• Title/Summary/Keyword: transverse impact

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Investigation of Impact Behavior by Thickness variation of Laminated Composite Subjected to Low-Velocity Impact (저속충격을 받는 복합적층판의 두께 변화에 따른 충격거동 조사)

  • Kwon, Suk-Jun;Jeon, Jin-Hyung;Kim, Seung-Deog
    • Proceeding of KASS Symposium
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    • 2008.05a
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    • pp.74-79
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    • 2008
  • In this study, impact transient responses of (Graphite/Epoxy) laminated composite subjected to low-velocity impact are investigated using a finite element method. Dynamic von-Karman plate equations considering large deflection of plate are modified to include the effect of transverse shear deformations as in Mindlin plate theory and also the rotary inertia effect is considered. The convergence of transient responses is used contact law established through the statical indentation test. We investigate displacements, contact forces and strains by thickness variation of various laminated composite. We compare and analyze each results.

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The Effects of Curvature Change on Penetration Characteristics of CFRP Laminate shell (곡률변화가 CFRP 적층쉘의 관통특성에 미치는 영향)

  • 조영재;이상훈;김영남;양인영
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.274-279
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    • 2004
  • Currently, carbon-fiber reinforced plastics(CFRP) are widely used in both space and civil aircraft due to their superior stiffness and strength to weight ratios compared to conventional metallic materials. This paper is to study the effects of curvature and stacking sequence on the penetration characteristics of composite laminated shell. And were performed to investigate the penetration characteristics of composite laminated shells by the oblique impact. They are stacked to [0$_3$/90$_3$]s, [90$_3$/0$_3$]s and [0$_2$/90$_3$/0]s, [90$_2$/0$_3$/90]s their interlaminar number two and fore. They are manufactured to varied curvature radius (R=100, 150, 200mm and $\infty$). When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistics-screen sensor located a known distance apart. In general, the critical penetration energy interface decrease and slope angle on the impact surface increased. [0$_3$/90$_3$]s and [0$_2$/90$_3$]s specimens higher than [90$_3$/0$_3$]s and [90$_2$/0$_3$/90]s specimens.

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CFD simulation of compressible two-phase sloshing flow in a LNG tank

  • Chen, Hamn-Ching
    • Ocean Systems Engineering
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    • v.1 no.1
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    • pp.31-57
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    • 2011
  • Impact pressure due to sloshing is of great concern for the ship owners, designers and builders of the LNG carriers regarding the safety of LNG containment system and hull structure. Sloshing of LNG in partially filled tank has been an active area of research with numerous experimental and numerical investigations over the past decade. In order to accurately predict the sloshing impact load, a new numerical method was developed for accurate resolution of violent sloshing flow inside a three-dimensional LNG tank including wave breaking, jet formation, gas entrapping and liquid-gas interaction. The sloshing flow inside a membrane-type LNG tank is simulated numerically using the Finite-Analytic Navier-Stokes (FANS) method. The governing equations for two-phase air and water flows are formulated in curvilinear coordinate system and discretized using the finite-analytic method on a non-staggered grid. Simulations were performed for LNG tank in transverse and longitudinal motions including horizontal, vertical, and rotational motions. The predicted impact pressures were compared with the corresponding experimental data. The validation results clearly illustrate the capability of the present two-phase FANS method for accurate prediction of impact pressure in sloshing LNG tank including violent free surface motion, three-dimensional instability and air trapping effects.

A Study on the Impact Behavior of the Beam-Like Laminated Composite by the Beam and Plate Theories (보와 판이론에 의한 보형상 복합재의 충격 거동에 관한 연구)

  • 김문생;안국찬;김규남
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.4
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    • pp.643-652
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    • 1989
  • The purpose of this research is to analyze the impact behavior of beam-like laminates due to the transverse impact of a steel ball according to the changes of stacking sequence and aspect ratio. For this purpose, it is carried out the dynamic finite element analyses using the modified beam theory for laminates and the first order shear deformation plate theory. The results of these analyses are compared with those of experimental impact tests. The composite materials are composed of [0.deg./45.deg./0.deg./-45.deg./0.deg.]$_{2S}$ and [90.deg./45.deg./90.deg./-45.deg./90.deg.]$_{2S}$ stacking sequences and have 4.5 t * 5(10, 20 & 30)w * 200(300)l(mm)dimensions. In all analyses, the specimens are clamped at both ends.cimens are clamped at both ends.

Axisymmetric vibrations of layered cylindrical shells of variable thickness using spline function approximation

  • Viswanathan, K.K.;Kim, Kyung Su;Lee, Jang Hyun;Lee, Chang Hyun;Lee, Jae Beom
    • Structural Engineering and Mechanics
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    • v.28 no.6
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    • pp.749-765
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    • 2008
  • Free axisymmetric vibrations of layered cylindrical shells of variable thickness are studied using spline function approximation techniques. Three different types of thickness variations are considered namely linear, exponential and sinusoidal. The equations of axisymmetric motion of layered cylindrical shells, on the longitudinal and transverse displacement components are obtained using Love's first approximation theory. A system of coupled differential equations on displacement functions are obtained by assuming the displacements in a separable form. Then the displacements are approximated using Bickley-spline approximation. The vibrations of two-layered cylindrical shells, made up of several types of layered materials and different boundary conditions are considered. Parametric studies have been made on the variation of frequency parameter with respect to the relative layer thickness, length ratio and type of thickness variation parameter.

Nonlinear dynamic response of axially moving GPLRMF plates with initial geometric imperfection in thermal environment under low-velocity impact

  • G.L. She;J.P. Song
    • Structural Engineering and Mechanics
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    • v.90 no.4
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    • pp.357-370
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    • 2024
  • Due to the fact that the mechanism of the effects of temperature and initial geometric imperfection on low-velocity impact problem of axially moving plates is not yet clear, the present paper is to fill the gap. In the present paper, the nonlinear dynamic behavior of axially moving imperfect graphene platelet reinforced metal foams (GPLRMF) plates subjected to lowvelocity impact in thermal environment is analyzed. The equivalent physical parameters of GPLRMF plates are estimated based on the Halpin-Tsai equation and the mixing rule. Combining Kirchhoff plate theory and the modified nonlinear Hertz contact theory, the nonlinear governing equations of GPLRMF plates are derived. Under the condition of simply supported boundary, the nonlinear control equation is discretized with the help of Gallekin method. The correctness of the proposed model is verified by comparison with the existing results. Finally, the time history curves of contact force and transverse center displacement are obtained by using the fourth order Runge-Kutta method. Through detailed parameter research, the effects of graphene platelet (GPL) distribution mode, foam distribution mode, GPL weight fraction, foam coefficient, axial moving speed, prestressing force, temperature changes, damping coefficient, initial geometric defect, radius and initial velocity of the impactor on the nonlinear impact problem are explored. The results indicate that temperature changes and initial geometric imperfections have significant impacts.

A Comparative Study of Transverse Cylindrical Projection Functions by A Series of Numerical Simulations (수치시험을 통한 횡원통 상사 투영함수 비교 연구)

  • Lee, Hungkyu;Seo, Wansoo
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.31 no.2
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    • pp.121-134
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    • 2013
  • The transverse cylindrical projection has been used in Korea since 1910s when the nationwide geodetic network was firstly established. However, the projection has a number of different types of functions according to a way of its mathematical derivation as well as a section of its coefficients and terms, for instance Gauss- Schreiber(GS) and Gauss-Kruger(GK) types. Although the transverse cylindrical projection itself is assigned to a system, projected coordinates would be diverse with respect to the function used in the actual calculation. In order to investigate impact of functions used in the computation, five different equations (i.e., 2 GS and 3 GK) were implemented in this study by using MATLAB. A series of numerical simulation tests has been carried out to compare and characterize them in terms of projection accuracy, difference of projected coordinates and distortion. Furthermore, a comparison between GS and GK function was made under the Korean gridding system, consisting of four zones. Results from the numerical computations were qualitatively analyzed and summarized in this paper.

A Study on the Impact-Induced Damage in CFRP Angle-ply Laminates (CFRP 사교적층판의 충격손상에 관한 연구)

  • 배태성;입야영;양동률
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.2
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    • pp.237-247
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    • 1993
  • Carbon fiber reinforced plastics(CFRP) have gained increased application in aerospace structures because of their specific strength and stiffness, but are sensitive to impact-induced damage. An experimental investigation was carried out to evaluate the impact resistance of CFRP according to the ply angle. The specimens of angle ply laminate composites were employed with [0.deg. $_{6}$/ .deg.$_{10}$/0.deg.$_{6}$], in which 6 kinds of ply angle such as .deg.=15.deg., 30.deg., 45.deg., 60.deg., 75.deg. and 90.deg. were selected. The impact tests were conducted using the air gun type impact testing machine by steel balls of diameter of 5 mm and 10 mm, and impact-induced damages were evaluated under same impact speed of V=60m/s. The impact damaged zones were observed through a scanning acoustic microscope (SAM). The obtained results were summarized as follows: (1) Delaminations on the interfacial boundaries showed th directional characteristics to the fiber directions. The delamination area on the impact side (interface A) was considerably smaller compared to that of the opposite side (interface B). (2) Cracks corresponding to other delaminations than those mentioned in SAM photographs were also seen on the impact damaged zone. (3) The delamination patterns were affected by the ply-angle, the dimensions of the specimen, and the boundary conditions. (4) The impact damaged zone showed zone showed the delamination on the interfacial boundaries, transverse shear cracks of the surface layer, and bending cracks of the bottom layer.r.r.r.

A numerical and theoretical investigation on composite pipe-in-pipe structure under impact

  • Wang, Yu;Qian, Xudong;Liew, J.Y. Richard;Zhang, Min-Hong
    • Steel and Composite Structures
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    • v.22 no.5
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    • pp.1085-1114
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    • 2016
  • This paper investigates the transverse impact response for ultra lightweight cement composite (ULCC) filled pipe-in-pipe structures through a parametric study using both a validated finite element procedure and a validated theoretical model. The parametric study explores the effect of the impact loading conditions (including the impact velocity and the indenter shape), the geometric properties (including the pipe length and the dimensions of the three material layers) as well as the material properties (including the material properties of the steel pipes and the filler materials) on the impact response of the pipe-in-pipe composite structures. The global impact responses predicted by the FE procedure and by the theoretical model agree with each other closely. The parametric study using the theoretical approach indicates the close relationships among the global impact responses (including the maximum impact force and the maximum global displacement) in specimens with the equivalent thicknesses, proposed in the theoretical model, for the pipe-in-pipe composite structures. In the pipe-in-pipe composite structure, the inner steel pipe, together with the outer steel pipe, imposes a strong confinement on the infilled cement composite and enhances significantly the composite action, leading to improved impact resistance, small global and local deformations.

A Study on the Damage of CFRP Laminated Composites Under Out-of-Plane Load (횡방향 하중을 받는 CFRF 적층복합재의 내부손상에 관한 연구)

  • Kim, Moon-Saeng;Park, Seung-Bum;Oh, Deug-Chang
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.11
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    • pp.98-109
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    • 1995
  • An investigation was performed to study the inner damage of laminated composite plates subjected to out-of-plane load. During the investigation, inpact velocity and equivalent static load relationship was derived. Reddy's higher-order shear deformation theory(HSDT) and Hashin's failure criteria were used to determine inner stresses and damaged area. And impact testing was carried out on laminated composite plates by air gun type impact testing machine. The CFRP specimens were composed of [ .+-. 45 .deg. ]$_{4}$and [ .+-. 45 .deg. /0 .deg. /90 .deg. ]$_{2}$ stacking sequences with 0.75$^{t}$ * 26$^{w}$ * 100$^{l}$ (mm) dimension. After impact testing. As a result, a relationship holds between damaged area and impact energy, and a matrix cracking was caused by the interlaminar shear stress in the middle ply and was caused by the inplane transverse stress in the bottom ply.

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