Composite pressure vessel CNG made of epoxy – carbon material with nonmetal liner is 60% lighter than aluminum vessel under the same conditions. One of the important parameters in the pressure vessels design is their resistance against impact and prevention of explosion. In this paper, the effects of low velocity impact on composite pressure vessel are investigated using FE analysis. The vessel reactions under velocity impact with different velocity, impact angle, and ply angle are studied based on Chang-Chang composite failure criterion. Finally, the effect of gas pressure inside the vessel before and after impact are analyzed. پرونده مقاله