The current research combined experimental and numerical study of the perforation and energy dissipation behaviour of the cylindrical sandwich shell with honeycomb core subjected to high velocity by a conical projectile. Experimental tests were performed by employing the high pressurised pneumatic gun at the subordinance velocity range (60�145 m/s). The experimental results obtained in terms of residual velocity, ballistic limit and failure pattern were validated with 3D finite element analysis performed in Abaqus/explicit solver. Furthermore, The Johnson Cook constitutive strength and fracture model, and ductile damage model was used to capture the damage and fracture evolution. Furthermore, a user-defined code was used to calculate the energy dissipation in plastic transverse deflection in different stretching directions. In addition, the influence of core geometries, i.e. cell wall thickness and side length, and face skin thickness on impact response of the structure, were calculated. From the result, it was found that irrespective of the geometrical parameters, localised dishing with petals formation, core crushing with hole formation was typical failure mode. Also, the geometrical parameters had a substantial effect on the transverse deflection, ballistic limit and energy absorption. The EA increased by 22.76 and 270.3 when the cell wall and skin thickness increased from 0.03 to 0.05 mm and 0.7 mm to 2.0 mm, respectively. However, EA decreased by 26.32 when the side length increased from 3.2 to 9.2 mm. Moreover, Increasing the face skin thickness and reducing the side length are two weight-efficient ways to enhance the perforation resistance for structure. Also, the energy dissipation cylindrical sandwich structure was highest in the circumferential direction followed by the tangential, radial and axial direction. © 2021 Elsevier Ltd