Structural integrity of linerless composite pressure vessels under drop impact: Comparative analysis of cylindrical, spherical, and toroidal geometries

Composite pressure vessels are highly vulnerable to accidental impact during manufacturing, transport, and handling. However, limited understanding exists regarding how vessel geometry influences this impact vulnerability, with no comparative study currently existing for non-cylindrical Type V geometries under certification-relevant drop conditions. Under an assumption of perfect interlaminar bonding, this study employs Abaqus/Explicit and the Hashin failure criterion to evaluate the intralaminar damage response of 18 configurations across three geometries, six drop orientations, and three layups. Simulations were conducted following the Global Technical Regulation (GTR) No. 13 guidelines, with a drop height of 1.8 m, for both unpressurized and pressurized cases. Vertical drops induced the most severe intralaminar damage, while the toroidal horizontal orientation remained completely undamaged. Optimizing layup to a [0/±45/90]_2s sequence significantly enhanced damage resistance and limited the spread of material failure compared to the cross-ply [0/90]_4s design. Internal pressure induced a stiffening effect that suppressed catastrophic fiber failure by redirecting damage toward lower-energy matrix cracking. These findings provide comparative numerical insights into the influence of vessel geometry and ply architecture on the intralaminar impact response.