In the research, the ballistic limit, dynamic response, damage, and energy absorption of glass fibre-reinforced polymer (GFRP) and carbon fibre-reinforced polymer (CFRP) laminates under high-speed fragment impact were comprehensively investigated. High-speed impact tests were conducted using a 14.5 mm ballistic gun to launch tungsten alloy fragment on GFRP and CFRP laminates. Additionally, a finite element (FE) model was developed to analyse the penetration, deformation, and damage of the composite laminates under ballistic impact. Based on the Lambert-Jonas equation, the ballistic limits of 8 mm thick GFRP and CFRP laminates were determined to be 517 m/s and 710 m/s, respectively. In the impact process simulated by the FE model, CFRP demonstrated superior resistance compared to GFRP in preventing projectile penetration. Additionally, the damage behaviour of GFRP was characterized by the separation of fibres and matrix, whereas CFRP exhibited a more brittle fracture mode. Finally, the energy absorption capabilities of CFRP were compared with those of GFRP. The results indicated that the ballistic impact resistance of CFRP was superior to that of GFRP. However, it was noteworthy that this advantage diminished as the impact velocity increased. This study provides valuable insights for ballistic impact resistance of GFRP and CFRP structures.

Taking pressure-bearing equipment as a prototype, the mechanical behavior of hollow corrugated sandwich cylinders under inner pressure loading was investigated. Considering the hollow cylindrical shell with finite length, the elastic closed-form solutions of hollow corrugated sandwich cylinders under inner pressure loading were presented. The optimization for minimum weight was performed. The stress distribution characteristics of the structures with different topological parameters were discussed. It can be found that an inflection point of the structure loading efficiency exists during an increase in the pressure, providing that under lower inner pressure loading, the loading efficiency of hollow corrugated sandwich structures is not invariably superior to homogeneous structures, yet while subjected to higher inner pressures, the sandwich structures exhibit a significant advantage in load-bearing efficiency.