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composite-cylinders
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Comparison of natural frequencies of composite cylindrical shells: A squared lattice with its equivalent seamless one
, Article Proceedings of the ASME Design Engineering Technical Conference, 15 August 2010 through 18 August 2010 ; Volume 5 , 2010 , Pages 835-841 ; 9780791844137 (ISBN) ; Jam, J. E ; Hashemian, A. H ; Sharif University of Technology
Abstract
Modern Latticed composite materials whose high specific strength and stiffness are utilized in spacecraft and rocket structures to a sufficiently high extent are now widely used in primary airframe structures. In this work a comparison between squared latticed composite cylinder shells and the equivalent hollow cylinder with same weight, outer radius, length and material is done. An analytical equation is derived for natural frequency of square latticed composite shells. The first fifth modes are taken to be compared. The analytical and FEM results are shown and compared to each other. Also, as discussed, the squared lattice cylinder shell reaches to their natural frequencies easily than the...
Multi-objective optimal design of stiffened laminated composite cylindrical shell with piezoelectric actuators
, Article International Journal on Interactive Design and Manufacturing ; Volume 14, Issue 2 , January , 2020 , Pages 595-611 ; Bohlooly, M ; Sharif University of Technology
Springer
2020
Abstract
The stiffeners and piezoelectric actuators are used in many aerospace structures as an auxiliary layer with laminated composites. A question then arises as to whether we can estimate the percentage of these materials in an efficient design. Due to the high computational cost, it is not easy to answer through numerical solutions. The objective of this paper is concurrently to maximize the buckling load and minimize the weight of the cylindrical shell. To reach this aim, a multi-objective optimization problem is developed based on the closed-form solutions of thermal/mechanical buckling and weight of the piezolaminated shell with eccentric/concentric stiffener. The Non-dominated Sorting...
Free vibration analysis of multilayered composite cylinder consisting fibers with variable volume fraction
, Article Composite Structures ; Volume 94, Issue 3 , 2012 , Pages 931-944 ; 02638223 (ISSN) ; Hashemi, M ; Sharif University of Technology
Abstract
In this paper, free vibration of a fiber reinforced composite cylinder in which volume fraction of its fibers vary longitudinally, is studied using a semi-analytical method. The distribution of volume fraction of fiber in base matrix is based on power law model. A micromechanical model is employed to represent its mechanical properties including elastic and physical properties of this composite cylinder. In addition, kinematically the first order shear deformation shell theory is employed for strain field. Then, weak form formulation and spatial approximations of variables are utilized to discretize the equations of motion. Different problems are solved in which primarily the validity of the...