Abstarct: In the present thesis, the experimental method is used to investigate the energy absorption capability of composite cylindrical shells. Traditionally two methods of vacuum bag molding (VB) and vacuum infusion process (VIP) are used in manufacturing composite shell cylinders. In the thesis, six parameters were opted to study their effects on absorption energy of composite shells including three geometric parameters of inner diameter, length and shell thickness and other three parameters of laxyer orientation, reinforcing fibers (glass and carbon fibers) and manufacturing process. The design of experiment was accomplished by Taguchi method and deploying an orthogonal array of L16 and sixteen experiments were determined accordingly. Axial Crushing tests were conducted on shells. Amounts of specific absorption energy of the specimens were calculated using the generated area under force-displacement diagram. Next, the resulting data was statistically analyzed which led into ranking the six parameters and proposing an optimized structure baxsed on the selected parameters. Finally, different kinds of complicated failure modes controlling absorption capacity were studied. Also effects of the six mentioned parameters on both stable and unstable crushing modes of shells were investigated. The comparisons showed the statistical analysis and failure mechanism analysis were highly consistent to each other and it is concluded that statistical analysis especially in experimental trials baxsed on the parameter of specific absorption energy is the best method for design and optimization of energy absorbing composite structures.