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Sadr-Hashemi, Farshid. "Buckling of conical shells". Thesis, University College London (University of London), 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685403.
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Ifayefunmi, Olawale Friday. "Combined stability of conical shells". Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569897.
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This thesis is concerned with the study of the elastic-plastic buckling of short and relatively thick conical shells subjected to combined loading, i.e., axial compression and external pressure acting simultaneously. This is both numerical and experimental study. Within the context of numerical study, a nonlinear finite element calculations were carried out in order to obtain: (i) the failure loads of cones under axial compression only, external pressure only and under combined loading, (ii) the spread of plastic strain and the effect of strain hardening of the material on failure loads, and (iii) the sensitivity of buckling loads to initial geometric imperfections or to structural defects under various loading conditions. The thesis provides results of extensive FE calculations. An experimental programme involved tests on thirteen conical specimens CNC machined with integral top and bottom flanges from 252mm diameter steel billet. The specimens were made from mild steel material with average yield stress of 230.6 MPa, Young's modulus of 21 0490 MPa and Poisson' s ratio of 0.28l. Prior to tests, the existing test rig had to be significantly modified and instrumented in order to accommodate independent/combined loadings. The test procedure has been developed and successfully implemented. Two models were subjected to axial compression, with further two subjected to external pressure. The remaining nine cones were subjected to combined action of axial compression and external pressure. Experimental results were compared with predictions of failure loads obtained from the existing design codes. For the case of axial compression an extension of the design rules is outlined in order to widen the range of applicability. For the case of external pressure, the test data compared well with the theoretical work by Esslinger and Van Impe, [40]. At the same time the test data highlighted how inadequate estimates of the load carrying capacity are given by the design codes. The case of combined loading, i.e., axial compression and external pressure is only covered by ASME code case 2286-2, [157], and experimental data does not exist. The current study provides the first and much needed test data. The thesis also looks into the concept of equivalent cylinder. Numerical results point out to the fact that this approach is unsuitable for combined stability scenario (axial compression and external pressure). Experimental data is also compared with predictions given by the Finite Element calculations. Details about various approaches to modeling material properties, shape, wall thickness distribution, and boundary conditions are discussed. The quality of FE models is assessed by comparing the FE predictions of the load carrying capacity with the test data.
3
Caresta, Mauro Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Structural and acoustic responses of a submerged vessel". Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2009. http://handle.unsw.edu.au/1959.4/44404.
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Excitation of the low frequency vibrational modes of a submerged vessel can generate significant radiated noise levels. Vibrational modes of a submarine hull are excited from the transmission of fluctuating forces through the shaft and thrust bearings due to the propeller rotating in an unsteady fluid. The focus of this work is to investigate the structural and acoustic responses of a submarine hull under axial excitation. The submarine hull is modelled as a cylindrical shell with internal bulkheads and ring stiffeners. The cylindrical shell is closed by truncated conical shells, which in turn are closed at each end using circular plates. The entire structure is submerged in a heavy fluid medium. The structural responses of the submerged vessel are calculated by solving the cylindrical shell equations of motion using a wave approach and the conical shell equations with a power series solution. The displacement normal to the surface of the structure in contact with the fluid medium was calculated by assembling the boundary/continuity matrix. The far field radiated sound pressure was then calculated by means of the Helmholtz integral. Results from the analytical model are compared with computational results from a fully coupled finite element/boundary element model. The individual and combined effects of the various influencing factors, corresponding to the ring stiffeners, bulkheads, conical end closures and fluid loading, on the structural and acoustic responses are characterised by examining the contribution by the circumferential modes. It is shown that equally spaced internal bulkheads generate a periodic structure thus creating a grouping effect for the higher circumferential modes, but do not have strong influence on the sound radiation. Stiffeners are found to have an important effect on both the dynamic and acoustic responses of the hull. The contribution of the conical end closures on the radiated sound pressure for the lowest circumferential mode numbers is also clearly observed. This work shows the importance of the bending modes when evaluating the sound pressure radiated by a submarine under harmonic excitation from the propulsion system.
4
Spagnoli, Andrea. "Buckling behaviour and design of stiffened conical shells under axial compression". Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/8821.
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Steyn, Brett Kenneth. "The effect of weld-induced imperfections on the buckling behaviour of spherical and conical shells". Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/4999.
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Includes bibliographical references.The early research was on general imperfections most commonly in the form of the lowest buckling modes. The use of steel pates to fabricate silos in a regular pattern led to the civil engineering interest in the weld-induced imperfection. This imperfection was found to be in the circumferential direction and the dominant cause for the reduction of the classical buckling load. As previous research was conducted on cylindrical shells the current thesis focused on studying two different shell geometries.
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Low, Hwee Min Charles. "Computation of acoustic scattering from elastic conical shells with endcaps using the hybrid finite element/ virtual source approach". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33421.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004.Includes bibliographical references (p. 101-102).
Studying and understanding acoustic scattering pattern from underwater targets has been of interest to various communities such as the archeologists and the navy for several reasons and applications. The present state-of-the-art technique in this area involves such methods as analytical approach and FEM/BEM numerical technique. This thesis aims to study and demonstrate the power of using the hybrid virtual source/FE approach where the physical presence of a target is replaced by virtual sources placed in the vicinity of the target and in a manner where the pressure/displacement relationship on the target surface is satisfied by the virtual sources when the target is being insonified. Accurate results for the far-field radiation of the target can be obtained by superposition of the point source Green's function of each virtual source. The hybrid virtual source/FE approach shows potential to be a computationally efficient method for computing acoustic scattering. The derivation of the dynamic flexibility matrix for an elastic conical shell with endcaps will be illustrated in this thesis. It will be shown that the dynamic flexibility matrix corresponds to the acoustic admittance matrix in the virtual source approach where the scattering functions are computed in the MIT's program OASES/SCATT.
(cont.) Moreover, the benchmarking and validation of the approach will be conducted with the hybrid analytical/ virtual source approach. Firstly, the approach predicts natural frequencies close to the theoretical analysis for higher order modes with more than 2 circumferential transverse vibration lobes. Secondly, it produces displacement profile that conforms to analytical results. The scattering functions are also in agreement those computed by the hybrid analytical/ virtual source approach, with discrepancies observed at lower frequencies. In exact terms, discrepancies start to appear for frequency in the range of 1000 to 2000 Hz for a 0.01m thick, 2 m long, 0.3m radius steel cylinder without endcaps. The scattering functions will be compared with the SCATT/OASES virtual source approach for pressure release and rigid cylinders and cones. For the hybrid FE/virtual source approach, the structural sound speed and density approach zero and infinity for pressure-release and rigid target respectively. On the other hand, in the SCATT/OASES virtual source approach, the pressure and displacement are required to vanish on the target surface respectively. It will be shown that the two approaches agree with each other.
(cont.) Moreover, scattering functions over steel cones and cylinders for various frequencies have also been derived in this research. The results will be interpreted physically and theoretically in this thesis. The importance of including structural damping in the finite element formulation of the target so as to reflect the effect of resonance on scattering will be illustrated. Other issues, such as effect of target orientations on scattering, will also be investigated in this thesis. The code has shown good potential for adaptation to compute scattering over other axisymmteric shapes using conical shells and circular plates as building blocks and the hybrid FE/ virtual source approach.
by Hwee Min Charles Low.
S.M.
7
Rossetti, Luigi <1978>. "Static analysis of functionally graded cylindrical and conical shells or panels using the generalized unconstrained third order theory coupled with the stress recovery". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5749/1/Rossetti_Luigi_tesi.pdf.
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A 2D Unconstrained Third Order Shear Deformation Theory (UTSDT) is presented for the evaluation of tangential and normal stresses in moderately thick functionally graded conical and cylindrical shells subjected to mechanical loadings. Several types of graded materials are investigated. The functionally graded material consists of ceramic and metallic constituents. A four parameter power law function is used. The UTSDT allows the presence of a finite transverse shear stress at the top and bottom surfaces of the graded shell. In addition, the initial curvature effect included in the formulation leads to the generalization of the present theory (GUTSDT). The Generalized Differential Quadrature (GDQ) method is used to discretize the derivatives in the governing equations, the external boundary conditions and the compatibility conditions. Transverse and normal stresses are also calculated by integrating the three dimensional equations of equilibrium in the thickness direction. In this way, the six components of the stress tensor at a point of the conical or cylindrical shell or panel can be given. The initial curvature effect and the role of the power law functions are shown for a wide range of functionally conical and cylindrical shells under various loading and boundary conditions. Finally, numerical examples of the available literature are worked out.
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Rossetti, Luigi <1978>. "Static analysis of functionally graded cylindrical and conical shells or panels using the generalized unconstrained third order theory coupled with the stress recovery". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5749/.
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A 2D Unconstrained Third Order Shear Deformation Theory (UTSDT) is presented for the evaluation of tangential and normal stresses in moderately thick functionally graded conical and cylindrical shells subjected to mechanical loadings. Several types of graded materials are investigated. The functionally graded material consists of ceramic and metallic constituents. A four parameter power law function is used. The UTSDT allows the presence of a finite transverse shear stress at the top and bottom surfaces of the graded shell. In addition, the initial curvature effect included in the formulation leads to the generalization of the present theory (GUTSDT). The Generalized Differential Quadrature (GDQ) method is used to discretize the derivatives in the governing equations, the external boundary conditions and the compatibility conditions. Transverse and normal stresses are also calculated by integrating the three dimensional equations of equilibrium in the thickness direction. In this way, the six components of the stress tensor at a point of the conical or cylindrical shell or panel can be given. The initial curvature effect and the role of the power law functions are shown for a wide range of functionally conical and cylindrical shells under various loading and boundary conditions. Finally, numerical examples of the available literature are worked out.
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Castro, Paullo Giovani Pereira [Verfasser]. "Semi-analytical tools for the analysis of laminated composite cylindrical and conical imperfect shells under various loading and boundary conditions / Paullo Giovani Pereira Castro". Clausthal-Zellerfeld : Universitätsbibliothek Clausthal, 2015. http://d-nb.info/1066715157/34.
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Dapic, Ignacio. "Numerical Model for the Lateral Compression Response of a Plastic Cup". Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34750.
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A numerical analysis based on the finite element method is developed to simulate the mechanical response of a typical sixteen-ounce plastic drink cup subjected to a lateral compressive load. The aim of the analysis is to simulate a test in which the cup is supported horizontally in a fixture on a testing machine platen, and a loading nose attached to the actuator is displaced downward into the cup. The numerical model is developed using the software packages MSC.Patran, ABAQUS/CAE, and ABAQUS/Standard. The high impact polystyrene material of the cup is modeled as linear elastic, considering isotropic and orthotropic material behavior. The structural model of the cup is a truncated conical shell including a ring at the open end of the cup and circumferential stiffening ribs. The analysis is based on small strain, large rotation shell kinematics, and the loading apparatus of the test is simulated with a rigid, circular cylinder contacting the cup. Coupons cut from the wall of a cup are subjected to tension to determine the ranges of the meridional and circumferential moduli of elasticity. Rings cut from the open end of the cup were tested in diametrical tension to aid in validating the finite element modeling. Reasonable correlation of the simulation to available cup compression test data is achieved. Parametric studies are conducted for several meridional thickness distributions of the cup wall, and for a range of orthotropic material properties.Master of Science
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Bleyer, Jérémy. "Méthodes numériques pour le calcul à la rupture des structures de génie civil". Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1043/document.
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Ce travail tente de développer des outils numériques efficaces pour une approche plus rationnelle et moins empirique du dimensionnement à la ruine des ouvrages de génie civil. Contrairement aux approches traditionnelles reposant sur une combinaison de calculs élastiques, l'adoption de coefficients de sécurité et une vérification locale des sections critiques, la théorie du calcul à la rupture nous semble être un outil prometteur pour une évaluation plus rigoureuse de la sécurité des ouvrages. Dans cette thèse, nous proposons de mettre en œuvre numériquement les approches statique par l'intérieur et cinématique par l'extérieur du calcul à la rupture à l'aide d'éléments finis dédiés pour des structures de plaque en flexion et de coque en interaction membrane-flexion. Le problème d'optimisation correspondant est ensuite résolu à l'aide du développement, relativement récents, de solveurs de programmation conique particulièrement efficaces. Les outils développés sont également étendus au contexte de l'homogénéisation périodique en calcul à la rupture, qui constitue un moyen performant de traiter le cas des structures présentant une forte hétérogénéité de matériaux. Des procédures numériques sont spécifiquement développées afin de déterminer puis d'utiliser dans un calcul de structure des critères de résistance homogènes équivalents. Enfin, les potentialités de l'approche par le calcul à la rupture sont illustrées sur deux exemples complexes d'ingénierie : l'étude de la stabilité au feu de panneaux en béton armé de grande hauteur ainsi que le calcul de la marquise de la gare d'AusterlitzThis work aims at developping efficient numerical tools for a more rational and less empirical assessment of civil engineering structures yield design. As opposed to traditionnal methodologies relying on combinations of elastic computations, safety coefficients and local checking of critical members, the yield design theory seems to be a very promising tool for a more rigourous evaluation of structural safety. Lower bound static and upper bound kinematic approaches of the yield design theory are performed numerically using dedicated finite elements for plates in bending and shells in membrane-bending interaction. Corresponding optimization problems are then solved using very efficient conic programming solvers. The proposed tools are also extended to the framework of periodic homogenization in yield design, which enables to tackle the case of strong material heterogeneities. Numerical procedures are specifically tailored to compute equivalent homogeneous strength criteria and to use them, in a second step, in a computation at the structural level. Finally, the potentialities of the yield design approach are illustrated on two complex engineering problems : the stability assessment of high-rise reinforced concrete panels in fire conditions and the computation of the Paris-Austerlitz railway station canopy
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Kotík, Libor. "Konstrukce sila na cukr". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227611.
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The matter of this thesis is static design and examination of prestressed storage tank to 50000 tons of sugar. Computational model of the steel roof structure is processed and its effect on the silos. Loads is provided of sugar. Optimal design is performed and assessment ultimate and serviceability limit state reinforced concrete and prestressing horizontal silo wall including local load. Next, it is performed the design of a reinforced concrete of the plane bed and column and assessment at the ultimate limit state. The thesis is also drawing documentation, technical report and visualization of construction process. The aim of this work is to the design of the main components based on the required storage capacity tank, mechanical properties of the stored material and technical amenities.
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Hung, Yu-Chang, i 洪余長. "ASYMPTOTIC THEORY OF LAMINATED CIRCULAR CONICAL SHELLS". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/60148966708607480565.
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Wu, Yi-Hsien, i 吳宜憲. "A generalized thermoelasticity problem of multilayered conical shells". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/03079841614371827940.
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博士國立中興大學
應用數學系
92
The problem of the two-dimensional axisymmetric quasi-static coupled thermoelastic transient response for the laminated circular conical shells and rotating annular multilayered cylinder subjected to arbitrary boundary conditions is presented. The analysis is carried out using a hybrid Laplace transformation and finite difference method. The present method divides the governing differential equations and boundary conditions into the finite difference method and then removes the time dependences from the discretized equations with the Laplace transform. The solutions were obtained by using the matrix similarity transformation and inverse Laplace transform. To demonstrate the proposed method’s validity, a series of problems of the thermoelastic transient response are evaluated as three categories: (1) the problems of laminated circular conical shells based on the curvilinear circular conical coordinates; (2) the problems of the laminated circular conical shells with clamped surface subjected to an internal blasting pressure and the external cooling process; (3) the problems of a rotating annular multilayered cylinder with inner and outer surfaces subjected to internal pressure in the inner surface and external cooling process in the outer surface. It was shown that the solutions are rapidly convergent. When applied to many nodes it takes an excessive amount of computer time. The present hybrid method can obtain stable solutions at a specific time; thus it is a further concluded that the method and the computing process of the generalized coupled transient thermoelastic problems are powerful and efficient. Solutions for the temperature, displacement and thermal stress distributions in both transient and steady state are obtained. Moreover, the effects of the different rotational speeds on these numerical results with the rotating annular multilayered cylinder were also discussed.
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Khatri, Kamal N. "Vibration and damping analysis of multilayered conical shells". Thesis, 1989. http://localhost:8080/iit/handle/2074/4961.
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Chen, Chia-Yu, i 陳家宇. "Bending Analysis of Laminated Conical Shells by Love's Theory". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/x83y83.
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碩士國立成功大學
土木工程學系碩博士班
90
The paper exams bending analysis of laminated conical shells by Love掇 classic shell theory (CST) using the method of differential quadrature (DQ). It shows stresses, strains and displacements for different thickness, shape and laminae arrangements. By Fourier expansion, the stiffness coefficients are assumed to be the functions of longitudes. By vanishing the semivertex angle (a), the conical shells are reduced to the cylindrical. In DQ methods, the governing equations and the corresponding boundary conditions are replaced by a set of algebraic equations with the function values at all the sampling points. The figures show the conducts of the various structure and the tables show the details.
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Lin, Chi-Hao, i 林啟豪. "Thermal stresses analysis of composite laminated circular conical shells". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/2hvq2h.
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Shadmehri, Farjad. "Buckling of Laminated Composite Conical Shells; Theory and Experiment". Thesis, 2012. http://spectrum.library.concordia.ca/974742/4/Shadmehri_PhD_F2012.pdf.
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Composite conical and cylindrical shells are gaining more application in aerospace industry (e.g., helicopter tailboom, airplane fuselage) due to their high specific strength and stiffness properties coming from material (composite) and geometry advantages. Stability is always a concern for these types of structures under different loading conditions. One of the major loading scenarios is the bending load in which composite conical shells can buckle under bending. Although there have been extensive studies on the buckling of conical and cylindrical shells under axial load, buckling under bending receives less attention in the literature from theoretical and experimental points of view. In this study, the bucking behavior of composite conical shells has been studied experimentally and theoretically.
In the theoretical approach, a first order shear deformation shell theory has been proposed to study buckling and bending behavior of composite conical shells. A semi-analytical approach (Ritz method) has been applied to study buckling under axial load and buckling under bending of composite conical shells. An analytical solution (Levy type solution) has been applied to study the bending response of cross-ply conical shells under sinusoidal bending load. Also, a new formulation has been proposed to study bending, buckling and vibration of cross-ply cylindrical shells using an analytical solution (Levy type solution). A different displacement field from what was assumed in the literature has been proposed and consequently a new formulation has been obtained for the problem.
In the experimental approach, a composite tube-bending setup has been designed and developed to study bending, and buckling under bending load, behavior of composite shells. The setup has been designed to apply equal bending moments at the both ends of the structure, simulating pure bending test conditions. Experimental result has been obtained for buckling under pure bending of composite conical shells.
Regarding the manufacturing technique, Automated Fiber Placement (AFP) has attracted the aerospace industry due to its fast production rate, repeatability, and minimum material waste. Advanced thermoplastic composites obtain special attention in the aerospace industry as well, considering their superior properties (e.g., fracture toughness) and their capability to make aero-structures without requiring autoclave treatment with respect to thermoset ones. Considerable challenges remained unresolved regarding optimum process parameters for manufacturing of thermoplastic composites made by AFP and their quality. This thesis also addresses the effect of autoclave treatment on the stiffness quality of the thermoplastic composite cones made by AFP. The determination of optimum process parameters for AFP in the manufacturing of thermoplastic composite (AS4/PEEK) has been performed from both stiffness and strength point of view.
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Cheng, Min Yuan, i 鄭敏元. "AN ASSESSMENT OF SHELL THEORIES FOR THE FREE VIBRATION ANALYSIS OF LAMINATED CONICAL SHELLS". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/11321500931277444969.
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碩士國立成功大學
土木工程學系
89
With comparison of the recently available three-dimensional (3D) elasticity solution, four classical shell theories (CST) (i.e., Donnell’s, Love’s and Sanders’ theories) and their extensions to the first-order shear deformation theories (FSDT) are assessed for the free vibration analysis of laminated conical shells. The simplifications of the initial curvature term made in the basic equations for various CST/FSDT are examined. The governing equations of various CST/FSDT are derived and expressed in terms of the displacement components. The distinctions among various CST/FSDT are made with the Kronecker’s Delta. The method of differential quadrature (DQ) is adopted for obtaining the solutions of various CST/FSDT. The present formulations of various CST/FSDT are applicable to the analyses of laminated cylindrical shells and annular plates by letting the semivertex angle of the cone are identical to and , respectively. The natural frequencies of isotropic annular plates, cross-ply cylindrical and conical shells with simply supported—simply supported (S-S) boundary conditions obtained from various CST/FSDT are computed. A parametric study for the effects of lamination schemes and geometrical parameters on the least natural frequency and the corresponding vibration mode is carried out to evaluate the performance of various CST/FSDT.
20
Li, Shi-Yu, i 李仕宇. "Vibration Analysis of Conical Shells by the Differential Quadrature Method". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/61345671565826841753.
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碩士國立成功大學
航空太空工程學系碩博士班
94
In this thesis, the free vibration behavior of truncated conical shells based on the Love’s thin shell theory is investigated by using the differential quadrature method (DQM). By using the DQM, the equations of motion of free vibration of conical shells in the differential form are reduced into algebraic equations. A new weighting matrix is obtained through natural coordinate transformation. To evaluate the accuracy of the new weighting matrix used in DQM, numerical results obtained by the DQM are compared with those in the literature. Furthermore, effects of the semi-vertex angle and the ratio of truncation on the natural frequency of truncated conical shells are studied. Numerical results show the superb accuracy, efficiency, and convenience of the DQM.
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LEE, CHIA-YING, i 李佳穎. "DIFFERENTIAL QUADRATURE SOLUTION FOR THE FREE VIBRATION ANALYSIS OF LAMINATED CONICAL SHELLS". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/09765317511943036172.
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Wu, Chang-Hsing, i 吳長興. "ASYMPTOTIC DIFFERENTIAL QUADRATURE SOLUTIONS FOR THE FREE VIBRATION OF LAMINATED CONICAL SHELLS". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/48803772307670426995.
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Hui-ShengZhang i 張會昇. "Maximization of the Fundamental Frequencies of Axially Compressed Rotating Laminated Truncated Conical Shells". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/73596688362818305225.
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碩士國立成功大學
土木工程學系
102
Composites possess light weight, high strength, high stiffness, corrosion resistance, low thermal conductivity and other superior characteristics. Composites is widely used in a variety of engineering structures. To avoid structures producing resonance phenomenon and to avoid materials exceeded the allowable limits, the natural frequency analysis of composites structures is essential topics. In this study, using finite element analysis software ABAQUS to analyze laminated truncated conical shells’s fundamental frequency. Subjected to the different boundary conditions ,geometric shapes, the axial pressure, rotational speed. The Golden section method is employed to find the optimal fiber orientations and its corresponding maximum fundamental frequency in the composite laminated cylindrical shells. Design a compressed rotating laminated truncated conical shell,which can avoid the incidence of resonance phenomena. Select the appropriate angle and geometry of the fiber to improve the fundamental frequency of laminated truncated conical shells. The research results are valuable to the industry.
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Lai, Cheng-Hung, i 賴政宏. "Free Vibration Analysis of Rotating Truncated Conical Shells by the Differential Quadrature Method". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/52792734815655275721.
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碩士國立成功大學
航空太空工程學系碩博士班
95
In this thesis, the free vibration behavior of rotating truncated conical shells based on Love’s thin shell theory is studied by using the differential quadrature method (DQM). The governing equations of motion of free vibration of rotating truncated conical shell in the differential form are reduced to a set of algebraic equations by applying the differential quadrature formulation. Natural frequencies of the rotating truncated conical shells are obtained. The accuracy of the DQM is assured by comparing numerical results obtained by the DQM with results in the literature. Furthermore, effects of boundary conditions, semi-vertex angle and the ratio of truncation on the natural frequencies of rotating truncated conical shells are studied. Numerical results show the efficiency, good accuracy, and convenience of the DQM.
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Chung, Youngjin. "Buckling of composite conical shells under combined axial compression, external pressure, and bending". Thesis, 2001. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2001-099.
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Shao-PinWu i 吳紹彬. "Application of moving least square method for large deformation analysis of the conical shells". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/f85cb4.
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碩士國立成功大學
土木工程學系
103
In this article, the assumption of first-order shear deformation and the principle of virtual work are employed to derive large deformation theory of conical shells. With the quasi-Hermite type formulation in moving least squares method (MLS), it can handle equilibrium equations, constitutive relations, to get the numerical solution. When solving the numerical solution, nonlinear equilibrium equations of the conical shells under large deformation is linearized by using the Newton-Raphson method, and using the iterative process to approximate it, and calculate the resulting force, and bending moments after large deformation. The numerical examples of the nonlinear behavior of conical shells are discussed, it include the buckling behavior of conical shells, nonlinear behavior of the shell under internal pressure, and the snap through behavior of opened conical shell.
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Hao-YangHuang i 黃浩洋. "Semi-Analytical Finite Element Methods for the Analysis of Functionally Graded Truncated Conical Shells". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g79xyg.
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碩士國立成功大學
土木工程學系
107
Based on the Reissner’s mixed variational theorem (RMVT), a semi-analytical finite annular prism method (FAPM) is developed for three-dimensional (3D) static analyses of bi-directional functionally graded (FG) truncated conical shells. The material properties of the FG truncated conical shell are assumed to obey a bi-directional power-law distribution of the volume fractions of the constituents through the meridian-thickness surface, the effective material properties of which are estimated using the rule of mixtures. Implementation of the current FAPMs shows their solutions converge rapidly and that the convergent solutions are in excellent agreement with the 3D solutions available in the literature.
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Hung-YiWang i 王弘毅. "Large deformation analysis of the conical shells by the arc-length and moving least squares methods". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/20953766042620631246.
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碩士國立成功大學
土木工程學系
104
In this thesis, the nonlinear theory for the large deformation of conical shells is investigated under the assumption of the first order shear deformation using the principle of virtual work. The functions of constitutive equations and equilibrium equations are linearized by the arc-length method and analyzed using the moving least squares approximation in the quasi-Hermite type formulation. Then, the deformed configurations and the associated forces will be obtained after the iterations. The numerical examples of the nonlinear behavior of conical shells are discussed in the study, and they includes the buckling behavior of conical shells, nonlinear behavior of the shell under internal pressure, and the snap-through behavior of the opened conical shell.
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O, Sheng-Chang, i 歐勝昌. "Influence of Geometry and End Conditions on Optimal Funddmental Natural Frequencies of Symmetrically Composite Laminated Conical Shells". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/84903223477983172104.
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Dai, Po-Chang, i 戴伯璋. "Large Deformation Theory of Conical Shell". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/39676001409061363205.
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碩士國立成功大學
土木工程學系碩博士班
94
Abstract In this paper, form the configurations of the opened conical shell before and after deformed, we derive its strains and equilibrium equations under large displacement. Using the coordinates of the middle surface of the open conical shell and its transverse shear strains as the field functions, five nonlinear partial differential equations are established for the system. To solve those nonlinear equations, we adopt the Newton-Raphson method to linearlize the differential equations and using the differential reproducing kernel method to solve the linearlized differential equations. A numerical solution for snap-through for the opened conical shell under two different boundry conditions.
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YAN, WEN-XI, i 顏文禧. "Electromagnetic scattering by a thin conducting conical shell". Thesis, 1987. http://ndltd.ncl.edu.tw/handle/44720321797343379152.
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Patel, Mrityunjay Prasad. "Vibration Analysis of Functionally Graded Nanocomposite Conical Shell Structures". Thesis, 2015. http://ethesis.nitrkl.ac.in/7161/1/Vibration_patel_2015.pdf.
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The present work deals with the free vibration analysis and buckling behavior of functionally graded nanocomposite conical shell structures reinforced with carbon nanotubes. The effective material properties of the functionally graded nanocomposite shell structures are obtained using the extended rule of mixture by using UD and some functionally graded distribution of singlewalled carbon nanotubes (SWCNTs) in the thickness direction of the shell. In this study the nanocomposite is forming by mixing SWCNTs as reinforced phase with the polymer as matrix phase and makes a superior quality nanocomposite material at nanoscale level with some extraordinary material properties which provides advanced performance and service level. A suitable finite element model of functionally graded conical shell structure is developed using the ANSYS parametric design language (APDL) code in ANSYS environment. The model has been discretized using an eight noded shell element. The solution is obtained for fundamental natural frequencies and deformation of the composite shell. The effects of various geometric parameters, CNT volume fraction, boundary conditions and material properties are presented and discussed