Thin fiber metal laminates comprising functionally graded ballistic-grade fabrics subjected to mechanical and damping characterization

• Published in: Thin-walled structures Vol. 185; p. 110628
• Main Authors: Pai, Anand, Kini, Chandrakant R., Hegde, Sriharsha, B., Satish Shenoy
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2023
• Subjects: Damping; Fiber metal laminates; Flexural strength; Shielding materials; Tensile strength; Damping; Fiber metal laminates; Shielding materials; Tensile strength; Flexural strength
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/j.tws.2023.110628

Fiber metal laminates (FMLs) intended for blast and ballistic resistance applications need to contain ballistic grade plies like aramid (Kevlar®), ultra-high molecular weight polyethylene (Spectra®) as supporting plies in addition to the metallic layers. The order of stacking varies depending on the functional grading of plies. In the current work, five sequences of fiber metal laminates made of AA6061-T6, aramid, ultra-high molecular weight polyethylene, and paperboard have been developed. The novelty of the work is the basis of the layering based on functional grading by the shock impedance of the respective plies. The FML sequences were subjected to mechanical characterization comprising flexural and tensile tests, as well as damping characterization for vibration characteristics. The key metrics of areal density, storage modulus, natural frequency, damping coefficient, tensile strength, tensile modulus, tensile strain-to-failure, flexural strength, flexural modulus, flexural strain-to-failure were considered for comparing the different layups of the FMLs. From the experimental studies, placing a low-impedance ply (paperboard layer) as the penultimate layer before the AA6061-T6 rear skin led to the best mechanical and damping performance as seen in the FML sequences BRSP-II and BRSP-IV. •Fiber metal laminates comprising ballistic fabrics and low shock impedance ply for armor materials.•Ply based shock impedance used for functional grading of layers.•Damping characterization using impact hammer setup, damping coefficient, natural frequency and storage modulus analyzed.•Mechanical characterization composed of tensile and flexural three-point bending.