber sheets were used for retrofitting in the plastic hinge region of concrete piers. The nonlinear behavior of bridge columns have been evaluated through their yield and ultimate strength, energy dissipation, displacement ductility and load-deflection characteristics under quasi-static cyclic loads. It can be concluded from the test that concrete piers strengthened with glassfibers have been enhanced for their ductile behavior by approximate 50%.

Prediction of Ballistic Limit for Composite Laminates Subjected to High-velocity Impact Using Static Perforation Test (정적압입 관통 실험을 이용한 복합재 적층판의 고속충격 탄도한계속도 예측)

  • You, Won-Young;Kim, In-Gul;Lee, Seokje;Kim, Jong-Heon
    • Composites Research
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    • v.26 no.1
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    • pp.21-28
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    • 2013
  • The ballistic limit of Carbon/Epoxy composite laminates with the finite effective area are predicted by using the quasi-static perforation test and semi-empirical formula. The perforation energy were calculated from force-displacement curve in quasi-static perforation test. Also, the actual ballistic limit and penetration energy were obtained through the high-velocity impact test. The quasi-static perforation test and high-velocity impact test were conducted for the specimens with 3 different effective areas. In the high-velocity impact test, the air gun impact tester were used, and the ballistic and residual velocity was measured. The required inputs for the semi-empirical formula were determined by the quasi-static perforation tests and high-velocity impact tests. The comparison between semi-empirical formula and high-velocity impact test results were conducted and examined. The ballistic limits predicted by semi-empirical formula were agreed well with high-velocity impact test results.

Laminate composites behavior under quasi-static and high velocity perforation

  • Yeganeh, E. Mehrabani;Liaghat, G.H.;Pol, M.H.
    • Steel and Composite Structures
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    • v.22 no.4
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    • pp.777-796
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    • 2016
  • In this paper, the behavior of woven E-glass fabric composite laminate was experimentally investigated under quasi-static indentation and high velocity impact by flat-ended, hemispherical, conical (cone angle of $37^{\circ}$ and $90^{\circ}$) and ogival (CRH of 1.5 and 2.5) cylindrical perforators. Moreover, the results are compared in order to explore the possibility of extending quasi-static indentation test results to high velocity impact test results in different characteristics such as perforation mechanisms, performance of perforators, energy absorption, friction force, etc. The effects of perforator nose shape, nose length and nose-shank connection shapes were investigated. The results showed that the quasi-static indentation test has a great ability to predict the high velocity impact behavior of the composite laminates especially in several characteristics such as perforation mechanisms, perforator performance. In both experiments, the highest performance occurs for 2.5 CRH projectile and the lowest is related to blunt projectiles. The results show that sharp perforators indicate lower values of dynamic enhancement factor and the flat-ended perforator represents the maximum dynamic enhancement factor among other perforators. Moreover, damage propagation far more occurred in high velocity impact tests then quasi-static tests. The highest damage area is mostly observed in ballistic limit of each projectile which projectile deviation strongly increases this area.

Seismic Performance of Concrete-Filled Steel Piers Part II: Pseudo-Dynamic Test and Residual Seismic Capacity (강합성교각의 내진성능평가 Part II: 유사동적실험 및 잔류내진성능 평가)

  • 조창빈;서진환;장승필
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.2
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    • pp.21-28
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    • 2002
  • Ductile behavior and strength of concrete-filled steel(CFS) piers was supported by many quasi-static cyclic loading tests. This test method, however, only estimates the member′s deformation capacity under escalating and repetitive displacement and ignores dynamic and random aspects of an earthquake load. Therefore, to understand complete seismic behavior of the structure against an earthquake, dynamic tests such as shaking table test and pseudo-dynamic tests are required as well as quasi-static tests. In this paper, following "Seismic Performance of Concrete-Filled Steel Piers Part I : Quasi-Static Cyclic Loadint Test", the seismic behavior of CFS and steel piers designed for I-Soo overpass in Seoul in investigated by the pseudo-dynamic test. In addition, the residual strength of both piers after an earthquake is estimated by the quasi-static test. The results show that both piers have satisfactory ductility and strength against well-known EI Centro earthquake although the CFS pier has better strength and energy dissipation than the steel pier.

A Constitutive Equation Including Strain Rate Effect for the Expanded Polypropylene (변형률 속도가 고려된 발포 폴리프로필렌의 구성방정식)

  • Kim, Han-Kook;Cheon, Seong S.
    • Composites Research
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    • v.27 no.4
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    • pp.130-134
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    • 2014
  • The purpose of this paper is to build DB in order to Propose new constitutive equations by redefining constitutive equations for Polyurethane presented by Jeong et al. [12] based on Quasi-static test and Impact test DB of Expanded polypropylene using cylindrical specimens with 4 different densities presentsd by Kim et al. [7] for EPP foam and combining the impulse-momentum theory.

Quasi-Static Tests for Seismic Performance of Circular RC Bridge Piers (단일주 원형 철근콘크리트 교각의 내진거동에 관한 준정적 실험)

  • 정영수;이강균;한기훈;박종협
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.2
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    • pp.55-66
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    • 1999
  • Eight RC bridge plers have been made on a 1/3.4 scale model and have been tested in a quasi-static cyclic load so as to investigate their seismic performance. The ultimate objective of this experimental study is to investigate the hysteretic behavior of reinforced concrete plers, which have been widely used for urban transportation facilities in Korea. Improtant test parameters are hoop ratio, axial load, load pattern, and etc. And noninear behaviors of test columns have been evaluated through their yield and ultimate strength, energy dissipation, ductility and load-deflection characteristics under quasi-static cyclic loads. From the quasi-static tests on 8 bridge piers, it is concluded that energy dissipation, ultimate strength and curvature for a given displacement factor ${\mu}={\Delta}/{\Delta}_y$ are higher for the seismically designed columns than for the nonseismically designed columns.

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Experimental Study for the Impact Characteristics of Expanded EPP/EPS Foams (발포 EPP/EPS의 충격특성에 관한 실험적 연구)

  • Kim, Han-Kook;Kim, Byeoung-Jun;Jeong, Kwang-Young;Cheon, Seong S.
    • Composites Research
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    • v.26 no.6
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    • pp.343-348
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    • 2013
  • In the present study, quasi-static tests and impact tests were performed for investigating the mechanical behaviour of EPP (Expanded polypropylene) and EPS (Expanded polystyrene). Four different density cylindrical type specimens were prepared for EPP and EPS and 0.001 $s^{-1}$ and 0.1 $s^{-1}$ of strain rate conditions for quasi-static tests and 100 J, 200 J and 300 J of incident energy conditions for the instrumented impact tests were considered.

Quasi Static Test of Lap Spliced Shear-Flexure RC Piers Using Real Scale Models (주철근 겹침이음된 휨-전단 RC교각의 실물모형 준정적 실험)

  • 곽임종;조창백;조정래;김영진;김병석
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.203-210
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    • 2002
  • The past bridge design specifications of Korea didn't include 1imitation on the amount of lap splices in the plastic hinge zone of piers, and so do current specifications. But these specifications include just limitation on the minimal length of lap splices. Thus, a large majority of non-seismically designed bridge piers may have lap splices in plastic hinge zone. In this study, model pier was selected among existent bridge piers whose failure mode is complex shear-flexure mode. Full scaled RC pier models whose aspect ratio is about 2.67 were constructed and quasi static test according to the drift level history was implemented. From the test results, effect of the lap splices on the seismic performance of bridges piers was analyzed, and the seismic capacity of the model bridges was evaluated by capacity spectrum method.

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A Study on Residual Strength of Damaged Sandwich Composite Structure (샌드위치 복합재 구조의 손상에 의한 잔류 강도 연구)

  • Kong, Chang-Duk;Kong, Hyun-Bum;Kim, Sang-Hoon;Song, Min-Su
    • Proceedings of the KSR Conference
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    • pp.2073-2079
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    • 2008
  • This study aims to investigate the residual strength of sandwich composites with Al honeycomb core and carbon fiber face sheets after the quasi-static indentation damage by the experimental investigation. The 3-point bending test and the edge-wise compressive strength test were used to find the mechanical properties. The quasi-static point load and damaged hole was applied to introduce the simulated damage on the Each damaged specimens were finally assessed by the 3-point bending test and the compressive strength test. The investigation results revealed the residual strength of the damaged specimens due to the quasi-static indentation.

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