High-Velocity Impact Behavior of Sandwich Composite with Compliant Skin and Sea Sand Strengthened Functionally Graded Core: Experimental and FE Approach

Abstract

The present study investigates optimizing the impact resistance of novel functionally graded sandwich composites using numerical and experimental approaches. The high-velocity impact (HVI) behavior of functionally graded core sandwich composite (FGCSC) with bio-based jute/natural rubber skin and epoxy/sea sand (varying sea sand percentage 0, 10, 20 and 30%, and varying core thickness 10, 20, and 30 mm) functionally graded core. High-velocity impact (HVI) tests are performed using gas gun equipment at an impact velocity ranging from 200, 275, and 350 m/s. The weight residual and burnout method were used to test the gradience of core; both techniques showing significant correlation, and the variance in gradation could be observed. For FE analysis, the FGCSC are represented as deformable bodies, and the bullet is defined as a rigid body using commercially available dynamic explicit software. The HVI test results show that the proposed FGCSC has higher energy absorption capabilities, with core thicknesses of 30 mm and sea sand composition of 30%, resulting in a 1.80% improvement in energy absorption. A finite element study is also carried out to correlate the results, and the obtained results are in better agreement with the experimental findings. The damage analysis indicates that the developed FGCSC with flexible face sheets results in better damage mitigation. The findings suggest that FGCSCs are highly effective for bullet-proofing applications, including personal protective gear and structural components in defense. Further study and optimization could enhance the applicability of these sandwich composites in various protective and structural uses. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.