Comparison of Natural Frequencies of Composite Cylindrical Shells: A Squared Lattice with Its Equivalent Seamless One

摘要

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 equivalent hollow cylinder shell.rnreticulated shells [9]. For reticulated shells, especially for lattice composite shells, there is very limited information available. In this work, governing equation for free vibration of a squared latticed cylindrical composite shell is derived and dynamic analysis of a unidirectional squared latticed composite cylindrical shell and their equivalent hollow cylinder is preformed by FEM method [10] to conduct and compare the natural frequencies.