Numerical and Experimental Buckling Strength Analysis of Composite Grid Stiffened Cylindrical Shells Before and After Applying Low-Velocity Transverse Impact

Composite materials became a great interest of researchers on light weight structures during the last decades due to their high specific strength and high specific stiffness. Lattice and grid stiffened structures are one of these efficient composite structures especially for axial compressive loads. In this research, the following main objectives are followed: (1) The buckling strength analysis of the lattice cylinders subjected to axial compressive force, (2) The impact response and damage analysis of the lattice cylinders subjected to the transverse impact of a falling object, (3) The buckling strength analysis of the lattice cylinders subjected to axial compressive force after applying transverse impact to the structure. In order to achieve the above purposes, the finite element and the experimental methods are used. In the finite element method, ABAQUS software is used to find maximum axial strength of the structure and the impact results of the structure due to its energy absorption and damage properties. In the experimental method, first, two samples of the lattice composite cylinders are made of Kevlar/Epoxy material and then they are subjected to impact test and also buckling strength tests before and after applying transverse impact when damage occurs in the lattice structure. Finally, the results of these two methods, including impact force, impact time and damage area have been compared. Results show that the damage of the structure due to the impact test, do not causes the maximum buckling strength of the structure to be reduced significantly.