No abstract

The impact resistance of the Nomex honeycomb sandwich structure subjected to strong dynamic loading of lightweight and deformable projectiles was studied experimentally. The deformation process and failure modes of the sandwich panels were investigated by using a first-state gas gun to launch aluminum foam projectiles. 3D-DIC was presented to investigate the dynamic response in terms of response rate and deflection-profile history. And the impact resistance of three structures, namely single-layer sandwich, rubber-honeycomb sandwich and double-layer sandwich, was compared in relation to the load intensity. The results show that the dynamic response process of the sandwich panel can be divided into discrete deformation stage, concentrated deformation stage，elastic stage, vibration stage and stabilization stage. As the impulse increases, the maximum deflection of the back face-sheet continues to increase. Under the strong load of a light and deformable projectile, both rubber-honeycomb and double-layer honeycomb sandwich structures can effectively reduce the deflection change of the back face-sheet and improve the load-bearing capacity of the structure. Qualitatively analyzing the relationship between structure, loading, and performance can be carried out to provide guidance for structural design.

To investigate the influence thickness has on the impact resistance of glass fiber woven composite laminates, a series of impact tests on 1–5 mm‐thick laminates impacted by the hemispherical‐nosed projectile on a one‐stage gas gun are conducted. The influence thickness has on the ballistic limit, energy absorption, failure mode, and damage mechanism of laminates is analyzed. The results show the ballistic limit velocity of 1–5 mm thickness to increase in a linear manner. It is found that the ballistic limit velocity of laminate 5 mm in thickness is 2.8 times greater than that of a laminate that is 1 mm in thickness. As the impact velocity of the projectile increases, the energy absorption of a laminated plate decreases to approximately 10% before becoming stable. Fiber tensile tearing and matrix cracking occurs on the back of the laminate, while the domain failure mode changes from fiber tensile fracture to shear as the velocity of the projectile increases.

No abstract