Abstract: Based on the Koiter's initial post-buckling theory and Thompson's discrete coordinate approach, the imperfection sensivity and impact buckling of cylinder under torsion are studied. It is shown that it corresponds to symmetric buckling. By solving the nonlinear dynamic equation numerically, it is found that in the process of post-buckling under step torque, the shell will vibrate with a longer period and its amplitude in increased a bruptly. Also, some experimental results for the impact buckling of cylinde...