• Title/Summary/Keyword: orthotropic plate

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Position optimization of circular/elliptical cutout within an orthotropic rectangular plate for maximum buckling load

  • Choudhary, Prashant K.;Jana, Prasun
    • Steel and Composite Structures
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    • v.29 no.1
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    • pp.39-51
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    • 2018
  • Position of a circular or elliptical cutout within an orthotropic plate has great influence on its buckling behavior. This paper aims at finding the optimal position (both location and orientation) of a single circular/elliptical cutout, within an orthotropic rectangular plate, that maximizes the critical buckling load. We consider linear buckling of simply supported orthotropic plates under uniaxial edge loads. To obtain the optimal positions of the cutouts, we have employed a MATLAB optimization routine coupled with buckling computation in ANSYS. Our results show that the position of the cutout that maximizes the buckling load has great dependence on the material properties, laminate configurations, and the geometrical parameters of the plate. These optimal results, for a number of plate geometries and cutout sizes, are reported in this paper. These results will be useful in the design of perforated orthotropic plates against buckling failure.

Development of Live Load Moment Equations Using Orthotropic Plate Theory (직교 이방성 판 이론을 이용한 바닥판 활하중 모멘트 산정식 개발)

  • Ahn Ye-Jun;Nam Suk-Hyun;Park Jang-Ho;Shin Yung-Seok
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.749-756
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    • 2006
  • Because of the orthotropic elastic properties and significant two-way bending action, orthotropic plate theory may be suitable for describing the behavior of concrete filled grid bridge decks. Current AASHTO LRFD Bridge Design Specification(2004) has live load moment equations considering flexural rigidity ratio between longitudinal and transverse direction, but the Korea highway bridge design specification(2005) doesn't. The Korea highway bridge standard specification LRFD(1996) considers an orthotropic plate model with a single load to estimate live load moments in concrete filled grid bridge decks, which may not be conservative. This paper presents live load moment equations for truck and passenger car, based on orthotropic plate theory. The equations of truck model use multiple presence factor, impact factor, design truck and design tandem of the Korea highway bridge standard specification LRFD(1996). The estimated moments are verified through finite-element analyses.

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Characteristics of Sound Insulation in Sandwich Plates with Orthotropic Skin Plate (이방성판을 사용한 샌드위치판의 차음특성)

  • Kang, Hyun-Ju;Kim, Bong-Ki;Kim, Jae-Seung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.853-856
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    • 2004
  • This study presents a prediction method for sound insulation of sandwich plate which consists of orthotropic plates as skin and mineral wool as core. Prediction by classic theory, which considers orthotropic effects, requires considerably complex and cumbersome process and moreover many assumption. However, experimental results of the sandwich plate with orthotropic plates as skin show that the orthotropic effects are disappeared or fade out. Hence, predictions by using sandwich model are conducted by a simple modelling that substitutes an orthotropic plate into an equivalent flat plate. Comparative results show that sandwich model gives a good agreements with theoretical prediction.

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Elastic Buckling Analysis of a Simply Supported Orthotropic Plate with Exponentialy Variable Thickness (두께가 변하는 직교이방성판의 탄성좌굴해석)

  • 장성열;정상균;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.25-28
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    • 2001
  • The problem considered is the buckling of a rectangular orthotropic plate, tapered in thickness in a direction parallel to two sides and compressed in that direction. Curves are presented showing the variation of buckling stress coefficient with the special loads. The type of thickness variation is exponential. While this paper is presented how to design for an efficient orthotropic plate taper from physical consideration.

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Axisymmetric dynamic instability of polar orthotropic sandwich annular plate with ER damping treatment

  • Yeh, Jia-Yi
    • Smart Structures and Systems
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    • v.13 no.1
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    • pp.25-39
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    • 2014
  • The axisymmetric dynamic instability of polar orthotropic sandwich annular plate combined with electrorheological (ER) fluid core layer and constraining layer are studied in this paper. And, the ER core layer and constraining layer are used to improve the stability of the annular plate system. The boundaries of instability regions for the polar orthotropic sandwich annular plate system are obtained by discrete layer annular finite element and the harmonic balance method. The rheological property of an electrorheological material, such as viscosity, plasticity, and elasticity can be controlled by applying different electric field strength. Thus, the damping characteristics of the sandwich system are more effective when the electric field is applied on the sandwich structure. Additionally, variations of the instability regions for the polar orthotropic sandwich annular plate with different applying electric field strength, thickness of ER layer and some designed parameters are investigated and discussed in this study.

Buckling of Fixedly Supported Orthotropic Plate under In-plane Linearly Distributed Forces (면내 선형분포하중을 받는 고정지지된 직교이방성판의 좌굴)

  • 정재호;채수하;남정훈;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.5-8
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    • 2000
  • This paper presents the results of an elastic buckling analysis of orthotropic plate under in-plane linearly distributed forces. The analytical solution for the orthotropic plate whose boundaries were assumed to be simply supported was derived in the previous work. In this study the loaded edges of plate are assumed to be simply supported and other two edges are assumed to be fixed. For the buckling analysis Rayleigh-Ritz method is employed. Graphical form of results for finding the elastic buckling strength of orthotropic plate under in-plane linearly distributed forces is presented.

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The Analytical Study on the Cause of Fatigue Damage and the Improvement of Fatigue Performance for Orthotropic Steel Deck (강바닥판 피로손상 원인규명 및 피로성능 개선에 관한 해석적 연구)

  • Kyung Kab-Soo;Shin Dong-Ho;Kim Kyo-Hoon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.647-654
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    • 2006
  • In orthotropic steel decks, it is likely to have defects due to fatigue damages because most of structural joints(the connection of longitudinal rib and transverse rib, the connection of deck plate and longitudinal rib) are connected by welds. However. orthotropic steel decks have many advantages. such as light weight and reduction of construction time. in comparison with concrete decks. Therefore. they are mostly used in long-span bridges and urban highway bridges. This study consists of the cause identication of fatigue damage and the suggestion of rational thickness on deck plate about the connection of deck plate and longitudinal rib. The results are as follows: fatigue damage cause at the connection of deck plate and longitudinal rib is local deformation in deck plate. And, rational thickness of deck plate is 16mm thickness.

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Harmonic analysis of moderately thick symmetric cross-ply laminated composite plate using FEM

  • Narwariya, Manoj;Choudhury, Achintya;Sharma, Avadesh K.
    • Advances in Computational Design
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    • v.3 no.2
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    • pp.113-132
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    • 2018
  • This paper presents the vibration and harmonic analysis of orthotropic laminated composite plate. The response of plate is determined using Finite Element Method. The eight noded shell 281 elements are used to analyze the orthotropic plates and results are obtained so that the right choice can be made in applications such as aircrafts, rockets, missiles, etc. to reduce the vibration amplitudes. Initially the model response for orthotropic plate and harmonic response for isotropic plate is verified with the available literature. The results are in good agreement with the available literature. Numerical results for the natural frequency and harmonic response amplitude are presented. Effects of boundary conditions, thickness to width ratio and number of layers on natural frequency and harmonic response of the orthographic plates are also investigated. The natural frequency, mode shape and harmonic analysis of laminated composite plate has been determined using finite element package ANSYS.

A Fundamental Study on the Effects of Pavement Stiffness to the Structural Behavior of Orthotropic Steel Plate Deck (포장체의 강성이 강상판의 거동에 미치는 영향에 관한 기초연구)

  • Lee, Hwan-Woo;Jung, Du-Hwoe
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.1
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    • pp.191-198
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    • 2003
  • The pavement stiffness is scarcely used in structural analysis to design the superstructure of bridge. It is reasonable not to consider it in the case of asphalt concrete pavement over concrete deck because the pavement stiffness compared with the concrete deck plate can be ignored. However, sometimes, the pavement materials have a similar amount of elastic modulus to concrete and are applied to the orthotropic steel deck plate which has relatively less stiffness compared with the concrete deck plate. In this paper, the steel plate deck of a real bridge project was analyzed by considering the pavement stiffness by linear elastic FEM. It was assumed that a perfect bond between the steel plate deck and the pavement exited. The results indicated that the structural behavior of the orthotropic steel deck plate can be estimated enough to affect the evaluation result of structural capacity in some cases. Therefore, the investigations by experimental tests and more advanced numerical model are indispensible in figuring the design formula for considering the effects of pavement stiffness in the structural analysis of an orthotropic bridge.

EN 1991-2 traffic loads design charts for closed rib orthotropic deck plate based on Pelikan-Esslinger method

  • Vlasic, Andjelko;Radic, Jure;Savor, Zlatko
    • Steel and Composite Structures
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    • v.9 no.4
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    • pp.303-323
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    • 2009
  • Charts for the bending moments in the closed rib orthotropic deck plate are derived, based on the method originally introduced by Pelikan and Esslinger. New charts are done for EN 1991-2 traffic load distribution schemes. The governing Huber plate equation is solved utilizing Fourier series for various bridge deck plate boundary conditions. Bending moments are given as a function of deck plate rigidities and span length between cross beams. Old diagrams according to DIN 1072, the new ones according to EN 1991-2 and FE analyses results are compared. For typical bridge orthotropic deck plates, it can be concluded that the new EN 1991-2 traffic loads produce larger mid-span bending moments when two lane schemes are used, then those of DIN 1072. For support moments, DIN 1072 gives larger values for any number of lanes, especially under span lengths of 5m. The relevant differences are up to 25%.