Aerospace Science and Technology
Ali Davar; Mahdi Mehrabani; MohammadReza Zamani; Mohsen Heydari Bani; Jafar Eskandari Jam
Abstract
The composite lattice cylindrical shells are analyzed in this research while they are subjected to transient dynamic loading. The equilibrium equations for the composite cylindrical shell are expressed in terms of classical shell theory. Additionally, due to the discontinuous distribution of stiffness ...
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The composite lattice cylindrical shells are analyzed in this research while they are subjected to transient dynamic loading. The equilibrium equations for the composite cylindrical shell are expressed in terms of classical shell theory. Additionally, due to the discontinuous distribution of stiffness and shell mass between reinforcing ribs and their proximity to one another (empty or filled with filler material), this issue has been expressed using an appropriate distribution function. On the basis of Lowe's first approximation theory, the strain-displacement and curvature-displacement relationships are considered. The Galerkin method is used to calculate the natural frequencies and shapes of structural modes for the boundary conditions, as well as the transient dynamic response of the composite cylindrical lattice shell to lateral impulsive loading applied extensively and uniformly on a specific rectangular surface. The convolution and a method for summing the effects of the modes are also obtained, and the obtained results are validated using references and ABAQUS finite element software. The effects of various parameters on free and forced vibrations are investigated, including geometric ratios, material properties, cross-sectional dimensions and distances, and lattice configuration. Finally, the effect of strengthening the cylindrical shell with lattice structures is investigated.
Aerospace Science and Technology
Ali Ansari; Jafar Eskandari Jam; Ali Alizadeh; Mohsen Heydari Beni; Majid Eskandari Shahraki
Abstract
This study was designed to investigate the ballistic behavior of ceramic-reinforced aluminum composite plates numerically and experimentally and to present an optimal sample design. The parameters studied were ceramic reinforcement percentage and type of matrix alloy. This study used the matrix alloys ...
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This study was designed to investigate the ballistic behavior of ceramic-reinforced aluminum composite plates numerically and experimentally and to present an optimal sample design. The parameters studied were ceramic reinforcement percentage and type of matrix alloy. This study used the matrix alloys 6061, 7075, and 5083. The percentage of ceramics used in this study is 15, 30, and 45% by weight. The samples are in three thicknesses of 20, 25, and 30 mm. 27 simulated samples were numerically analyzed with Abaqus finite element software in this study based on existing ballistic protection criteria, one then determines the optimal numerical sample. Using the squeeze casting method, a laboratory sample has been made and experimentally tested to evaluate the numerical results. Lastly, the numerical analysis and the experimental test were compared and the optimal sample was determined.
