Experimental and numerical analysis of vibration of FML- stiffened circular cylindrical shell under clamp-free boundary condition

Most of composite cylindrical shells always are used under dynamic loads not static loads in working cycle of themes and Application of dynamic loads cause to large deformation and strength reduction. One way to reduce this negative characteristic is to make the fiber metal laminated shells that named FML in abbreviation. Also dynamic loads cause to vibration in structure. In the present study, firstly the fabrication of stiffened-FML cylindrical shell is explained. Then the vibration behavior and natural frequencies of three samples of FML-stiffened cylindrical shells are derived under clamp-free boundary condition. Moreover the vibration behaviors of these shells are investigated using abaqus finite element software and the FEM results are compared with experimental results in order to shows in agreement with each other. Also the effects of various parameters are studied in this article. For this purpose the frequency response of stiffened and unstiffened FML shells are compared with together and the vibration behavior of FML-shell are compared with glass/epoxy composite shell. One of the most innovations of this study is the experimental results that can be used as a benchmark for further study.