Yazar "Karamanli, Armagan" seçeneğine göre listele

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    Bending, buckling and free vibration analyses of shallow-to-deep FG curved sandwich beams using a global-local refined shear deformation theory
    (Elsevier Science Inc, 2023) Lezgy-Nazargah, M.; Karamanli, Armagan; Vo, Thuc P.
    This paper investigates the bending, vibration, and buckling behaviour of functionally graded (FG) curved sandwich beams using a global-local refined shear deformation theory. Material properties of these beams are varied through the thickness according to the power-law distribution. A beam element with a combination of Hermite cubic and quadratic Lagrange shape functions is developed to solve the problems. The obtained results are compared with the results from finite element software (ABAQUS), and other higher-order beam theories. It can be observed that the present model can predict accurately static, vibration, and buckling responses of both shallow and deep FG sandwich beams with arbitrary boundary conditions.
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    Bending, buckling and free vibration behaviours of 2D functionally graded curved beams
    (Elsevier Science Inc, 2023) Karamanli, Armagan; Wattanasakulpong, Nuttawit; Lezgy-Nazargah, M.; Vo, Thuc P.
    The flexural, free vibration and buckling responses of 2D-FG curved beams with various shear deformation theories are presented by using finite element model. Their material properties via both directions (length and thickness) are varied with power-law distribution. A two-node beam element satisfying C1 continuity requirement is employed to solve the problems. Various problems including isotropic, 1D- and 2D-FG curved beams are analysed and the obtained results are verified with those available in the literature. Comprehensive parameter examinations are carried out to depict the effects of gradation indexes in both directions, open angles, end conditions and aspect ratios on structural behaviours of 2D-FG curved beams.
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    Comprehensive analysis of bio-inspired laminated composites plates using a quasi-3D theory and higher order FE models
    (Elsevier Sci Ltd, 2024) Karamanli, Armagan; Vo, Thuc P.; Eltaher, Mohamed A.
    A comprehensive study is carried out by employing various finite element models (FEMs) for the bending, buckling stability and free vibration analyses of bio-inspired helicoidal composite plates with various lamination schemes. A higher order quasi-3D kinematic plate theory is developed to include a shear deformation effect. The variational formulation of the problem is exploited to derive the equations of motion, element stiffness, geometrical stiffness, and mass matrices based on a non-conforming rectangular element. Three different finite elements models are derived based on non-conforming elements with different number of nodes and degree of freedom. The developed finite element model has been validated with those found in the open literature. The effects of boundary condition, lamination scheme, orthotropy ratio and aspect ratio on the mechanical response of the bio-inspired helicoidal composite plates are examined. Notably, for the lamination schemes investigated in this study, no shear locking phenomenon was observed in the analyses conducted using these FEMs. Dimensionless centre deflections, critical buckling loads and fundamental frequencies of bio-inspired helicoidal composite plates vary depending on the type of lamination scheme, boundary condition and aspect ratio. The new orientation schemes can replace the traditional ones to overcome the shear singularity and overcome the delamination defects.
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    Higher order finite element models for transient analysis of strain gradient functionally graded microplates
    (Elsevier, 2023) Karamanli, Armagan; Vo, Thuc P.; Civalek, Omer
    In the study, three different higher order finite element models (HOFEMs) are developed to perform the transient analysis of functionally graded (FG) microplates subjected to different dynamic loads, namely, sinusoidally distributed step and exponential blast loads. A normal and shear deformable plate theory with five unknowns is used to present displacement field and modified strain gradient theory is employed for small-scale effect. A rectangular four-noded element and Newmark's method is used to solve transient analysis of FG microplates. The effects of boundary condition, type of dynamic loading, thickness to material length parameter, aspect ratio, gradient index and CPU time are investigated. It is found that two of the HOFEMs developed based on the C1 and C2 continuity requirements produced almost same numerical results. However, the one with 36 unknows per element yields slightly different results than the others. The HOFEM satisfying the C1 continuity requirement consumes the minimum computational time.
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    Transient analysis of bio-inspired shear and normal deformable laminated composite plates using a higher-order finite element model
    (Taylor & Francis Inc, 2024) Karamanli, Armagan; Vo, Thuc P.; Eltaher, Mohamed A.
    A study based on the transient responses of bio-inspired helicoidal laminated composite plates is performed by using a higher-order finite element model (HOFEM) consisting of the thickness stretching effect. The obtained results show good agreement with those available in the open literature. The shear locking phenomena is not inspected by employing the developed HOFEM for the helicoidal lamination schemes. The effects of path of the concentrated moving load, lamination scheme, boundary condition, speed, aspect and orthotropy ratios on the transient responses are investigated. Dynamic dimensionless center deflections and dynamic amplification factors are affected by considering not only the lamination scheme but also the path of the load, boundary condition, orthotropy and aspect ratios.
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    Transient vibration analysis of strain gradient multi-directional functionally graded microplates under a moving concentrated load
    (Elsevier Sci Ltd, 2023) Karamanli, Armagan
    In the study, the modified strain gradient elasticity theory is used to investigate the transient vibrations of the multi-directional functionally graded square microplates subjected to a moving concentrated load by employing a normal and shear deformable plate theory with five unknowns based on the Newmark's method for the first time. In-plane displacement and thickness stretching component of the transverse displacement are approximated by using a rectangular four-noded element with 16 unknows satisfying C1 continuity requirement. In addition, bending and shear components of the transverse displacement are presented by employing a rectangular four-noded element with 24 unknows called as a higher order finite element model (HOFEM) is developed to analyse the dynamic amplification factors and time history analysis of strain gradient multi-directional functionally graded square microplates. The effects of the boundary condition, thickness to material length parameter, gradient index in three directions, aspect ratio, and dimensionless load velocity parameter are examined. It is exhibited based on the results that dynamic amplification factors and dynamic dimensionless center deflections of multi-directional functionally graded strain gradient microplates are significantly affected by the variation of the analysis parameters provided above.