• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.595-603
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• 1989

Free vibration of orthotropic laminated composite conical shells with constant thickness are considered. Governing frequency equations are derived based on the Flugge theory and Galerkin method is applied for the numerical analysis. Comparisons are made between present results and others for the isotropic conical shells and numerical results are obtained based on these results for the specially orthotropic laminated composite conical shells with simply supported edges. Variations of frequency parameter on the change of material properties, stacking sequences, stacking number, geometrical parameters and orthotropic parameters are considered in the analysis.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.251-256
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• 2000

이방성 재료에서 균열의 성장을 예측하는 것은 실제 구조물의 안전성을 정확하게 해석하기 위한 중요한 문제이다. 이방성 재료 내에서의 균열의 거동은 등방성 재료의 경우와는 다르기 때문에 이방성 재료 내의 균열 해석 문제가 중요한 관심을 끌게 되었다. 비등방성 재료에 대한 지금까지의 연구는 대부분 직선균열의 해석, 직선균열의 초기 전파 각도에 대한 해석에 대하여 이루어져 왔고 곡선 균열에 대한 연구［1-4］는 많이 이루어지지 않았다.(중략)

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.944-953
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• 1991

본 연구에서는 일반적인 이방성재료에 대한 코스틱방법의 적용을 검토하는 일 환으로서, 직교이방성재료중 특성방정식의 근이 동일함으로 인하여 균열의 응력장이 특이성을 갖게 되고, 따라서 지금까지는 코스틱법의 적용이 어려웠던 재료(의사등방성 재료)에 대하여, 코스틱상 및 초기곡선의 식을 이론적으로 구하였고, 이 식을 예상되 는 여러가지 경계조건 하에서 컴퓨터 그래픽(computer graphic)으로 가시화하여, 시편 제작의 어려움으로 인하여 실험이 곤란한 의사등방성재료의 코스틱상을 예시하였으며, 또 이들 재료에 대한 응력확대계수 산출법을 제시함과 동시에 이 산출법이 등방성 재 료 및 일반적 직교이방성재료에도 사용가능함을 밝혀 다음 제2부에서 실험을 통하여 검증되도록 하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.2
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• pp.36-43
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• 2003

The analytic solution of radial displacements of thin cylindrical pressure vessel with carbon fiber T700/Epoxy orthotropic composites was obtained using equilibrium equations of the orthogonal curvilinear coordinate system. The governing equations with the simplified strain versus displacement relation of 3-dimensional curvilinear coordinate system were derived from the variational principle and the virtual work principle. Some theoretical analyses were presented and compared with the results of hydraulic tests for the pressure vessels with some various thicknesses. The results of the theoretical analysis and the hydraulic test were reasonably matched.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.41-50
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• 2012

Improvement of steel material quality made fatigue problems more critical than failure of the material itself. In many cases, cracks on the welded parts of steel deck bridges are reported against the failure of steel materials. And the cracks are caused by alternate stress on the welded parts due to live loads on the bridge. The range of alternate stress on the welded part is related to property of the sections which compose othortropic steel deck. Othortropic steel deck is mainly composed of deck plate, ribs and floor beams, wearing surface, etc. In this paper, a methology to estimate the alternate stress for pthortropic steel deck using Pelikan-Esslinger method and signed Von-Mises equivalent stress is proposed first. Parametric study served references for fatigue stresses when designing or repairing othortropic steel deck bridges, by analyzing relationship between alternate stress range and properties of steel deck members.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.1
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• pp.21-28
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• 2012

In this paper, we present the analytical study results pertaining to the buckling of the orthotropic plates and local buckling of structural compression members composed of orthotropic plate components. Fiber reinforced polymeric plastic (FRP) materials, have many advantages over conventional structural materials such as steel and concrete. The advantages of the FRP materials are high specific strength and stiffness, high corrosion resistance, right weight, etc. Among the various manufacturing methods, pultrusion process is one of the best choices for the mass production of structural plastic members. Since the major reinforcing fibers are placed along the axial direction of the member, this material is usually considered as an orthotropic (tranversely isotropic, more specifically) material. However, pultruded fiber reinforced plastic structural members have low modulus of elasticity and are composed of orthotropic thin plate components the members are prone to buckle. Therefore, stability is an important issue in the design of the pultruded FRP structural members. In this paper, the buckling of orthotropic plates and the local buckling of pultruded FRP structural members are investigated by following the previous research results and the local buckling strength of the member produced in the domestic manufacturer is found.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.701-708
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• 2010

The stress and displacement fields of a permeable propagating crack in orthotropic piezoelectric materials under anti-plane shear mechanical load and in-plane electric load are analyzed. The equations of motion for the propagating crack in piezoelectric materials are developed and the solution on the stress and the displacement fields through an asymptotic analysis was obtained. The influences of the piezoelectric constant and of the dielectric permittivity on the stress and displacement fields at the crack tip are explicitly clarified. Using the stress and displacement fields obtained in this study, the characteristics of stress and displacement at a propagating crack tip in piezoelectric materials are discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.10
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• pp.1807-1815
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• 1992

The vibration characteristic of thin laminated orthotropic cylindrical shell is investigated based on the Donnell theory. The Rayleigh-Ritz variational procedure is employed. For the variety of shell end conditions, the beam characteristic function is used for the axial mode function. The result of the present analysis is in good agreement with some available analytical results and NASTRAN and BOSOR4 calculations. In the present study, the relation between natural frequencies and orthotropic parameter k is investigated. Introducing the frequency parameter, this study shows that the frequency parameter increases as the orthotropic parameter k approaches to one.

• Composites Research
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• v.17 no.2
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• pp.9-14
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• 2004

In this study, analytical investigations on the flexural behavior of FRP reinforced concrete slab were discussed. In the derivation of analytic solution, the FRP reinforced concrete slab was modeled as a structural orthotropic plate. To determine the flexural rigidities of an orthotropic plate model, the elastic equivalence method was employed. In the finite element analysis, the approximate method to determine the rigidity matrix of orthotropic plate element was also suggested using the elastic equivalence method. The results obtained by the analytical solution and the finite element analysis were compared with that of experiment.

• Composites Research
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• v.12 no.2
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• pp.46-52
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• 1999

In this paper result of an analytical investigation pertaining to the elastic buckling behavior of orthotropic plate under combined in-plane shear and bending forces is presented. The existing analytical solution developed for the isotropic plates is extended so that the orthotropic material properties can be taken into account in the buckling analysis of web plate. For the solution of the problems Rayleigh-Ritz method is employed. Graphical form of results for finding the elastic buckling strength of orthotropic plate under combined in-plane shear and bending forces is presented. Brief discussion on the design criteria for the shear and bending interaction is also presented.