• 제목/요약/키워드: shear effect

Search Result 4,344, Processing Time 0.028 seconds

Prediction Model Using Upper Bound Theorem of Shear Strength for RC Beams Strengthened by FRP (상한계 이론을 이용한 FRP로 보강된 RC보의 전단강도 예측 모델)

  • 홍성걸;문선혜
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2003.05a
    • /
    • pp.908-911
    • /
    • 2003
  • This study was performed to verify the effect of reinforcement of RC Beams strengthened($90^{\circ}$ strip type) by FRP(CFRP) and Predited the shear strength of them using the upper bound theorem. The prediction model was confirmed with the result of the FEM analysis. The analyzed result showed thar shear-damaged RC beams by strengthened by FRP was improved their shear capacity.

  • PDF

Shear Effects on Production of Lignin Peroxidase by Phanerochaete chrysosporium

  • Sang, Byeong-In;Kim, Yong-Hwan;Yoo, Young-Je
    • Biotechnology and Bioprocess Engineering:BBE
    • /
    • v.1 no.1
    • /
    • pp.26-31
    • /
    • 1996
  • Since biosynthesis of lignin peroxidase from Phanerochaete chrysosporium was known to be sensitive to shear, it is interesting to understand the effects of the shear sensitivity for the overproduction of lignin peroxidase. In stirred-tank fermentor, the shear-sensitivity in lignin peroxidase biosynthesis was quantified by using Kolmogorov length scale. It was found that agitation at 80$\mu$m Kolmogorov length scale is advantageous for the production of lignin peroxidase from P. chrysosporium. To overcome the shear sensitivity in lignin peroxidase biosynthesis caused by the agitation,P. chrysosporium was immobilized on various solid carriers. The nylon-immobilized P. chrysosporium was chosen in the present study as a way to overcome the shear sensitivity at the ranges of above 50$\mu$m Kolmogorov length scale. The adhesion force between immobilized cell and carrier can be predicted by thermodynamic approach and used as a criteria to select an adequate carrier materials for immobilization.

  • PDF

Numerical study of the effect of periodic jet excitation on cylinder aerodynamic instability

  • Hiejima, S.;Nomura, T.
    • Wind and Structures
    • /
    • v.5 no.2_3_4
    • /
    • pp.141-150
    • /
    • 2002
  • Numerical simulations based on the ALE finite element method are carried out to examine the aerodynamics of an oscillating circular cylinder when the separated shear flows around the cylinder are stimulated by periodic jet excitation with a shear layer instability frequency. The excitation is applied to the flows from two points on the cylinder surface. The numerical results showed that the excitation with a shear layer instability frequency can reduce the negative damping and thereby stabilize the aerodynamics of the oscillating cylinder. The change of the lift phase seems important in stabilizing the cylinder aerodynamics. The change of lift phase is caused by the merger of the vortices induced by the periodic excitation with a shear layer instability frequency, and the vortex merging comes from the high growth rate, the rapid increase of wave number and decrease of phase velocity for the periodic excitation in the separated shear flows.

Shear Strength Properties of Fiber Mixed Soil (섬유혼합토의 전단강도 특성)

  • Cha, Hyun-Ju;Choi, Jae-Won;Lee, Sang-Ho
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.44 no.4
    • /
    • pp.123-128
    • /
    • 2002
  • This study was performed to use fiber mixed soil which has clayey soil or sandy soil with fibrillated fiber or monofilament fiber on purpose of construction materials, filling materials, and back filling materials. In addition, this study was conducted to analyze strength properties and fiber reinforcing effect with fiber mixed soil by direct-shear test. In case of fibrillated fiber mixed soil, the more quantity of fiber was in both cohesive soil and sandy soil, the larger shear stress was in respective step of normal load. The respective mixed soil at 0.5% and 0.1% mixing ratio of monofilament fiber mixed soil showed maximum shear stress. According to unconfined compression or direct-shear test, making specimen of the monofilament fiber mixed soil, it is required to be careful and stable mixing method, while it is expected that monofilament fiber mixed soil doesn't increase strength.

The Shear Effects of the Web Reinforcement Area and Arrangement in R.C. Deep Beams (철근콘크리트 깊은보에서 전단보강근량 및 배치가 전단거동에 미치는 효과)

  • 윤정민;김미경;연규원;박찬수
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2000.10b
    • /
    • pp.885-890
    • /
    • 2000
  • 12 RC deep beams with a/d = 1.17 are reported. This paper is to study the effect of vertical and horizontal web reinforcement and web reinforcement arrangement on inclined cracking shear, ultimate shear strength, midspan deflection, and inclined crack width. Test results indicated that web reinforcement produces and arrangement seems to moderately affect inclined cracking shear, ultimate shear strength and crack width. However, addition of horizontal web reinforcement(pv = 0.0085) little or no influence on inclined cracking shear, ultimate shear strength and crack width. The member which vertical and horizontal web reinforcement concentrate on the center web considerably increases in load-carrying capacity.

SEISMIC RESPONSE CHARACTERISTICS OF THE MULTI-SPAN CONTINUOUS GBRIDGE WITH SHEAR KEYS (전단키와 있는 다경간 연속교의 지진응답특성)

  • 이지훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 1998.10a
    • /
    • pp.120-127
    • /
    • 1998
  • This paper deals with the dynamic responses of the multi-span continuous bridge with longitudinal shear keys. It is motivated by a need to understand the effects of longitudinal shear keys which may be used for the reduction of the longitudinal seismic force in continuous bridges. The results show that (1) The force reduction of fixed pier is proportional to the ratio of gap size and elastic maximum displacement of the bridges without shear keys ; (2) The thermal movement has little effect on the response of the continuous bridges with shear keys. Also the simplified equation is proposed to calculate the maximum response of the continuous bridges with longitudinal shear keys. The equation requires only the elastic analysis results of the bridge and the gap size between superstructure and shear keys.

  • PDF

Shear Strength Equation for Slender Diagonally Reinforced Coupling Beam (세장한 대각보강 연결보의 전단강도 예측식)

  • Han, Sang Whan;Kang, Jin Wook;Han, Chan Hee
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.20 no.6
    • /
    • pp.361-368
    • /
    • 2016
  • Coupling beams serve as primary source of energy dissipation in coupled shear wall systems during large earthquakes. However, the overestimation of the shear strength of diagonally reinforced coupling beams may be adverse effect on the seismic performance of coupled shear wall systems. In order to force coupling beams to properly work during earthquakes, coupling beams should be designed with accurate shear strength equations. The objective of this study is to propose the accurate shear strength equation for slender diagonally reinforced coupling beams. For this purpose, experimental tests were conducted using three diagonally reinforced coupling specimens with different amount of transverse reinforcement under reversed cyclic loads to evaluate the hysteretic behavior of the specimens. The test results show that transverse reinforcement of slender diagonally reinforced coupling beam affects the maximum strength and drift ratio.

Effects of details of lattice reinforcement for punching shear strength of slab-column connections (슬래브-기둥 접합부의 뚫림 전단강도에 대한 래티스 보강상세의 영향)

  • Kim, You-Ni;Park, Hong-Gun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2006.11a
    • /
    • pp.17-20
    • /
    • 2006
  • A flat plate-column connection is susceptible to brittle punching shear failure, which may result in the necessity of shear reinforcement. In previous, experimental tests were performed to study the capacity of slab-column connections strengthened with various shear reinforcement, and the capacity of the specimens with lattice reinforcement are superior to the others. In present study, to study for effects of details of lattice reinforcement, experimental studies was performed. Main parameters are the amount of lattice shear reinforcement, arrangement of lattice and the effect of flexural re-bar. And capacity of the specimen with small amount of lattice reinforcement was higher than the capacity of other shear reinforcement.

  • PDF

Study of shear and elongational flow of solidifying polypropylene melt for low deformation rates

  • Tanner, R.I.;Kitoko, V.;Keentok, M.
    • Korea-Australia Rheology Journal
    • /
    • v.15 no.2
    • /
    • pp.63-73
    • /
    • 2003
  • An experimental technique was developed to determine the strain-rate in a tensile specimen. Then one can calculate the transient isothermal elongational viscosity. Both shear and elongational viscosities were measured to study the effect of shear and elongational fields on the flow properties. The comparison between these viscosities shows that the onset of rapid viscosity growth as crystallization solidification proceeds occurs at about the same value of time at very small deformation rates (0.0028 and 0.0047 $s^{-1}$). The comparison of these measured viscosities as functions of shear and elongational Hencky strains also reveals that the onset of rapid viscosity growths starts at critical Hencky strain values. The behaviour of steady shear viscosity as function of temperature sweep was also explored at three different low shear rates. Finally, the influence of changing oscillatory frequencies and strain rates was also investigated.

Vibration and stability analyses of thick anisotropic composite plates by finite strip method

  • Akhras, G.;Cheung, M.S.;Li, W.
    • Structural Engineering and Mechanics
    • /
    • v.3 no.1
    • /
    • pp.49-60
    • /
    • 1995
  • In the present study, a finite strip method for the vibration and stability analyses of anisotropic laminated composite plates is developed according to the higher-order shear deformation theory. This theory accounts for the parabolic distribution of the transverse shear strains through the thickness of the plate and for zero transverse shear stresses on the plate surfaces. In comparison with the finite strip method based on the first-order shear deformation theory, the present method gives improved results for very thick plates while using approximately the same number of degrees of freedom. It also eliminates the need for shear correction factors in calculating the transverse shear stiffness. A number of numerical examples are presented to show the effect of aspect ratio, length-to-thickness ratio, number of plies, fibre orientation and stacking sequence on the natural frequencies and critical buckling loads of simply supported rectangular cross-ply and arbitrary angle-ply composite laminates.